T.R | Title | User | Personal Name | Date | Lines |
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1244.5 | | BASHER::DAY | I might as well be parking cars | Wed Apr 08 1987 08:10 | 21 |
|
Weeeell, I've never actually flown a real trainer
so I can't really comment. I started of with my Wot 4,an
almost symmetrical,no dihedral wing tail dragger. It's
very precise and a quick flyer... I feel very comfortable
with it,it's capable of most aerobatic maneouvers,and with
my 60 in it it will take off vertically and climb out of
sight.I've just increased the aileron/elevator throws so it
rolls and loops like crazy. My current favourite trick is to
put it into a vertical climb,then when it gets to a
reasonable height put in full left rudder,throttle,up elevator
and left aileron.
cheers
bob
|
1244.6 | WOT 4? Why not? | AKOV11::CAVANAGH | R/C planes..The bigger the better! | Fri Jan 26 1990 15:13 | 50 |
|
This morning I ordered 2 Chris Foss Designs WOT 4 Mk 2 airplanes. One
for Steve Smith and one for myself. The description of the plane is below.
This seemed to be a better plane for me than the ACE 4-60 since the WOT 4
has the ability to 'grow' as my skills do. Just add a larger
engine (ala Panic) and you have what seems to be a totally different plane.
When I get mine I'll let you know about the kit quality and building.
Jim 'WOT' did I get myself into?
-------------------------------------------------------------------------------
(Please note that most of the strange spellings and wording are straight from
the fact sheet. This is an English kit.)
The original WOT 4 was conceived following a design exercise to formulate
an ultralight highly manoeuvrable and versatile 'fun' machine powered by a
.60 cu. in. size engine.
Subsequent development and refinement, resulting in the Mk 2 version has
produced an extremely practical aerobatic machine capable of being powered
by an unusually wide range of engines.
When fitted with a .30 size engine the WOT 4 is ideally suited as an
'aileron' trainer for the relative novice who has acquired the basic flying
skills on a rudder and elevator trainer. Moreover, the power/weight ratio is
adequate for the more experienced pilots to exploit its aerobatic qualities
to the full.
The additional power of a .40 engine puts real sparkle into WOT 4, giving
more advanced pilots a fast smooth yet highly manoeuvrable machine, with
superb log speed qualities, capable of performing the complete aerobatic
repertoire.
The performance with a .60 engine will satisfy even the most extrovert
with vertical climbs out of sight, violent 'snap' manoeuvres, instant
take-offs and real slow landings. An ideal 'tug' for glider towing and
the ability to operate in and out of restricted spaces makes a perfect
demonstration machine for local fetes and public shows.
Ultra simple and speedy construction is comprehensively covered in an
excellent full illustrated instruction manual. Wings are foam and veneer
construction with straightforward fully sheeted fuselage and tail surfaces.
Engine is radial mounted on front bulkhead and enclosed with an A.B.S. cowling,
whilst the undercarriage simply clamps in position and is designed to pull
free in the event of a crash.
Total construction time 10 - 15 hours.
Kit contains: Ready veneered foam wing panels : Selected pre-cut balsa
and ply parts : Stripwood : Pre-formed U/C components : Molded cowling :
Hardware pack comprising control horns, rods, links, hinges, U/C clamps and
bolts, tailwheel leg and bracket, screws, wing joining tape : Self adhesive
decal sheet : Instruction manual.
52" span universal aerobatic model - from aileron trainer with a .30 cu. in.
engine to expert 'fun' machine with a .60. a truly versatile design!
|
1244.7 | It's a rainin', time for a ramblin' | HPSRAD::AJAI | | Tue Aug 07 1990 18:54 | 66 |
| >>Are you building the Wot-4 currently or just psyching up to get started?
I get the strange feeling you know me too well. OK, I'll face public
humiliation rather than lie, unlike Pres Bush who did BOTH when came to
taxes. Nope, I haven't got started building yet.
[Pause for deafening silence]
But I've been doin' a helluva lot of flyin' lately, including 10 minutes on
Jim-the-Cavanagh's WOT4 that's powered with a 40 size engine. Man, that is
real nimble compared ty my FS! I did some inverted flying, and found it
climbing! Guess I got too used to holding up elevator with an inverted flat
bottom winger! Outside loops were a snap to do. My FS _barely_ staggers
through one, and that too, only if it doesn't fall out of it at the top! The
WOT4 rolled a lot faster too! Of course, for raw speed, with the OS SF 46 on
my FS, the 40 powered WOT4 is no contest. I can't even imagine the
consequences of mounting an OS SF 61 on it!! I should try Steve Smith's 60
powered WOT4 next.
That apart, I have been flying everyday (nearly), including 18+ hours in
July, 14 hours in June and 38 hours for this year! What a blast! I was
relieved it rained last evening - that way I could stay at home and do
errands without feeling guilty, or suffering withdrawal symptoms! If it
keeps raining, I should get my WOT4 built real quick. I got everything I
need except for the engine. I am expecting my T60 radio back from
Airtronics, being converted from AM to narrow band FM.
You would think I could get the WOT4 built real quick, except for one thing.
Roommates. Mine has got real interested in something call a girlfriend, and
will be moving in with her. So what's this got to do with RC? Well, as is, I
resent giving the landlord 2 OS SF 61's with pump EACH MONTH in rent, and
now, I am faced with the daunting prospect of coughing up double that
instead! No Way! I'm gonna keep those extra engines each month. This means I
got to MOVE. Gawd! Another of those 4 letter words that I have come to hate
with a passion. Moving means packing. Packing means NO BUILDING MODEL
PLANES. Gosh! After I declare this the YEAR OF RC, you would think I would
be treated better, but nooo! Doggone it. There should be a law against
inflicting such pain!
I fared much better in last Sunday's fun-fly, though I darned near broke my
plane. It was a Reno event. Roll die, do the number of loops and rolls, then
land, pick up plane, and roll same number again. Clock stops. It was windy,
and as I came in for a landing too hot/high, I really wanted to go around,
but with contest pressures (!), I figured I couldn't afford to lose the
time. In the meanwhile, my brain got overloaded, and I dumb-thumbed the FS 3
feet above the ground. Cartwheeled. Tail wheel mount came off, and rudder
pushrod got bent. One wubber-band bwoke, while the west spwang off my model,
saving the wing. Minor damage that I fixed in 20 minutes and continued.
Just last Friday, I did 105 touch and go's from left to right in 44 minutes
and two flights, bettering the 63 minutes I took 3 weeks ago. With nearly
500 T&Gs logged on the FS, I was sure I could land in my sleep, but the
contest pressures got me all fouled up. Bah! Anyhoo, I was mucho satisfied
to learn that I topped the 60 seconds to landing event, taking 62 odd, and
touching down within the marked square. Sorry, spot landings don't count
this event, I wuz told.
Wull, ther's always a nex time.
ajai
ps. almost forgot - Just when I thought I was saying "I know that" mentally
to yer poin'ers, I found myself sayin' "I didn't think of that!" when it
came to the rudder having 4 hinges because it takes a beating from the tail
wheel. On my FS, the tail wheel is not shock isolated from the rudder, but
will be on the WOT4.
|
1244.1 | This plane should build quickly! | HPSRAD::AJAI | | Wed Sep 19 1990 10:19 | 43 |
| I know of at least two people - Jim Cavanagh and Steve Smith - who have
buit this plane - a high wing, semi-symmetrical (the aerofoil "looks"
symmetrical to the eye at a glance, though) fun-fly/aerobatic machine
that takes 30 to 60 size engines. Others, including folks across the
pond, who have built/flown this plane might consider adding to this
note...
I had been sitting on the templates for the fuselage and tail feathers
for over a month, that I had got from Charlie Watt, as I was busy with
moving (shifting), attending a friend's wedding at Kansas City and
incidentally playing official photographer, doing a 200 mile bicycle
ride for a cancer fundraiser, and settling down in the new place.
Anyhow, the impetus to start building came when Steve wanted to have
the templates back to build his second, lighter WOT4. I begged that
American aid to my third world building efforts not be withdrawn for a
few more days, while I trace out and cut the parts, and luckily, Steve
relented!
I am using balsa from Tower Hobbies for the plane. I could cut out all
the parts for the fuse sides, top and tail feathers from 2 1/2
1/4"x3"x36" sheets and 3 1/8"x3"x36" sheets. It took me 5 hours to
decide the layout, choose the best sheets, and cut the parts with a
knife. I have yet to sand down the excess that I left to get down to
the exact dimensions. The fuse sides have been tacked together so they
are identical after I am done shaping them.
I still have to trace out the plywood parts, and make copies of the
"plans" - an instruction book, really, with _some_ full size drawings.
Gee, all I told Steve when we were talking about the current Gulf
crisis was, where was America (and the world) when China decided to
swipe Tibet, which is only a thousand times the size of Kuwait, forcing
hundreds of thousands of Tibetan refugees into India, and why was it OK
to invade Panama.
All that Steve then said was he wanted his templates back, and was
withdrawing all US support for Injun model aviation efforts!
ajai
ps. yeah, OK, so I lied about that conversation. :-) :-)
|
1244.2 | WOT'S that you say????? | RVAX::SMITH | I FEEL THE NEED | Wed Sep 19 1990 13:14 | 44 |
| Actually, I have no thoughts what-so-ever on impeding Injun model
avaiation. I just don't think our transplanted Injun should be
waiting for Ghandi to be resurrected before he starts building.8^)
I'm glad Ajai created this note. There has been little said about
this fantastic airplane. It is designed and kitted by Chris Foss,
the creater of the "Panic". How could I describe it. Well, it's
a trainer, no, it's a stunt flyer, no, it both airplanes in one.
How many ads have you seen where its stated that such and such an
airplane is a great trainer, BUT WILL ALSO DO ALL THE AIROBATICS
YOU WANT. Yet, here you are looking at a plane with a flat bottom
wing. Well, in the case of the WOT-4, it performs as advertised.
With a 30/40 size engine, it is a very stable, slow flying plane
that is great for training. With a 60, it will snap roll so fast
you can hardly follow it. Knife edge, 4 or more point rolls, inverted
flight, outside loops, anything you can think of. It's as fast as
you'd ever want an airplane of this type to go, yet you can almost
hover it into a landing with a fair head wind. The last person to
see the WOT-4 for the first time, Jean-Paul, was very surprised
at how slow it landed after watching it do it's thing in the air.
He thought I was going to loose it for sure when I was just doing
a normal landing.
Jim Cavanagh is running a 40 on his WOT-4 and fly's at about 1/2
to 3/4 throttle. I gave it it's check ride and it was so slow compared
to my 60 it took me a minute to get adjusted so that I wasn't always
ahead of the plane. The flexibility of this ship is truly amazing.
I've also been using the WOT-4 as my fun-fly ship. I've flown it
in 2 fun-fly's and it's gotten me a 1st and a 3rd. Actually it's
been in 2 1/2 fun-fly's and never made it through the third one
which is why I'm now building another fuse. I built the first one
totally stock and did some beefing besides. I never even weighed
it. This time, I'm going for a weight reduction for even better
performance.
Eric the Evil recommended this plane to me and he couldn't have
been more on the mark. I would recommend this plane as a first solo
ship and as your skills increase, all you have to do is put a bigger
engine on the front. The cost is about $60 dollars American which
is cheap for wot you get. Ajai is making a wise choice in building
this plane and he will enjoy it tremendously.
|
1244.3 | Chris Foss | GALVIA::ECULLEN | It will never fly, Wright ! | Fri Sep 21 1990 05:50 | 6 |
|
Since there are a number of kits by Chris Foss why don't we put em
all in here. I have two Acro-Wot's one with a OS46SFABC (not completed
quite yet) and the other with an OS90 Surpass 4-S.
Eric();
|
1244.4 | with Ajai's inspiration, the WOTs flew over here | BRAT::RYDER | perpetually the bewildered beginner | Fri Sep 21 1990 07:22 | 11 |
| I've added a new keyword, PLANE_WOT4, and I'll move to this topic some
of the notes that discussed this model. (They were under obvious topics
like "hinges", "winter projects", and "rambling".)
I have mixed feelings about the ACRO-WOT. I have the impression that
the WOT4 with appropriate power is a reasonable first plane and should
be considered by a beginner. I don't recall that the same can be said
of the ACRO-WOT, so I have not moved over the ACRO-WOT notes. If
someone strongly feels that the commonalty of designer is an
over-riding consideration, I'll go along with that; you do have the
alternative of creating a PLANE_ACRO_WOT keyword if that is desirable.
|
1244.8 | More progress building. 11 hours so far | HPSRAD::AJAI | | Fri Sep 21 1990 10:12 | 51 |
| I got another 6 hours of work done in the past 2 days. I got the tail
feathers sanded down to the right profile after glueing together the
various parts; this being done whenever a 3" wide sheet was inadequate.
I also sanded the surfaces smooth, so what is left is to mark and drill
the holes for the hinges, and taper/round the elevator and rudder.
While I have a picture of the WOT4 for reference, and have even
seen/flown one, I am amazed that I kept putting the rudder on backwards
onto the fin, whenever matching up to check if the hinge line had no
gap!! I would always wonder why it looked so yucky, and figured there
might have been a design change or some such thing that hadn't been
undocumented!! last night, I fipped the rudder (exchanging l.e. and
t.e.), and lo, behold, what a difference it made! I was looking at
clean lines again!! Never mind...
Well, it is a pleasure to get back to scratch building again, after
over a decade, since that is how I used to build 1/2 my planes back in
India. Of course, the one difference is that I have an "infinite"
supply of balsa, and can actually afford to be picky about what I use.
Every model I build seems to be with new tools added to my set. It was
the Magic (magnet) builder last time, and this time, it is the Mitre
Master by Fourmost products. This is a tool that lets you sand precise
angles, especially invaluable for stick and glue construction. I had to
sand some bulkheads made of 4 balsa "sticks" glued together, so it came
in handy. Once I got the hang of it, it was easy to use to make
precision fitting joints ideal for zapping.
Basically, it consists of a slider with vertical face that rides in a
slot on a wooden "table". The vertical face has sandpaper stuck on it,
and the table has pieces of plastic that help you jig the job at the
right angle (pun intended). There is a slight slop in the slot in which
the slider rides, so the vertical face that does the sanding can move
laterally 1/32" or so. I thought this was a manufacturing defect, but
in reality, is key to the "technology" involved. In effect, it gives
you the ability to sand off material from the job 1/32" at a time.
Great stuff. highly recommended. Can be home made if you have a router
for carpentry, and a routing table...
I wimped out of the plywood cutting job, in favour of using a band saw
at Charlie Watt's place tomorrow. Shaping the tail feathers (cross
section wise) should keep me busy this evening.
ajai
PS. The Acro-WOT is plane with D Y N A M I T E looks. I was drooling
over the photo, and later, Evil Eric's glassed version with a super
sexy finish job. Yeah man, that is a must-have for me, and my next
project. Will probably stick in a pumper OS SF61 ABC tho...
I say we should have separate note for it, since it is a low winger...
|
1244.9 | Couple of questions | RVAX::SMITH | I FEEL THE NEED | Fri Sep 21 1990 13:42 | 10 |
| RE. .5
Just out of curiosity, how much does your WOT-4 weigh and what make
60 are you running on it???? While were at it, what size prop are
you turning??? Mine will climb out of sight with a head start, but
not from the ground. I'm building a new fuse now to try and get
it lighter. I never did get around to weighing the original but
I'd estimate it came in about 6/6.5 pounds.
Steve
|
1244.10 | Inset control surfaces - how to finish? | HPSRAD::AJAI | | Thu Oct 11 1990 15:41 | 13 |
| The WOT4 I am building has elevators and ailerons that don't extend all
the way to the tips. I suppose that is to keep them out of the vortex
at the tip, and prevent/reduce the possibility for control surface
flutter.
Question - how do I finish the end of the elevator or aileron nearest
the tip? Round it or keep it square (cross-section wise)? What about
the elevator/aileron side of the immobile tip?
Me thinks I should leave them square, but seek benediction of the local
gurus (Gods?) before proceeding.
ajai
|
1244.11 | | SNAX::SMITH | I FEEL THE NEED | Thu Oct 11 1990 16:17 | 20 |
| Ajai,
If I understand your question, I think you left the wing
trailing edge stock too short. It should extend out beyond the
end of the wing aprox. an inch and a half. When you put the wing tip
in place, it curves back to meet flush with that piece. Then, the
space between the end of the aileron and the wing tip is filled in
with a piece of aileron stock glued to the trailing edge, and extending
back the same distance as the aileron. It's like the piece you put
on the trailing edge center section that holds the aileron push rods.
I suppose you can always add a piece to make up the distance.
As for the elevator, there are supposed to be two tip pieces for the
stab that extend back the same distance as the elevator. The elevator
then fits inbetween them.
If any of this isn't clear, give me a call.
Steve
|
1244.12 | BE SQUARE....! | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Thu Oct 11 1990 17:46 | 16 |
| Ajai,
knowing nothing of the Wot-4's specific construction, I bow to Steve's
comments in .-1. However, in ANY case where the ailerons and elevators
(even flaps) are configures as you describe, keep the surface end and
the corresponding tip piece SQUARE!
Aerodynamic effects of rounding one or both are unknown to me but,
bottom line, it'd look damned foolish! :B^) Keep 'em nice and square
to each other.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.13 | Scratch buildin' the WOT4. Clock is at 21 hours | HPSRAD::AJAI | | Fri Oct 12 1990 11:38 | 37 |
| Aw'right, jes' lik ah' suspected in da furs' place. Ah'll keep 'em
square.
Over 4 days in the past coupl'a weeks, I got another 10 hours of work
done on the WOT4.
Marked out where the hinges would go on the rudder and elevator. I put
in 3 per elevator half, and 4 for the rudder. Drilled out the holes
with my brass pipe drill "set". I think a jig and drill press would
have been a LOT faster, and saved me from having sore thumbs turning
that 1/8" brass tube.
Also drilled for the elevator joiner, grooved the elevator l.e. to
recess the joiner, and used a knife to widen the holes to accomodate
the "fat" hinge joint.
At laaast, I got the fun part of using my plane to "vee" the l.e. of
the rudder/elevator, and also to give 'em a tapered cross-section. I
always love the crisp sound/feel/sensation of the plane shaving the
wood, and besides, gives my bedroom cum workshop the look of a
carpenter's den.
A couple of the holes (the longer ones I drilled for the joiner) got
exposed by the tapering process, but that will get covered with
monokote/filled with epoxy.
I really like the look/feel of the Robart hinges. Besides, I won't have
to worry about whether the flexible plastic hinges are going to be held
securely by the epoxy going through the few holes they come with for
anchoring.
I should be done with the fuse rather quick, now that the [slow] tail
feathers are done.
ajai
|
1244.14 | 30 hours and counting. | HPSRAD::AJAI | | Wed Oct 17 1990 14:42 | 57 |
| I had to taper the rudder, which is about twice as wide as the
elevator. Upon finishing the taper to 1/16" at the t.e. of the rudder,
I found that it would flex under finger pressure. Wouldn't be much good
with an OS SF 61 pulling it along on a knife edge, I mused.
Sooo, rather than feel uncomfortable about it, I used some 1/16" balsa,
and stuck it on cross grain to form balsa ply, so-to-speak, along one
side of the rudder. Sanded it down flush, and voila, I had a super
strong rudder.
I had rough cut the fuse side skins, and tacked them to-gether so I
could later sand them to identical size. Using a try-square
(set-square), I sanded the sides down to the marking I had made. It is
awfully hard to keep the block perpendicular to the side-skin, and even
so, your hand rocks as you sand away, so you don't get a crisp,
perpendicular, flat surface to glue the top/bottom of the fuse on to.
Again, I was wondering how I could do a better job - a la factory
precision cut/sanded parts.
Sooo, after some mulling, I went back to the mitre master. I took off
the jig in the middle of the block that allows you to position parts at
angles, and did 6" sections of the fuse. Mmmmmm. Boy! Was I happy with
the results. More power to the Mitre Master. I even vowed to build
myself a bigger one in the future. They say a good workman never blames
his tools. I say you can judge a good carpenter/builder by the tools
that keep him company!! :-)
With all the transfering of templates, etc.., some of the dimensions
were off, so I had to, based on how things fit together, re-do some of
the outline. Sanding the ply wing saddle pieces, was, to quote Charlie
Watt, like sanding steel. I persisted.
I have yet to cut the slot for the tail plane (stab), and mark the
other side of the fuse before sticking all the reinforcing pieces on.
I find that I have to put in time to get the quality in the model that
I want, rather than rushing along with a that's good enough attitude.
Hell, this is _MY_ hobby, so why be hassled if I take more time, if it
gives me pleasure? Yeah, so what if others can do it in half the time,
huh? :-) :-)
I am thinking of sticking some 1/16" sheeting cross grain, on the
inside of the fuse, to prevent splitting in the event of a crash. I
should think the weight penalty will be minimal - a few 10s of grams?
(Sorry, I don't understand ounces!)
The design asks you to use a 1/4" sq longeron as a strengthening member
along the fuse side-skin, from wing t.e. to stab l.e. (approx). One of
hardwood for a 60 size engine. I was thinking of using a 1/4" x 1/2"
balsa strip, figuring it would be _just_ as, if not _even more_
stronger. Isn't the strength of a beam proportional to some power of
its cross sectional area?
Gimme another 10 hours for the fuse box to be done.
ajai
|
1244.15 | Clock sits at 38 hours. | HPSRAD::AJAI | | Mon Oct 22 1990 15:09 | 50 |
| More WOT4 ...
I marked up the other side of the _temporarily_ joined fuse skins, and
slotted it for the stab, making sure to keep a tight fit for now.
Later, depending on how level the stab sits, I have room to sand down
the slot and not have a sloppy joint.
I also stuck in the bracing members, and the triangle stock that
supports the firewall and landing gear plates. Using a scale that
Charlie Watt lent me, I piled on the fuse skins, noting the weight.
Then, I added a sheet of 1/16" balsa, and noted the difference - about
10~20 grams!! Sooo, I decided to add it in cross-grain on the insides
of the fuse side skins. Not the entire length, but in 3" strips every
6"~9".
Again, I used the mitre master to sand all the protruding reinforcing
members flush _AND_ perpendicular. Worked great. Felt good _inside_
when I was done, if you know what I mean!! Man, if it was in my hands,
I'd give whoever designed the mitre master a Nobel Prize. The thing is
awesome!
I was talking to Steve Smith and Charlie Watt at the flying field
yesterday, and concluded that I should construct a balsa wing for the
WOT4 as it will be lighter than a foam type. Took out my T60 plans to
look 'em over, and begin cogitating on how I would "design" my WOT4
wing. Since it will take me the same time to build a foam wing as a
balsa wing (approx.), and since I won't be able to beat ole man
winter, I might as well take my time and do it right. Besides, Towers
wants me wait until Jan 1991 for my OS SF 61 ABC with pump. The non-
pumper is currently available though.
Can't help feel that Al, who dislikes pumps (actually, likes
simplicity in hardware), might have told his buddies at Tower *NOT* to
sell me a pumper :-)
ajai
ps. If I want to build a wing like the T60, with the spars for the
l.e., t.e., top and bottom interlocking with the ribs, what's a good
techinique for slotting the spars once I have marked them? I used to
scratch build NON-INTERLOCKING wings before - i.e. rib did not sit in
slot in spar(s). As for the ribs, I figured I would cut two ply
"formers", sandwich all the blasa sheets for the ribs in between them,
and sand down to get them all identical. Then use a band saw
(Charlie?!!) to slot them for the top/bottom spars.
and a 1/16" sheet of
balsa
|
1244.16 | slotting the spars ?? | GENRAL::KNOERLE | | Tue Oct 23 1990 13:26 | 7 |
| I would not recommend slotting the spars since you'll loose strength
provided by spars. There's really no need for doing this once you
slotted (sp?) the ribs. The marks on the spars will help equal spacing
of the ribs.
Bernd
|
1244.17 | So how do I go about slotting the spars? | HPSRAD::AJAI | | Fri Oct 26 1990 14:34 | 29 |
| Bernd,
Your remark that slotting the spars will weaken them is true based on
how deeply you slot them. On the T60, the spars are 3/8" x 1/2", and
it was slotted to 1/16", so I would say the loss in strength is
minimal.
Btw, I pulled out my T60 wreckage, and the T60 plans, and was looking
it over for construction techinque, and loading my my brain with the
3D picture of what I want to build for the WOT4. Used a measuring tape,
ruler, and calculator to decide the building supplies I needed.
The T60 wing is built _real_ strong. Too bad it had to argue with a
tree trunk. Wasn't a fair fight, if you ask me!! I'll probably pick up
the wood at the new hobby store that is to open tomorrow (courtesy
Jim Cavanagh).
Sooo, *ATTENTIOn* scratch builders, how dO I go about slotting the
spars, l.e., t.e. to take a given thickness of rib - say 3/32" or
whatever? Use a band saw, jig the part on the table for cutting to a
certain depth,and make repeated cuts spanning the width of the slot or
what?
C'mon, c'mon, c'mon, stop arguing over ARF's 'n gimme an answer or two.
Other notes seemed to confirm my ply template at each end of a stack of
ribs idea.
ajai
|
1244.18 | don't bother to slot the spars | DIENTE::OSWALD | Randy Oswald | Fri Oct 26 1990 17:21 | 25 |
| Ajai,
The answer, strength aside, is still don't bother. Of the 9 kits I've built in
the last 18 months only one, the Trainer 40, had slotted spars. Its a nice
touch that in truth serves no useful purpose other than to space the ribs
properly. If you're building over a plan just be careful and your alignment
will come out correct. If you are not building over a plan mark the
spars where you want the ribs. You'd have to do this anyway to slot them. Then
be careful about aligning the ribs over the marks. I've done 4 scratch built
wings this way and not a problem among them. I now use an Adjusto-Jig and
build the starightest wings you could ask for, with very precisely placed ribs
and not a spar slot in the bunch.
If you insist on slotting your spars you're probably going to have to do it by
hand with a razor saw. A bandsaw won't work unless you've got a good sized one
because you won't be able to reach the middle of the long piece. I suppose a
scroll saw will work, but you'll have to be very careful. Each slot must be
of a precise width and depth. You must insure that each slot is a tight
slip-fit over the rib or it serves no purpose at all. This will be a long
tedious process at best.
Good luck either way. Scratch building is very rewarding, but don't make it
more difficult than it has to be.
Randy
|
1244.19 | Don't waste your time | ROCK::MINER | Dan Miner, DTN:225-4015, HLO2-3/D11 | Fri Oct 26 1990 18:04 | 20 |
| I agree with Randy. Don't bother to slot the spars or L.E. or T.E.
It's done this way in kits to make it easier to build. BUT if you
have to cut the slots yourslef, I think it's more difficult in the
long run. I too have scratch built wings and have never slotted
the spars.
I do have to agree though that the Great Planes slotting does make a
*KIT* go together easier. Just don't waste your time when scratch
building. It'll work just great without the slotting.
_____
| \
| \ Silent POWER!
_ ___________ _________ | Happy Landings!
| \ | | | | |
|--------|- SANYO + ]-| ASTRO |--| - Dan Miner
|_/ |___________| |_________| |
| / | " The Earth needs more OZONE,
| / not Castor Oil!! "
|_____/
|
1244.20 | Clock at 41 hours and counting | HPSRAD::AJAI | | Tue Oct 30 1990 16:31 | 28 |
| Got in another 3 hours of building done. I also spent a couple of hours
mulling the scratch-built wing project, coming up with a parts list, etc..
Other than that, I had to clean up my wkshop cum bedroom.
Well, it appears as though no one is in favour of slotting. I was thinking
there might be some benefits of increased strength in doing so, though, I do
realise that kit manufacturers did it partly to make the building
goof-proof.
I got the last cross-grain sheet stuck on the fuse sides, and separated the
two halves after sanding down excess material. Apart from the ply firewall,
the other two bulkheads don't seem to give much strength, much of which, I
suspect, is derived from the 1/4" sheeting on the top and bottom. The 2
balsa stick bulkheads are flimsy, and seem to be there only to aid
in construction until the top/bottom gets done.
I was mentally trying to figure out how to jig the fuselage to ensure
maximum accuracy in building the fuse, though instructions give Chris Foss'
version of going about it. It was getting late, and I sleepy, so rather than
risk bungling in my stupour, I decided to postpone the work until tonight.
I should be getting my engine by the end of the week, so I can plan on
building a balsa block cowl around it. The engine is supposed to be side
mounted. Any guide lines on building the cowl? Back in India, balsa is gold,
and I didn't waste it to build cowls, since you would break the plane and
need the wood to repair/build another plane anyway!
ajai
|
1244.21 | BE SURE TO USE AN "RC" COLA BOTTLE.....:B^) | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Tue Oct 30 1990 17:31 | 12 |
| Re: .-1, Ajai,
You might consider using the bottom of a 1 liter(?) soft drink bottle
as an easily obtainable/replaceable ring cowl. With a 2-3" spinner,
this would yield a fairly clean nose area, almost as clean as an
in-line type cowl which fairs right into the spinner.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.22 | 45 Hours | HPSRAD::AJAI | | Wed Oct 31 1990 14:25 | 60 |
| You mean I got to drink that awful tasting coloured sugary water, with CO2
fizzing [belch] out of it, before I can [belch] have suitable cowl
material? He[belch]ck.
[belch]
If I was around before COKE happened, I'da sworn it wouldn't make it,
leave alone become one of the biggest companies in the world! Gee, why
do people drink the stuff when there are great juices like OJ? I always
find the darned CO2 gets in the way. Then again, folks the world over
have, for 1000s of years, been drinking fermented [read: ruined]
juices and grain and calling it great liquor. Maybe I am just not
[hick] up to figuring such things out, and should stick to building
my WOT4 instead. Maybe I should tell you my secret about
drinking/eating curdled milk and calling it great yoghurt. :-)
Well, I was a lot more sober last evening when I got back to the work
bench [read:discarded junky dresser]. I stuck on the firewall to one
side, using a try square to keep it vertical. I then jigged the other
side parallel to the first one, by raising it off the table with 3"
balsa/ply sheet pieces, which, conveniently for me and the designer,
was the width of the firewall. To ensure the second side was directly
over the first, I checked at different points around the periphery with
the try square. My magnet builder table included some magnetically held
plastic pieces that gave me a vertical edge that I could move around. I
positioned a number of these around the periphery of the side skin, so
the second one could be "dropped" in from above.
Then got my first bulkhead glued - things were not as simple here - If
you imagine a rectangular box shape for the fuse, and triangular stock
glued to the inside bottom corners, then you know that the bulkhead
must have 45deg beveled corners at the bottom. However, in the WOT4,
the bottom of the rectangular box is not parallel to the top, so the
triangular stock runs at an angle, meaning that you have to make the 45
degree beveled corner of the bulkhead at an angle also, if you want to
have a flush joint. My sanding was accurate, and the joints flush, so I
could glue using hot CA instead of the slow/gap filling CA.
Then clamped the tail end of the fuse sides together, making sure that
one side didn't project beyond the other. Then slipped in the second
and only other bulkhead. No triangle stock here, and no funny angles.
Easy goin'. Finally, the tail end had to actually be separated by a
1/4" piece of balsa, that I put in, ensuring it was big enough to take
the entire length of the Robart hinge.
The plans/instructions tell you to used 1/8" scrap pieces at the tail
when you are building the sides (so the 2 pieces add to 1/4"), but that
would have messed up the hinge hole [to be drilled], since the two 1/8"
pieces would be joined with a "V" shaped gap in the middle. Soooo,
instead, I put in a 1/4" piece of balsa in the middle of the converging
sideskins at the tail, leaving a "V" gap on either side that I
filled/braced with gap-a-zap.
Then put in the top sheet going from wing t.e. to tail. I had cut the
piece to size, but things would have been more comfortable had I left
an extra 1/16 (or less) extra. I just pushed in the sideskins a tad to
match the profile, before zapping in place.
ajai
|
1244.23 | Some pondering and questions instead of building... | HPSRAD::AJAI | | Thu Nov 01 1990 11:52 | 34 |
| Yesterday was my turn to cook, and since my roommate had swung a free
months rent (lease to be signed anyday) taking advantage of the
beleagured New England housing/rental market while bargaining, I
stirred up a feast.
That meant no time to build. Spent what little time I had ordering more
goodies from Tower, and then playing with the glass (arrow shaft?)
pushrods I had got, figuring out how I would drill under the English
Channel so the pushrods have as straight a shot as possible to the
rudder/elevator control horns. Given the bracing longeron that runs the
length of the fuse (1/2"x 1/4"), and under the stab as support, I find
it is a little crowded in there. The kwik-klip wire sticking out the
back end of the push rods will have to bend a bit.
I say, how does one do the crossing pushrods technique to get more room
for them to run straight? Is the elevator servo mounted inverted
and the rudder servo the right side up (or vice-versa?) Hmm. Can't
mount a servo inverted, as you can't drive the servo mounting screws...
You would need
to have the servos separated vertically, so there is room for the push
rods to cross w/o touching. I'd appreciate if someone would let me know
the technique, and tell me if it is worth the trouble. Hopefully that'd
be before I drill the holes for the push rod exits this evening.
I was also thinking about the colour scheme. Tom T's hot pink is
definitely too girly-girly for me :-) I was thinking I would try the
scheme used on the Spectrum electric, that is featured on the cover of
the latest Tower Talk and the 1991 catalog. It had blue, red, orange
and yellow on it. Looks real nice, though it will mean more work. Heck,
what better way to spend a winter's evening, anyway?
ajai
|
1244.24 | AIN'T NO MYSTERY 'TALL...... | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Thu Nov 01 1990 13:42 | 47 |
| Re: .-1, Ajai,
There's not too much mystery to the crossed-pushrod setup. You merely
mount the rudder and elevator servos on opposite sides of the fuselage,
then run each pushrod diagonally such that it exits on the opposite
side at the rear. I've never staggered the servos' height but that
would probably help is required. Generally, there's enough difference
in the height of the elevator and rudder control horns that the
pushrods will clear each other with minimum fuss. Bear in mind that
the pushrods will cross somewhere back in the aft fuselage, _NOT_ right
where they come off the servos so it only requires 3/8-to-1/2"
differential in the height of the horns to provide adequate clearance.
Also, remember that a "slight" amount of rubbing of the pushrods really
doesn't hurt anything as long as it doesn't put too much drag on the
linkage. I strive for clean clearance of the rods but, when the engine
is running, it's not uncommon to be able to actually _hear_ the
pushrods vibrating against each other to no ill effect. However, to
prevent transmitting this vibration to the servo(s) (even in an
uncrossed installation), I always install a guide an inch or two behind
the servos which bears the weight of the rods and provides a bushing
(made of inner nyrod) for the wire portion of the pushrod to slide
through. This is unnecessary at the other end as the exit slot in the
fuse side serves this purpose if carefull cut. Simply slide a piece of
nyrod over the wire before Z-bending, soldering on a clevis or whatever.
Then, when everything's hooked up and working to yer' satisfaction,
install an upper and lower false former across the fuselage notched to
capture the nyrod bushings...works slick!
________________________________________
| nyron bushings 2-plcs | upper false former
| / \ |
|--------O------------------O----------|
| | lower false former
|______________________________________|
One trick (if you want to call it that) is to mount the elevator horn
on _top_ of the elevator (like the Ugly Stik does) rather than the more
conventional location on the bottom. This provides even more clearance
for the pushrods where they cross. It also gets the horn up out'a
harms way where it can't be bumped/snagged/knocked loose/damaged by rough
terrain.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.25 | Reverse servo ends | SOLKIM::BOBA | Bob Aldea @PCO | Thu Nov 01 1990 14:25 | 26 |
| Re: .23 Ajai,
I had a similar goal when I built my Amptique. The inside dimensions
of the fuselage at the stab leading edge are only 3/4" high and
perhaps 5/8" wide.
My solution was to use balsa pushrods, and add the wire which attaches
to the servo on top of one pushrod and on the bottom of the other. The
"Z" bends are opposite so that one sits under the servo arm and the
other sits on top. That way you begin with the rods separated by the
thickness of the servo arm plus two wire thicknesses at the servo end.
_____________ _______
_________|____________ Upper Rod (Rudder)_______|_______clevis
___|
====== Servo Arm
____
|_____________________ ______________clevis
|__________ Lower Rod (Elevator)_________|
In my installation the Rudder horn is just under the stab, and using
the full 3/4" length of the elevator horn for the other pushrod left
plenty of clearance. I wasn't able to eliminate the bends at the horn
ends, but crossing helped to minimise them.
Good luck...
|
1244.26 | Thanks for the great info. More dumb questions. | HPSRAD::AJAI | | Thu Nov 01 1990 15:09 | 49 |
| As always, this notes file is a gold mine!
re -1, Bob, on my FS, though I haven't crossed the pushrods, I did
exactly what you mention - i.e., put the wire on top of one pushrod,
and the bottom of the other, to create more room. However, since I used
the EZ connectors, I couldn't duplicate your z-bend and reverse-z-bend
idea. Good point though! Will keep it in mind.
re -2, Al, thanks a ton. Yeah, I had figured on putting the elev/rudder
servos next to the fuse sides. What had nixed my mental simulation was
the fact that I ignored the fact that the rudder and elevator horns
attach to the clevis at different points, giving the needed height
differential! Hence the gymnastics with servos being possibly inverted,
etc..
I suspect the reason I forgot /ignored the difference in how the
elevator/rudder horns are positioned, is that the plan showed slots cut
at the l.e. of the stab in the same location for both the left and
right fuse sides. I have't cut the slots yet though.
Now, dumb as the question may be, I gotta ask now rather than regret
later - Given that the aim of the game is to get a straight shot from
the servo horn to the control surface horn, and given that we want to
take advantage of the 3/8"~1/2" height difference in rudder/elevator
horns, does this not mean that the slots cut on each fuse side be at
different heights?
Also, would I cut a SLOT, or drill a HOLE, in which I insert a nyrod
outer and sand flush? While the latter would look neater than a slot, I
suspect I'd have a hell of a time snaking the wire end of the push rod
through the projecting nyrod outer within the confines of the rear of
the fuse, once the fuse box is all sealed up.
And finally, I suppose it might help to have the servos installed so
the horn of one servo is closer to the tail than the other, helping to
add (subtract) to the height differential if done right (wrong).
The throttle servo sits in the middle of the other two and you use a
throttle cable, right?
Boy, was I right when I figured I was doing more material science in
India, than aeromodelling. The light/strong arrowshaft seems to be
ideal tail boom material.
Some other project, some other time...
ajai-the-gold-miner
|
1244.27 | ANSWERS..... | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Thu Nov 01 1990 15:40 | 29 |
| Re: .-1, Ajai,
1. Yes, the exit slots in the fuse sides will be at different heights.
2. The exit is usually a slot. But, you can easily duplicate the
bushing trick I mentioned for the other end, i.e. slide a length of
inner nyrod over the clevis wire BEFORE terminating the end. Once you
have the slot located anf the pushrod operating satisfactorily, you can
then CA the nyrod bushing into the slot, then fill the excess slot area
with scrap balsa then filler to blend it nicely into the fuse. I do
this on models I intend to fly from water to minimize the amount of
water than can migrate into the fuse through the normal slot-type
exits. However, I seldom bother with it on a normal model. You wind
up with both ends being bushed and the pushrod suspended in between
which is fine. But, yer' pushrod runs must be close to perfect as the
rods normally run through a slight arc at both ends and binding can
result if'n you get it set up too tight.
3. Yeah, I suppose that'd work if necessary but I've always put the
servos at the same location, sharing the same set of servo rails. The
throttle servo can either be placed in the middle, using cable for the
pushrod or set just ahead of one of the servos against the side keeping
the cable run near the side where it can be easily supported.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.28 | Method to locate the slot position/orientation? | HPSRAD::AJAI | | Thu Nov 01 1990 16:19 | 24 |
| Are there any standard techniques that are used to locate the slots, or
does one just guesstimate, and let the flex in the pushrod/wire lead
out make up for any goof up in slot location?
Some quick thinking tells me that I could use the side view and top
view on the plans, draw lines representing the pushrods from servo to
horn, and transfer these on to the side skin to locate the slot. i.e.,
side view on fuse side tells you orientation of slot, and top view
gives you the fore-aft location. Does this meet DOD standards, or is
there a better way?
Boy, now I am really wringing out info!!
ajai
ps. About -.1, -.2, point #3, I would use the same servo rails for
rudder/elev servos, but merely flip on servo around 180 deg (about a
vertical axis), and drop it in. Anyhoo, Al, you approve of the general
idea _if_ necessary, so I'll keep it in mind.
I had to do this on the FS as I wanted to keep the throttle servo next
to the fuse skin, so the elev/rudder servos sat next to each other,
making things crowded.
|
1244.29 | Side by side and opposite ends works fine | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Thu Nov 01 1990 16:31 | 10 |
| Ajai,
In tight glider fuselages I've done just that and that puts the
servo arms at differen ends so the width is minimal. With the micro
servos I've done this and then had the horns hang over the end of the
other servo so they don't bind with the fuselage sides. Generally I
need maximum rudder throw so that hangs over and the elevator can go
on the fuselage side so they aren't both on the "center" side. This
works out well when your trying to put three abreast and the center
one is the throttle as Al mentioned.
|
1244.30 | MAKE YER' BEST GUESS AND GO FER' IT! | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Fri Nov 02 1990 09:47 | 25 |
| Re: .-2, Ajai,
I know of no scientific method for precisely locating the pushrod exit
slots. The approach you mention is one was of defining the approximate
location for the slot and, occasionall, you'll even hit it dead nutz!
However, if you miss a little (and the error should be slight if you
work carefully), don't rely on pushrod flex to accomodate for the
misalignment! Move the slot!! That is, open the slot as necessary to
provide a completely drag free throw of the pushrod. Then, if you
opted to slip a nyrod bushing over the rod prior to terminating the
clevis end, slide it in place in the slot and secure with CA. Then, fill
in the any gaps with scrap balsa and or filler and yer' all set.
BTW, I should remind you to check, double and triple-check that the
crossed pushrods are free of binding and/or hanging up by stirring the
elevator and rudder sticks (simultaneously) in every imaginable
direction and combination of control inputs. A slight rubbing at some
extreme is acceptable but excessive rubbing/binding is not good and
must be corrected.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.31 | 3 more hours | HPSRAD::AJAI | | Fri Nov 02 1990 12:08 | 50 |
| Thanks for your replies, Jim and Al. I got home last night, and did some
more poking with the pushrods in the fuselage. Due to the 1/4" x 1/2"
reinforcing longeron, there just isn't enough room at the back for me to
apply the crossing techinque, without having to do hack out some of the
longeron. This would also effectively reduce the length of usable
arrowshaft, while increasing the wire end length!!
But, but, if I put the elevator horn on top, voila! Al's "trick" made all
the difference. This way, there is oodles of space between the crossing
pushrods, while the elevator rod exits *ABOVE* the longeron, the rudder rod
exits _BELOW_ the longeron on the other side!! No drilling/hacking, and
everything is clean. The only bit of reconciliation I had to do was about
the elevator horn sticking out from the top. Won't look as purty, y'see?
Well, question - can't the elevator horn come out from the bottom, and the
rudder horn be moved up? Will this look better? Or is there a need for the
rudder horn to be as close to the tail wheel as possible?
After nearly an hour of pokin' 'n' swearin' 'n' mullin', ah fig'ged one way
or another, the pushrod installation/slotting was a done deal. I could
proceed to sheet the bottom of the fuse and seal it off, with my mind at
peace with the rest of the world. :-)
First, I had to get the ply plate for the l/g epoxied in place. As I had
been using this piece as a support during construction, I had to sand off
stuck, remanent balsa on the faces. Then I squared/smoothed the sawed edges
on the mitre master, and using some epoxy stirring sticks with rubberbands
as a clamp that I set up first, glued the l/g plate in place. I wish I had
remembered to rough up the to-be-glued surfaces first.
Stuck in one 3" strip of balsa, and was in the process of getting another
ready, when I found I had been sleeping for a while at the foot of my bed.
It was 1:00 AM. I turned off the lights and hit the sack.
ajai
ps. Do you guys always mount the horn with its "surface" perpendicular to
the hinge line, or at an angle to accomodate an angular exit by the push
rod? Angular placement still won't hold proper alignment as the control
surface is moved though, necessitating a ball and socket joing at the horn
end - found out the hard way on the FS, with its raked back rudder, that I
needed such a horn on it. Not having put it, I had the clevis pin show wear
with all the flights I have put in!
I could mount it perpendicular, and let any misalignment be taken up by the
flex in the wire end of the push rod.
Now, and off to Crow island for the "end of the season" bash! Its 70 deg
out...!!
|
1244.32 | MORE ON PUSHRODS.... | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Fri Nov 02 1990 13:22 | 21 |
| Re: .-1, Ajai,
Is makes no difference I can think of which rushrod you route above the
elevator...whichever you feel is better aesthetically better ought'a
work just fine.
Compromising the angle of the horn (relative to the hinge line) and the
angle of the pushrod as it exits from the fuse should produce a
sufficiently bind free attachment of clevis-to-horn. I, personally,
recommend AGAINST using ball links on critical control surfaces, i.e.
aileron and elevator...remember Murphy's Law about things failing if
there's the remotest chance of them doing so. I've seen any number of
crashes caused by ball links popping off critical control linkages
and, therefore, refuse to use them, EZ connectors or the like to
connect to either servo or control horn.
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.33 | 4 1/2 more hours | HPSRAD::AJAI | | Tue Nov 06 1990 12:03 | 96 |
| I slid the stab into the slot in the fuse, and was dreamin' on, when I
realised that with the fin in place (the bottom of the fin sticks through
the fuse and sits on the stab), I would have little or no room that would
let me put one pushrod go above the stab, and one below!!
Anyhow, I decided to continue and sheet the bottom of the fuse, leaving out
the area under the stab for any surgery I might have to perform during
pushrod installation. This would also help me glue in the stab better!
I had some scraps of 1/4" sheeting lying around. For instance, the elevator
is only 2" wide, so when I cut it out of a 3" sheet, I had a 1" strip left
over. Again, when I cut out the trapezoidal piece for the fuse top, I had
two triangular pieces, about 1" wide and 18" long left over.
Sooo, having been used to a balsa starved third world diet (no, I didn't say
food, and no, that's not my secret to being thin:-) ) for nearly 20 years, I
instinctively figured on using the different pieces to finish the bottom
planking. That would help reduce wkshop clutter, too!! The mitre master came
in _reeeal_ handy once again, in squaring up the sides of the planking that
would butt against each other, while the overhang beyond the fuse sides were
rough cut and to be sanded down later.
Things went quickly. The pieces mating with the ply l/g plate were epoxied
in place, while the rest were hot CA'ed. I had about 10 strips in 10",
before I was out of scrap wood, and began using a fresh 3" sheet. Again,
like on my previous planes, I used my old trick of flipping the plank over
for every adjacent 3" section of the bottom that I planked. I cut the plank
at the fuse taper angle, and use the rest of the plank for the next section
by flipping over, with minimum of wastage!
I forgot to mention that I put in the t.e wing hold down before commencing
planking. There is a strip of ply reinforcing the wing saddle on each fuse
side, and the t.e. wing hold down butts against the saddle so it can't be
pulled out. While it had been sanded/cut to mate w/o a gap, unfortunately,
the excess expoxy from glueing the ply saddles formed a fillet which proved
too hard to remove, even with a dremel tool, without wrecking the balsa
side skins. I gave up and filled the 1/8" gap between the hold down plate
and the saddle strips with lots of epoxy.
To get back to the planking - once done, I sanded the sides flush to the
fuse contour, and then the bottom.
And therein lay the gotcha! When I got done, the bottom surface, though
smooth, was like a roller coaster, going up and down!! Closer inspection
revealed the cause of the problem to be due to the varying densities of the
scraps of wood I had used! Soo, instead of using the 3M rubber sanding
block, I wrapped sandpaper around a piece of wood, mustering my sanding
skills gained building numerous chuck (hand launch) gliders during my early
years in aeromodelling (I still want to build some), and paying a hell of a
lot more attention to what I was doing, worked out the bumps.
That, at any rate, made for a few moments of consternation. Next time, I'll
settle for playing rich American, and used a fresh plank all the way!
Of course, there too, you can get bitten if the wood density varies across
the width of the plank. Then again, you DO come across the kind of problem I
faced, routinely, though in an extreme sort of way, in so far as the super
hard ply l/g plate amidst all the balsa planking is concerned!!
Since the bottom of the fuse is curved, and the top is the only flat part
(on which Chris Foss suggest you build), I checked out that the sides were
vertical, with the fuse flipped over, lying on its top. Not that I could
have done much at this point if it looked dicey, but I checked any way.
Thumbs up.
The edges are yet to be rounded - I want to cut out the slot for the fin in
the top sheet before that (so my measurements are easier to make with the
squared edges). I have also yet to plank the top section of the fuse, in
front of the wing l.e. I want to fuel proof it first, as also put in the
blind nuts in the firewall for the engine mount. I would also have to drill
the holes for the plumbing, the Du-Bro kwik-filler, and check out that the
tank sits in fine.
The OS 61 pumper has a tube going to the pump, and and excess return from
the pump from/to tank. The third line to the tank is the overflow/vent line.
On the Trainer 60, which also had a pumper on it, I had put the kwik-filler
on the clunk line (= pump inlet). Currently, I am thinking of using a
sintered bronze clunk as it is supposed to offer the ultimate in filtering
(comments?). I figured that if I filled via the pump excess return line
(instead of the clunk line), I wouldn't have to pump _through_ such a
filter. The only advantage I can think of pumping through the sintered
bronze clunk, is that it would help unclog at each fill up (not to imply
that the fuel being filled will not be prefiltered). What do people say?
Dan-the-Miner lent me his ajusto-jig for the wing yesterday, at the CMRCM
meeting. It seems the UN Security council, comprising of representatives
from Germany and the US, have vetoed the Indian proposal to slot the
spars/l.e./t.e. The proposal arose from WWII observations made during
construction of the T60, an American kit, since building w/o slotting has
been the traditional Injun practice all along! I have since been informed
that this was done primarily to yield a self-jigging kit, rather than for
strength.
800 million people can be wrong. Injun accepts UN resolution.
ajai
|
1244.34 | 12 Hrs brings clock to 65, including 5Hrs for wing. | HPSRAD::AJAI | | Fri Nov 16 1990 12:35 | 68 |
| Give me an interference fit, or give me death!
I had to slot the top of the fuse to accept the fin. I deliberately left the
edges square while sanding the fuse, so making measurements to mark the slot
would be easy. That thinking certainly paid off. I cut the slot a little
narrower than 1/4", so the fin had a friction fit. It sat perpendicular to
the stab, which, I checked was skewed by 1/8" when measuring from stab tip
to table top. I flipped the fuse over and used the flat side for reference
when I did this.
Then, after some discussion with Charlie Watt, I traced out the rib pattern,
allowing for the 3/32" sheeting/cap strips, onto the cardboard backing of a
depleted letter pad, and cut it out. Then, traced the ribs onto 3/32" x 3" x
36" sheeting. I did some juggling to see if I could do better than just 4
ribs/sheet, by staggering the layout, but the best I could do was 4 1/2
ribs, which didn't make sense, so I went with the 4/sheet. Besides, I got a
1" strip that I could use for te sheeting. 9 ribs in all for each 2' wing
half. One of the 9 was cut from 1/4" sheeting.
I want to use this 1/4" rib itself as the aileron servo tray, perhaps
reinforcing it with 1/16" ply around the servo well. I plan on using 1 mini
servo per aileron, so that I am not plagued by flutter problems like on the
T60, and yet retain clean lines.
I cut the remaining 2"x36" of 3/32" sheeting into four 9" sections for the
ribs, but didn't have time to cut them out to the outline with a knife. Off
to Charlie's to use his drill press to stack drill 'em for the ajusto-jig.
We figured it would be better to cut out the ribs before stack-drilling, for
better alignment. Drilled and bolted them together for sanding later. I
wanted to use ply end plates to speed up the sanding, but Charlie figured I
could put the ply to better use.
Finally, I seem to have done this just like I used to in India. The kits
there don't come with die cut parts - just wood with the parts to be cut
printed on them. I used to cut them oversize, then pin them together for
sanding to identical shape.
While at Charlie's immaculate and new workshop (he has built a new centre
table, and his wkshop exceeds my bedroom in area!), I decided to drill out
the firewall for the engine mount. Turned out that the engine mount that I
had was too small, with too much material needing to be removed from the
bearers, which would weaken them. I had _specifically_ asked Tower while
ordering for a mount for my OS SF 61, and _yet_ they goofed. Bah! Now I have
to return the Dave Brown mount. Btw, the bearers are NOT parallel, as
advertised!!
Since the fw drilling got scuttled, I decided to bend the piano wire for my
l/g. I used my new Mighty bender from K&S for the 5/32" wire - with Charlie
sighting to ensure that all bends were made in the same plane. It was
child's play. No more grunting with pliers, or whacking a wire held in a
vice with a hammer, going twwwwaaaaang, twwwwaaaaang, every time, while you
lean back with fright at the thought of launching a broken piece as
shrapnel. The tool is great. Bending the second 5/64" piece was even easier.
Sanding the stacked 'n' bolted ribs to final shape took me a total of 3
hours. I used a try-square to monitor progress. I got into trouble when I
used the two ends of the stack interchangeably, drawing different
conclusions on what side to sand down. I had forgotten the old carpentry
rule about having a REFERENCE SIDE from which to base all measurements!
The ribs at one end of the stack had got skewed a bit with pressure from
tightening the bolt! I have to next "notch" the ribs for the top and bottom
spars - if you can call a 1/2" x 3/8" cut a notch. Then to ajusto-jig and
wing it. The fuse is stalled until I get the mount, as I can't work on the
built-up cowl until then. I could make the push rod slots though...
ajai
|
1244.35 | 'nother 4 | HPSRAD::AJAI | | Fri Nov 16 1990 13:12 | 37 |
| -.1 should have been posted yesterday, but I forgot to stick it in before I
left...
Last night, I marked the ribs to take 1/2" x 3/8" spars on top and bottom. I
used 3" sheeting as a guide to mark where the le sheeting would end (along
the rib), so I could position the spar such that it projected a little
beyond, so the cap strip can sit on it.
Since the aerofoil is near-symmetrical, the curvature of the top and bottom
of the rib is different. This means I would have to locate the spar on top
at a different distance from the l.e. than the the spar on the bottom, if I
am to use the same 3" wide le sheeting. Or I could settle for trimming the
sheeting. However, if the spars are not located one on top of the other, I
can't put in shear webbing.
I finally settled for having the spars at the same distance from le, and no
trimming the sheeting - the cap strip on the bottom spar will have to start
at a different location on the spar, that's all.
Using an Xacto saw, I made multiple cuts to clear out the first notch in the
ribs. Then sanded down to final size, checking to ensure that I had a tight
fit with the spar.
For the second notch, I grew bolder, and cut much closer to the final line,
so I could reduce the sanding I had to do. Besides taking *much* less time,
it turned out to be the better fitting one. The first notch got sanded too
deep, leaving a slight gap between bottom of spar and rib, while the second
notch fit snug on all 3 sides.
The t.e. of the ribs wasn't absolutely flat, so I put it back on the mitre
master and fixed that problem in 5 mintues.
Then adjusted all the rib-holders on the ajusto-jig to give me an even 3"
spacing, so I get a 24" wing-half with 9 ribs. I'll have to re-adjust the
rib-holder for the single 1/4" servo rib I have, though...
ajai
|
1244.36 | Question time | HPSRAD::AJAI | | Fri Nov 16 1990 13:28 | 40 |
| Question time, being posted separately, so all you lazy
I-can't-read-ajai's-long-postings don't have an excuse to not share you
knowledge/experience :-)
1. Where do I stick the aileron servo in each wing-half? i.e., how far
from the centre?
2. Given that I am mounting the servo for each aileron flush with the
rib, using it as a servo-tray of sorts, I would expect to mount it with
the servo wheel/horn axis away from the aileron, rather than towards,
so the steel pushrod for the aileron moves more "axially" rather than
with a pronounced "up/down" motion. This will allow me to make a
cleaner exit.
Correct?
Anyone out there who has done this kind of setup before? If so, any
gotcha's?
3. Rib lightening holes - Kits do 'em. Should I? I do need to put a
hole to snake out the servo wire, though the ajusto-jig alignment holes
will take care of pressure equalisation within the rib bays.
4. I need to make the t.e. piece (1/2" x 3/8") wedge shaped, so it will
follow the contour of the rib for good contact to the t.e sheeting. Any
nifty tricks here, other than trying to plane/sand it to shape by
eyeballing, prior/after glueing?
5. What do you use for the wing bolts to rest against (at the le) -
hardwood or ply? The T60 used a 1/2" x 1" x 3" hardwood block. Is this
easily available at a hobby store? I saw some engine mount hardwood
yesterday...
I'd like to get the wing jigged and glued this wkend, so I'm an eager
beaver...
ajai
|
1244.37 | The WOT4's been giving me a ribbing | HPSRAD::AJAI | | Thu Nov 29 1990 12:01 | 76 |
| Another 5 1/2 hours.
Having final sanded the ribs to shape, and cut out the slots, I was all set
to unstack the ribs and put them on the ajusto-jig. Let me check just once
again before I do that, I said.
The end ribs followed the template closely. I then used two 3/32" sheets on
top and bottom of the rib stack, near the te, to simulte the cap strips +
t.e. sheeting, to see if the 1 1/2" x 3/8" aileron stock would butt flush.
There was a 1/8" step going from wing te to aileron stock!! The stock is
glued in the centre section and towards the wings tips, and moves, forming
the aileron elsewhere.
Dang it! This would definitely not do. It wasn't _even_ close! Chris Foss
does not give full size plans, no doubt making it as difficult as possible
for scratch building, and I would do the same were I in his place. There is
no COMPLETE full size wing cross section diagram, soo...
I dug through the instruction manual for the full size le and te cross
sections, that I then xeroxed and cut out. I first checked that the machine
copied to full size, w/o reduction, though. I also had to get the chord of
the wing. As a first approximation, I measured the saddle on the fuse, and
found it to be 11" approx. I then dug through the instruction book again,
and found measurements for the saddle (given in connection with placing
bulkheads, etc..), and computed the wing chord to be *exactly* 11"
With the xeroxed wing le and te cross-sections, I could re-create the
cross-section, and thence the rib-pattern.
I used the chord lines drawn through the partial le/te sections, and the
pattern that had been traced out from the kit (that has served as my
template thus far), and the wing saddle to help come up with a composite
wing x-section!
Then, retraced taking 3/32" off to allow for the sheeting/capping, and also
the extra inches at the le/te, to come up with the final rib pattern! This
was longer, besides being narrower than the original pattern I had been
using.
I re sanded the rib-stack to the new pattern, and decided to compensate for
the reduced length with a wider te piece. Sanding to the first [wrong]
pattern, and then again to the second [right] pattern wasted a lot of my
time. I'll remember to check all this out ahead, the next time, since this
is the first time I am scratch building w/o full size plans.
I then re-cut the slots for the main spars a little deeper, and un-stacked
and numbered the ribs.
Just to check , I put the two end-of-stack ribs against each other, and they
are identical. Then, inserted the 5/32" rods that are used on the ajusto-jig
to check again. I find the left-wing end rib sits lower than the right rib
in general, and also the left wing-tip's te will be much lower (1/8"?) than
the right wing-tip. This means I would get a wash-in on the left wing and a
wash-out on the right wing.
My choices, given that all the ribs are identical in shape, are:
1. Prop up the rods that are used in the jig (that go
through all the ribs) at one end to compensate for the
wash in/out. Since I can't support the rod(s) at the
right height at each rib station, they will tend to sag,
giving me bowed wings.
2. Ditch the ajusto-jig and build on a flat surface, using
a strip of wood as a shim to keep the te of the ribs at
the same height. I could use my magnet builder as I did
on the T60. Remember, all the ribs are identical in
shape.
3. Use the rib-holder-cum-hole-template that comes with the
jig, and re-drill a new pair of holes I need in each rib
to use on the ajusto-jig.
I am beginning to get sick of ribs :-)
ajai
|
1244.38 | Tomorrow's note - 3 hours to redrill holes ;^) | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Thu Nov 29 1990 12:33 | 9 |
| Choose #3.
Redrill the holes offset from the current ones. The adjusto-jig is
great when you want to rotate the wing 180 degrees and sheet the
underside of the wing without changing you alignment. Pulling the rods
out is one of the last things you do to the wing and that's what holds
the alignment so well.
You've taken this long, what's another set of holes?
|
1244.39 | Ajai, have you tried a modelling aid called beer? | DIENTE::OSWALD | Randy Oswald | Thu Nov 29 1990 14:51 | 25 |
| Ajai,
You are without a doubt the most persnickity model builder I have ever heard of.
Don't, I repeat don't try scale. None of us hackers could ever hope to compete
with you, if you ever got finished that is. (lots of :-) ) Now, I know of a
medication that can help you with this problem. I know you don't imbibe, but I
strongly suggest that you try a beer or two, strictly for medicinal purposes
you understand, before each building session. I think you'll find that these
little 1/8 inch problems shrink quickly to insignificance. Who knows, you
might even get to where you can build two models in one year! I personally
recommend Watney's, but I'm sure the Rat would argue for Colorado Cool Aid -
take your pick.
Tongue firmly in cheek,
Randy
Oh yeah, the info I had which prompted me to start this was:
That 1/8 inch difference between the T.E. and the aileron stock in your
original ribs would probably have had *NO* effect on the performance of the
airplane. On my Panic the T.E. is damn near a half an inch thick. The ailerons
are .25 inch sheet - no taper. The only problem with them is that they're
so darn sensitive that I have absolutely minimum mechanical throws and 40%
throw on the dual rates to get it flyable.
|
1244.40 | Happiness is... | HPSRAD::AJAI | | Thu Nov 29 1990 15:47 | 61 |
| ... building according to them pictures.
Randy,
The thought of ignoring the fractions of inches here and there does
cross my mind, but the thought of having to deal with this little voice
in my head that keeps saying - And you couldn't build it right? - is
too terryfying a prospect to ignore! Ya gotta feel good inside, y'know!
Nonetheless, everytime I do something, the little voice says - This
won't do! After a few attempts, I finally hang tough, but the little
voice always seems to have the last laugh - You can improve on
this, This, THIS and T H I S the next time!
Maybe the beer silences the little voice, from what you tell me.
But I run into another problem. It's my tongue, which insists on
tasting everything that I eat/drink, and has to pass unsolicited
comments. A true story from my bicycle ride across the Rockies in the
summer of 1986 - I was huffing and puffing up a mountain, when I heard
someone yelling at me
Man-in-car : Hey Man, want a drink? [holding out a cold can of beer]
Me[Thinking]: Oh! It's another darned motorist yelling at poor ole
bicyclist me.
Man-in-car : Hey Man, wanna beer? [still stretching hand from window]
Me[Thinking]: Gee, it'd rude to refuse jes 'cos ah don' dwink.
Besides, he is bein' reeal na'hce ta me. This is the Wild
West, you know...
[Say] : Yeah, thanks a lot.
[Take a sip in the setting Utah sun, grunting along another impossible
slope]
My Tongue : What's that horrible tasting liquid you are drowning me
me with?
Me[mumbling]: Why, that's beer, of course.
Tongue : It tastes yucky, and don't you dare do that to me again.
Besides, it is a diuretic, and you are going to get
dehydrated.
Me : Aw, c'mon. Be nice. Loosen up. Why do you have this
high'n'mighty snooty attitude.
Tongue : One las time, I'm tellin' ya. Gimme Coconut water, OJ or
plain ole water. None of this hanky panky stuff.
...I finished the beer...
I was again offered beer when I pulled into a campsite in N.W.
Colorado, and drank that too, saving both cans as souvenirs! I have
tried all kinds of liquors, with Scotch being the worst of the lot. I
sipped some neat (straight), and spat it out in less than a tenth of a
second, with my mouth "ablaze". Swilling model plane glo fuel comes a
close second to that feeling...
Sooo par'ner, it isn't for lack of trying. Sometimes, I wonder why I
am built sooo complicated.
The good news is, I'm enjoying myself and the hobby thoroughly, with
memories of painful crashes fading into the distant past...
ajai
:-) :-)
|
1244.41 | Well, Ok | DIENTE::OSWALD | Randy Oswald | Thu Nov 29 1990 15:49 | 6 |
| Ajai,
As long as you enjoy it then thats the way to do it. I enjoy reading about
your exploits, this time I just coultn't help myself and had to respond.
Randy
|
1244.42 | AREN'T FOAM CORES AVAILABLE FROM ERIC/CHARLIE/?? | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Thu Nov 29 1990 16:17 | 13 |
| Ajai,
I'm still wondering why you didn't go with the foam wing (or am I
mistaken in the belief that Wot-4's are flying back there with foam
wings?). Of course, I admire you wanting to do a built-up wing as I'm
not terribly crazy about foam but it sounds like a foam wing would
save you a lotta' time and aggravation. :B^)
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.43 | Adjusto-Jig holes... | KAY::FISHER | Stop and smell the balsa. | Thu Nov 29 1990 16:22 | 22 |
| On my BJ's second set of ribs (I had to throw away the first 150) here is
what I did.
After cutting ribs (no holes or spar slots) then I used the Adjusto-Jig
to hand cut all the Jig holes. Then I put all the ribs on the Jig but
bunched them up to each other. Then I sanded till they all were the same
(with my few plywood ribs on the outside edges. Then in the Jig I filed
and sanded the slots for the spars.
Then I repositioned all the ribs on the Jig at the correct spacing and
rubber banded them to the plastic alignment things. Then...
The secret to the Adjusto-Jig is to make the Jig holes early in the game
and to make the holes in places that are convenient to building. That
is the aft hole will not be so close to the trailing edge that it is
easy to break the rib. I placed my spars at locations that were convenient
to work around on the Jig.
Bye --+--
Kay R. Fisher |
---------------O---------------
################################################################################
|
1244.44 | Explanations... | HPSRAD::AJAI | | Thu Nov 29 1990 16:39 | 33 |
| re -.2,
Al,
The Wot4 uses foam wings, and Charlie had a set to spare. That was the
intended route, when I heard Steve Smith say he was going to dump his
foam wing in favour of a built-up wing, as the latter would be much
lighter.
Since I didn't see myself finishing the WOT4 before winter set in (too
busy flying, to be building :-) ), I figured I might as well got the
built-up wing route and do it (r/l)ight the first time.
So it is clearly Steve's fault for sending me on this trip :-)
re -.1,
Kay,
I believe I have already done what you mentioned. The ribs were rough
cut, stacked together, and drilled on a press for the ajusto-jig holes,
keeping the obstruction to work the ajusto-jig that you mention, in
mind. Two holes were also drilled to bolt the stack together. After
sanding the bolted stack, I cut the slots.
What went wrong? I hand sanded the rib stack (no ply rib templates at
end), using a try square to keep checking. However, the wood musta' got
bowed with the bolts holding the stack together. Soo, even though the
ends of the stack match the template, the stack has been sanded skewed
wrt the holes drilled for the jig.
End result is the wash in/out I see leading to subsequent grief :-(
ajai
|
1244.45 | Getting even with the recalcitrant ribs. | HPSRAD::AJAI | | Fri Nov 30 1990 10:40 | 35 |
| I had to go out last night, but this is what I found - no, I didn't take 3
hours to re-drill the holes :-) - in a few minutes.
I placed the left and right most ribs on the 5/32" rods, and placed it on
the jig and re-measured. (The night before, I had merely eyeballed the
thing, holding the rods in my hands - as it was getting late).
Here are the new numbers...
drift in datum line = 1/64" (negligible)
skew in datum line at t.e. = 3/64" (i.e. slightly less than 1/16")
I think this happened as my hand sanding w/o end templates wasn't perfect.
Now, heeeeere's what I figured (pat. pend.) I could restack one half of the
ribs (for one wing half) in *REVERSE* order. This would have the effect of
changing
1. any drift in datum line to a dihedral (or anhedral if you did it
backwards).
2. any skew (twisting) in datum line to a washout (or wash in) in each wing
half.
I submit this to the DoD for approval so wing construction of the F25 may
begin without further delay or added labour. Additional labour will be
provided if DoD feels proposed plan is in violation of agreed upon contract.
ajai
ps. Randy, I do have this dream of building and flying a scale Spitfire
someday, but like you said, let me get done building with my "scale" WOT4
first :-)
ps2. Charlie's idea was to stack alternate ribs, so things would even out.
|
1244.46 | Or you could call Charlie and get that foam core ;^) | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Fri Nov 30 1990 10:51 | 3 |
| How about stacking them 1st, last, 2nd, last-1... and then lightly
resanding them. This would even them out further and any deviation
would end up being noise level
|
1244.47 | Got dem ribs to behave at last... | HPSRAD::AJAI | | Wed Dec 05 1990 12:55 | 32 |
| Inspite of the reverse-stacking half the ribs idea, I did not like the
thought that I was using a fancy-schmancy ajusto-jig only to build a wing
that wasn't flat. Why, pray, use the jig with its advertised 0.01% jigging
accuracy?
Sooo, I resolved to drill a fresh set of holes in the ribs, using the rib
indexing tool that is supplied with the jig. After all, if all the ribs were
identical in shape, and the indexing tool does it's job, I _ought_ to get a
straight wing!! Worst case, I'd end up with an extra pair of holes in each
rib, and be none the wiser.
I used a 5/32" brass tube to first mark the holes, then drill them out. Took
me 45 minutes to drill 38 holes at the approximate rate of 1/minute, and in
the process getting a blister on my thumb from twirling the brass tube. I
don't think Jim Reith could have fared better, unless you mount the tube in
an electric drill. Regular twist drills mess up the balsa, tearing out the
wood...
Put the stack back on the jig with the two rods going through, and all but
one rib was out of line. Sealed up holes, and redrilled. Looked great! Then
for the acid test of butting the left and right most ribs against each other
- Voila! They lined up near perfect!!
Now that I have triumphed over the battle of the ribs, I need to cut holes
in two ribs to take in the aileron servos, and drill holes in the rest in
between to snake out the aileron wire. Then, I'll be all set to stack 'n'
glue, as the ole Rat would say.
To night.
ajai
|
1244.48 | THIS GUY COULD BUST AN ANVIL....... | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Wed Dec 05 1990 13:11 | 12 |
| Re: last several,
Sheeeesh, Ajai! I never hoid'a someone having soooooo much trouble
operating the simplest of devices! Tell me, do you also have
difficulty using a Crescent-Wrench, otherwise known as an "Injun Socket
Set?" :B^) :B^) :B^)
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.49 | servo-wire = model RR wire | WRASSE::FRIEDRICHS | Brand New Private Pilot | Wed Dec 05 1990 13:13 | 29 |
|
ajai,
You say that..
>Now that I have triumphed over the battle of the ribs, I need to cut holes
>in two ribs to take in the aileron servos, and drill holes in the rest in
>between to snake out the aileron wire. Then, I'll be all set to stack 'n'
>glue, as the ole Rat would say.
Why do you need to drill more holes for the aileron wire?? You already
have two holes in each rib! Do you feel you need to make the hole
large enough for the connector?? If so, don't bother! All you need
are 3 pig tails for the radio, and some 3 conductor wire... I found
some *great* 3 conductor wire the other day... In the model train
section of the hobby shop! The stuff is the same gauge wire and each
conductor is a different color.
So, feed the wires through the holes used for the wing jig then solder
on the connectors..
Tell us more about why you are cutting ribs for the aileron servos...
I can't say that I have ever been very close to a WOT-4, but I can't
imagine that the wings are so close that you can't fit a servo between
the ribs...
cheers,
jeff
|
1244.50 | Arrested on what charge? | HPSRAD::AJAI | | Wed Dec 05 1990 13:31 | 15 |
| re -.2,
OK Sheriff Al,
>>I never hoid'a someone having soooooo much trouble
>>operating the simplest of devices!
Before ya arrest me, wuja tell what the charges are? :-)
Seriously, dunno if we are on the same frequency here - What device are
you talking about? Me thinks ya's might have taken a left toin some
where.
ajai
|
1244.51 | THE MACHINE WITH NO MOVING PARTS, OF COURSE.... :B^) | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Wed Dec 05 1990 13:36 | 8 |
| AHA! _NOW_ we know the problem: you don't even know what device it is
that'cher usin'! I was referring to the Adjusto-Jig, seen-yore. ;b^)
__
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.52 | I'm bein' framed! Yipes! | HPSRAD::AJAI | | Wed Dec 05 1990 14:56 | 22 |
| Me thinks the Sheriff's doin'a frame-up job so he can keep his prison cells
full, and fool the citizens of Phoenix into thinking he is doin' a great
job. Ya should be goin' after *REAL* gangsters instead of tyin' poor
innocent injuns to yer favourite saguaro cactus, Chief.
:-)
Well, Al, I did not have problems with using the jig as intended by the
manufacturer. Once I had a stack of identical ribs, and used the indexing
tool to mark and drill 'em out, I was all set in an hour or so.
Where I *DID* get nailed, is when I tried to stack and drill on a press,
_then_ sand the ribs to final shape. Here, due to hand sanding, the stack
got sanded skewed, so the drill-press jig holes appear in a different
location on each rib when you hold them stacked unskewed. Lemme untwist my
tongue...
The instructions for the ajusto jig warn against using a drill press, but I
figured that applied to pre-shaped ribs only. I don't believe ply/aluminum
end ribs would have helped prevent skewed sanding either.
ajai
|
1244.53 | RE. .-1: I REST MY CASE...! ;B^} | UPWARD::CASEYA | THE DESERT RAT (I-RC-AV8) 551-5572 | Wed Dec 05 1990 15:58 | 6 |
| __
| | / |\
\|/ |______|__(o/--/ | \
| | 00 <| ~~~ ____ 04 ---- | --------------------
|_|_| (O>o |\)____/___|\_____|_/ Adios amigos, Al
| \__(O_\_ | |___/ o (The Desert Rat)
|
1244.54 | Jigged at last! | HPSRAD::AJAI | | Wed Dec 05 1990 17:25 | 50 |
| Now that I have got my name cleared at the local county office, lemme
report las'night's pwo-gwess, or lack thereof, as most people see it
:-)
I cut out 2cm x 4cm holes just aft of the main spar slots in the 2 1/4"
ribs I have for supporting the mini-servos. I had to make sure that the
servo wheel would clear the shear-webbing when I put it in. Then, stuck
1/16" balsa cross grain on both sides of the rib around the servo hole,
and cut holes in 'em as well. Had to re-drill the jig holes, as they
got covered by the veneer.
Anyhoo, boy, did *that* stiffen up the rib big time compared to the
rest of the wimpy 3/32" rib stock! I'll glue two 1/4" spruce servo
rails on the rib after I build the wing and get it off the jig, as I
don't want to drill the jig holes in the rails by glueing them on now.
I also drilled all the ribs with a 5/8" brass tube, to allow for the
connector end of the servo lead to pass through. Sorry Jeff, your idea
came too late! Also, to answer Jeff's question - while there is enough
space between the ribs to mount a servo platform, the wing section
isn't thick enough to take in the servo completely - I'd have to have
the servo wheel/horn stick out the wing. I am trying to conceal
everything, so all you see is the 1/16" piano wire push rod coming out
the bottom of the wing to the aileron horn.
I realise having clean lines is unnecessary, but am using the
opportunity to learn the ins and outs of such a setup, so I am armed
with info/knowledge/experience should the need arise on my scale job n
years down the road.
Then, I got everything onto the jig. I had all the rib holders set 3"
apart, so I had to re-adjust the ones for the thicker servo ribs so
that the centre lines of all the ribs are 3" apart - so that with the
cap strips on, the rib bays look equal on the covered model.
It was - what' the amerikanski e pression - neato,to be able to
lean the partly jigged wing up against one corner of my room when I
hit the sack. the only time wings I worked on have gotten vertical, has
been _after_ I finished glueing, so it felt funny. I can see the
advantages of being able to sheet the wings (almost fully) before I
get it off the jig.
To-night, I'll get the spars, le, and te in place and glue 'em. I have
to plane the spars to follow the rib contour though, since cutting
angled slots for the spars was out of the question, given that I
want to put shear webbing (that has to sit flat on the spar sides).
Things should be smooth sailin' from now on...
ajai
|
1244.55 | 83 hours of cheap third world labour so far... | HPSRAD::AJAI | | Tue Dec 11 1990 15:40 | 46 |
| See, I am being careful not to post the incremental hours worked, just the
total, so the RC-notes-file-cops waiting for a chance to give me a ticket
for over-parking, will get foiled!! Devious, eh? :-)
I did not have much time this past wkend to progress the WOT4 wing to the
extent that I would have liked, but I did get in a couple of hours...
I glued on the 1"x1" triangle stock for the l.e., as also the 1/2"x3/8" t.e.
stock. Initially, I was debating as to how I should hold these pieces
against the ribs. I could have used clamps, clamping the le/te to the 5/32"
rods running through the ribs, but I felt rubber bands would be better.
Initially, I wasn't sure how I should use the rubber bands to clamp. Should
I used the bands around the entire jig and wing? Or should I make little
s-hooks from wire, to hook the rubber bands from the rods? What about
putting the ribs alternating with rubber bands onto the rods, then mounting
on the jig, and finally using them (having to cut the rubberbands to take
them off)? I must'a been blind, for it took a while before realisation
dawned that I could use the same "hooks" provided on the ajusto jig for
banding down the wing, to band down the le/te. I had to make bigger
rubberbands tying two together though, so the tension wouldn't be so great
as to mash through the soft balsa le/te.
After banding the le/te, I lifted off the le/te at each rib station to let
the rib spring back to its normal flat self - putting on the rubberbands to
clamp down the le/te inadvertantly bowed all the ribs. I checked all the
ribs for straightness before zapping in place. All joints came out snug, but
anyhoo, I went over the hot zapped joints with gapping CA, so I would get
the added benefit of strength from the glue fillet - perhaps an unnecessary
precaution.
While cutting out the slots in the stacked ribs, I had used a SOFT piece of
1/2" x 3/8" balsa to check out the interference fit. I had not used the
actual spar, which is much HARDER. This way, the umpteen insertions/removals
of the soft piece to check the slot width/depth in the stacked ribs resulted
in it getting squished a bit. Sooo, when, on the jig, I put on one of the
regular, hard[er] spars, I had a *nice*, TIGHT fit. I do have to plane the
top of the spar a tad to get it to follow the rib contour.
While cutting the slots in the stacked ribs, it had been impossible to get a
clean rectangular cut, short of using a router. The inside corners of the
slot got rounded with sanding. However, with the ribs being separated, it
was easy for me to push on the spars at each rib, to "cut" into the rounded
spar slot corners.
ajai
|
1244.58 | 87 hrs... | HPSRAD::AJAI | | Tue Dec 18 1990 16:24 | 16 |
| I got the spars glued in place, after taking off material to make it
match the rib contour. Interestingly enough, my own ability to take off
the material improved with each succeeding spar.
I also cut out the balsa blocks that will be used to sandwich the wing
hold down hardwood pieces between the centre section rib bays. Ze Mitre
master was used to square up the ends in a jiffy. I had left the
hardwood stock at work (brought to cut on a band saw and save me work -
never did get around to it), so I couldn't progress there. I _have_ to
have the wing hold down piece glued before commencing sheeting.
Sooo, I decided to cut out the shear webbing - finished the pieces
needed for one wing...
ajai
|
1244.59 | WOT-4/1 complete | SNAX::SMITH | I FEEL THE NEED | Wed Jan 30 1991 11:14 | 31 |
| Well, the WOT-4 is finally complete and ready to go. Finished it up
night before last. It took at least twice as long as it should have, but
building was interrupted by building the Ninja, the wife, loss of motivation,
the wife, money, the wife, etc, etc. I'm happy with the way it came out,
but a little disappointed with the weight. All up weight is sitting almost
dead on 5 pounds. I never got around to weighing the first WOT-4 so I'm not
exactly sure how much I managed to save, but I'll estimate maybe a half
pound. It should still go pretty good with a 61 hanging off the nose and it
can't be any worse than the original. Trouble is, I'll probably have to wait
till spring to test it.
I found while building that the thinner wood, 3/32 as opposed to 1/4, needed
beefing up in certain areas which eliminated the weight savings. For instance,
when I went to test for flex in the rudder push-rod assembly, the rudder
itself was bending in my hand. So, I ended up sheeting the rudder in order
to eliminate the flex. I also found that the large open area under the wing
(fuse sides) was very weak. I ended up having to put some braces in that area
on both sides of the fuse. I made a mistake when I installed the landing gear
block (put it in the wrong place) so now I have a 1/4 inch piece of ply as
part of the fuse bottom that should be 3/32 balsa. I'm also going with a
14 ounce tank rather than the original 12. I think if you really want to save
weight on this plane, you have to do what Ajai is doing and build a built up
wing. I also shortened the nose on this version in order to be able to install
soft mounts. After all was said and done, I ended up needing to put about 2
ounces in the tail to get it to balance at 30% of cord. I figure it's worth
it to be able to keep the soft mounts.
This new version also has the new X347 installed. I have it set up so that I
can fly with aileron and rudder coupled, elevator and flap coupled, flaperons,
and some other things I haven't figured out yet. Should be interesting trying
to keep track of all the switches.
|
1244.97 | antenna routing notes moved (following 1085.37); key = ANTENNA | BRAT::RYDER | perpetually the bewildered beginner | Sat Mar 02 1991 09:01 | 1 |
|
|
1244.60 | He's back buildin' again, but he ain't no faster!! | HPSRAD::AJAI | | Tue May 21 1991 17:54 | 52 |
|
Getting married (and still remaining squawless),
travelling over 25,000 miles, and putting the Gulf war
behind, I resumed building my new hoss last night after
a 5 month intermission!
These past few months after my return had been spent
attending to chores - wedding photos, umpteen letters,
giving Uncle Sam a share of my spoils from last year
(actually, telling HIM what he *owed* ME), fixing up the
car, and on and on and on.
Soon after my return, I had to INVADE and colonise my
11'x12' room, to make habitable by the injun. I mean, if
I couldn't conquer my _own_ room, how could I _possibly_
invade and conquer America, to return to the Injuns to
whom it rightfully belongs? :-) :-)
I had boxes and packing material from gifts and more
gifts that I had taken to India, that I got rid of. I
also came loaded with most of the wedding gifts that my
wife and I had been given! Space was at premium, and
even after storing boxes of my things at a friends
house, I had to stick 18 of 'em under my bed to create
floor space! Cripes, I would think even the Japanese in
Tokyo must have it better!
I spent an hour staring at my WOT4 fuselage and
unsheeted wing (still on the a-justo-jig), trying to
"link up" with the soul of this incomplete machine, so I
would know what was left, and where to begin.
It took me another 3 hours to install the l.e. wing hold
down blocks - this is the hardwood piece that goes
between the ribs at the wing root on each panel, and is
sandwiched between filler balsa blocks.
The hard maple was surprisingly easy to cut with the
x-acto saw, but took a while to square up on the
mitre-master. I had already got the filler balsa blocks
ready, but had to shape them to the wing profile. I
decided it was easier to do this *before* glueing,
rather than after, so I marked the rib outline , then
planed and sanded to shape. This way, I wouldn't be
inadvertently sanding the ribs!
Now to sheet the l.e., and put in the shear webbing.
Ahh!... for it is time to meditate and mend the body,
and soothe the soul with this great hobby ...
ajai
|
1244.61 | | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Tue May 21 1991 18:04 | 2 |
| Just goes to show you that there is life after a "balsa-slow" (TM of
Jim Cavanagh Industries) overdose!
|
1244.62 | 94 hours and counting... | HPSRAD::AJAI | | Wed May 22 1991 12:20 | 39 |
| Gimme another 3 hours!
Last night, I sheeted the l.e. of the wings. Since I
used 1" x 1" triangle stock for the l.e., I had to bevel
the edge of the sheet so it would butt snug against the
triangular stock. Also, even if you ignore the bevel,
the edge of the sheet isn't always straight. Depending
on how poorly the lumber had been dried before the
sheets were cut, it can be bowed along the plane of the
sheet.
Sooo, I used the edge of the steel plate that comes with
the Magnet Builder board I have as a straight edge to
sand against, giving the sheet a beveled AND straight
edge.
I wasn't too happy with how the sheeting came out - I
couldn't get the sheet to butt flush against all the
ribs, and some times had gaps up to 1 mm! Sure, I used
glue fillets, and the wing is strong, and it won't
matter much that the wing doesn't have the exact
cross-section intended, but I don't feel good inside, if
you know what I mean!
I even tried the Zap University /Exam technique of using
Slow Zap on the ribs, and shooting up the sheeting with
kicker before glueing in place, but I couldn't avoid a
gap at the l.e. Literally every other joint on this
plane has zero gap, so I could use Hot CA (unless I
wanted to use epoxy). Perhaps I should try jigging the
sheeting in place, and then dribbling hot CA in the next
time...
I also put in the shear webbing on one wing - my first
time ever - and man, does it make the wing muucho
strongo! Guess it'll end up being built like a baseball
bat!
ajai
|
1244.63 | 94+21=115 | HPSRAD::AJAI | | Tue May 28 1991 14:50 | 142 |
|
I'm still aching all over from the mega-progress made on
the WOT4 this wkend...
FRIDAY, I spent 2 hours cutting the shear-webbing for
the remaining half of the wing, and glued them in place.
SATURDAY was a wash-out, and literally too, for I had to
do my laundry among my other household chores.
Sunday was an 8 hour day. I had to shape the t.e. to a
wedge (trapezium) shape, BEFORE I could glue on the t.e.
sheeting. I planed the t.e. stock most of the way, but
the plane kept smacking into the ribs making horrible
sounds and splinters. While I was doing this, I managed
to _ACCIDENTLY_ "tap" the t.e. and it broke clean off
the ribs!! Great, now I could shape the t.e. stock off
the wing, and glue it back in place! It worked out
great, so I *DELIBERATELY* knocked off the t.e. stock of
the REMAINING panel, shaped, and re-glued in place!
The t.e. sheeting was cast-off pieces from the sheets I
used for the ribs. Again, the original sheet (and now
t.e. sheeting) edges weren't straight, so I clamped each
t.e. sheet strip on to the magnet builder board, and
sanded the edges flush with the steel sheet's machine
cut edge forming the template. Then, glued the t.e.
sheets in place.
Cap strips! I love doing cap strips, but didn' have any
3/32"x3/8" stock, so I cut them out from scrap pieces
left over from building the T60. The mitre master came
in real handy in sanding the ends of the cap strips so
they would sit snug. I marked the cap strips and
l.e./t.e. sheets for alignment, so the strips would be
centred over the ribs. (What? You don't do that? No
wonder your plane flies funny! Oh! You got a foam wing
and no cap strips? Those won't fly at all :-) :-) ).
I decided to use the technique of spraying kicker on the
cap strips, and placing them by hand over the pre-glued
ribs, and it worked with amazing success. The alignment
marks came in handy, as you don't have the time to fuss
with positioning - the glue grabs and hardens real
quick! Last time I glued cap strips, on the T60, I
messed around by first tacking with CA. The kicker
technique is faster, and goes to show you need to *know*
your tools to do a good job. I guess my Rip Van Winkle
days aren't as yet over!!
I could get the cap strips on the top side of the wing
panels, as the a-justo-jig came in the way on the
bottom. So I got the panels off (for the first time in 6
months!), flipped them around, and re-banded them back
to the jig, before capping the bottom.
Gee, doesn't sound like a lot got done in 8 hours, eh?
MONDAY was a back busting 11 hour day. I sanded he ends
of the wing panels flush, and glued them together,
BEFORE sheeting the centre section of BOTH panels at
once. Also, while glueing the panels together, I decided
to use one arm of the jig to support both panels, and
provide my 0 degrees dihedral. To do this, I slid out
the 5/32" jigging rods in one panel, and half slid the
rods from the other panel into the first, and banded the
"wing" onto ONE arm of the jig. Of course, the rods
being 3' long, and the wingspan being 4' meant that the
ribs at the tips of the wing would be unsupported, but
that was still better than laying the panels on the
table for glueing together...
The night before, I had got this brainwave to
incorporate GLIDER-TUG features into the WOT4 during
construction. I am talking about attaching a tow line to
the WOT4 here. Of course, the glider will have it's own
release, but as an added safety measure, I am providing
a tow line release on the WOT4 as well.
Since I have the ailerons controlled by individual
servos in each wing panel, the centre section of the
wing, that normally has the aileron servo well, is
vacant. I decided to put in a piece of hardwood (1 1/2"
x 3/4" x 3/8") butting against the back of the top main
spar, and the root rib of the left wing panel. I braced
this with balsa on all sides (the top is of course the
sheeting) for added strength.
The idea is to anchor the glider towline "hook" in this
block, which is pretty close to the CG. I will drill a
hole through the block, going through the entire
thickness of the wing, through which a servo operated
plunger rod will slide. The servo can be taped to the
aileron-servo-free bottom centre of the wing. On top of
the wing, where the plunger rod sticks out, it will rest
against an inverted "U" shaped rod that is also anchored
in the hardwood block. The Glider tow line will be held
between the "U" and the plunger, with the "U" taking the
towing load. Also, by angling the holes for the "U", and
ensuring a friction fit, I can hand-insert the "U" when
tug-duty calls, and yet not have the "U" slip out under
tug load, which means my WOT4 can retain a 'clean' look
for non-tug flights!
The block was sized not to extend beyond the fuse, when
the wing is mounted on the wing, thereby reducing
unnecessary weight. Also, I mounted the wood on the left
side to keep away from the engine exhaust.
All this takes more to explain, but merely an hour to
do. I then sheeted the centre section of the joined
wing, using the balsa sheeting to add strength to the
joint. Of course, the FG tape will come later... Again,
due to the jig coming in the way, I was forced to sheet
the bottom off-jig.
Then, it was major sanding time. I used the plane to
rough shape the 1"x1" triangular stock l.e. and GOOFED!
By the time I checked with the aerofoil template, it was
too late! My "eye-balled" reasonable shape actually
turned out be unreasonable! So I cussed and moaned and
bitched. Luckily, the damage was limited to having
beveled the corner of the triangular stock l.e., so it
looked like a trapezium, instead. I got out of trouble
by glueing a 1/4"x 1/2" strip, and paying more attention
the second time around, sanding mostly with 40 grit
paper!
I got the l.e. and one side of the wing sanded smooth,
but after 11 hours, I was beat, and stopped rather than
risk botching up.
ajai
Tue May 28 13:26:39 1991
ps. weighing all the pieces of the plane/engine/radio etc..,
I expect my WOT4 to weigh 5 1/4 lbs (Aaargh! Pounds!) or
2.4 Kgs, giving a wing loading of approx 22 oz./sq. ft.
(huh?) or 66 gm/sq. dm. The instructions talk of a 40
size plane being 18.75 oz./sq. ft. typical, so with a 61
pumper, I guess I am not doing too bad.
|
1244.64 | ... and a minor 'goof' | HPSRAD::AJAI | | Wed May 29 1991 14:32 | 26 |
|
In my pervious note, I forgot to mention that I goofed
up on the aileron servo location.
You see, at least mentally, I had figured on having the
aileron horn located in the middle of the aileron, which
is 20" long. So, I chose the rib that is 10" away from
the centre of the wing to embed my servo in - my servo
installation is concealed, with the servo output shaft
axis being parallel to the l.e.
Hah! I complete forgot that I have 4" of fixed t.e.
going out from the wing centre, before the aileron
'starts'. Consequently, the horn will now be located on
the aileron 6" outboard, instead of the planned 10".
This is roughly 1/3 of the aileron length, so I should
still be fine.
If I had realised my mistake earlier in the game, just
by joining the other ends of the panels (that form the
wing tips now), I could have 'moved' the aileron horn by
3", which is the rib spacing.
ajai
Wed May 29 13:32:09 1991
|
1244.65 | Another 2 biting the dust! | HPSRAD::AJAI | | Thu May 30 1991 14:35 | 64 |
|
With all the sanding I have been doing, I seem to have
discovered some muscles that I never knew existed! I
wake up each morning with sore arms and shoulders!!
Groan!!
I might bicycle 2500+ miles a year, but my upper body
sure ain't strong! Perhaps I should have done a few
weeks of laps at the pool, or some rope skipping like a
boxer, to train for the sanding session!
I stopped off at the hw store on my way home, last
evening, to pick up some sticky-back sandpaper, to
innaugurate my new, 20" sanding "Tee". I seem to have a
new tool to try with each new plane I build. With the
T60, it was the Magnet builder board and Fast fingers.
Now, with the WOT4, I have used the A-justo-jig, the
Mitre Master, and finally the Tee.
I first sanded the t.e. of the wing flat. Initially, I
tried holding the wing vertical on my building table,
and worked the Tee by holding the T. Pretty shaky
arrangement, that I had little control over! Then I
pushed one end of the wing against a box by the wall,
still keeping it vertical on the table, but I couldn't
keep the Tee from wobbling. Finally, realisation dawned
that I could exercise more control by clamping the wing
down on the table with one hand, t.e. sticking out
beyond table edge, and hold the Tee like a sanding
block, sanding in the vertical plane!
I also sanded the cap-strips - especially the joints
where they meet the l.e./t.e. sheeting. The 20" Tee
allowed me to sand with CONFIDENCE, instead of having to
pussy-foot around, being eternally AFRAID of breaking a
cap strip, or gouging one edge of a capstrip with the
end of the sanding block. Or worse, sanding a depression
into the capstrip(s) that you have to fill with
microballoons.
With the Tee, I could sand one ENTIRE panel at a time,
using the 20" sanding swath to follow the wing contour.
Also, using a sanding mask (instead of a kerchief) and
goggles, plus putting my industrial shop vac to frequent
use kept the sawdust level low, so I was relatively
allergy free.
Yeah, just think of a masked injun, in a room with open
windows, and a 500W halogen lamp blazing well past
midnight, for all to see from the street, attacking a
hunk of balsa with a ferocious look, and the vacuum
growling into life ever so often...
I'll say that mega-whomper halogen lamp instead of a
wimpy 100 W incandescent jobbie has certainly eliminated
the need to *peer* at my work.
ajai
Eeeks! Look at all the American I have liberally
sprinkled my note with! My English teacher would
definitely frown!
|
1244.66 | 117+14=131 | HPSRAD::AJAI | | Mon Jun 03 1991 15:10 | 61 |
|
The family owned, third world sweat shop stayed open the
weekend with no respite, supplying more cheap labour
while the Amerikanski's were out enjoying themselves
[and rightly so!], getting their *much* needed rest
flying their model planes! :-) :-)
I toiled for another 14 hours.
First, I sanded the *other* side of the wing. Then,
epoxied the fixed t.e. to the wing center, using the
wing saddle in the fuse as a jig to get the angle right.
Then, after sanding, tacked on 6" Fiberglas cloth with
hot CA, keeping it stretched taut in the process.
Brushed on diluted Epoxy - I used 5 minute stuff like on
the T60, but it jelled up after I got just one side
done, so went to the 30 minute stuff instead. Normally,
diluting with alcohol slows down the kicking time, so
dunno what changed since my T60 days. I am using a
different brand of 5 minute epoxy, for sure! I also
glued in the sheet balsa wing tips, plus the gussets.
Then, it was aileron servo installation time. The 2 ribs
that take the 2 servos are 1/4" thick blasa, with 1/16"
balsa cheeks stuck cross grain to form a "ply".
I had already cut the holes for the servos in the ribs
before assembling the wing, so I could simply drop the
mini servos in both the ribs. I screwed each servo to a
ply bearer stub, and _then_ glued the bearer with epoxy
to the rib, with the servo acting as a jig.
Having to deal with the servo mounting screws in the 3"
space between the ribs, using an offset screwdriver is
doable, but painful, so I chose to avoid it altogether.
I did work the screws a couple of times before gluing,
so when the time comes to remove them, it will be
easier.
The dual servo route, besides reducing the possibility
for aileron flutter, will allow me to use a programmable
radio to mix aileron and flap functions, by merely
unplugging the "Y" harness, and plugging each servo into
an individual channel on the RX. When the time comes for
an "upgrade", it won't take blood and tears - merely a
few minutes!
That, is the difference between designing to please a
manager (for short term gain and obsolescence), and
DOING THE RIGHT THING! :-) Luckily, when I build
aeromodels, _I_ am the boss, so things get done right.
:-)
Next, I have to hinge the ailerons. Then I have to glue
in a balsa sheet over each of the "servo" rib bays, to
provide support for the covering where the aileron
pushrods exit the wing.
ajai
Mon Jun 3 14:02:06 1991
|
1244.67 | 136 | HPSRAD::AJAI | | Wed Jun 05 1991 17:17 | 46 |
|
I got to do the aileron - the left aileron to be precise
- last night. I debated a bit over how many hinges to
use, and finally settled for twice the density on the
T60 - about one hinge every 4 inches or 11 cm. After the
lessons on aileron flutter I had on the T60, I wanted to
apply ALL that I had learnt.
I wanted to have a hinge as close to the end of each
aileron. The original WOT4 design comes with a fixed
outboard t.e., so the aileron is 'inset' and out of the
wing tip vortex. I also wanted to have the aileron horn
centred over a hinge, locking it in place, adding a
measure of safety in case all the other hinges fail.
Finally, I settled on 5 hinges for the 20" aileron. If I
wanted even hinge spacing, and also a hinge in line with
the servo horn, I had to sacrifice being able to locate
a hinge at the very extremities of the ailerons! I put
the outboard hinge about 1/2" from that end of the
aileron, and the inboard hinge about 1 1/2" from the
other end of the aileron. I figured the inboard hinge
distance shouldn't be much of a problem.
I don't have a drill press, and hand drilled the 1/8"
holes for the Robart hinges using a sharpened brass
tube. I got blisters twirling the tube - my fingers kept
slipping. I finally stuck strips of masking tape with
the sticky side facing alternately in and out, to give
me a sticky-grip to twirl the brass tube drill with. My
thumb is still sore from doing just one aileron! This is
the part I _detest_ about using the Robart hinges!! I'm
waiting for the day when I have my own drill press, and
can jig the ailerons/wing and do the job in a few
minutes, and without pain!
Then I planed the l.e. of the t.e. to a bevel - this
being the part I most enjoy! Trial fitted the left
aileron, and stood back to evaluate my work...
The dreadful thing is, I still have the other aileron to
do! Bah!
ajai
Wed Jun 5 15:52:55 1991
|
1244.68 | | SA1794::TENEROWICZT | | Thu Jun 06 1991 08:58 | 11 |
| Ajai,
Five's a good number. that's what I usually use on most pattern
ships. I usually set one hinge 1/2" from each end. Then one in the
middle and then one hinge in between on either side of the middle
hinge spaced evenly. I think the hinge at the tip 1/2" away is very
important to help prevent flutter. Also stiff control rods. I embed
the servos in the wing (2 servos for ailerons). I then use 4-40
rods to connect the servo to the control horn.
Tom
|
1244.69 | Inboard hinge 1.5" from aileron end | HPSRAD::AJAI | | Thu Jun 06 1991 12:35 | 12 |
| Yeah Tom,
Glad to hear I am on the right track. In case you haven't read my
earlier notes, I too have embedded 2 servos in the wing, one per
aileron, and will be using 4-40 rods.
I am assuming that aileron flutter will be more of a problem at the
outboard ends of the wing, where the hinge is just 1/2" in. The inboard
hinge is 1.5" from the aileron end near the wing root.
ajai
|
1244.70 | | SA1794::TENEROWICZT | | Thu Jun 06 1991 13:22 | 30 |
| Ajai,
If you've install a hinge 1/2" from the outboard
end of the aileron and if the control rod linkage is slop free,
the only other simple thing to do is seal the hinge gaps with clear
plastic packing tape. I've even used Scotch brand 3/4" wide
tape with success. I'd suggest that you use the Dubro styled
horns that use a 4-40 bolt and a strip aileron connector tab
as the control horns. They work mint and provide infinate
adjustment.
One of the hot pattern pilots in New England has
gone to using a 4-40 bolt and tab set up with a little twist.
Most pattern kits face the ailerons with 1/4" thick stock. This
guy cuts the aileron back anough to use 1/2" stock. Then after
the bevel is carved he drill a hole through the remaining 1/2" stock
and floods the hole and area using thin CA. then the bolt it screwed
in from the top until the head is flush with the top surface. The
length of the bolt extending through the bottom of the aileron.
that all the support used. No hard points,fiberglas etc.. And it
works. I haven't seen one yet pull out or for that matter show
any signs of play coming loose.
Tom
P.S. I'll use this on my next foam winged bird
|
1244.71 | Third World aileron drilling technology for Robart Hinges | HPSRAD::AJAI | | Thu Jun 06 1991 13:52 | 55 |
| Bad Credit? Loans denied? No problem! Call
1-900-EZE-LOAN...
Hell, this is America, land of opportunity, so if I
don't have a drill press, borrow! Besides, my thumb was
so sore from blisters that my brain was working overtime
thinking up ways to reduce, if not altogether avoid the
painful hand drilling for the Robart hinges...
Sooo, I stopped off at the lab during lunch today, to do
a "government job" with the drill press located therein.
Rather than risk the entire aileron, I cut out 3 pieces
of 2" length aileron stock (1.5" x 3/8") for a
prototyping test run.
On one of the 3 pieces, that I designated the "alieron",
I pre-drilled (using a 1/8" brass tube) the hinge holes
(that I centred using the Goldberg tool) a few
millimeters so I would know where to drill on the press.
I then sandwiched this between the other two pieces,
that I turned around, so the l.e. and t.e. of each
aileron stock alternated, allowing me to jig the aileron
vertical to the press table for drilling. Picture
this...
AILERON, drill here
|
V
- ----- -
/ \\ // \
/ \\ // \
----- - -----
^ ^
| |
Additional stock for
jigging aileron vertical
to drill press.
The results were simply grrreat! In a few seconds, I
drilled out a couple of holes, going nearly 1 1/4" of
the 1.5" stock, without showing through the aileron
surface on either side! Only 3 out of the 5 I hand
drilled two nights ago came out properly aligned. The
remaining 2 were skewed, making unsightly holes on the
top/bottom of the aileron.
Tomorrow, I'm going to drill out the 'real' right
aileron! I haven't figured out how to jig the wing to
drill out the t.e. holes, though, but I know the
blisters on my thumb will be happier...
ajai
|
1244.72 | Another rich American...gag | ELMAGO::TTOMBAUGH | A Fistful of Epoxy | Thu Jun 06 1991 17:52 | 22 |
| re .70
Tom,
The 4-40 bolt with the aileron tabs (so that's what those little
white things are called) for a control horn, is what the Legend
kit uses for a rudder horn. It was a snap to install, just drill
a 3/32" hole with my DREMEL DRILL PRESS (eat your heart out, you
know who you are), thread on one tab, insert bolt in hole, thread
on opposite side tab.
After reading your note it dawned on me that this will work for
the flap and aileron horns on the Legend. It uses a 3/8" aileron
l.e. backed up by a 1/4" piece in the area where the nylon horn
mounts. The nylon horns are bigger than necessary and the screws
and plate look goofy. I was going to use my usual horns cut out
from circuit board material with my DREMEL JIG SAW, but the bolt
method is even better.
Of course I will finish off with a few passes from my T-BAR SANDER.
Terry
|
1244.74 | | SA1794::TENEROWICZT | | Fri Jun 07 1991 09:03 | 11 |
|
Tetra of Japan sells a slick set-up for pull/pull including cable but
they usually run about 6.00 a piece. I've used the dubro set-up a
number of times with great success. The LA-1 I'm now finishing will
have pull/pull on the rudder and elevator halves. I've got three
of the Tetra set-ups so it's getting them. The molding on the tetra
is a little more streamlined but for the money I'll go 100% with the
Dubro in the future.
Tom
|
1244.75 | Time flies. Another 18 hours. Wing done. | HPSRAD::AJAI | | Mon Jun 10 1991 17:32 | 96 |
| I drilled out my other aileron at work on Friday in 20
minutes. It was painless.
Saturday, I installed the aileron horns, and Z-bent the
threaded rods from the aileron servos. I could have done
a much nicer job with a Z-bend tool, but I made do with
a pair of long-nose pliers. I also planked the bottom of
the wing - just the two servo bays - cutting slots for
the steel pushrods to exit. I was careful to glue only
from "inside" the wing, and let the planking protrude
beyond the capstrips (which I had already been sanded)
just a tad, so I didn't have too much sanding to do to
get the new piece flush. I also squared up the dinged
wing tip t.e.
Got carried away, playing with the ailerons, stirring
the stick on the TX. Perhaps the personal-first twin
servo aileron setup mesmerised me, or maybe I was simply
too tired, and entertaining myself? I figured I could
get differential throw if I wanted, but didn't need it
with a near-symmetrical aerofoil.
At hour 147, I was done with the wing (minus the
covering). What a relief? :-)
Sunday, I woke up with my body aching all over - just
like good ole times... I jigged up the l/g (u/c) for
binding with tinned wire, and soldering. Of course,
sanded the parts where I would be soldering them, and
"fine tuned" some of the bends. I didn't have tinned
wire to proceed, so I put that aside temporarily.
Onto my T60 wreckage... Pulling it out from the body
bag, I extracted the fuel tank. My Du-Bro kwik-filler
was still on, although corroded. My idea of a thread
locker had been CA(!!), so applying debonder didn't help
as quickly as I had hoped. So I hacked out the
kwik-filler from the fuse side of the T60 that I had so
lovingly :-) sanded 2 years ago, and used debonder from
_behind_ the nut. Worked like a charm!
Time heals all wounds, and I was surprised I could play
surgeon with the carcass of my baby, WITHOUT flinching.
Spent some time disassembling the tank, to clean out the
green deposit from the Tower fuel I had used in it.
Finally had to resort to using a tooth brush, detergent,
and even a rag wrapped around a pencil to remove the
green residue.
I also planned out the plumbing for the OS 61 SF ABC
pumper. This time, I plan to use a sintered bronze clunk
pick-up, to give me the "ultimate" in filtering (per the
ad, anyhow). To fill the tank, I want to use the Du-Bro
kwik-filler on the return line from the pump, so I don't
have to fill through the clunk.
Also, the fuselage isn't wide enough to let me use a
12-oz. Sullivan tank in the usual orientation. I'll have
to turn it through 90 degrees, so the narrowest
dimension of the tank sits across the fuse width.
I am planning to build up a cowl around the engine, just
to get some experience under my belt - never having
build a cowl before - back in India, I would skip on the
cowl to save the balsa wood for making a more critical
part of another model!
I also stippled the area under the aileron horn with a
pin, and soaked it with CA, to provide a hard base. The
holes for bolting the horn got clogged, and trying to
drill the hard CA with a hand drill, I wasn't too
successful. The bit veered off the original hole, and
made a big mess, drilling into the hole I have made for
the robart hinge!
How do you spell F I A S C O?
I plugged the horn-mounting holes, taking care not to
plug the hinge hole. Not that I succeeded. Re-drilled
the hinge holes today on the drill press at work, but
messed up the horn mount holes again! Aaaarrrrgh!!! Bah!
Got to take the ailerons back home to plug up, and bring
back tomorrow! Next time, I am going to drill these horn
mgt holes *AFTER* I harden the balsa.
Heck! Nonetheless, I am getting that feeling you get
when a model nears completion! I am beginning to see
light at the end of the tunnel. It might still be too
soon for me to say this, but perhaps, _just_ perhaps, I
might end up SCRATCH building the WOT4 in 200 hours,
versus the 300 I needed to build the T60 from a KIT!
AT LAST.
ajai
|
1244.76 | plus 8 = 162 | HPSRAD::AJAI | | Fri Jun 14 1991 17:26 | 72 |
| Let me catch up with what I have been up to, before I
forget...
I jigged and bound the landing gear for soldering. I
couldn't find tinned wire, so I stripped some 7-strand
22 gauge wire, and used a strand to bind with. I
used silver soldered for the first time - low
temperature stuff - melts at 490F. Apart from having to
use zinc chloride for flux, the actual soldering process
was no different from using the regular solder. I had to
wait a while to let the joints heat up before I could
melt the solder on the joint though...
I also marked the wing for drilling the wing hold-down
bolts. The l/g will be held by 2 f/g strips (old pc
board) that has a pair of parallel notches cut in them,
so the l/g wires will be 'recessed', and so immobilised
against the fuse. The two f/g strips are bolted to the
ply fuse bottom, by two 1/4" nylon bolts. While the f/g
can flex and absorb some l/g movement in a lousy landing,
the nylon bolts will shear off if the landing is really
bad. Anyhow, all this is per the original WOT4 kit - not
my idea...
As with the Trainer 60, Charlie Watt donated a couple
hours of his time, energy and tools to drill and tap
the wing and l/g bolts, plus holes in the firewall for
the engine mount. My WOT4 with the OS SF 61 looked tiny
in comparison to his nearly finished Giant (?) Super
Hots, that uses a Zenoah G38 mega-whomper gas engine,
that was sitting on his workbench!
The engine is mounted with the cylinder about 45 degress
below horizontal, so the snuffler runs directly beneath
the fuse, between the l/g. This installation gives my
WOT4 a zany look, compared to the usual vertical or
somewhat rarer horizontal mount for engines. We figured
the problem of flooding the engine and dousing the plug
wouldn't be as bad as when the engine is inverted,
though I still have to watch out for hydraulic lock...
The mount will be drilled and tapped once I get the rest
of the plane done, so I can balance the plane w/o
additional weight being added.
At the June DECRCM meeting, Eric made the valid comment
that scratch building is so named, because you spend a
significant amount of your time scratching your head,
figuring out what to do next! Of course, you could be
doing some of that even with a [unfamiliar] kit, or if
you are scratch building for the n'th time, breeze
through the building process... In general though, I'll
readily admit that I have indeed been spending quite
some time pondering my next move, much like a chess
player!!
Eric also commented on not having to lug around an
additional servo (meant for the emergency tow line
release when playing glider tug) ALL the time, since the
weight penalty would affect the vertical climb, for
instance.
Some more scratching my head :-) after I got home, and
it dawned on me that I could attach the towline release
servo under the wing with velcro when tug duty called,
and simply pull it off at other times!
Now to install the elevator/rudder/throttle servos...
ajai
Fri Jun 14 16:18:41 1991
|
1244.77 | plus 5 = 167 | HPSRAD::AJAI | | Wed Jun 19 1991 14:28 | 41 |
| I used a hacksaw to cut two strips from the green FG
pcboard material, which is about 4mm thick. This clamps
the l/g onto the fuse bottom. The nylon bolts that hold
these strips can be tightened more or less depending on
how easily you want the l/g to 'let go' in the event of
a bad landing. I also sanded the hacksawed edges, as the
FG burrs threatened to shred my fingers as I handled
them. Overall, this scheme seems to have worked out
really well.
I then cut the l/g bolts, made of nylon, to size. I
figured I could use the crashed T60 wing mount bolts for
this non-critical application. I also cut the new wing
mount bolts to size. Likewise with the bolts that hold
the engine mount to the fueslage - I used my Dremel tool
for this (as I have no vise at home to clamp the bolt
while I saw). The sparks flying off the cutting wheel
looked colourful as I worked late into the night.
Then, spent some time loading up the fuselage with the
servos, radio, battery, foam, and placing the tail wheel
+ assy. on the stab, while I checked out the balance
with the wing bolted on. I had to unbolt the wing a few
times, and juggle the order of things, to compensate for
the nose-heaviness.
I find I have to put the battery and servos as FAR BACK
as I can. In fact, I located the battery just AFT of the
wing t.e.!! I couldn't get the WOT4 to balance level
whatever I tried, so it seems evident that I will have
to mount the engine as close to the firewall as I can,
and count on needing some tail weight.
It would be too much work to cut out the fw, and move it
back. Besides, the CG, while off, is not off by that
much.
ajai
Wed Jun 19 13:25:55 1991
|
1244.78 | 5 more to 172 | HPSRAD::AJAI | | Thu Jun 20 1991 13:11 | 63 |
| The building drug must have been coursing in my veins -
I was up until 2:30 AM working on my WOT4! Earlier in
the evening, Dan Miner and Leo (of CMRCM) had stopped by
to pick up their fuel - I had ordered a 54 gallon drum
of fuel, and filled 50+ jugs at considerable savings.
Dan made a very encouraging comment when he toured my
shop cum room - "Gee, your WOT4 looks not much different
from when you brought it for the DECRCM meeting" [that
was 10 days ago]! Obviously, getting the engine mount
on, and the l/g bolted, as also the wing, didn't count
:-)
Of course, fact of the matter is that there has been
little or no "woodwork" done - mostly installation,
which isn't as obvious to see.
Anyhow, last night, I got the tail wheel assembly done.
I had to measure the length of the tail wheel wire on
the tiny drawings accompanying the WOT4 instructions,
and scale it up to get an idea of how long to make it.
3" long, surprisingly enough!
Then, I wrapped the battery with foam, and wedged it on
the fuse floor, aft of the wing t.e. To secure the
battery from falling on the pushrods [guess what
happens?] during negative G manoeuvres, I hot zapped a
couple 1/4" square pieces of balsa. I really didn't
bother restraining the battery from moving backwards in
the fuse - merely relying on the fuse taper to 'wedge'
it. Besides, the plane has to fall on its tail before
the battery gets incentive to move backwards! Just in
front of the battery, is a fuse former, which will hold
the battery from moving forwards. Working within the
confines of the fuse was time consuming. Good thing I
have long, bony (efficient radiators designed for 100
deg temperatures) fingers!
I also installed the wood servo bearers plus the servos.
I usually drill the holes for mounting the screws AFTER
I glue the bearers in, which is inconvenient. This time,
with the aft-ward installation of the servos, I wouldn't
be able to get a drill in the fuse, so I marked and
pre-drilled the bearers before glueing in place. It was
much quicker and hassle free - I'll adopt this method
for future planes... Well, I mean reeeealy waaay out
into the future planes... :-)
Now, to install the elevator and rudder pushrods, plus
the throttle cable...
ajai
Thu Jun 20 12:01:57 1991
ps. Jim Reith stopped by my place at 6:30 this
morning, per our earlier plans. I was surprised
to find I got up a minute before he arrived,
and my own alarm went off while he was in!
He must have talked to Dan Miner, because he
too didn't notice much difference in the WOT4
since the meeting:-).
|
1244.79 | Another of Jim C's test cases gone public! | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Thu Jun 20 1991 14:18 | 9 |
| I did notice that it was still uncovered and unflown 8^)
I think Jim C. has played a cruel joke with another variant of
"Balsa-slow" tm. I think he has come up with a new version which
doesn't reduce the desire to build, just thwarts the process by
reducing progress to the microscopic state. 8^) 8^)
Jim (^8 who scratch built half a 2 meter wing last night - to be flown
sunday 8^)
|
1244.80 | Foam wing hocus pocus? | HPSRAD::AJAI | | Thu Jun 20 1991 14:59 | 2 |
| Wow! So your wing building speed can actually be measured in an integer
number of meters per day! Amazing. I should come by and watch.
|
1244.81 | Ever work a production (i.e. piece work) job? | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Thu Jun 20 1991 15:14 | 14 |
| Stock size Gentle Lady wing using S3021 ribs in the center panels
transitioning to S3014 on the tip panels. The spar system consists of a
3/16"x1/8" spruce spar, .007 CF laminate on top, 3/16" balsa vertical
grain shear webbing between the ribs and topped with another layer of
CF laminate and spruce spar. Ribs all cut out individually using a
plywood template and a sharp knife and then stacked and touched up with
a sanding block. Stacked and sanded the tip ribs (two sets) to shape
and helped my son finish up his GL tail and attach them to his
fuselage. I started during the Red Sox pre-game show and went upstairs
when the game was over.
Now that I think of it I'm working in the building across the street
from Dan Snow so maybe it's something in the Littleton water that
counteracts the "Balsa-slow"?
|
1244.82 | | WILLEE::CAVANAGH | | Thu Jun 20 1991 17:40 | 20 |
|
Re: Balsa-slow (tm)
Actually Jim I've been amazed at how well this new formula works. I
wasn't going to announce this newly improved version until I had the final
test results (when/if Ajai finishes the Wot 4).
I did find that certain compounds found in the drinking water could
serve as an antidote to old formula. I had originally thought that the
only cure was sniffing old crusty sweat socks that can't be washed because
they're your good luck charm at fun flys (don't ask how I found that cure).
I also came up with a variant of Balsa-slow called Balsa-go-slow. This
curbs the urge to fly fast. I slipped some to Bill Lewis and Charlie Watt
which explains their interest in gliders now. The Balsa-go-slow doesn't
last very long though and I expect both of them to be tearing up the skies
with REAL airplanes soon.
Jim
|
1244.83 | fasten the battery | BRAT::RYDER | perpetually the bewildered beginner | Thu Jun 20 1991 18:35 | 15 |
| re Note 1244.78 by HPSRAD::AJAI
>> I really didn't
>> bother restraining the battery from moving backwards in
>> the fuse - merely relying on the fuse taper to 'wedge'
>> it. Besides, the plane has to fall on its tail before
>> the battery gets incentive to move backwards!
Until the time you hold it up to adjust the throttle and then the
vibration of the running engine will set it back --- thereby moving
your CG.
This happened to me a couple of years ago. The plane crashed.
Alton who now restrains his battery pack even in a glider
|
1244.84 | Pushrods done, exits drilled, horns mounted. Plus 6 | HPSRAD::AJAI | | Fri Jun 21 1991 16:27 | 78 |
|
Got the holes drilled for the pushrod exits for the
elev/rudder. My idea was to have the pushrods cross over
in the fuse, with the left servo being hooked up to the
rudder via the right exit, and the right servo being
hooked up to the elevator via the left exit.
However, as I had strenuously argued about gotchas with
pushrod placement in the X configuration, sometime late
last year, in this same note, I found my ponderings to
be true. Namely, I had said that you would need to have
the servos staggered and at different heights above the
fuse floor, and if clearance wasn't adequate, to
vertically stagger the exits also.
I had considered the latter, with one exit BELOW the
stab, and one above, but rejected it from space
considerations. Anyhow, I found that the pushrods had to
flex by half their diameter, and given their short
length on the WOT4 (15"), this made for considerable
friction!
Given the left exit is for the elevator and the right
for the rudder, I had planned on a Rud/Throt/Elev servos
keeping the X configuration in mind. Now, I will have to
go with Elev/Rud/Throt, as the friction from the
threaded rods rubbing against the plastic tube exit
bushing (T60 memorablia) with the pushrods parallel, is
negligible compared to the friction when the rods rub
against each other in the X configuration.
I guess this X configuration is really meant for planes
which have a wide fuse area under the stab, assuming the
servos are all located at the same height above the fuse
floor. One might consider the 2" of fuse under the stab
adequate for staggering the exits, but a bracing
longeron under the fuse skin reduces that width
considerably.
Of course, even if room permitted me to stagger one exit
above and one below the stab, it would detract from the
appearance of the plane. After much mental and physical
gymnastics, the X configuration has successfully eluded
me again!
Before drilling the holes for the elev/rudd horns, this
time, I first hardened the area with CA, after stippling
with a pin. Came out right, much nicer, and took just
one attempt.
I am using the Dave Brown [yellow] fg pushrods. They
come with end plugs for the wires, but, man, I had one
heck of a time inserting the wires through them. Perhaps
they were deliberately made slightly undersized, to
realise a slop-free fit, though, I should think epoxy
would fill any gaps.
Progress on my plane nearly got wiped out last night, as
I was woozy from the previous nights 2:30 AM stint, and
a mere 4 hours of sleep. However, an hour of shut eye in
the evening plus dinner, got me all recharged, and I
kept goin' until 1:30 AM. I am looking forward to
keeping saner hours again!
Incidentally, today, it is one month since I got back to
building this year. At that time, the WOT4 had 87 hours
on it. I put in another 90 in the interim.
ajai
ps. Al Ryder - that was a good observation about engine
vibration making the battery slither down the fuse when
the plane is vertical - a point that had escaped my
attention.
However, as I said, the battery really doesn't move back
to finger pressure - maybe a couple mm at best. However,
I will recheck. Thanks.
|
1244.85 | Actually, they're sized for 2-56 thread. | ELMAGO::TTOMBAUGH | A Fistful of Epoxy | Fri Jun 21 1991 17:08 | 6 |
| The Dave Brown pushrod ends are sized to take 1/16" diameter music
wire. If you used the threaded-on-one-end wire from
Dubro/Goldberg/etc., they are slightly larger than 1/16" diameter.
Nobody knows why. This explains your insertion struggles.
Terry
|
1244.86 | Yeah, sort of. | HPSRAD::AJAI | | Mon Jun 24 1991 15:02 | 16 |
| Well, the instructions with the Dave Brown pushrod ends said that two
were drilled for 1/16", and two for the fatter, threaded-on-one-end
wire, for the two pushrods in the bag.
I checked that the fat threaded rods could be inserted into NEITHER
kind of end. I had some 1/16" music wire, that I could insert into one
kind of end only. Soooo, it seems Dave and his cronies seem to have figured
in the relative difference in dia for the two, but not absolute dias,
as getting each on was a struggle.
Lacking a drill press, and loving my fingers, I didn't have
the temerity to re-drill with a bit. Instead, I had to settle for the
safe, but arduous twist-on-by-hand approach, and watch the
teensy-weensy spirals of plastic come out.
ajai
|
1244.87 | Cut twice and still too short! | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Mon Jun 24 1991 15:35 | 3 |
| Rather have them too tight than too loose. Some plastic parts I used to
use required soaking in hot tap water to expand them for installation
and then once cooled they were locked tightly together.
|
1244.88 | Epoxy fills all voids | HPSRAD::AJAI | | Mon Jun 24 1991 18:04 | 2 |
| Yeah Jim, but the epoxy used to glue the ends would have filled out any
spaces!
|
1244.89 | In this land of plenty, I'll take 20. To 198. | HPSRAD::AJAI | | Mon Jun 24 1991 18:06 | 196 |
|
I was thinking Jim C/R's Balsa Slow (tm) was all a joke,
but realised they were really serious, when I woke up
Friday morning with a red swelling on my neck!!
Something had bitten me!
It hurt big time! By the time afternoon rolled around, I
was feeling cold. In the evening, I was feeling
exhausted, and my head also hurt. I hit the sack for a
15 hours snooze, eliminating progress Friday night!
Geeze Jim(s), I didn't thing you guys would stoop to
biological warfare - the kind you didn't want Saddam to
engage in!! I guess your radio controlled, stinging
insect made it way into my room, guided by the 500W
halogen lamp, as I toiled into the night on an earlier
occassion! That's a low blow!
Friday evening, despite my distressed state, I stopped
off at Ray's RC using directions posted in the notes
file. Ray must be one helluva TOUGH businessman. His
neighbourhood is a dump, and there is NO CLUE outside as
to the existance of his RC shop. No sign. No display
windows. Nothing! I braved a "BEWARE OF DOGS. NO
TRESPASSING" friendly sign (after first knocking on the
wrong door of the wrong building), to let myself in
through a gate to read the tiny label on a mailbox that
said 'Ray's RC Specialities' that you can't see from
more than 6' away. Those who get through all 36 chambers
of Shaolin, get to do business with the man! What a guy!
He did mention the problem of fortnightly visits by
prowlers...
I picked up my 16 oz. fuel tank and left [escaped?], as
Ray latched on to another customer to shoot the
breeze... As someone in the shop said, the sign outside
should read BEWARE OF THE OWNER!!!
I also bought some goodies [tools] at Spags. To the
uninitiated, this is a crowded store that is an
institution in Central Mass that you go to, and has a
huge following. The prices are usually on the low side,
and assorted goods cram the shelves from floor to
ceiling, and you have to elbow your way through people.
Every trip is a challenge. It is like discovering the
world again and again. Great fun if you are Injun like
myself, used to the company of 800 million plus
countrymen, but can be claustrophobic for the average
westerner...
Saturday, I woke up noontime to find I still had the red
welt on my neck, though reduced in swelling, but I
wasn't feeling cold or feverish any longer. I was
getting over the sting - so nothing like some
aeromodelling to convalesce and recuperate!
I began late afternoon, and kept goin' until 5:30 AM
Sunday. What a blast! And now for the details...
I sanded the pushrod exit tubes flush, and sprawled on
the floor to figure out how much the lengths of the
threaded rod, the fg arrow shaft, and the music wire end
should be. Basically, I pulled out the threaded rod a
ways, and hooked it up to the elev/rudder horn, and kept
pushing it in, until the arrow shaft hit the fuse side
with normal control throws, when I backed off a bit.
Then, it was easy to cut the arrowshaft to length to
allow for a 4" length of music wire 1/16" dia.
Assembled and epoxied the lot together. For a 23"
pushrod, I have 13" of fg arrowshaft. About 50%. Not a
lot, but it makes for more positive controls than using
threaded wire for the entire length...
Then, installed the throttle cable, which actually
turned out to be sloppy. So, I switched the cable for
1/16" music wire, as on my other planes, and it made all
the difference. Due to the 45 deg below horizontal
location of the engine cylinder, the throttle cable has
to be routed from the fuse right side to the firewall
bottom, and yet not eat up room in the middle of the
fuse, where my fuel tank will be located.
Despite the 5:30 AM bed time, I woke up at 10 AM Sunday
to resume the battle. The red swelling was still there,
but I wasn't worse for it, UNLESS I happened to touch
it! @#$@%@#%*%^
I then assembled the 16 oz. tank, which is mounted
sideways in my plane. I really don't prefer a slant tank,
but Sullivan doesn't make a rectangular above 12 oz.,
and I don't want to carry spares for umpteen brands of
tanks to the flying field...
The tank has 3 lines - a OVERFLOW/VENT, that goes to the
'top' of the tank [which is sideways - rotated 90 deg] a
RETURN that goes nowhere in particular, and a CLUNK
line. I used a sintered bronze clunk this time. I
notched the top of the OVERVLOW/VENT line, and also
ensured that it doesn't touch the tank, and break from
vibration as happened 30+ hours flying into last year.
I didn't have the patience (surprise!!) to get the
RETURN line to the 'bottom' of the tank - it is hard
enough trying to snake a 2 armed 'anchor' in through the
narrow tank mouth, leave alone a 3 armed version, and
then get the prongs alinged right!!
The end result is, that should I wish to pump the tank
empty, I must flip the model over, and use the
OVERFLOW/VENT line to pump out via. And to let air in
via the RETURN line. Since the RETURN line is hooked up
the pump return on my OS SF61 via a kwikfiller, I will
have to activate the filler valve to let air in.
Complicated? Here is a crude "word" picture, that gives
the spatial relationship.
Tank top
OVERFLOW/VENT
RETURN <----------+-------------< OS SF 61 RETURN
|KWIK
CLUNK |FILLER
Tank bottom |
^
Normally
fill fuel here.
Let air in while
defuelling from
OVERFLOW/VENT with
upside down.
It is not the most elegant method for defuelling, but it
works, and I don't have to make new holes to get at the
clunk line. Having the sintered bronze clunk filter
means you can't fill via the clunk line, or all the junk
will collect inside the clunk line, and be sucked into
the engine!
I flushed the tank and all the fittings with fuel before
assembly, and checked out operation.
Getting the tank into the fuse took some nimble fingers.
I haven't got the fuse top glued in, in front of the
wing, so I can see what I am doing, but I practiced a
dummy attempt at getting the tank in place with the
plumbing in place. I found that one tube had a tendency
to slip off - I have twisted on some copper wire as a
hose clamp on a test basis, to see if it will cut
through the silicone tubing...
The tank CG is located just ahead of the model's CG,
under the wing - the idea being to install everything as
far back as I can to compensate for the nose heaviness.
This left just enough room between the tank back and
servo rail to insert the receiver in sponge vertically.
I put in the switch aft of the servos, and the charge
jack under them.
The installation is very tight, and as far back as I
could make it. The end result is that there is a big
empty 'hole' just behind the firewall, where you would
normally find the fuel tank!!
I also sealed off the last 5" of fuse bottom that I had
left open to allow access during pushrod installation.
With all this, I find the plane balances level with 2
oz. ( a 2.75" Du-bro wheel) weight on the tail. Not too
much dead weight.
Before I forget, being the second pumper I have owned
(first one? - sob! sob!!) I licked the problem of
locating the hole position for the pump lines that go
perpendicular to the backplate and the firewall, and
inside the 'ring' of the engine mount, where is no
space to see what's going on...
I simply pushed on a 1/2"length of silicone tubing onto
the pump nipple, and heavily painted the end with
correction fluid. Then placed the engine on the mount
rails, and slid it back until the silicone tubing
touched the firewall, leaving a nice round, white ring.
Drill for perfect alignment with no fuss/muss.
ajai
Mon Jun 24 17:02:52 1991
|
1244.90 | Magic 202 | HPSRAD::AJAI | | Fri Jun 28 1991 17:41 | 45 |
| Another 4 hours flew by doing some minor stuff.
I normally tack the servo rails with CA, and then put
epoxy around as a 'fillet', but with the tight
installation, I couldn't afford the space to let the
epoxy ooze. So this time, I glued the rails in with gap
filling CA. As a safety measure, I added some gussets in
the form of 1/4" triangle stock.
I also had to sand oneside of the fuse to allow the
throttle servo breathing space - the original design
fuse skin is 1/8" balsa, but I had put in some 1/16"
cross grain sheeting. I ended up sanding out some of
this sheeting in the vicinity of the throttle servo, so
I could 'rock' the servo by hand, when mounted, on its
rubber bushings.
Sanded the tail end of the fuse flush, that I had sealed
up Sunday. I also actually mounted the tail wheel assy
on, and found that the end that is supposed to be hooked
by a rubberband to the rudder bottom, interfered with
the rudder bottom, which meant that I had to put a shim
under the tail wheel bracket, and increase the
clearance. Dug out a scrap piece of 1/8" ply, and cut
and sanded it to size, then drilled it for the mounting
holes.
Then I realised that I had forgotten about routing the
antenna out the fuse. Drilled an exit hole just aft of
the wing t.e., and another in the fin l.e. to take a
hook salvaged from the T60 wreckage. The antenna hw is
the standard Du-Bro stuff.
I had noticed that the 'new' 102 servo output shaft has
a lot more slop than the 'old' 631, so I called up Jack
Albrecht at Airtronics, to confirm this. He agreed. I
had also noticed that my 72 MHz and 53 MHz radios had
Tx/Rx antennae of identical length, despite operating on
different frequencies. He again confirmed this, and said
that they tuned the loading coils in the Rx/Tx to take
this into account.
ajai
Fri Jun 28 16:38:46 1991
|
1244.91 | Engine mount drilled and tapped | HPSRAD::AJAI | | Tue Jul 02 1991 13:16 | 23 |
| These past few days haven't been too good for me - or more
specifically, the WOT4. Progress has all but virtually stalled. Better
the progress than the WOT4 in flight, me thinks :-) I have been invaded
by guests Friday, Saturday, Sunday and Monday! This evening will be no
better, since I got to write my weekly report to the 'boss'. Tomorrow
is laundry day (postponed that one too long) and I get invaded by
guests again for the July4th weekend!! Hooray! That means no more
progress for a while! Yuck.
There should be a law or sump'in' against guests, especially when I am
so close to finishing !
I did manage to stop by Charlie Watt's place for a quick half hour
drilling-tapping session with the engine mount, now that I have
determined that the plane is nose heavy, and will need tail weight!
Also, some of my guests arriving this July4th wkend, want to 'taste'
some rc flying, so I am dusting off my First Step. Putting the TX
through some charge-discharge cycles, as also the RX, for which I use a
100 Ohm resistor stuck in the battery jack overnight...
ajai
|
1244.92 | WOT4 the YF?? 205 hrs. | HPSRAD::AJAI | | Thu Jul 11 1991 18:08 | 85 |
| Last night, I got another 2 1/2 hours of work done,
including some pictures taken to record the progress
made, and to prepare the wife for how we breath life
into pieces of wood and make 'em fly :-) :-)
The visa "queue" moved again today. To put things in
perspective, 4 months ago, my wife was 8 months from
reaching the Green Card serving counter. Now, she is 7
months from reaching the head of the queue. If you
extrapolate, that means I have a 28 month wait!
I l o v e this!
ALSO, they won't let her visit me! Can you BELIEVE that?
People of the same and opposite sex COHABIT without the
benefit of marriage in this country, but legally
married, LEGALLY-AND-PERMANENTLY-RESIDING yours-truly
has to part company with his wife for years after the
FIRST month of marriage! This is sheer LUNACY!
Not only that, the TERRORISTS who are holding my wife
hostage, are getting weekly RANSOM payments through TAX
dollars.
Boston was famous for spreading the idea of NO TAXATION
WITHOUT REPRESENTATION. This is also known as negative
to an EE. After 5 years of Taxation without
representation, I think it is high time for the Indians
to hold a Boston Tea Party, and dunk the halfa**ed
politicians and bureaucrats from DC in the Boston
Harbour until they sober up, and think straight with
their heads!
The Numbskulls should take a dose of their own medicine,
split up from their wives after their first
month/day/week of marriage, and tell me if they like it.
If it is too late for them, then perform the experiment
with their kids.
I am taking active part in stirring the Injuns to riot
in Industries and Universities nationwide - serious! The
pen is mightier than the sword, and it time to put it
to work.
Bah!
Getting back to the more gentle art of aeromodelling -
specifically my WOT4 - I cleaned up my 'workbench' and
proceeded from where I had left off 2 weeks ago.
Cut off the excess bearer lengths of the engine mount.
At first, I tried my dremel tool, but finally resorted
to hand sawing. I should get one of those circular saw
blades for the tool and try again...
Then, it was time to get started on the holy cow-l.
First, I had to cut out a circular 1/16" ply plate that
goes right behind the spinner.
I rough cut the plate oversize, using a fret saw (that
you'd use for fret work, but dunno whacha call it in
'merican, but let me quit fretting over my English, or
more precisely, the lack of yours :-), then drilled a
hold in the centre and bolted it on to a mandrel - much
like the cut off wheel of a dremel tool.
Running my dremel tool at the lowest RPM, I ran some
sandpaper against it and it rounded out the disc
beeeutifully, much like turning wood on a lathe!
By holding the rotating disc at an angle against
sandpaper, I got a bevel - to match the flare of the
conical spinner! Then, cut out a smaller disc from the
inside to end up with a ring. I sanded off the burr on
the inside with the cylinderical sanding "drum" mounted
on the dremel tool. 2 more uses for the tool!
Then, I tacked on spacer ply pieces to the ring that I
tacked to the spinner back plate. Mounted spinner onto
engine. Fixed Mount to FW,and engine to mount.
Now to glue in the pieces of wood around the engine and
sand the holy cow-l to shape.
ajai
|
1244.93 | | CLOSUS::TAVARES | Stay low, keep moving | Thu Jul 11 1991 18:17 | 2 |
| Better enjoy model aeroplaneing while you can Ajai! If your wife
doesn't quench it, the kiddies will.
|
1244.94 | Build or Kill the Holy Cow-l? 205+8=213 | HPSRAD::AJAI | | Fri Jul 12 1991 14:10 | 34 |
|
Last night was a marathon 8 hour session, as I was
determinted to get the holy cow-l done. Dan Miner had
wagered that I would not be able to make the balsa holy
cow-l in the 4 hours that I claimed, and he was right!
What the hell, it was a character-building exercise at
worst!
It sounds wierd that slapping on 4 blocks of balsa
around the engine should take so long, but besides being
my first attempt at cowling an engine, I had to keep
bolting and bolting the engine and mount, constantly
checking for clearances and interference and how to
remove/insert the engine and mount as I progressed!
Also, the fact that the engine is mounted at 45 deg
below horizontal, added an interesting twist :-) Least
someone think that the cowling fits around the engine
like a glove - it does not! I have left plenty of space
around, managing t 2 sides fully, and 2 partially. Also,
the joints are sloppy compared to the rest of the plane
- I will be relying on microballoons (Goldberg Model
magic) to fill gaps...
I didn't final sand the cowl - the easiest part - as I
didn't want to run the vacuum in the wee hours of the
morning.
I estimate the entire cowl project has taken 10 hours -
some people build a few gremlins in that time :-). To be
fair I had been warned, but it was fun. What the heck.
ajai
|
1244.95 | 213+10=223 | HPSRAD::AJAI | | Tue Jul 16 1991 17:18 | 47 |
| I did the final sanding on the holy cow-ling, after
taking some pictures to record the before and after
effect of adding a cowl!
Initially, I used the Dremel tool to sand, but then
figured a sanding block would give me a better feel for
shaping the holy cow-l.
Boy! What a difference it makes! (Adding the cowl, that
is!) While the mount goes on without much manoeuvring,
the engine is inserted easiest if I remove the carb.
I also got the wing centre section filled and sanded.
Meanwhile, I was thinking of my conversation with Jack
Albrecht of Airtronics - he had mentioned routing his
antenna through the fuse, so I decided to investigate
the possibility of running a 1/8" tube. A concealed
antenna seemed intriguing, and good exercise for a
future scale project!
After contemplating running the tube to emerge on one
side of the fin, above the stab, I finally decided upon
getting it out the rear end of the fuse, at the rudder
hinge line (and route it through a hole in the rudder).
One problem with this setup, is having to deal with the
fin sitting on the stab making a "T" joint, leaving
room for little else. Drilling a hole through the
length of the bottom of the fin was too tedious, besides
weakening the structure, so I filed a beveled notch into
the "te" of the fin that disappears into the fuse.
Hardened with some CA. This helped deflect the 1/8" tube
as I pushed it in from the rear.
I failed at threading the antenna wire through the tube,
so I inserted a throttle cable, and glued one end of the
antenna to it, and pulled it through w/o problems. Then
pulled it all out, as I have yet to glue in the tail
feathers...
I am on the verge of beginning covering, but spent some
time flying my FS instead.
ajai
Tue Jul 16 16:18:14 1991
|
1244.96 | Another tip out of the Ol' Buzzard | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Tue Jul 16 1991 18:00 | 6 |
| Glider guiders route their antennas this way also. Being concerned with
tailweight, I use light, clear soda straws taped together with scotch
tape as an antenna tunnel. This also allows me to slip an inner nyrod
into the tub which I then slip the antenna end into and gently pull it
through to the tail. I like the bigger diameter for the ease of
removal/rerouting when I swap out Rx's.
|
1244.98 | plus 2 | HPSRAD::AJAI | | Wed Jul 17 1991 16:10 | 18 |
| I had sanded the wing centre section during the weekend,
but held off sanding the model magic applied to smooth
the transition from the glass cloth to the wood. Last
night, I found out that sanding the dried model magic
took a good deal of time.
Also, my WOT4 wing is held on by 3 bolts, with 2 up
front, and one at the t.e. I wanted to glue in a ply
washer at the t.e. to reduce wear and tear, and improve
support, and was wondering what to use, when it occurred
that I could utilise the cut off inner disk from the ply
ring I made for the cowl. Again, the Dremel tool came in
handy. I held it at an angle to get a 30 degree bevel,
so the covering would make a gradual transition from
glassed wing top, to washer.
ajai
Wed Jul 17 15:09:48 1991
|
1244.103 | Plus 3 | HPSRAD::AJAI | | Thu Jul 18 1991 14:40 | 23 |
| Got the wing saddle sanded to make the wing and stab parallel. It was
already very close, so I had to remove less than 1/32" of material on one
side. Didn't sand the other side, as I could see no gaps.
Incidentally, I have some Goldberg wing bolts, that have a hemispherical
head with a slot in it (pan head?). Absolutely horrible idea. Don't know how
the designer got away with that one! The slot has got chewed! Hey Jim,
didn't you get into the nylon bolts business a while ago? Where do I get
some decent 1/4" jobbies? Charlie gave me one for the t.e. bolt, but I need
longer ones (2.5") for the l.e. bolts. I'll check out the local hardware
store...
I also stuck in the wing centre fairing, that blends it with the cowl, and
sanded.
Now, all that is left is to glue in the tail feathers, and final sand before
applying Nitrocellulose dope, that's s'posed ta' make the monkeycote stick
better.
ajai
Thu Jul 18 13:40:22 1991
PS. Previous note, I forgot to insert the :-) :-)
|
1244.105 | Maybe if you drill 'em out | HPSRAD::AJAI | | Thu Jul 18 1991 17:41 | 10 |
| Talking of shearing - when my T60 ploughed into THE tree, it took off
the right wing section completely! To the right of the glass cloth
that, is!
None of the nylon bolts sheared off, and infact TOOK OUT THE HARDWOOD
BLOCKS WHICH HELD THEM! These were Great Planes original nylon bolts
At least the 2 1/2" bolts should lean back a bit :-)
ajai
|
1244.107 | ... and you may now kiss the bride :-) +4=232 | HPSRAD::AJAI | | Fri Jul 19 1991 13:13 | 47 |
| Here comes the Bride...
Jeeze - I'm getting delirious from the 1AM building
sessions. Aeromodelling can be sooo disruptive to ones'
life:-)
Last night, I got the fuse edges sanded - using the
dremel tool drum sander to attack the nasty ply in short
order. Also, final sanded the fuse and tail feathers.
Then glued in the empennage (Yahoo! I actually got to
use the darn' word!) and then inserted the 1/8" tube for
the aerial=antenna. I had to cut the end at an angle, to
ease insertion. Anchored the end in the fuse in a block,
stretching it taut, so hopefully, I won't get a rattle
induced by engine vibration!
Then I final checked the wing/stab alignment, and had to
sand the wing saddle a wee bit more. Vacuumed the fuse,
and put on the second coat of epoxy to fuel proof the
cowl/firewall, and hung up the plane.
Tonight, I get to begin covering, after painting with
Nitro dope, per the John Smith demo at CMRCM. It has
been a long 232 hours to get to the covering stage -
perhaps as much as I spent on the T60 - with the
difference being that the WOT4 is scratch built.
Last evening, as I bicycled home, the vegetarian injun
picked up some freebies - fresh vegetables from a
strangers bountiful garden - left under a sign by the
sidewalk. It is time to shamelessly extend the third
world begging bowl again - say Jimbo - do you have any
1/4" dia nylon bolts 2" long? I stopped off at two of
the local hardware stores, and could only find them in
1.5" lengths - the same kind I got from Charlie. Boy, I
never knew they carried zillions of kinds of fasteners
of every size and shape. Washers. Grub screws (= set
screws). Allen bolts. You name it! I should check it out
at leasure.
I did pick up tack cloth to pick up all the sawdust off
the model, though.
ajai
Fri Jul 19 12:12:27 1991
|
1244.108 | | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Fri Jul 19 1991 14:01 | 10 |
| Bolts:
I've got a few 1/4-20 bolts but they have the big hexagonal tops so
unless the heads are recessed into the plane they might cause too much
drag/be too unsightly. If I have some that are 2" long I'll try to
remember to bring them sunday.
BTW: If you end up going to Annapurna(sp?) in Worcester on a weeknight,
Ray's just up the road has them (that's where I got mine originally) At
a $1 for 4 nylon 4-40s I started looking elsewhere...
|
1244.112 | Building clock stops at 310 hours. +17 for the wkend | HPSRAD::AJAI | | Thu Aug 08 1991 13:26 | 57 |
|
It has been a while since I entered a note. WOT4?
What with the rain last Friday and Saturday, I was able
to work on my plane without feeling guilty about losing
weekend flying time.
Hinging all the control surfaces took 4 hours - the time
being limited by the 30 minute epoxy that I used to glue
the robart hinges! While hinging the rudder, I had
already filled up the hinge holes with epoxy using a
toothpick (great tool for this job!) and had to 'stake'
the rudder on, when the wife called from India! Gawd! I
didn't fancy redrilling all the holes, so I asked her to
call back 15 minutes later - the first time I have done
that for an internation call! - by which time the glue
would have set! I expected to get a *firing* for asking
her to call back, but I got lucky!!
I used liberal amounts of epoxy thinner to get the
excess epoxy off the control surfaces. I find it helps
to separate the surfaces after pushing them all the way
on, to give you the room to swab out the epoxy that
overflows onto the hingeline. You can then push back the
control surface on all the way.
By far, the Robart hinges HAVE to be the EASIEST I have
ever had to glue. It works grreatt, and is highly
recommended!
The rest of the 13 hours went off in installing the
pushrods, attaching the control horns, installing the
fuel tank and plumbing, installing the radio + switch
and charge harness, snaking the antenna out the rudder
and installing the engine plus spinner-prop assy. Tail
wheel assy too. Having done all of this before hand,
with the model uncovered, I had no problems.
I even remembered to put in my name, address, AMA# and a
"REWARD" note! Took a few pictures, and cleaned up the
bedroom-cum-workshop.
My first, completely scratch built RC plane (4th RC
plane to date) was all done in 310 hours. (How does that
compare with RC plane #2 - the Trainer 60 - that took
300 hours being built from a kit?)
Having got used to sleeping late - between 1 and 5:30
AM, my body rebelled at the thought of having to go to
bed at 10 PM Saturday night!
Life can at last return to normal.
ajai
Thu Aug 8 12:22:40 1991
ps. Next, the test flight.
|
1244.113 | WATT test flies WOT4 Sunday, 4th August 1991 PM. 5yrs @ DEC | HPSRAD::AJAI | | Thu Aug 08 1991 14:22 | 116 |
| It should come as no big surprise that Charlie WOTT
turned out to be the test pilot for the WOT4.
Initially, Charlie had indicated he might be out sailing
the wkend, and I had asked Steve Smith to do the
honours, being an ex-WOT4 owner and test pilot himself!
We had everything set for Saturday, but got rained out -
besides my not finishing until that night.
Sunday AM, the rain continued to pour! The RC Gods
*KNEW* I had finished my plane, didn't they!!
While the afternoon wasn't bright and sunny, the rain
cleared. I arrived at the field carrying my share of
nervous baggage that you get with a new bird.
I ran two tanks full of gas through the engine, and was
relieved to note that my 'complicated' plumbing job (see
an earlier note) *DID* deliver fuel to the engine! It
would have been awful to rip things apart to set right!
I was complimented on the covering job on the WOT4 by
just about every one who saw the plane. Apparently, the
53 hours spent on the 5 colour scheme showed enough for
all to tell. Charlie called it the Master's quality
WOT4, and even asked me to cover his SuperHots! Now,
when you consider that *everyone* asks _Charlie_ to do
the covering job for them, I felt honoured!! I still
want to get in touch with John Smith, who did the
covering demo at CMRCM, and whose recommendations I
followed, and ask him for additional pointers.
Charlie helped (as usual) with the tuning process. We
couldn't get it to run at the same mixture setting for
different throttle positions. IF the top end ran fine,
then the mid range was rich. The engine would finally
drown and quit. We finally decided to proceed with a
cantankerous engine.
The first 3 take-offs had to be aborted as the engine
quit with the WOT4 clearing the far side of the field at
3' altitude, and coming down in the tall grass.
I was a bundle of nerves and glad that Charlie was there
to deal with that FIRST flight for me. Finally, we got
it up.
The plane is a rocket ship, said Charlie, needing just a
touch of up-trim to fly hands off. He did a few rolls
and split-S's before declaring the airframe airworthy. I
got to fly 4 minutes, before handing back the TX for a
landing. The engine died prior to touch down.
The light breeze made for ideal test flying conditions.
After more fussing with the engine, I took it up myself.
The exponential rates on the ailerons made the plane
touchy, so I changed that back to linear rate.
It seems to take a lot more elevator to do a loop -
compared to the flat bottom trainer I have been used to
flying. Also, it moves extremely fast compared to my
First Step - even at 1/4 throttle! I made a few passes,
coming lower each time, yet scared to leave the engine
idling too long, before finally landing. I did try
hovering - it behaves just like the FS! The engine again
quit on finals, but the landing was not too bad.
On a subsequent flight, the engine quit while I was
downwind. Not being used to the glide characteristics of
the WOT4, I decided to land downwind. The plane flew the
entire length of the field, and finally settled atop a
pricker brush! I had to use a machette and a friend to
hoist me (leg lift) to retrieve the plane.
My FS has always emerged unscathed from such encounters,
but I suppose the extra speed of the WOT4 made for
greater energy to be dissipated. The covering over the
l.e. was nicked at a few places, and some balsa
splinters showed through! Luckily, the damage was
limited to single colours of monokote, and did not cross
a multi colour boundary, which take a lot more time to
fix. (I nicked the rudder twice with the cut-off wheel
on my dremel tool, while cutting the excess lengths of
the control horn bolts! Had to patch!)
The plane an covering was no longer a virgin, or
pristine! I could now breath easy. Like the first needle
prick of an injection, nothing bothers you as much as
the first ding in the plane. The rest raise nary an
eyebrow.
I had one more flight, and returned home with some minor
cosmetic repairs. All landings have been deadstick so
far - I am sure I can do a better job learning landing
symmetrical wings if power assist was available to let
me go around for a better approach, instead of having to
get it right on the one and only chance I get to land
per flight with a balky engine!
Then again, I shouldn't be flying with an unreliable
engine.
ajai
Thu Aug 8 13:06:35 1991
ps. My thanks goes out to Eric Henderson for introducing the
WOT4 to the Boston crowd, with Jim Cavanagh and Steve
Smith being the others who have built it locally.
I also wish to thank Steve Smith (and Charlie Watt?) for
having traced out the parts, from which I could scratch
build the plane.
And last, but not the least, another thanks to Charlie
for giving freely of his time and tools while building
the plane, and again as test pilot.
|
1244.114 | Loaner 'suction' carb infuses fun into flying the WOT4 | HPSRAD::AJAI | | Fri Aug 09 1991 18:17 | 117 |
|
Well, everyday I have been flying since last Sunday, my
engine has been giving me trouble - and every single
landing I have done has been dead stick!
A couple of evenings ago, Edward Prentice approached me
at the flying field - he was a read-only noter from DEC,
though I new see a few postings from him today - and
having followed nearly a year's worth of notes on the
WOT4, he was familiar with the plane! Barely 5 minutes
after we had met, when I mentioned my engine problems,
he said he had a OS SF 61 non-pumper version, and
offered to loan me his brand new carb - which is the
suction (standard) variety!
He is building a T60, and will not need the carb for a
couple of months, so I was free to borrow it! I was
flabbergasted at how quickly things had proceeded given
that we were relative strangers! As Al Casey has often
remarked, this notes file has made friends for all of us
without a face-to-face meeting!
That evening, I followed Ed home, and borrowed not only
the carb, but also the stock OS muffler (I have a
snuffler) ! Ed showed me the wings he had finished for
the Trainer 60. From my experiences with aileron flutter
on that plane, I recommended that he install two servos
- one per aileron - and save himself future grief. His
current progress on the wings have not eliminated that
possibility with minimal work.
I tried the muffler at the field last night, not really
expecting it do anything for me. As expected, it did
not. Earlier, I had tried bypassing my qwik-filler with
a brass tube, just in case it was restricting the pump
return, and making my engine run rich/hard to adjust.
That failed to produce results.
I also called up OS to get advice, but learnt nothing I
did not already know. It seems like they have some
clowns up there, who don't listen to you carefully. Even
after telling their expert I had a 61 pumper, I was told
to use a tachometer as it is hard to tell the rpm on
4-strokes. Moron! The 61 is a 2-stroke, dummy! He
corrected himself, but the conversation was infructuous.
At any rate, last night, I spent 2 hours removing the
engine and tank, swapping carbs, bypassing the pump, and
replumbing for a muffler-pressurised-tank suction-fed
carburettor - without drilling any new holes, and
retaining the kwik-filler. Here is what I did.
The clunk is hooked up to the carb via the original hole
in the firewall. The pressure line from the muffler is
hooked up to the overflow line that enters the fuse via
the hole in the fuse-bottom. The 'pump return' on the
tank is hooked up the kwikfiller, with the other nipple
on the filler being blocked off (silicone tube with knot
in it :-)
I also had to do some minor cleaning up, and make a new
throttle 'wire' from 1/16" music wire, which is
relatively slop-free compared to cable.
Anyhow, coming to the meat - or as I would prefer,
vegetable - of it... I flew lunch time today with nary a
problem. My initial setting on the needle valve of 2 1/2
turns proved to be too rich, but I didn't have to fiddle
with the idle-mixture screw. Suddenly, my 61 was infused
with the reliability of my 46.
The ability to use the throttle meant I had to thaw my
left thumb! But the dependable engine instantly lowered
my average flight cieling. I did my first "powered"
landing, as also a few T&Gs. At last, I am having FUN
with this plane!
I tried some knife edges at elevation, as also slow
flight and hover. The plane seems *MUCH* easier to land
with power, than without, which is just the opposite of
my experience with the FS. On my last flight, I tried
some inverted hover, and the engine quit, and I landed
downwind, dumping my plane in the mowed grass at the end
of the field!
Last night, I spent nearly an hour looking for Jim
Reith's downed Gremlin. I was flying my WOT4 when it
went down, so I didn't see it disappear. I hope he has
found it.
Fun and games this weekend will have to wait, as I am
doing a 200 mile bicycle ride for charity - for my 5th
consequitive year.
I also flew an LTA gremlin last night - smooooth plane!
I *DREAD* the thought of building so soon, but given
that it will be non-WOT4-quality, and given I need to
salvage my flying season while in India for September,
the weary elves will back at work at North pole.
ajai
Fri Aug 9 17:07:19 1991
ps. My public, and heartfelt thanks to Ed Prentice for the
loaner carb. At least, I can get some hassle free flying
in before my trip. I plan to send my engine while I am
away to OS fwiw [zero cost, no down time], but if they
don't fix the problem, I'll tinker with the pressure
adjustment screw on the pump.
ps2. The pumper puts out oodles more power than the suction
carb!!
ps3. I have about 5 hours of air-time now...
ps4. I keep forgetting to take a fresh jug of fuel every
other trip to the field. This thing is a guzzler!
|
1244.115 | Minor mods, and the plane is getting more fun to fly! | HPSRAD::AJAI | | Wed Aug 14 1991 19:59 | 53 |
| I got to the flying field after some minor work on the
WOT4 this morning, after a 192 mile bicycle ride
fundraising this weekend put a dent in my flying
calendar, making me miss the fun-fly.
Per Eric's recommendation, I installed 3" Du-Bro wheels
instead of the Sullivan Skylite 2.5" jobbies, that used
to make my plane bounce on landings like a scalded
beast! I pulled these fresh off the T60 wreckage from 2
years ago, that I disinterred last night. One of the
tires had come off the rim in the impact, so I had the
challenging job of putting it back on!
I also re shrunk the covering over the fuse between the
wing and empennage, as also on one elevator. I got to
find out what I did wrong, since the monokote on the
rest of the plane hasn't bubbled from storing in a hot
car!
Using a 'chicken stick' on my prop, I had scoured the
cowl. Re-heating the affected Monokote made the 'scar'
disappear. The engine backfire on occassion, and I need
to find out a way to start the engine without getting my
finger whacked - maybe I should pull out my starter!
I also applied foam tape to the wing saddle. Until now,
I had not used any, confident that no fuel would make
its way from the exhaust, located below the fuse, all
the way to the top! I found out that the monokote on the
fuse saddle, and the monokote on the wing that it came
in contact with, had melted from the heat created by
friction + vibration!
I got in another hour of flying time today, with the
engine continuing to be a pussy cat - or should I say
Pissy cat? Ever since I changed to the pressure fed
suction carb, the fuel in the tank gets all black and
cruddy, though it works just fine! Is absolutely clean
with the [currently bypassed] pump though!
The wheels made a difference to my landings, and I did
about a dozen T&Gs. I find I can land the plane *real*
slow, at near FS speeds, using a lot of up elevator,
finally touching down when I run out of up elevator!
I am still getting comfortable with the plane, flying it
much lower given the reliable engine, but the 'bonding'
process is far from complete.
Man and machine have yet to become one.
ajai
Wed Aug 14 18:56:07 1991
|
1244.116 | Check Muffler | LEDS::WATT | | Thu Aug 15 1991 10:06 | 9 |
| Ajai,
The gunk in your tank is comming from the pressure tap on the
muffler. It probably means you have something wearing in either in the
muffler or in the engine itself. Check the muffler for loose parts.
You could add a filter in the pressure line. I've done this on my
4-strokers because I get carbon in the fuel from the muffler.
Charlie
|
1244.117 | International Gremlin, and a report on the OS 61 pumper | HPSRAD::AJAI | | Wed Nov 06 1991 13:17 | 143 |
| Well, after my recent trip to India to see the wife, and
leaving her teary-eyed and distraught when I hopped on
the plane back, and suffering the intense separation
depression that comes as a consequence right after I got
back, it is time to get back on the [elusive] RC notes
saddle and make life worth living...
I did take my Gremlin to India and try to fly it there.
A local test hop a few days before I left the US,
resulted in a vicious death spiral from 3 trees high.
Surprisingly enough, my OS SF 46, that has over 100
hours of air time on it, survived, merely needing
disassembly to remove the dirt from the corn field where
it landed. The severity of the crash will become
poignant if you see the hub of the Graupner prop that
remained. 30% of the hub is missing! Inspite of a 2 1/2"
spinner!! Caramba!
Moving the CG forward for the 2nd flight in India, was
the only change I made. That flight too lasted 3
circuits of the field, and crashed in similar fashion,
so I decided to seek out the Boston Gurus, and brought
back the wing - which now has over 20,000 miles on it!
Thanks to vacuum bagging technology supplied by Dan
Miner Composite Materials, Inc., the wing basically
survived, save a few 'wrinkles' on the surface and a
broken pine l.e. section that I didn't fix.
Now that the same plane is flying like a pussy cat
thanks to Charlie Watt playing test pilot, I can only
conclude that the high rate ailerons were too much for
me to handle.
OOh! Well, besides feeling stupid and embarassed at not
having been able to fly a perfectly flyable plane while
in India, and transporting it around the world, there
were some lessons learnt, including the fact that the
Gremlin is, when vacuum bagged, the ultimate
transportable RC plane. People even put their hand
baggage on it (when I had fallen asleep, and didn't
notice until I disembarked from the plane) and it was
none the worse from the experience!
What's all this Gremlin talk doin' in a WOT4 note? Let's
make this post legal by writing about what I had
intended to initially...
Remember my OS 61SF ABC pumper was plagued with problems
- ran too rich in the mid-range, and would sputter and
die? As a consequence, all of my landings with the WOT4
for the first week were dead stick, until I put in the
suction carb!
Well, I sent it back to OS, with a looooong, 2 page
letter, telling them that I had bought a 61 SF RINGED
pumper 2+ years ago [now lost in the T60 tragedy] with
which I had no problems ... repeat customer ... others
with similar pumped 61s could not adjust it right ...
combined RC experience over 50 years for all those who
got their hands on the engine and gave adjusting it a
shot ... engine runs just find with a suction carb,
bypassing pump ... don't hesitate to spent top $$, but
expect merchandise to deliver advertised performance,
... test the engine out as mounted 45 deg below
horizontal in WOT4 ... used 12% Red Max ... etc.. etc..
I got it back from OS in 2 weeks. The clowns didn't pack
it right - they had left the needle + carb on, making it
susceptible to bending during transit, but luckily, that
didn't happen. In an enclosed letter/invoice, they
mention - "Technician ran engine under normal operating
conditions, and could not find any problems. Engine
tached at 11,200 RPM and 2,600 RPM with a 12x7 prop".
Labour $10. Waived as a service to the customer.
[Morons! The engine is under a 2 year warranty]!
Drat. So they didn't touch the engine, huh? I was
getting frustrated, when I decided to check out the 2
fuel pump pressure adjustment screws on the back of the
engine. There was evidence of tampering :
1. Brass screw slots had burrs from their having to break
it loose from the paint sealing the threads.
2. Original OS paint dab to seal/lock the screws occupied
just a quadrant. Now, the ENTIRE screw top had paint on
it.
3. Paint at periphery of recessed brass screws had bubbled.
Original was bubble free...
In retrospect, I should have xeroxed the pump on my
engine before sending it off - a thought that had
occurred, but been forgotten. That way, I could have
PRIMARY evidence to compare against, instead of sifting
through the clues...
Anyhow, clearly, they had changed the pressure settings
- something I could not do myself for fear of voiding
the warranty - SO IT WAS WORTH MY WHILE TO TRY RUNNING
THE ENGINE.
I mounted it on my WOT4, with original plumbing and
clunk filtered tank - the works. I had to redo some of
the plumbing that had been changed to accomodate the
suction carb that Ed Prentice had been kind enough to
lend me. As our CMRCM field is closed for the hunting
season, I took the plane out to the parking lot for the
engine check.
I had a 11x8 prop on it, and it started up without a
fuss. Idling was OK for short durations, but the engine
would quit when I opened up after idling for a while.
Darn! Same ole problem again? I leaned out the low end a
bit.
Second run. Idle to wide open response good. So, decided
to run the engine at 1/3rd throttle for a while. A
minute later, the engine quit. Damn! Maybe they didn't
really fix it? It pissed out some fuel from the near
inverted (45deg) carb. I leaned out the low end again.
Third run. Idled great! Top end, I got 2 horses pullin'
my WOT4, so I got to lean back and hang on!! I get
instantenous response from idle to wide open. Idle for 5
minutes. Opens up thereafter without missing a beat! Ran
at different intermediate throttle settings for extended
periods. Eureka! It works!
And thereby ends yet another tale of mystery in this
ever perplexing hobby of ours...
ajai
Wed Nov 6 13:07:01 1991
ps. Actual flight testing of WOT4 with readjusted OS 61
will have to wait until I can free up my Championship
radio from the Gremlin's tentacles. The CS7P radio has
elevon mixing, that I will now have to hardwire into my
VG4R as a dedicated Gremlin radio.
ps2. Dunno why, but it seems like OS doesn't want to admit
to having fixed a problem - in writing.
|
1244.122 | WOT4 tours the WRAM show | HPSRAD::AJAI | | Tue Feb 25 1992 16:22 | 157 |
| <<< CSVM14::SYS$SYSDEVICE:[NOTES$LIBRARY]DECRCM.NOTE;2 >>>
-< Welcome to the High Tech Air Force conference >-
================================================================================
Note 172.75 WRAM SHOW '92. 75 of 75
HPSRAD::AJAI 150 lines 25-FEB-1992 16:06
-< WRAM 92 - another example of Americans doing things in a big way >-
--------------------------------------------------------------------------------
The WRAM show was simply fantastic, and re-affirmed my
faith in these United States being choice numero uno for
aeromodellers the world over. The amount and variety of
stuff on display was simply incredible. Not only did I
get to SEE all the great stuff but could also BUY some
of it - something that I would not have been able to
even see in India!! As the guy running the Major Decals
booth was telling me, "We Americans don't know what we
got!"
I got to White Plains at 1 AM Saturday, and stayed with
a friend from IBM country, to shake off his blues, renew
mafia ties, catch up on happenings, and reminisce on key
events from our undergraduate school days.
Despite going to bed at 4 AM, I was up at 8, and drove
down to the WRAM show just 4 miles away by 9. Just 2
days prior to the show, I had seen their ad in MA, and
realised they had a static contest, so I decided to take
my WOT4 along to bring some third-world representation
from the sub-continent.
We were asked to fill out some forms, and display the
plane in the appropriate area. Even at 9 AM, I couldn't
find enough space in the sport aircraft section, and
squeezed in the WOT4 at the back end of the display
section. The chopper/gliders/old-timers sections were
reletively unoccupied, but the organisers said no
rearranging until all the models come in. I left to
check out the booths by 10, when they opened.
I was going on adrenalin until 6 PM when they closed.
Lots of people were present in the morning, and the expo
floor - a basket ball court? - was jam packed, with
people breathing down your neck! Talk of tropical
weather! The Westchester County Community Centre where
the WRAM show is held, is a showpiece for IBM's wealth
having permeated the White Plains area.
Primarily, my goal was to see what the WRAM show is all
about, being my first time. I did not intend to buy rc
goodies, since I want to fly my WOT4 this year, and not
spend more time building planes. Notwithstanding all
this, I managed to part with $350, readily succumbing to
the capitalist's gentle art of persuasion and thought
control :). I was proud to do my bit for the slumping
economy.
My purchases were mostly odds and ends - micro servos
for the PREDATOR, a 250 MAH battery pack, long drill
bits from Mr. Harry Higley himself, locknut washer
substitutes for my 61 and 46 so the prop doesn't fly
off, #11 blades, decals, shrink wrap tubing in case I
decide to make my own batteries, dremel router bits at
$0.50 a pop (normally go for $7), catalogs and brochures
that some demanded payment for, nylon bolts for the
Gremlin, 1/64" birch ply going for $0.20 for a 4"x6"
piece, a Higley book, some chuck (hand launch) gliders
to remind me of my humble beginnings in this hobby when
I was 8, Graupner props, the infamous tube of PFM, AMA
patches. I also got all the freebie mags. the M.A.N.
stand seemed to be a dumping ground. Every hour, they
were changing the issue they had for grabs, and by the
end of the day, I had picked up nearly 6 back issues!
The Zap stand wanted $7 for a 2 oz. bottle, and was more
expensive than Tower, so I held out. He didn't give me
any freebies like y'all, either.
I completely forgot that the WRAM is a show case for the
RC industry, and that I should be looking for
not-yet-in-the-stores-or-ads items here. Instead, I was
more a kid in a candy store. I did see that Heli
simulator demo running on the PC, but didn't have the
courage to expose my non-existant heli skills in public!
Finally, when I spotted a fixed wing simulator in a
lower level stall, I asked for the TX box. The guy
pointed to a sign that said "$1/minute". Even my gas
guzzling WOT4 doesn't cost me that much to fly, so I
moved on. This guy should be running a video games
parlour, not a WRAM demo stall.
I did spend time at different stalls listening to the
sales pitch. Wrt NiCds, it seems the best approach is to
purchase your own individual cells, a connector, some
shrink wrap, and solder 'em together. I also
contemplated on replacing the 600 mAH pack on my WOT4
with a 1000 mAH pack that seemed only slightly
bigger/heavier, to give me a greater safety margin, but
I didn't yield to lucifer's wishes to acquire more
material wealth.
Sunday, 23rd Feb, I stopped in at 3 PM to pick up my
plane, and also witnessed the awards ceremony. Kay
Fisher won third place in the Glider category with his
superbly finished HLG. I was the first HTA to
congratulate him as he stepped of the stage, but he
lamented "Coming Third - that is the story of my life!"
Mine too. I am a third-worlder. :)
The competition among the scale aircraft was stiffer -
there were far more entries in this category than any
other. The best of show went to a twin engined aircraft
- darned if I remember the name - but I talked to the
owner who had spent 4000 hours building it, in 18
months. He is retired, and worked on it full time, he
said. My 310 hour WOT4 is like a gremlin in comparison!
It was awesome, and I knew it would win hands down. He
knows Charlie Nelson and Jack Buckley, and asked me to
look him up at the qualifiers at Orange.
Among the Pattern aircraft, there was a Karl mumble who
entered two aircraft with multicoloured paint jobs. Both
had a glass smooth, killer finish (multi-color) and
looks. I don't know if he used DuPont's killer Imron
paint :), but this guy knew his building, and I promptly
added him to my list of RC gurus/hall of fame, to seek
his guidance when opportunity next permitted. Not
surprisingly, he got the first place in the Pattern
category.
Oh! Yes, there were boats and boats and boats. Many
scale jobs, that reminded me of model railroad dioramas,
except that these floated in water! I also saw
mega-whomper RC cars, powered by what looked like
quadra's to the untrained eye. I examined and played
with an exposed suspension and learnt a few tricks that
might come in handy with a/c l/gs.
There was a bipe with a 'flame job' in monokote. Another
with a speckled paint finish. Amazing what people come
up with! I also learnt a thing or two about displaying
planes - you got to use a tripod; Some people had
write-ups on their creations, stuck on foamcore. One
car dude had a flashing bike light to attract the
crowd's attention, while another played music from a
radio!
I left regretting not having discovered the WRAM earlier
- for I have always been within 200 miles of it all my 7
years in the US of A. Next year, I'll be back with
vengeance. And more money to spend. And yes, most of the
items didn't seem cheaper than mail order, but it was a
lot of fun spending with thousands to give you company.
ajai
Tue Feb 25 16:12:52 1992
Sorry to hear about the Connecticut toll ya had to pay,
Jim. I always figured ya wuz safe in a crowd, but now I
know better.
|