Conference vmszoo::rc

>                      <<< Note 1113.57 by 7983::WALTER >>>
>                     -< Airfoil for hand launch gliders? >-
...
>I'm interested in building a handlaunch glider so I can fly it around the
>chopper pad here in front of MRO at lunchtime. I tried to order a Gnome from
>Hobby Shack, but they have none in stock. I don't know of any other good HLGs,
>so I started thinking about building my own.
>
>The first question that came to mind is what airfoils are proven to be good
>for handlauch gliders? I'm assuming a wingspan in the 60" range, with total
>wing area around 300-400 sq.in. That gives a chord around 6"-7". I would
>build it pretty light, going for light wing loading, and use a built up wing.
>
>Any suggestions?

Sounds great Dave.  The AMA definition of HLG is 1.5 meters or less which
comes out to 59.005 inches so that is why you see a lot of 59" span HLGs.

I am working on a Chuperosa that I got from NorthEast Sailplane Products.
They are at 16 Kirby Lane, Williston, Vermont 05495 phone (802)658-9482
for what it's worth.  Their $3.00 catalogue is worth every penny.

The Chuperosa is a balsa fuselage with the half aft of the wing an open
structure (sounds weak but it is strong) and the wings are foam core
and come in 1 of 4 configurations.  Straight with ailerons or polyhedral.
E214 or S4061.  I ordered S4061 but after several weeks of waiting because
of order screw ups I changed the order for a E214.  I had mixed feelings
about the S4061 because deep in my heart I wanted a floater and would
gladly trade off the speed range.  I also got a flyer from Hobby Shack
and they advertise this same Culpepper Models kit.

Since I haven't completed it yet I can't say anything positive about it
but the kit is a joy to put together - great wood and different enough
to be really interesting.  I also want to fly it in our parking lot in
Littleton (after I get proficient at a more remote site).

I was just reading Dave Thornburg's book and he solders his antenna to
the rudder cable to save weight.  He also advocates only building the fuselage
large enough to hold the servos in line.  

I also hope this will be a good plane for modest slopes so perhaps we
can spend a Saturday or Sunday at Bose Mountain?

Now since were in notes - could a moderator move (or copy) these notes
to a (New?) base note for R/C HLGs.  It would be instructive if someone
could compile a list of all the HLG kits.  I don't think you should
design your own because there are several that have good reputations
and they are all real cheap.  My Chuperosa is $40 and for a HLG that
is almost the upper price limit - the exception being the Dodgson HLG.
The real cost in HLGs is the fact that you probably need to purchase a
new battery pack (read smaller (read $32.95 from SR batteries)) and new
micro servos (read $33 each for S133s from Futaba).  If someone finally
sells a new dual conversion micro receiver that will set us back another
$70.  In that light the $40 for a kit is peanuts - as opposed to peanut
scale :-)

Help - one of the magazines (Model Builder or RCM or Model Aviation) had
a construction article on the Chuperosa a few months (or a year) back.
Anybody know what one so I can dig up the article.  I'm sure I have it but
I don't know where to start looking.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
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>          <<< Note 399.336 by 8713::TAVARES "Stay Low, Keep Moving" >>>
>                              -< Schweitzer I-34 >-
...
>I have a Sagitta 600 in the box and I could be persuaded to part
>with it...I'm really tickled to get the Schweitzer.

I'm tempted - if for no other reason than I would like to try again 
and see if I couldn't build it lighter.  At 42+ oz mine is a lead sled.
But alas I have way too many kits in progress and no signs of light at
the end of the tunnel.  

Speaking of weight - I finally balanced and flew my Chuperosa.
It comes in at 18 oz.  Wow - I thought - that's great - then I read
the construction article (published in Jan 1988 RCM (which I lost))
and the proto came in at 18 oz also but the author explained that
was because of a full size receiver and he build 3 others ranging
from 13.5 to 15 oz.  WOW!  I am using a full size receiver but I have
a 350 ma battery pack (in the nose plus I still needed a few little
chunks of lead so the battery weight is sorta free) and Futaba S133
micro servos.  About the only thing I could do is cut out the nyrod guide
tube that holds the antenna and save a fraction of an ounce in the tail.
But...The kit has foam sheeted wings and the scratch built ones had built
up wings - suppose he saved all the weight there.

Anyway - I have a few Chuperosa questions.  I'm running an E214 with
ailerons and fixed mechanical aileron/rudder coupling.  I don't
like the way it turns.  Can't really put my finger on it but if it is flying
fast it seems to turn pretty good but when flying modest to slow I have to
add lots of up elevator to stop from dropping down in the turn.  This slows
it up instantly.  

I was in one nice turn and accidentally had my aileron dual rate on (at 50%
normal throw) and when I went to flatten out the turn and go straight it
just didn't want to come out.  I was getting close to the ground and just
got the wings level in time - holding full right stick.  I disabled my
dual rates as soon as I landed. 

I haven't had it on the high start yet (maybe at lunch today if it don't
rain) but had an hours worth of hand launches.  It stalls REAL good - takes
allot of altitude to recover.

Comments?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    re .339
    
    Sounds like nothing more than a consequence of using the E214 on
    a small wing operating at low Renolds #. I think that may be why
    they offer the S4061 as an option.
    
    Terry
    

>         <<< Note 399.340 by ELMAGO::TTOMBAUGH "High Plains Drifter" >>>
>                   -< With all due apologies to Dodgson... >-
>
>    re .339
>    
>    Sounds like nothing more than a consequence of using the E214 on
>    a small wing operating at low Renolds #. I think that may be why
>    they offer the S4061 as an option.
>    
>    Terry

I thought it was fixed non-adjustable aileron/rudder coupling.  
It doesn't tip stall - even tho I have brought it to the ground
at a high bank angle at or near stall - enough to cartwheel.

Also I won't swear how true my E214 is because it is sheeted foam
and my first attempt.  I had some of the lower surface list from
the foam (because I scraped too much epoxy off before bagging) and
I poked pin holes in it and UFOed it back down.  Also I have a ton
of wood grain showing despite two coats of Balsa Filler.

Besides you can't get off that easy Terry - even if it is a consequence of
the E214 on a small wing at low speed - I need to either learn to adjust
my flying technique for it or change the characteristics.  I think I am
willing to add another servo for individual rudder control or perhaps
get a second wing that doesn't have ailerons?

I wish I had a sunny afternoon today and the three other wings to experiment
with (E214 with poly, S4061 with ailerons, S4061 with poly) and another
fuselage with a separate rudder servo.

So think about this - suppose that the ratio of Aileron/Rudder coupling is
wrong.  I can't just dial this into my Vision and experiment - I have to
create a new servo horn.  So how can I determine which direction I should
change the coupling?  It is easiest to add more or less rudder - very
hard to change the amount of aileron throw.  

Speaking of Aileron differential - WOW - I have lots.  Because of the
klutzy way I hinged the ailerons I have lots of up aileron and very very
little (almost no) down aileron.  Perhaps this is the key to the problem
of loosing speed in the turns - the ailerons are really spoilerons.

To fix this I will have to rip them off and re-hinge and re-paint.
Well - at least that would give me another chance to fill my balsa grain :-)
But... Even tho they are functionally spoilerons once into a turn I neutralize
them and just hold up elevator so they shouldn't be two inefficient.

Thoughts?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################
    

    Aha! A possible culprit emerges. If you have a lot of up aileron,
    I'd start right there, and reduce it. I went through the same drill
    a month ago while sorting out my Vibaro. I was intially very careful
    to have about a 4:1 differential to avoid adverse yaw and that good
    stuff, but the inbd. wing would always drop excessively at turn
    initiation, and then would sort of yaw around and be generally sloppy
    when I corrected. Since I was using the Vision, it was simple to
    start dialing back on the up aileron throw until it was about 50%
    differential and 45% travel volume. This smoothed things out nicely.
    Also I've found that switching to low rate on the ailerons, presently
    at 50%, when thermaling while keeping the rudder at 100%, makes
    things even smoother with adequate control, although I always switch
    back to 100% for low altitude work.
    
    The moral of this story seems to be that less differential is better,
    travel volume can be moderate, and have plenty of rudder.
    
    I'll be starting on the Orbiter soon, and will be using mech. coupled
    rudder/ailerons. I'll look in the construction manual, and enter
    any info that bears on this subject. He's using S4061.
    
    Terry
    

    
    
    
         Hi Kay
    Al mentioned you are flying a Chuperosa. I built mine last fall and
    flew as many times as possible during the winter. I built mine using
    the S4061 and I added a little dihedral. My previous ship was a 
    Gnome and it had a lot of polyhedral maybe a little too much. Too
    much can cause ballooning on turn reversal. The Chup looked like it
    needed a little more to be able turn briskly. At any rate with a bit
    more (about an inch total added at the center) than stock this craft
    turns very nicely with neutral reversals. I don't know very much
    about airlerons on the Chup except that dihedral is generally at odds
    with airleron coordination. That is the adverse yaw created by
    airlerons is perceived by the wings as rudder input . Unfortunately
    it is opposite to the desired turn direction. As I see it with an
    airleron wing the only dihedral necessary is that needed to create
    a slight groove to keep pilot fatigue at a minumum in turbulent air.
        I am so pleased with the Chuperosa it would be hard to imagine
    it turning any better. Many times I have been able save it from as
    little as 20 feet and get it back up on high. Under some conditions
    it can have a nasty stall probably because the stab stalls too and
    this increases the time it takes to get the nose headed down.
           Got to run now but will chat some more later.
                                        Terry Sweeney
                           
    

    The aileron version of the Chuperosa has cables from the ailerons
    attached to a servo in the fuselage.  My landings are sometimes
    sufficiently violent to separate a wing from the fuselage, and that
    would seem to have implications regarding the longevity of the servos.

    What is the experience/precautions amongst aileron Chuperosa owners?

    I think I have a bug in my Chuperosa directions/prints/kit.

    The instruction supplement refers in wing step #8 to an improvement in
    the size of the core beds and an additional trimming step.  I followed 
    those instructions to the letter.  After bagging the wings I measured
    the wings, cores, beds, and *prints*.  It seems I received the new
    instructions with the old beds and cores; I should not have trimmed off
    1/4 inch from the trailing edge.  I now believe I will have a wing that
    differs in chord from the prints by that 1/4 inch; I anticipate having 
    to modify the wing saddle accordingly.

    Question #1:  Should I care?  Does it matter? (I'm not a good pilot.)

    Question #2:  Is this really a bug or did I misread things?  Is it also
    true for others?  [It seems to be true for another modeler in Merrimack.]

        The prints show a wing root chord of 8 1/8th inches consisting of a
        quarter inch of wooden leading edge, a 7 5/8ths core, and a quarter
        inch of foam-less trailing edge.  But the beds are 7 5/8ths and the
        core was dutifully cut off a quarter inch shy of that.

    re.80, 81
    
    If you mount a micro servo in the wing center section, upside down,
    all the linkage remains intact if (when) the wing flies off in a
    hard landing. One of the beauties of the Chup wing hold down design
    is that the wing can skew or pop off without damaging anything.
    I havn't built my aileron wings yet (just cut the cores) but will
    use the self contained method as the plane has come through from
    many wing bolt snapping landings unscathed, and I don't want to
    give up that capability.
    
    The completed wing root chord of a Chup should be 8", that was the
    original design. I noticed my plan dimensions were a little off
    too. Losing ~ 1/4" of chord won't kill you, but it's simple to cut
    the sheeting 1/4" wider to make it up. Sandwich a strip of glass
    cloth between the sheets before bagging, to recover any lost stiffness.
    
    If the cores and beds were the same chord dimension before trimming,
    then you've got the latest kit version.
    
    Terry

>   <<< Note 124.80 by ABACUS::RYDER "perpetually the bewildered beginner" >>>
>                       -< aileron Chup linkage question >-
>
>    The aileron version of the Chuperosa has cables from the ailerons
>    attached to a servo in the fuselage.  My landings are sometimes
>    sufficiently violent to separate a wing from the fuselage, and that
>    would seem to have implications regarding the longevity of the servos.
>
>    What is the experience/precautions amongst aileron Chuperosa owners?

I have sheared my wing off several times.  Once I cracked the plastic
servo horn - but haven't hurt the servo yet.  I'm using stock Futaba
S133 micro servos.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    Steve Young, Dick Easton, and I flew at Merrimack this noon with two
    planes between us.  Both planes crashed.

    Steve, a beginner, had his Electra and Dick, who is an instructor,  was
    flying it when he lost it behind the trees.  After a long search we
    found it high in a tree a quarter of a mile away at the river landing. 
    Last seen, it was still up there, intact and untouchable.

    I put my new Chuperosa into the trees near the river.  The damage was
    impressively minimal.  The wing had hit a sizable branch very hard, so
    in the leading edge I have a notch to remove.  The 8-32 Nylon wing bolt
    failed to fail, and the receiving block in the fuselage came loose
    instead.  The fuselage speared the ground from the 70 foot fall, but
    the only damage there was when the receiver took out the bulkhead just
    in front of it.  Repair won't take long; this is a *sturdy plane*!

    I had felt that the 8-32 was too strong for a wing bolt;  I will
    replace it with something smaller --- a 6-32 or 4-40.  Comments?

    Alton who hadn't put anything in the trees hard for a long time.

    I've been using a pair of nylon 4-40s on each of my planes with good
    success. Even there, the bolts were intact after I shreaded my wing at
    Biddeford last month. I think some of the problem is that the wing is
    set up to pivot and absorbs some impact. Like I mentioned to Ajai in
    the Wot4 note, I believe you need close, tight contact in order for the
    shear to happen. I think the wing twisting counteracts some of that.
    Kay seems to shear bolts periodically on his (usually when he doesn't
    have a spare with him). With a one point holddown, I think it's going
    to shear less than usual "dowel in front" designs.
    
    Is this the foam tail boom version we talked about and how much did it
    end up weighing?

>>  Is this the foam tail boom version we talked about and how much did it
>>  end up weighing?

    This is the repaired version, not the rebuilt version.  The repair
    consisted of sheeting the Warren truss on all four sides with 1/64th
    birch plywood.  The weight increased by about 0.1 oz to about 19.35
    The plywood is very stiff in its own [geometric] plane.

    I changed the way the pull-pull lines attach to the servo, adding
    relatively heavy screw eyes that are included in the new weight.

    The complete repair is strong and stiff.

    Sweeney flies my plane very well.  I'm outclassed.  In his hands, my
    Chup glides much better than his but turns less sharply.  They seem to 
    never tip stall, but stall recovery takes a long time/distance.

    I'm going to start/collect a Chuperosa note.

    The Goldenrod Kevlar pull-pull system provided 2-56 thread screw eyes
    and nuts which attached to clevises that allowed you to take up the
    slack and adjust. I found that using nylon clevises instead of the
    provided metal ones eliminated the locking nut problems (mine always
    backed off until I used the nylon clevis. A simple knot on the horn and
    the clevises at the servo moves the extra weight towards the CG (if not
    in front of it)
    
    Re: Long delay for recovery...
    
    I've only flown two Chups and they're very different. Kay's is 19oz (at
    least that's what he admits 8^) and his throws are set a lot less than
    I prefer. I found that if I got out of shape on landing (making that
    "one more turn") I couldn't pick up the dropped tip quickly enough. The
    other one is about 16oz and belongs to the guy I fly in Ware with. His
    was similar to Kay's initially but I talked him into more aileron and
    it's very responsive. The only other thing I might suggest to him would
    be to put exponetial rates on the ailerons so there's a less sensitive
    band in the center. My theory on this is that the plane likes to fly
    fast and doesn't need much in the way of throws at speed. In a stalled
    condition, you need to get back up to that speed range to become
    effective again. With larger throws you're effective sooner but touchy
    at speed. The exponetial rate should give you a center band where you
    can fly without being twitchy. I personally don't feel you should be at
    full deflection unless you're in trouble otherwise you bend the sticks
    in a critical situation and it gets you nowhere.
    
    On a building note... The 1/64" ply gussets might be a stronger, light
    weight replacement for the tristock endgrain pieces we chuckled over in
    the tail boom. I may give that a try on mine (once it gets to the head
    of the queue).

    The following note may (or may not) have been lost by an old bug in the
    Notes software.  I managed to catch it, so I'm saving it before it
    might be lost forever.  If it later is a duplicate, I'll fix the mess.
    
    Alton, fighting the dragons in VAX Notes.
    
================================================================================
Note 128.15      Chuperosa, a hand launch glider from Culpepper         15 of 15
ELMAGO::TTOMBAUGH "A Fistful of Epoxy"               22 lines  25-JUL-1991 11:30
                          -< Yet more Chup comments >-
--------------------------------------------------------------------------------
    The 8-32 nylon bolt on my Chup shears fairly easily, under impacts
    which, if described, would be far less dramatic than Alton's tree
    episode. Also I've never had any aft fuselage damage. 
    The only damage its sustained has been popping the fuse side loose
    from the nose block.
    
    I tried the Goldberg pull-pull system but didn't like all the hardware,
    so went to a simpler system wherein I insert the cord into the rear
    of the clevis, metal or nylon, then jam a toothpick into the threaded
    portion, from the front, then hit it with instant CA and cut the
    excess toothpick off.
    After no problems in several planes, this technique received its
    ultimate test in the Legend crash. The rudder servo had its shaft
    sheared off flush with the top of the case as it tried to depart
    but was restrained by the pull-pull cords and metal clevises.
    The toothpick/CA joints held perfectly. 
    If you need adjustability the threaded hollow barrel type of fitting
    (can't remember what Goldberg/Dubro calls them) can receive the
    cord and CA and the clevis can then be adjusted at the threaded
    end.
    
    Terry

    This note documents the deviations from stock in my first Chuperosa. 
    There will be successors --- I like this bird.

    There are three areas of change: the empennage is pull-pull on both
    controls, the nose/bulkheads/hatch area is improved, and the wing has
    carbon fiber reinforcements at the poly breaks.  Of the three, the
    hatch changes are a clear winner, the pull-pull is moot, and the wing
    change is nil (unnecessary benefit for nil effort, but a neat trick).

    Hatch changes:

    As designed, the hatch squarely abuts the nose block. The rear of the
    hatch impedes the forward travel of the wing (or wing half when the
    wing rotates about the hold-down bolt); this impediment would seem to
    vary from kit to kit.  I was concerned that in a crash there might be
    damage to the joint between the nose block and the fuselage wall.  I
    have seen/owned/repaired several planes with structural vulnerability
    to the inertia of the wing.  [At least the Chup doesn't have a bulkhead
    distinctly sticking up in front of the wing.]  My modifications were
    intended to allow the wing a free exit without damage to the fuselage.

    The bulkhead in front of the wing was cut off below the height of the
    fuselage sides.  The curve of the wing saddle continues forward instead
    of sweeping up.  Only the hatch is in front of the wing.

    The front of the hatch rests on a ramp instead of a square abutment
    against the nose block.  To get that I did the following:  The hatch
    was built according to the plans with a square front.  I then set it in
    place on the fuselage and zapped the front one inch permanently to the
    fuselage sides and nose block.  With a razor saw I cut off this
    attached portion of the hatch at an angle of twenty degrees below the
    horizontal.  The original front of the hatch became a ramp.  

    To get self-alignment of the hatch, I glued vertical side walls to the
    inside of the hatch extending down into the fuselage a bit.  The hatch
    is held in place by a rubber band between the roof of the hatch and the
    floor of the fuselage.

    This modification works beautifully.  The wing rotates on almost every
    landing, and the hatch twists ajar.  Nothing is ever hurt.


    Pull-pull:

    As designed, the rudder control linkage is completely conventional with
    the push rod exiting the fuselage side.  Converting this to pull-pull
    was also ordinary.  I brought the lines out of the top of the fuselage
    to a mid-rudder horn pair for strength and ground clearance reasons.

    The flying stab linkage was another matter.  The kit fin is a
    lamination with a delicate push rod (cable) inside the fin.  At the
    slot for the front wire of the stab, the cable terminates in a tiny
    [electrical] connector that just fits this wire.  For my pull-pull
    change I put three pulleys into the fin and replaced this connector
    with a short piece of tiny brass tubing.  From the servo, the line
    enters the bottom of the fin inside the fuselage, turns upward around a
    pulley, does a clove hitch at the brass tube, turns downward at another
    pulley, turns forward at the last pulley, and continues to the servo. 
    The line never exits the model, although it can be seen at the slot. 
    The action is smooth and without slop.  Although it was designed to be
    easy to replace the line, there has been no damage or discombobulation
    to this assembly in the two crashes that broke off the fuselage.  This
    fin assembly, fin attachment, and pull-pull arrangement is a clear
    winner that I will duplicate on other models.

    However, I now believe that the combination of pull-pull tension and
    the design flaws of the Chuperosa fuselage rear make a bad combination. 
    Either by itself is a winner.  The Chup fuselage is very light weight,
    and the design is repeated in the new Alcyon kit from Culpepper.  This
    pull-pull is a winner.  But together they lose.  The fuselage longerons
    have "S" bends as they transition from parallel and close together at
    the fin to parallel and apart at the wing.  The bend just in front of
    the fin is a weak spot in compression; the pull-pull lines pre-compress
    it --- just waiting for a crash to over-stress the wood.  After two
    crashes that broke the fuselage in two at that point, I finally wrapped
    the area in 1/64th ply.  So much for my weight reduction efforts.  My
    next Chuperosa fuselage shall not have this delicate construction.

    Using pull-pull on both channels resulted in changes to the servo
    locations and the fuselage bulkheads.  Except where the rudder lines
    exit the fuselage, the line paths are straight shots with no need for
    guides.  I put in coffee stirrer guides at places where there might be
    contact, and I flared the ends of these guides to protect the Spectra. 

    The current servo locations are too far rearward.  Fortunately, it will
    be easy to relocate them when I have time, and that will reduce flying
    weight significantly.  At the same time, the receiver, which now wedges
    against the sides of the fuselage nose, will be moved to the rear; that
    will reduce the threat to the fuselage integrity.


    Wing reinforcement:

    The Chuperosa wing is bullet proof, even the polyhedral version that
    has no reinforcement at the polyhedral breaks.  I reinforced it anyway. 
    I put vertical carbon laminate "spars" into the breaks *after* I had
    sheeted the cores and joined the wing sections.  To do this, I laid a
    board on the bottom of the wing.  Using the board as a guide, I razor
    sawed a kerf into the poly break.  That gave me a double triangle
    shaped slot, thick at the break and tapering away at both ends.  I cut
    a matching piece of carbon laminate, smeared it with slow UFO, and
    jammed it quickly into the slot.  Poifect!  And the taper avoids a
    sudden stiffness transition.

    The center of the wing was given a conventional wrap of UFO'ed glass.

    The total weight of these reinforcements was 0.18 ounces (5 grams).

    To date, I have several times used a gorilla high start, and I have
    flown into a tree with enough force to put a thumb size crush/notch
    into the upper leading edge of the wing.  The reinforcements held.  


    Other changes, now and future:

    I made the mistake of using the 8-32 wing bolt supplied in the kit.  It
    did shear once, but when I hit the tree the mounting block tore out of
    the fuselage without damage to the Nylon bolt.  I should have used a
    [single] 6-32 bolt instead.  I'm not sure I would trust a single 4-40
    on the winch launches.

    I made the mistake of using the tow hook supplied in the kit.  It is a
    beautiful two hook --- light weight, strong, and of high quality, but I
    strongly recommend that this hook be discarded the moment the kit is
    opened.  The threads are 3-48, a bastard size around here.  Mine broke,
    and replacements are not locally available.  I switched to a 4-40 tow
    hook, but my next Chup will have a Fritz Bien hook.

    I didn't line the finger hole box with 1/64th ply as Sweeney had
    suggested.  The box now needs to be replaced.

    The fuselage tapers to the nose a bit too soon.  If I scratch build my
    next Chup to get a different rear, I may widen the forward fuselage a
    bit unless I use two 94501 servos.  The current Chup uses one 94501 and
    one S133.  The more expensive 94501 is smaller than the S133.

    Alton

    Saturday I rearranged/re-ordered the electronics in the Chup according
    to the plans.  My original order was battery, receiver, and servos; now 
    the receiver is in the rear.  The purpose of the move was to get the
    receiver out of the tight nose where it could wedge out the fuselage
    sides and to get the intrinsic CG forward to obviate some lead.

    This was a significant mistake!   The CG may have moved REARWARD; it
    certainly didn't move forward.  The free space for the battery cable
    that used to be above the receiver has now completely disappeared; the
    cable threatens to tangle in the control linkage.  It is so bad, I'm
    considering tearing it all out and restoring the old order.   Arrrgh.

    If you are building the polyhedral version of the Chuperosa, give
    serious consideration to putting the receiver forward of the servos.  

    Interesting set of mods, Al.
    
    I haven't experienced any of those problems on my Chup except the
    hatch/nose block.
    The rear fuse. seems stronger than the average HLG, to me. At any
    rate I havn't experienced any problems in that area.
    
    My stab linkage is stock, but do use pull-pull on the rudder with
    vinyl/kevlar cord, exiting under the stab.
    
    The receiver has always been furthest forward, and was a close fit
    with the Vanguard 6 chan. (only thing I had available at the time.)
    Since switching to the RCD micro, there is plenty of room, but had
    to add a touch of nose weight.
    
    My wings are stock and hold up well on winch launches, not full
    bore of course. The 8-32 bolt has always sheared faithfully, and
    often, not on  launch of course.
    
    The tow hook also sheared on mine, mysterious at the time as I was
    landing straight ahead on grass, but I think there is a basic weakness
    caused by the bend or metallurgy. I replaced mine with a small
    Airtronics hook.
    
    No problems with the finger hole, I coated the surface with CA,
    and of course the #220 sandpaper on the forward wall for max. grip
                  
    Dollar for dollar, you can't get a better HLG.
    
    Terry

>    The tow hook also sheared on mine, mysterious at the time as I was
>    landing straight ahead on grass, but I think there is a basic weakness
>    caused by the bend or metallurgy. I replaced mine with a small
>    Airtronics hook.

I broke my tow hook once after landing on Tar more than once.
I called Culpepper Models and told them and he said if it was defective
he would send me another free - I explained that it was not defective
and that I had landed on tar several times so I volunteered to
pay for a replacement.  Anyway I think I sent him a buck and he
sent me a tow hook and nut.

I have since landed on Tar several more times and may have to replace
the hook again one day - now a buck every year for tow hooks is reasonable.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

re Note 128.20    -< I vote for building stock. >-
>>  now a buck every year for tow hooks is reasonable.

    My point is made by your note, Kay.  First, it isn't the buck per year,
    it is the down time waiting for the replacement unless you stock them
    in advance.  Second, the unusual (albeit standard) thread size means
    that you cannot jury rig from the local hardware store.  Third, none of
    the local hobby shops stock Culpepper's hook, not even Tom's; Tom does
    stock [Goldberg's?] 4-40 tow hooks, and 4-40 hooks you could make from
    push rod stock if your Hi-start isn't a killer.

    I broke mine either on the launch or in the grass.  I went up on my
    [killer] Hi-start, landed on the grass, and then noticed that the hook
    was no longer there.

Alton

    I'm using the CG 4-40 tow hooks with some of those 4-40 threaded brass
    inserts in the bottom of the plane. This allows me to move my tow hook
    depending on where I balance/conditions. I did find that I like useing
    a washer/lock washer/nut on the tow hook to keep it firmly in place. It
    would be easy to replace but I haven't broken one yet. I'm using a 2-56
    pushrod end on my Gnome with a jam nut also.

Hi,

I just ordered a Chuperosa from Northeast Sailplanes.  He didn't
have any in stock and said he probably would be able to ship by
end of next week.  This will be the first aileron ship that I'll
be flying.  I'm in the process of building a Robbe ASW-19 and I
think it was foolhearty buying such an expensive ship as my first
aileron model.

Question I have concerning the Chuperosa is the airfoil.  Sal from
Northeast recommended the 7037.  After reading the Chuperosa note,
I quickly realized that no one mentions this airfoil.  Should I be
going for the E214 that you guys are using?

Thanks,

Tom Forero
dtn 352-3150

    Don't overlook the S4061 that is available on the Chup, or has been.
    
    My poly Chup uses it and I think it's superior to the E -214 on
    a small unflapped wing.
    I have a set of 7037 cores that will be built with ailerons, if
    I ever find the time.
    
    The Robbe ASW-19 could be a handfull as your first aileron ship,
    not necessarily because it has ailerons, but because it is a high
    wing loading design that is a little more prone to tip stalls
    and requires more pilot alertness to head off incipient disaster.
    The ailerons will actually be a help in keeping the wing tips up.
    
    At our last club meeting, a guy was asking what a  good aileron
    "trainer" glider would be. My best suggestion in the <$100 range
    was a Sagitta 900 built with a flat wing, a common mod. that
    isn't shown on the plans, so I'm told.
    I think there is an aileron version of the Riser 100 with ailerons
    now.
     Dollar for dollar the Chup will probably be as good as any.
    
    Terry

    Well, my reasoning is simple. The E214 was the original wing and the
    older kits came with only one choice. Seems that each year has added an
    airfoil choice. 7037 is the latest (and probably the one that they're
    currently cutting)
    
    Once I get rolling on vacuum bagging wings, I hope to make a set of
    each type and compare them. The nice thing about the Chup is that the
    servos are all in the fuselage so an extra wing doesn't tie up any
    servos. I know full well that haveing spare wings on hand will ensure
    that my fuselage will be the thing that constantly breaks.
    
    The airfoils are all in the library so new wings are just a matter of
    cutting the proper cores. I plan on making the center section bottom
    flat where the wing saddle is so I don't run into problems mating
    several different wings. As Tom T mentioned a while back, this just
    requires a piece of the core bed.

There is a review of the Chup in the latest Flying Models.  
Got my interest up.  The kit in the local hobby store shows 
a choice of two airfoils, while the article mentions 3. 

Is the Chup a good airleron trainer?  

Is it a good kit to learn how to do foam wings?    

    How good a trainer it is depends on your experience level in other
    types of RC flying. The smaller the plane, the more problems you can
    experience. This is a 1.5 meter plane. A larger aileron ship might be a
    better trainer. I'm having trouble converting a friend who's
    rudder/elevator over to flying his aileron Chup. It responds much
    faster to turn (roll) commands than he's used to and he has to level
    the wings which can be avoided in some polyhedral planes (the plane
    settles back to flat automatically). He's somewhat discouraged by his
    initial flight but I think he'll get the hang of it soon enough. The
    plane flies wonderfully and is part of the reason I'm building one for
    myself. Depends on the instructors you have available to initially trim
    it and help you get used to it. Orientation is harder on a smaller
    plane so you fly lower with altitude for fewer mistakes below you.
    
    I'll let someone else answer the wing question fully but my concerns
    are that the small wings will be more sensitive to  uneven
    balance/weight issues but are smaller and easier to handle during
    construction.

    I agree with Jim on the flying issues.
    
    The Chup wing is good for learning foam sheeting techniques because
    it is small and has a simple spar structure and trimming the sheeting
    to shape is simpler.
    It uses 1\32" sheeting rather than the more common 1\16", and this
    requires a bit of extra caution in handling.
    Mine was so untraumatic, I can't even remember actually doing it!
    But I don't think there is such a thing as a Construction Fairey,
    that sneeks in at night while you sleep, so I must have done it
    myself.
    
    Terry

    The Chup nose tapers to a point.  My receiver is located in this taper
    section, and it just barely fits.  (The crystal cover has to be removed
    to allow it.)  In a sudden stop the receiver moves forward, wedging the
    fuselage sides apart with damage to the servo rails, the nose block
    joint, etc.  This problem was hardly helped by a bulkhead in front of
    the receiver; the momentum of the receiver pushed the bulkhead, and the
    bulkhead did the wedging; I stopped replacing the bulkhead --- it
    wasn't effective.  Stiff foam didn't help either, but last night I
    solved the problem.

    I hung [in a horizontal direction] the receiver in a sling of
    fiberglass ribbon.  The ribbon is bonded to the fuse sides near the
    rear of the receiver and is a free fabric from there forward where it
    crosses from one side to the other in front of the receiver.  It works! 
    Besides the usual abuse today at the glider contest, the fuselage was
    speared into the ground twice.  [No, I was not trying to get landing
    points!]  One spear penetrated 5.5 inches, the other just enough to
    leave the plane standing on display with the wing still attached.  The
    force of the deep spear was enough to bend a stab rod.  The sling held
    and the fuselage did not split at all today.  It works because the
    force on the fuselage sides is almost all forward with almost no inward
    component.  It might fray and wear out, but it hasn't broken.

Ok gang, I have watch long enough, I sold off some planes and stuff last night,
so I have some glider money put aside.

I am going to buy a Chup unless someone can talk me out of it.

What I want, and I think the Chup will give me is:

A small, 2m or less plane that I can build with a 3 piece wing, center section
and two tip panels, full flying stab.

I want something that I can build so that when broken down into travel mode it
doesnt take up much space, hence the 3 piece wing and removeable horizontal
stab.  I would like it to be foam and glass completely but just havent brought
myself to doing it, plus I think it is harder to get light with foam and glass.
I know it can be done and think that some of the layups for wings I have been
doing have been gross overkill, I think you ought to be able to do a chup type
wing with say 1 layer of 3oz or something like that and have it be fine.

Things I'm not looking forward to on the Chup.
Monokote, I like glass better
That open structure rear part of the fuse, but so what.
Buying a micro fm receiver, I have plenty of micro servos (never give them up)
but only receiver's I have are the 8 and the 6 channel Airtronics FM's.  Serovs
will be either 133's or JR 3001's. 

any other hints you guy's can give me.  What airfoil should I get?  I'm going
to build it as a poly with rudder and elevator and use it for handlaunch/small
upstart at the football field, and to take camping and maybe some slope.
I want an airfoil that will penetrate vs higer lift.  They have wind in Utah
just like here in Colorado.

Where would be the best place to order, would someplace that carries it carry
micro recievers too?  I'm gonna need a micro reciever right and 250ma batt?

What micro reciever should I get, I like the Airtronis because of its shape, it
will match all the other airtronic stuff I have. But I wouldnt mind a RCD or
whatever, just cheap, 4 channels or more, FM or PCM, and airtronic or JR plugs.

Thanks guys...

I'm going to order it here real soon and have it shipped to my parents in Utah
and then start building once we are settled in over there.

    The Airtronics 6 ch. FM rcvr. will fit in the Chup. Flew mine
    with one before I got the RCD micro. Mount both servos in the under
    wing area to make this possible.
    
    The stock Chup poly wing is one piece, awkward for traveling, but
    simple to build, mount, and it's strong.
    Converting to a 3 piece poly would require mods to the mount method
    and adding tube and rod for the plug-ins, meaning extra weight.
    The V-dihedral with ailerons would be handier for traveling but
    requires another servo and more weight.
    
    The wing sheeting is 1/32", and adding 3 0z. cloth and using mylar
    with the paint transference method wouldn't add much weight and would
    eliminate the Monokote drill.
    
    I like the S4061 foil on mine, and have some 7037 cores that will
    someday be finished, with ailerons.
    
    Terry
    

    Consider building it as a two piece wing. Less tubing and weight and
    the tip panels aren't really all that tall off the building board.
    Building a fiberglass fuselage for it would let you justify the 2 piece
    wing by going to plug in panels. The guy I got the fuselage info from
    (871.last) thought that 4oz for an empty fuselage would be about the
    best you could do. I did my wings with 3oz cloth. I also used CF
    laminate for vertical spars. I don't think I'd do a 3oz sparless wing.
    
    I'll also put in a plug for the S3014 Predator that Dave made.
    Penetrates nice and handles well on the slope. Doesn't have the
    removable stab though.
    
    Terry, what extra servo in the aileron version? Kay (and the plans)
    have the linkage hooking up in the fuselage with ball links to the
    "rudder" servo.

    Jim,
    Ooops! you're right. And the Orbiter uses that method too, but when
    I built the Orbiter I put ail. servos in the wings, then when thinking
    about the Chup I thought I was recommending the "old" method which
    never existed in the first place and....never mind.
    
    Also I was wrong about needing to modify the bolt-on wing mount
    on a three piece wing. The dihedral in the center section wouldn't
    interfer with the bolt, because that's the way it is on the stock
    version. But, a two piece wing would interfere with the mounting bolt.
    
    Terry

I also have the Airtronics 6 channel FM receiver in my Chup.
It's tight - but fits.  This was before there were any 1991
dual conversion micro receivers available.

If the goal it to tear it down and put it in a flat travel box
then perhaps the Chup is not the way to go.  As much as I like
my Chup I don't take the wing off unless I break something
and I never remove the tail.

I haven't seen much HLG success yet but the Dodgson Pivot Plus
tears down nicely.  It is a great slope ship (according to others)
and I have seen two guys flying HLG with it.  I've got one
in the box waiting it's turn in the workshop.

Consider the Predator!  Great HLG.  Folding flat - I don't
know - ask Dave Walter in the Predator note.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

I guess, I dont really plan to break it down that much, except for air travel.
and seeing how I will be leaving DEC and not able to travel back to the New 
England area to fly at Acton with the rest of the crew, SNIFF SNIFF, I wont
be doing much air travel, with exception to the once a year trip to DECUS that
I will start enjoying again!!!!!!

On the way from N.E. Sailplane products is a 7037 Poly Chup, a CH14 Airtronics
Micro receiver, and a Pinnacle UP-Start.  I had them Ship it to my parents house
in Utah so I wouldn't have the temptation to opening it until I get moved out
there here in a couple of weeks.  I'll be sure to forward all my glider
happenings, including building the Chup to Dan Eaton via Internet mail.

They quoted me $69.95, he said he would have to get one, dont know where he gets
it from, but I believe tower is about $5 higher plus they can pile it all in one
box and save the shipping.  I do need to order something from tower to keep the
catalogs comming, maybe some monocote for the Chup, 2 rolls plus shipping beats
2 rolls at the hobby shop, at least it has in the past!!!

From:	DECPA::"mantry%[email protected]" "CC6410::MANTRY" 24-FEB-1992 10:23:44.92
To:	"ryder" <ryder%[email protected]>
CC:	"reith" <reith%[email protected]>, "fisher" <fisher%[email protected]>
Subj:	re: The Chuperosa flies!!!!!!

Well I finished my Chup this weekend and flew it on Sunday afternoon out in 
front of my house.  The wind was pretty stiff, about 12mph so that didnt help 
things and I still dont have a good feel for it. But judging I think it will do 
OK.  I'll try to put a better note(actually mail it to you guys) later.  

The only mod I did to mine was to build the wing as a 3 piece with a center 
section on 2 tips.  The draw back to that is the wing comes out at 8oz's what 
does your wings weigh?  I guess the extra weight is all the ply I put in as 4 
carry through ribs and 4 semi-root ribs on the poly breaks then the 1/8" music 
wire (about 3.75" on each one) and the 5/32" brass tubing they go into.  I used
a 270mah battery, 2 s-33 servos and the airtronics 4 ch micro reciever (dual 
conversion of course).  The fuse weighs in at 11 oz's so total weight is 19oz's 
a little heavy than I would hope but I remember someones weighing 18oz's so I 
guess it's OK.

I'm not sure if the CG is quite right, it seemed to want to tip stall on some 
turns but with the wind and etc I wouldn't want to say anything.  The wings are 
straight and not twisted(they have 1 degree in washout at the tips so that 
should help).  I set the CG as on the plans which is about 3.25" from the LE.  
If I run my SAIL analysis on it it reads as:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
This program will Calculate the Mean Aerodynamic Chord,
its position, Area and Aspect Ratio of Wings along with
optional Stab and Pitch Stability Calculations.
NOTE:  All dimensions are in decimal inches and weight in OZ's.


How many different sections does this wing have?
A single taper flat wing would have 1, a polyhedrel plane
will probably have 2, Schuman 3, etc.
Number of sections          ? 1


               First Section


What is the length of the root chord of this section                  ? 8
What is the length of the tip  chord of this section                  ? 6

The offset is how far the Leading edge of the tip is
back from the Leading edge of root.  Example: If you had a
10in root and a 6in tip and the leading edge was square the 
offset would 4in....
What is the offset of the Tip chord from the Root Chord               ? 2
What is the span of this section          ? 29.25


What does the model weigh (oz's)          ? 19


Do you wish to do Stab Calculations (Y/N) ? y


What is the length of the root chord of this stab                     ? 3.5
What is the length of the tip  chord of this stab                     ? 2.5
What is the offset of the Tip chord from the Root Chord               ? .5
What is the span of this stab             ? 8.375


Do you wish to do Pitch Stability Calculations (Y/N)    ? y
What is the lenght from the Leading edge of the Wing to
the leading edge of the STAB              ? 22.5
At what percent of the CG will this plane be balanced at              ? 35





The Total Wing summary is:
      MAC               7.04762 
      MAC offset        .952381  from Leading edge of the root
      Area              409.5  sq in
      Aspect Ratio      8.35714  to 1
      Wing Span         58.5 
      Wing Loading      6.68132  oz/sq foot
NOTE: CG would be calculated as CG % * MAC + MAC offset
      measured from leading edge of the root



The First Section summary is:
      MAC               7.04762 
      MAC offset        .952381 
      Area              204.75  sq in



The Stab Section summary is:
      MAC               3.02778 
      MAC offset        .236111 
      Aspect ratio      5.58333  to 1
      Area              50.25  sq in
      Span              16.75 


The pitch stability summary is:
   Effective Tail Volume Factor  .331529 
 Model WILL be stable in Pitch
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
Looking at this, the CG at 35% should be more like 3.41" from the LE so that 
would mean the CG was a little far back than it should have been.

The wing loading looks Ok so it ought to be a floater.  I did have to put about 
2 oz of lead in the nose and now it looks like it will need more....sigh

I covered it ala Al Ryder colors but I made the fues and underside of the wings 
flouresent Green and the top of the wing/stab flouresent Pink  OH BOY!!!! I 
liked the ultracoat.  I liked the paper backing instead of that plastic stuff, I 
liked the adhesive it had (semi tacky to start out with)  I did do 1 boo boo and 
that was I was covering the top surface of the wing and noticed a crack in the 
wing sheeting near the TE so I zapped and kicked it, well when I put the 
covering over it, it discolored just like the warning lable on the covering said 
it would, oh well.  Hope to fly it tonight and get a better idea how it goes.

Take care guys....

Mark Antry


% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Received: by mts-gw.pa.dec.com; id AA17023; Mon, 24 Feb 92 07:21:41 -0800
% Received: by inet-gw-1.pa.dec.com; id AA11113; Mon, 24 Feb 92 07:11:06 -0800
% Message-Id: <[email protected]>
% Date: 24 Feb 92 08:05:00 MDT
% From: "CC6410::MANTRY" <mantry%[email protected]>
% Subject: re: The Chuperosa flies!!!!!!
% To: "ryder" <ryder%[email protected]>
% Cc: "reith" <reith%[email protected]>, "fisher" <fisher%[email protected]

I got my Chup kit in October and in a few weeks it was done.
I got the SD7037 Poly kit.  Anyway, it turned out okay but not great.
The problem was me of course.  Everytime I am a little anxious I tend to
make lots of little stupid "mistakes" that lessen the overall
quality.  It came in about 16.5 ozs -- probably 17 or so by now.  

I used the iron-oned white glue
for the sheeting semi-satisfactorily.  I have not yet tried sheeting with epoxy
but someday will break down.  (I have 4 more wing sets from jim in a box
here  -- 2 E214 and 2 SD7037).  Anyway, neon pink (monocote) fuse, top of wings
are center section flourescent/neon green ultracote, outer panels striped
flour green and flour yellow ultracote.  Underides are opposite and underside
center is ultracote flour yellow.  The horizontal control things (what are 
non T-tail flying stabs called?  flying stabs?  ANyway, they are green on one
side and yellow on the other, one each green on top and yellow on top).
The hatch/canopy is black and on the front fuse are small green/yellow
"symbols"   Enough of this blabbering (but I like the looks)

It flies ok.  Have not done a lot but I broke the fuse in half already
(and pseudo repaired).  I threw it out on the slope and ...

Anyway, last saturday I was on this small slope again in a very light breeze.
I am not experienced sloper but threw it a few times.  Kept getting
disoriented even though I fly power okay without disorientation.
Anyway, broke my bolt and have had to rethread to M4 screws.  But the whole
point of this blabbering:

I have started construction of

The Chuperosa CL Mark I/214

This is my scratch built fuselage I am building from the plan.  WHat that means
is that I am using the plan for a guide but am using different building
techniques, etc.  I am using 2mm balsa sides (all the way back) reinforced
in the front with 2  layers of 0.4mm ply (1/64" about) (one layer slightly
less than the first).  The front bottom is 1/8" light ply left over from my
Spitit kit I think (or maybe the Eagle II).  The tail top and bottom are
cross beams like in the plans (and balsa longerons on top, some other wood
on the botom).  The tail sides are the balsa.  A little CF will go in the
ail and in the nose (where the two hardwood things under the hatch go).
The vertical stab is the same as in the plan but the flying stab halves are
built-up.  I will use one of my E214 core sets from Jim and make an aileron
version.  The other core set maybe a poly, don't know).  If this one works
out then I will build 

The Chuperosa CL Mark II/7037

which will use lighter balsa and less 64" ply (one layer) and more CF and Kevlar
for reinforcement.  This will be cut for the SD7037 cores I have.  These are
all my experimenting and stuff.  They may work, may be heavy, and may be fragile.
But then again, maybe not!

The Mark I fuse is almost done, just need hatch, attaching flying stab, "huts" 
and building the wing.  Unfortunately I don't want to afford the balsa now
for the sheeting and have to travel 30 miles anyway to get it sort of
reasonably priced.  Good news there is that it is about 4" wide (10cm) and
you only need to sheets to do one wing half side.

Chad
who also has to finish his Ridge Runt and get his predators going now that that
wood has come (and get his Eagle II recovered and going :-)

    I built a chup this week. I found that by moving the elevator cable to 
    the same side as the rudder cable, I was able to make the receiver bay
    just wide enough that my standard sized Futaba R128DF fits in just
    fine.
    
    Thanks to everyone for all the advice in here...
    
    Loren

    Well, I am starting to think about opening up the Chup kit...
    
    I have 2 sets of wings for it, S4061 (with precut spar channels) 
    and SD7037 (without channels).
    
    My thoughts are to build one set of wings with ailerons and the
    other without..  I am also willing to condemn one wing to handlaunch
    only (ie no winches or highstarts) to save weight.  The aileron
    wing will be by definition heavier, thus I will build that to be 
    strong enough for winch/highstarts...
    
    Now, my problem is, which wing do I use for which??
    
    Terry seems to indicate that the S4061 wing is a good poly airfoil 
    and that the SD7037 would be good for ailerons.
    
    How would it be the other way around??  SD7037 as a poly wing and S4061
    with ailerons??  If that is reasonable, then I would not even cut a
    spar into the SD7037, I would just lay some cloth triangle under the
    sheeting of the main panels..
    
    Of course, I could order up another set of cores from Jim...
    
    Comments are welcome!
    
    cheers,
    jeff
    

I think you need more cores 8^) I've still got some NJ's left!

I've heard the 7037 as the better aileron wing as well. You might 
want to try posterboard as the covering for the HLG only wing. That's 
what I've been playing with and I like it.

If the slots are precut, I'd build that one for the winch. Simpler.

    That is exactly my problem...  The precut ones are ones that I
    would have planned on using for the poly wing...
    
    I guess I do need some more cores!!  You have some left from New
    Jersey?? :-)
    
    jeff
    

    As long as you're asking for comments...
    
    The one that's designed for winch is probably best to use ailerons.
    Then you can fly it on the slope as well, and they are great little 
    slope soarers in this configuration.
    
    The one that is strictly handlaunch should be polyhedral (my opinion)
    and AS LIGHT AS YOU CAN MAKE IT! I emphasize that because all the Chups
    I've seen have been way too heavy, like 18 oz or more. That just won't
    cut it in handlaunch competition. I think you should target 15 oz.
    Don't include the towhook block "just in case". Use pull-pull at least
    on the rudder. Figure out some way to reduce the weight of that full
    flying stab. Etc, etc. When my Predator got above 18 oz, it just
    stopped being a fun plane to handlaunch. It wouldn't hang tough in
    those nubile young thermals that build near the ground. When I built
    a new fuse and got back down to 15 oz, it transformed it back into a 
    nice little soarer. And my arm got a little less sorer.
    
    Opinion: Polyhedral handlaunches fly better than aileron. I don't know
    why. Maybe because they're more stable in slow thermal turns. Maybe
    because the wings are simpler and lighter. And maybe because I just
    haven't seen a good small aileron handlaunch. Anybody know what kind of
    wings are used by the best chuckers in the business, like Agnew, Wurts,
    and Jolly? I think they're all poly.
    
    Dave
        

    Yea, my Predator came out at 17oz, but was steadily increasing as I 
    tried to get it balanced..  I never did get it flying right and Terry
    Sweeny bought it...  He and a friend worked on it and he told me at the
    contest that it has been flying pretty well all summer...  once they
    got it balanced..
    
    I really thought I had built it light, too...
    
    Yes, the poly will be the handlaunch wing....  But which airfoil??
    
    jeff