Conference vmszoo::rc

    Eric,
    
    I have added DECRCM to my account.  I have terminal at home so I can 
    access it while building if need be.  Are the notes current with the
    latest secrets and tricks?
    
    Jim Reith will mail my kit next week.
    
    Happy landings,
    
    Ron

    
    The first New Mexico Gremlin made it in yesterday.  I hope to test fly
    it on Sunday.
    
    Ron

There's a few flying down near Los Alamos.

    Remember the Alamos - was there more than one?

    
    I look forward to seeing a full Gremlin report on Monday Ron. 
    
    George

    
    I will look into the Los Alamos Gremlin scene.
    
    How about a Gremlin Fiesta?  We could have a mass ascension with 650
    Gremlins!  Eric will have to work out the frequency part though....

Yes and we could use our Gremlins as Pinatas!

    
    Well Mr. Mouser, has a Gremlin conquered Sandia Peak or what ?
    
    George

    George and company,
    
    There have been numerous delays including blood poisoning and possibly
    rabies, depending on how the tests come out.  I was bitten by a stray
    cat that I was feeding!  Talk about biting the hand that feeds you!
    
    Anyway, I changed my plans.  I sent the radio I am going to use to
    Futaba (don't say it Airtronics men) to be repaired and tuned.  It is
    a four channel AM, the R114 receiver.  This radio has been in my " I
    don't care-fly daring planes" and has been pounded hard 4 times before
    it gagged.  Not bad really.
    
    I also decided to go the Ace Christy mixer route, so I am waiting for
    that too.
    
    I sheeted the wing with thin balsa and added thicker wingtips so I
    could embed wire skids at the tips, along with one under the engine
    for a trike skid affair.  All of our flying surfaces here are actual
    runways.  Was never a problem until I was "Gremlinized".  Besides I
    wanted the "DEBUT" Gremlin to put on a good first impression.  I got
    a second wing core with the kit for fighting, I mean combat.
    
    I was given a Clarence Lee reworked K&B 40 to use.  It turns an APC
    9x8 at 14,200 rpm, so that should more than compensate for the extra
    weight of the wing.
    
    George, back to the cat bite. If I do get rabies, do you want me to bite
    anyone here? I'll do it for one wing core per bite!  Unless it is some-
    one I would bite anyway, they are free.
    
    I'll be back in touch when flight time comes, probably Nov. 13 if the
    mixer comes in.
    
    Ron
    

    
    Hi Ron,
    
       Sorry to hear about the cat bite. Hope everything turns out OK. See
      me off line for a list of individuals to bite. 8-) I forgot about the
      non-existance of grass runways out there. Sound like you've made the
      appropriate mods though.
    
    George

    Gremlinites,
    
    The fever is beginning to spread and I have'nt even finished mine yet!
    Oh, by the way.  Mine will not be the first in Albuquerque.  A guy
    named Bill Wilson showed up at the club meeting Monday night and
    applied for membership.  His AMA number is 4072, been around a while.
    He has 2 Gremlins.  4 more to come if mine does well, but we know that
    is no problem!
    
    Question time.  Due to increased weight of the sheeted wing, I have
    decided to go with the souped up K&B 40.  To make 6.75" distance from
    the leading edge to the prop and get the CG right at 1.7" I assume I
    will have to move the battery, receiver, servos back.  If so, will
    there be problems with the battery and receiver, and Christy Mixer
    sloshing around?  What are your experiences with engines bigger than
    the 25?
    
    Will Velcro be strong enough?  Or for the first time, should I go with
    the 25 until I get some experience?  I have been reading the Gremlin
    notes in DECRCM and I did'nt really see any about this.
    
    I'm at the point where I must drill the holes in the fuse to mount the
    wing and cut the ply engine mount, so I have to decide what I will do.
    
    If I go with the 25, showtime is this weekend, if Mother Nature will
    allow.
    
    
    Ron

RTFM:

The method to balance the plane remains the same. You mount everything 
where you want it to be (where it's convenient) and youslide it back 
and forth in the wing saddle until it balances then you mark and drill 
the wing bolt holes LAST. This ends up around 6.75" with a .25FP. With 
a bigger engine, it will be somewhat shorter. If the back of the 
fuselage overhangs the elevons, trim the plastic to fit. With a sheeted 
wing, you'll be more pleased with the 40 for performance. BTW: sheeting 
the wing actually makes it more brittle than the unsheeted wing. The 
unsheeted wing is designed to flex and absorb the impact while the 
sheeted wing will take some extra abuse but then fail more dramatically. 
This is covered in the frequently asked questions sheet (printed "2 up") 
included with the instructions.

    I usually drill the rear wing bolt hole in the fuselage first, when    
    balancing the plane. If I am off on the CG I can make another hole or  
    even a slot. Then I drill the front holes. (Never have all of the holes
    as slots because the fuse will move on impact and change the elevon
    settings).
    
    The 6.75" was just a place to begin. It can be 4" and still work. Some
    folks have used 20's and had to go 1.5" further forward.
    
    The best plan is to tape the battery to the RX and place that behind
    the tank. Mount the servos near the rear avoiding the rear bolt hole.
    Put the Christy mixer between the rx and the servos. (Drill holes in the
    fuse sides, later, and use tie-wraps to hold the loose parts in place).
    
    Then I masking tape the fins in place. With a completely assembled
    fuselage, inc engine muffler prop spinner etc. I trial CG the whole    
    thing INVERTED om a piece of triangular sectioned wood or metal. You
    hang the fins over the bench. I then marke the rear hole THROUGH the
    wing. Drill and bolt the fuse on with this rear bolt.
    
    Now put the plane upright. Mark the CG on the fuse near the top and
    drill two 1/16' holes. I use 1/16" wire to then re-test the CG. I all
    ooks good drill and bolt on the fins etc. Fit the aileron pushrods and
    retest the CG. If it needs adjusting file the rear hole a little to
    allow the fuselage to move. Then if it balances, and only then, do I
    mark, through the wing again, the two main wing bolt holes.
    
    FYI CG observations.
    
    1.6 - 1.7" =  very stable very hard to spin. Tracks well near ground.
    
    1.8. - 1.9" = loops tighter, will spin and come out! Bobs a little on
    low passes. Floats on landings.
    
    2.0"+ ->  Loops very tight, will spin and not come out. Tricky near
    ground.
    
    
    I balance all my combat versions at 1.7" so that they will not snap or spin
    out during combat.
    
    Hope this helps.
    
    E.

    Jim,
    
    The only reason I sheeted the FIRST wing was to support skids embedded
    in the tips to keep it away from the asphalt on the runways.  Poor me,
    all I have to land on are real runways.  Dirt is out of the question.
    After I figure out how to deal with that, the second wing will be less
    fancy.
     
    I was thinking about some way (maybe glassing just the bottom?) and
    just patching it as I grind it off.  Every flying site here is asphalt,
    no grass.

The guys in Reno that are flying off gravel put a set of Williams 
brothers thin wheels on a short axel under the motor mount place 
and a tail skid. They keep the wheels close to the fuselage and 
this minimizes drag. They can't launch with them but it does keep 
the plane (read engine) out of the gravel. This would probably work 
on aphalt as well and it's all supported by the fuselage so the wing 
can be made standard.

8^(Sorry about the RTFM but it's been a bear of a week here)^8

    The thought of landing on desert gravel or hard-top makes me cringe.
    
    I know that a couple of the guys made runway landings at Orange last   
    season and lived to regret it.
    
    There must be a bit of grass somewhere?. If not how about a big net???
    like a soccer goal but without the posts!.
    
    E.                                              

    
    
    Normally, asphalt is the best.  What I have done for now is embedded a
    wire skid in each wingtip and bolted a third behind the engine.  The
    wing is sheeted with 1/32 balsa and a Clarence Lee reworked K&B 40 up
    front.  The second wing is bare bones, no sheeting, no skids, etc. I 
    will use Jim's response and bolt a single wheel assembly under the 
    engine with a skid at the rear. That should do the job OK.  Weight is
    3 1/2 lbs with the 40.  The other wing will use the OS 25FP at 2 1/2
    lbs.
    
    By the way, the first flight this weekend was cancelled by UPS and 
    Mother Nature.  The mixer did'nt show, but 5 inches of snow did. Can't
    see the runway.

    The snow is good news. Gremlins do just fine in the snow. I even had one 
    with a ski made from down-pipe. Amazing what you can do with a heat
    gun. It needed about 15 degrees of up incidence at the LE.
    
    Also maintain the CG. Mine got a little tail heavy and spun all the
    way.................. You need to put the ski point out in front of the
    prop!.
    
    
    E.

    
    Is it possible to have a larger wing on the Gremlin? I was thinking
    about a 96 inch wing. Can Jim make that size foam wing?
    
    Dennis
    

    One panel x 48" is cutable on one cut.
    
    The bigger ones fly just like the smaller ones, (BTW I am contemplating
    a 28" span, 3 ch, .049 version!), just as long as you get the CG right.
    
    The Gruesome Gremlin had a ST2000 on the front. What are you
    considering?
    
    Also we had to fit wheels because some folks would not hand launch the
    thing. Also it saved major damage on landings. Use big scale hinges.
    The builder of the Gruesome Gremlin used cloth hinges and they came
    apart on a low pass-g-splatterrrip!.
    
    Tail dragger main wheels need to be 25%, of the average cord, ahead of 
    the CG.
    
    I would also advise using a straight LE.
    
    Regards,
    
    E.
                                         

    Thanks for the data Eric. I haven't decided on the engine yet.
    Question, how do you make a wing into a tail dragger. My goal is to get
    to a sacle of the B2 bomber.
    
    Dennis
    

    
    Dennis,
    
        Why would you want to do a taildragger? The B2 has a nosewheel.
    
        As a rule, taildragger Gremlins don't work very well due to the
    short moment from front gear to tailwheel. Nose gear configurations
    work MUCH better.
    
                                                              Dan
    
          
    
    

    My point exactly. Eric mentions a taildragger Gremlin in 1565.20 was
    wondering why?
    
    Dennis
    

I wouldn't take LG recommendations from Eric. The only Gremlin of his 
I ever saw with wheels had them on the top and used the top of the fins 
as tail wheels!

    True!.
    
    

    
    Weeeeeeeeeeeell, after a delayed Christy Mixer delivery and bad weather
    passing, the time came for the first flight.  Everything was PERFECT
    for the first flight.  The engine started right away, a little
    tweaking, and party time. NOT!  right before launching, I noticed the
    right elevon stuck all the way up so high the servo arm for it was hit-
    ting the throttle servo arm.
    
    Kill engine, drain tank, go home.  Troubleshoot at home, no problem
    found, even when vibrating the fuse with a back massager.
    
    Theory: the receiver I'm using has been sitting in a box for about a
    year.  The connectors probably have some tarnish on them that was
    loosened during troubleshooting.  I will spray them with some contact
    cleaner, reassemble and go again this weekend, weather permitting.
    
    I guess the worst that could happen is it will turn around after
    launching and go after me.  That would be exciting!  At least it did it
    before the first flight while it was still on the ground.
    
    'Til next time.
    
    Ron

    I would suspect the mixer.
    
    

    Charlie,
    
    I am troubleshooting it tonight.  Has there been a history of problems
    with the Christy Mixer?  How do they take "hard landings"?
    
    Ron

    Ron,
    	I haven't used one myself but it could easily have a bad connection
    or a bad pot that could cause the full deflection you were seeing.  Try
    moving the adjustment pots and look for dead spots where the controls
    jump.  It is definately a place to look for failures.  It's not a
    simple circuit.  It has to take pulses in, turn them into analog
    signals, combine them with sum and difference, and turn the results
    back into pulses to go to the servos.
    
    Charlie
    

    I have a question. Did the full throw occur have any relationship to
    full throttle?
    
    There is another mixer on the market that I played with in Wally's
    w/shop the other day. I will check on its name. I allowed you to
    specify four modes and vary the mix amount percentatges using little 
    flick switches. It was very small and if it works well I will report it
    in the file.
    
    Back to the Christy. I agree with Charlie that it could be a bad pot. I
    have seen this before on the rudder/aileron mixer version.
    
    Regards,
    
    E.  
                                        

    The pots set the amount of mixing so if one was bad you could get full
    deflection.  Shake the mixer unit and look for any servo motion.  Try
    inducing some vibration also.  You might also get full deflection if
    one of the input channels to the mixer is not getting a signal from the
    receiver.  Check that you have solid connections at all connectors.
    	Did the mixer come with plugs for your Reciever and servos or did
    you have to add them?
    
    C.
    

    A readily available and good source of vibration is an electric shaver.
    
    I have used them to find several faults in RX's over the years.
    
    (Those that are tempted here - please resist).
    
    Regards,
    
    E. 
                                          

    I can't resist.  He's also started using it on his face again. :-)
    
    He's got his beeper for the other thing.
    
    
    
    C.
    

    Gentlemen,
    
    I have the answer!  The mixer is innocent!  The receiver I TRIED to use
    was a pre 1991 Futaba (don't say it) AM.  I wanted to use it first, as 
    they can take a tremendous beating and keep going.
    
    The elevator channel was hosed!  I put another receiver in and Voila!
    I have an electric back massager that resembles an orbital sander.  I
    stuck that to the receiver and mixer with no failures.  If Mother Na-
    ture is willing, the Gremlin is ready again.
    
    Wish me luck.  I already have a fair size crowd that is interested
    after just looking at it.  It is black, metallic purple, and NEON
    yellow.  Very visible.  Came in at 3 pounds, 9 ounces with a 40 in
    it.  
    
    By the way, what is the wing area?  I guesstimated 470 sq. in.
    
    Ron

    Ron,
    	Good Luck.  When everything's ready and working get someone to
    launch it for you.  That way you can be ready on the controls.  We
    always do this for maiden flights when the trim is unknown.  Get a
    level launch - you don't need to throw it hard with a 40.  You'll be
    loving it as soon as you have it in trim! (Your CG and control throws
    are in agreement with the plans?)
    
    Charlie
    
    First Gremlin Launcher during the Exciting Test Flights.
    
    

    Charlie,
    
    Thanks!  Throws are set at 3/8" elevator and aileron.  CG is EXACTLY at
    1.7 inch from the leading edge.  In an earlier reply on this note Eric
    gave several locations and the responses they would have.  I chose 1.7
    as the "middle of the road" which would not spin.
    
    A fellow DECCIE here who was once a student will do the launch honors.
    Saturday about noontime, 2PM your time, think of us here!  I've already
    started the second wing.  It will be the lighter .25 powered version.
    
    
    Ron

    
    Ron,
    
       Bring a camera with you on Saturday...... We'd love to see a couple
      of snapshots of the Southwestern Gremlin !!!! Good luck on Saturday.
    
    George
    
    P.S. Video tape would be even better !!!!!

    Ron,
    	Sounds like you have the bases covered.  The best Gemlins I've
    flown were light 25 powered ones.  Let us know how the test fights go.
    Hope Mother Nature coperates.
    
    Charlie
    

    
    Well Ron,
    
        Were you able to get in the test flight on your Gremlin ??
        Give us all the details please.....
    
    Thanks,
        George
    

    Gentlemen,
    
    I would have had the scoop in earlier, but I was locked out of entering
    replies this morning.
    
    Saturday was hosed.  The weather was perfect.  Again, when time came to
    start the engine, the radio gagged again!  On the way home, we picked
    up a scope and found a cold solder joint at in input to an op amp. So,
    I actually had two electronic problems.
    
    Sunday.  Mother Nature said I got good weather Saturday and blew it.
    Sunday was cold and windy.  I said that thing is flying if it is a
    blizzard.  The wind was a crosswind about 20 mph.  Finally I get to
    the point to start up and the radio did NOT freak out.  This is the
    farthest I have ever gone!
    
    The engine wouldn't quite peak like normal, but we launched finally.
    A slight dip about a foot and then it was gone in a hurry.  Slight
    right aileron trim and its level hands off.  It didn't matter about
    the rpms down slightly, it was rippin' the sky up.  The cross winds
    didn't phase it at all.  I flew the tank out, and landed on the run-
    way.
    
    The skids promptly collapsed. So much for that idea.  The only damage 
    was when the wind blew it off the stand and crunched the fins (balsa).
    Some Ca fixed that.  I replaced the skids with a small aluminum strut
    and small wheels.  Takes care of asphalt landings.
    
    All in all, a very straight, predictable flight.  Weather killed any
    more, but the first flight was essentially perfect!  Good job guys!
    
    Question:  Will it fly OK if the fins are perpendicular to the wing?
    That would make removable fins much easier to do.  
    
    The second wing will have its own fuse so I can leave the 40 in # 1 and
    put my Christmas FP 25 in # 2 and move the radio around.  The servos
    come out as a single unit so now I will have 2 Gremlins.
    
    After a a couple of alterations, # 1 will debut to the clubs this
    coming weekend.  I can see how and why these caught on so well.  My
    two Deccie flying buddies that were there are starting to build also.
    
    By the way, we got still pics and video.  The video is not exciting as 
    it just flew straight out and too far fot the camera to see in a few 
    seconds.  It is VERY fast.  I will leave it as it is for what I call
    FREAKY FLYING and # 2 for combat.
    
    And so the Gremlin Chronicles continue.........
    
    Ron

    Congrats matey!.
    
    Welcome to "It flys"!.
    
    The Gremlin club continues to expand.
    
    Exactl-E.

    
    THANKS!  It was the most predictable and stable first flight I have
    ever had.  Due to the speed factor it was a real "adrenalizer" too!

    Congrats Ron. Glad to hear it went well. One thing you've already found
    out about the Gremlins. They don't mind the wind. Back East here, when
    it's too windy to fly ANYTHING, we break out the Gremlins.

The other thing you'll find is that you'll break out the Gremlins 
on normal days and end up not flying anything else anyway 8^)

Glad you worked out the kinks in the mixer

    
    Now if I can justify a trip out to ABO with my Gremlin we can have
    a little combat fun !!! Regardless, it sounds like you'll be in
    combat mode with the club in no time !!!!
    
    Congrat's on the flight !!!!!
    
    George

    George,
    
    Thanks for the idea!  I'll cut some chilies out of Monokoe and put them
    on the wing.  I have a picture to send now, but I like the chili idea
    so much, I will add that and take a new picture.
    
    How about a mailing address to send the picture?  I could send a video
    copy also, but it is rather uneventful.
    
    Yes, combat is looking closer all the time........................!

    Ron,
    	Congrats!  It is nice as Jim says to have a Gremlin on those nasty
    wind days.  They cut right through it and overcome any fears of flying
    in wind.
    
    Charlie
    

    
    Hi Ron,
    
       Send to    George Higgins
                  100 Lindell Ave
                  Leominster, Ma. 01453
    
    I'll see that Jim and all the rest of the Gremlin guiders get to
    see it. Maybe we'll even send it into MA for the combat column if
    it has you in the picture with it.
    
    George

    George,
    
    Happy New Year.  The pictures of Gremlin #1 are on the way.  I spaced
    out a picture with me in it.  But #2 only needs some contrasting trim 
    and it will go up this coming weekend.
    
    Number 2 weighs exactly 3 pounds with under carriage.  I did not put an
    OS 25 FP in it, but an ASP 25 (don't say it, we have great luck with
    these as cheapy bang around engines).  I got it for less than the OS
    and they do perform.  The wing I covered with Econokote.  It only added
    1.5 ounces to the wing weight.
    
    Three other guys flew number 1 with great results.  The bug is catching
    on.
    
    I will send a pic of number 2 and myself if you want.  Number one has
    the green chiles on the left wing.
    
    Rich Lewis is a DECCIE here at ABO.  He has redesigned the Christy
    Mixer to be built with more available parts here.  I will be testing
    the prototype in Gremlin # 1.  Parts cost is about $6.
    
    More to come later............
    
    Ron

    
    Thanks for the pics Ron. I haven't gotten them yet but should soon.
    I'll shre them with the rest of the guys....
    
    George

hi masters of gremlin,

i discovered a new variant of the gremlin last weekend!

it was built out of:

Jamaica Rum
Lime,
Champagne,
Melon liqueur

quite a different taste!

have fun!
joe t.

    
     Bet it does REALLY good spins! :)

And then you go deadstick and land on your belly 8^)

For the NH guys, Bob at R/C Buyers is starting to carry Gremlins so if you need
one in a hurry or someone asks at the field, support your local hobby shop. He
makes a few buck on them. I just mailed him three full kits.

Jim

    Just heard from Gordon Banks that he was running a Gremlin review in
    the December issue. Then Dan Snow called to tell me he had his copy
    already and liked what he read. Sounded like a good review.
    
    jim

    Jim,
    
    I read the article yesterday... It was favorable.  His only complaint
    was the "lack of detail for the throttle servo placement."  He stated
    that he would not even mention it, but everything else was so well
    detailed that it was the only thing he could mention.
    
    It got his endorsement and a few things in the article made me chuckle. 
    Read the last few paragraphs of the article and you'll see what I mean. 
    
    Regards,
    
    

My first question for Dan were "did they build it stock with a reasonable
engine?". I was pleased to hear "yes".

I can't remember if the magazine arrived and got piled with the others before
the trip or not. It wasn't in the P.O. box this morning.

I did like the comments about the control throws and his initial self-launch.
I'm looking forward to finding the mag.

Jim

    Which magazine is this?????????????
    

R/C Report (Gordon Banks). The December 1995 issue that was just mailed out

    
    	I think I asked this before, but probably filled the answer
    	away and its forgotten:
    
    	I'm in the UK, and I want to put a Gremlin together..
    
    	what's the simplest way of getting ether kit or plans?
    
    	cheers
    
    	Brian

    Well, I can mail you one but the shipping is expensive so it might be
    too much. If you have someone coming over to the greater Maynard area,
    they could bring one back.
    
    Plans are available from R/C Modeler but with a foam wing and PVC
    fuselage, you don't get much for the money (besides, they have the
    wingtip size wrong)
    
    Best to contact me offline (mpgs::reith)
    
    BTW: Do you know Chris Plant on your node? If so, wish him "Get Well"
    for me. I know him and Jackie Warren from elsewhere.

Just got off the phone with Bob at R/C Buyers and he's out of kits. He'll be
getting three on monday UPS.

    My son and I have nearly completed our pair of Gremlins - having an
    extra pair of hands (and his afternoon hours to continue the effort) sure
    makes these critters come together in a real hurrry! Definitely a
    pleasure after the epic US60 project!
    
    I did have a few minor (and perhaps dumb) questions:
    
    - for the tape "spars" - the instructions mention applying two lengths
    of fiber reinforced tape at the high point of the airfoil. I
    interpreted this to mean the wraps should be side-by-side, as opposed
    to one on top of the other (ie: two layers thick in one band). Did I
    get this right? 
    
    - the TE stock had me a bit buffaloed: the thin edge of this
    rectangular cross-sectioned stock matched the TE of the cores, but was
    *much* thinner than the leading edge of the aileron stock. On the other
    hand, the December R/C Report article had a minor gripe that the
    leading edge of the elevons was *thinner* than the trailing edge of the
    wing, and the TE stock was *square* sectioned! (I was so cornfused!)
    
    I finally decided that I had to shave the TE of the cores (about 1/4"
    trimmed back) to match the *thicker* edge of the TE stock, then after
    gluing the TE stock to the core, bevel this with a razor plane to match
    the LE of the elevon stock. 
    
    Comments?
    
    - in the "2-up" notes, tapering the outer 1/3rd of the elevons is 
    mentioned to reduce flutter. I was wondering if anyone had considered 
    cutting a couple of inches off the end of the aileron stock and gluing the
    2" pieces at the wing tips, to get the ends of the elevons away from 
    any tip vortex?
    
    - has anyone used iron-on gapless hinges for these critters? I've never
    used this stuff before, and I was wondering (a) if it's advisable given
    the foam being so close to the TE material, and (b) how one deals with
    covering the wing (ie: does low-temp film stick to the cloth hinge
    material OK, and is it harder to cover the elevons if they're alreay 
    attached to the wing?)
    
    - my sons 6VA doesn't have elevon mix capability. Rather than use the 
    mechanical mixer approach, which seems prone to adding control slop and
    aggravates the weight distribution issues, I'm leaning towards an 
    aftermarket electronic mixer. I've read about the Christie units, but I was
    wondering if anyone ever used the Quillen mixer?
    
    - finally, is it possible to get (low temp) shrink covering to work
    completely around the tip plates, or should those be covered with
    separate pieces?
    
    Thanks in advance!
    
    /dave (If this thaw keeps up we may be putting the kids skis away and break
    out the flight box!)
    

>     - for the tape "spars" - the instructions mention applying two lengths
>    of fiber reinforced tape at the high point of the airfoil. I
>    interpreted this to mean the wraps should be side-by-side, as opposed
>    to one on top of the other (ie: two layers thick in one band). Did I
>    get this right? 

This is talking about using the common 3/4" wide tape. Yes, they should be
side by side. You can leave a gap between them since they will work
independently. If you use the 2" wide stuff, one piece is sufficient. People
have trouble finding the 2" wide stuff.

>    - the TE stock had me a bit buffaloed: the thin edge of this
>    rectangular cross-sectioned stock matched the TE of the cores, but was
>    *much* thinner than the leading edge of the aileron stock. On the other
>    hand, the December R/C Report article had a minor gripe that the
>    leading edge of the elevons was *thinner* than the trailing edge of the
>    wing, and the TE stock was *square* sectioned! (I was so cornfused!)
>    
>    I finally decided that I had to shave the TE of the cores (about 1/4"
>    trimmed back) to match the *thicker* edge of the TE stock, then after
>    gluing the TE stock to the core, bevel this with a razor plane to match
>    the LE of the elevon stock. 

The stock was changed to be taller than thick due to this comment. It is
oversized and should be trimmed to match the core thickness. The core TE
thickness does vary a bit with placement on the cutting table and I've
adjusted the airfoil as few times to allow for a 5/16" thickness. It's a
quality issue that keeps me on my toes. You might have gotten a set that was
on the thinner side of tolerance. Trimming them should correct the problem.
With the 2" elevons, the wing area won't be missed.

>    - in the "2-up" notes, tapering the outer 1/3rd of the elevons is 
>    mentioned to reduce flutter. I was wondering if anyone had considered 
>    cutting a couple of inches off the end of the aileron stock and gluing >
   the 2" pieces at the wing tips, to get the ends of the elevons away from 
>    any tip vortex?

Yes. As a matter of fact, the Feb 1994 RCM review did exactly that for that
reason. One of the few things I agree with from that review. (this is the .46
powered plywood sheeted rockets)

Can't comment on that mixer. The Christy one works well.

>    - finally, is it possible to get (low temp) shrink covering to work
>    completely around the tip plates, or should those be covered with
>    separate pieces?

I always cover the wing tips first and then overlap the wing covering 1/8"
and seal them together.

I need to get one flyable now. (yes, I DID get Kay his replacement...)

    
    Whoops! So, I reckon that the two bands of 2" wide reinforced packing
    tape I used is a bit of overkill, eh? ;^) Oh well, what's an ounce or
    two more...
    
    The TE stock thing wasn't a big deal - I just made things fit - but I
    was curious to know what was going on there, especially after reading
    the RCR article...
    
    If by some stroke of imagination I want to play target drone this
    summer, is it legal to fix the outer 2" of the elevons, or does that
    violate the "class" rules? I'd think this would not only cut down on
    high-speed flutter, but it should make the stalls (on landing) a bit 
    softer as well.
    
    Thanks for the tip about covering the tips - I won't bother to struggle
    covering the tips with the wings in one shot!
    
    /dave

>    Whoops! So, I reckon that the two bands of 2" wide reinforced packing
>    tape I used is a bit of overkill, eh? ;^) Oh well, what's an ounce or
>    two more...
    
Remind me not to midair you 8^)

(yeah, I'll get reminded of that a LOT 8^)

>    The TE stock thing wasn't a big deal - I just made things fit - but I
>    was curious to know what was going on there, especially after reading
>    the RCR article...
    
Well, the 1/4 square was too small. The 1/4x2" ailerons were too wimpy so I
went to 5/16x2 to beef them up. I then went to 3/16"x1/4 TE which needs to be
beveled. I had to change the airfoil slightly to get a thicker TE on the core.

>    If by some stroke of imagination I want to play target drone this
>    summer, is it legal to fix the outer 2" of the elevons, or does that
>    violate the "class" rules? I'd think this would not only cut down on
>    high-speed flutter, but it should make the stalls (on landing) a bit 
>    softer as well.

nothing wrong with fixing the outer portion. The big squak is when people
make major mods to elicit advantage. the Spirit of the event is same plane,
different pilots to test pilot skills.

    Thanks again, Jim! Ought to have this pair all done by Sunday nite...
    
    /dave

Good luck. I'm trying to graft a wing together for sunday. I still need my
January flight and have nothing but the chopper flyable.

    Jim:
    
    Sorry to be a pest, but I have another question on the Gremlins:
    
    - a few places (here and in the instructions) I see references to the
    initial placement of the fuse to the leading edge as being somewhere in
    the neighborhood of "6.75", to start on the CG. This is referenced to
    the rear of the prop hub. 
    
    However, for the fuses I received, if I were to spot the front of the
    fuse this close to the LE, the aft section would overhang the wing TE
    by a good inch or more, regardless of the CG. If I had to slide the
    fuse back, I'd have to cut quite a bit of the aft fuse section off to
    clear the elevons.
    
    In fact, my initial attempts at finding the CG put the aft edge of the
    fuse right in the middle of the 1/4" TE stock, with the rear of the
    prop hub more like 7.75-8" from the LE. Any further back and I wouldn't
    be able to balance at the 1.7" point without adding weight to the nose.
    
    This was with the fuel tank/lines/filter crammed to within ~0.5" from
    the back of the OS25FP engine, the RX/battery pack/switch right behind
    it, and the servos about an inch behind the RX/batteries. I had the
    fins taped to line up the bevels over the hinge lines, and taped the
    control rods with their movable bits attached into the fuse to make
    sure all of the weight (except for covering) was accounted for. 
    
    (fwiw: The engine is mounted to the ply mount so that the front two
    bolts miss the PVC fuse while the rear two go through it, and I'm using
    5/8" dia. Aluminum spinner nuts, so I think I got everything put
    together per plan).
    
    So I guess my question is, did you happen to make the fuse longer since
    the instructions (and the entries in this thread) were written?
    
    Just wondering - it's apparent that the key is to maintain the CG
    regardless of the fuse position, and I shouldn't have any problem
    achieving that.
    
    Cheers!
    
    /dave

>     - a few places (here and in the instructions) I see references to the
>     initial placement of the fuse to the leading edge as being somewhere in
>     the neighborhood of "6.75", to start on the CG. This is referenced to
>     the rear of the prop hub. 

That's from the original instructions from Eric which I never got the master
to.

>    In fact, my initial attempts at finding the CG put the aft edge of the
>    fuse right in the middle of the 1/4" TE stock, with the rear of the
>    prop hub more like 7.75-8" from the LE. Any further back and I wouldn't
>    be able to balance at the 1.7" point without adding weight to the nose.
    
The point of sliding the fuselage is to avoid adding weight. You night have
had better luck if you had a flat battery pack inserted under the tank. The
fuselage is sized the whay it is from balance testing.

>    So I guess my question is, did you happen to make the fuse longer since
>    the instructions (and the entries in this thread) were written?
 
Yes, I believe so. The fuselage material varies quite a bit as well.
   
>    Just wondering - it's apparent that the key is to maintain the CG
>    regardless of the fuse position, and I shouldn't have any problem
>    achieving that.

The hub distance measurement is a ballpark starting point. Just keep sliding
it forward until it balances. Better nose heavy than tail heavy.

Jim

    Thanks Jim. I *do* have a flat battery pack, but even with the tiny
    (4oz) tank, with both the battery pack and tank wrapped in 1/4" latex
    it'd be tough to cram them both together into that space - it'd
    compress the foam so much that the point of using the foam would be
    mostly lost!
    
    'Tis no problem either way. I made it balance just fine, without
    cutting the fuse, and without impeding the elevon movement. Again, I'm
    just sanity checking what's been gradually appearing on my bench to
    make sure I'm not wandering off the intended path. So far it appears
    that the differences between what I see and what I read are
    evolutionary changes that aren't reflected in the instructions. 
    
    Thanks again! (and I'll try not to find something else to chirp about ;^)
    
    /dave (covering starts tonite!)

Well, I need to revamp the instructions but the time to retype them hasn't
been available. It has been a pain not being able to fix the little things.
Maybe I'll give it to my youngest as a task to do.

Keep chirping 8^)

    fwiw: I took your advise, Jim, and crammed the battery pack under the
    fuel tank (wrapped the pack in its own baggie, then wrapped foam around
    the combined tank/pack, then bagged the combination). This tucked up in
    the nose nicely.
    
    Needed to do this because (as I should have figured) by the time the
    wing and fins were covered the CG had moved back about a half-inch or
    so. With the battery relocated the CG is now  1.65" from the LE on both
    Gremlins...
    
    I decided to forgo cutting off and gluing down the outer ~2" of the 
    elevons for now, but I did seal the gaps. After re-reading all the 
    Gremlin entries I didn't see anyone complaining about control surface
    flutter. I could still do this in the future if needed, but for now
    we'll see how things go...
    
    My younger son is raring to go - he's been putting in a lot of hours on
    the DB RCFS getting ready for the spring :^)
    
    /dave

Great news Dave. Time to get out there and get some sticktime on them. Still
no official dates for contests next season. Sturbridge will have one about May
(to be determined on the 27th of this month)

    Dave,
    
    Why wait until spring. Gremlins are great in the snow. They don't
    really like chunks of ice though. I smashed my spinner on some
    last weekend. 
    
    BTW: Did you ever find out how to get the SkySport to support
    elevon mixing? I'm very interested in seeing how this works.
    
    Rich
    
     

And, if it's an undocumented feature that can work, I'd like to supply it in
my hints section.

    re: last .couple
    
    I've been considering taking the Gremlins out to fly some time soon,
    now that they're both done. While the thought of wet alcohol fuel and 
    cold air doesn't actually appeal to me, if we get a warm spot there's
    a good spot to go flying about a mile from our house. 
    
    It'd probably have to be the weekend because I haven't been getting out
    of work during daylight recently. On the other hand, I'm about to try
    skiing again after healing up from back surgery, so that'll wipe
    out the next weekend or two. And I just inventoried the parts for the
    EasySport kit I'm building for one of my sons...So many things to do/so 
    little time to do them all! ;^) 
    
    As for the SkySport/6VA: yes (eureka!) I have gotten the elevons
    working without any add-on doo-dahs. It should have been obvious but I
    missed the implications of the existing mixers: you enable *both*
    the flaperon mixer *and* elevator->flap mixing to through the back panel 
    switches, and enable the flaps with the toggle switch on the top/right
    of the front. Initially set the flap knob to the center of its travel.
    
    Then play with  the  servo reversers and mixing pots on the back so
    "up" elevator stick causes  the "flaps" to *raise* instead of the
    normal droop. Then adjust the pots some more to adjust the throw
    contribution from  aileron and elevator sticks.
    
    I'll post the exact details for the record when I get home this evening...
    
    One side effect (that might be a bit disconcerting at first) is you
    lose the normal elevator trim to the left of the elevator stick. That
    functionality moves to the flap control knob. Might take a moment to
    get used to I reckon.
    
    I haven't been able to get a copy of the Model Builder article yet that
    contains the (apparently) detailed review of the SkySport that had all
    this good information. Ordering a back issue looks like my best best on
    that score. 
    
    Cheers!
    
    /dave
    
    PS to Jim Reith: When I poke at http://www.racores.com, I end up
    at Ultranet (I think - or was that TIAC). Whatever - one or the other.
    But there are no actual links to either a "company" account or a
    personal web page. What's up with that?

    Shoot! I wrote this whole thing up, but when I went to exit the editor
    and save it, it went in the bit-bucket because I had lost the
    connection to the host...Wouldn't you think that the &$%#@! notes
    application would at least create a journal file? Sh*t no!
    
    Oh well...
    
    To setup elevon function on the Futaba 6VA SkySport:
    
    - right elevon servo connects to Channel 1
    - left  elevon servo connects to Channel 6
    
    - on the front upper/right of the tx, set the ELV->FLAP toggle switch
    to the On (towards the front) position. Also, rotate the FLAP control
    knob to the middle of its range.
    
    - remove the battery compartment panel.
    - set the ELV->FLAP switch (Switch 7) to the ON (up) position.
    - set the FLAPERON switch (Switch 8) to the ON (up) position.
    
    - it will be helpful to initially set the rate trimmers for both
    ailerons and elevators to their full scale positions until after the
    next few steps are completed. Also make sure that the front panel
    aileron trim is centered.
    
    The next couple of steps are dependent on whether the servo reverse
    function is enabled for the elevon servos. In my case, with the elevon
    control horns on top of the control surfaces, and the servo horns
    mounted "in between" the two servos (ala Gremlins), the reverse
    switches for both channels 1 and 6 are in the ON (up) position, to
    cause the elevon control surfaces to move in the right direction
    relative to the aileron stick. Before proceeding, make sure aileron
    stick movement is translated into correct control surface movement
    (viewed from behind the model!)
    
    - The ELV->FLAP trimmer in concert with the FLP TRIM trimmer (both at
    the right side of the back panel controls) are adjusted to get the
    elevons to move in the correct direction when the elevator control
    stick is moved. Note that both trimmers have a center "0" position, and
    positive and negative ranges on either side of "0". The direction that
    you set these trimmers will depend on whether you have the servo
    reversers for channels 1 and 6 enabled or not.
    
    Per the User's Guide, the ELV->FLAP trimmer sets the direction and rate
    of movement for the elevons relative to elevator stick movement. The
    FLP TRM trimmer adjusts the flap trimming operation direction and
    "variation width" when the flaperon mixing function is enabled.
    
    Whatever...
    
    In my case, with both reversers enabled, the ELV->FLAP trimmer is set
    full scale negative, and the FLP TRM trimmer is set slightly negative -
    around the "11 o'clock" position. This gets the elevons moving in the
    right direction and amount when the elevator control stick is moved off
    center.
    
    Now you can go back and set the rate trimmers for the aileron and
    elevator functions. I set the high rates to slightly exceed the
    3/8"-per-max-control-deflection recommended for the Gremlin, and the low
    rates to slightly below that same spec.
    
    Note that the front panel elevator trim function moves from the normal
    lever to the FLAP control knob once you have elevons set up. And don't
    forget that the ELV->FLAP toggle switch *must* be in the ON (towards
    the front) position before you launch (the *ultimate* Crash Switch! ;^)
    
    Cheers!
    
    /dave

>    One side effect (that might be a bit disconcerting at first) is you
>    lose the normal elevator trim to the left of the elevator stick. That
>    functionality moves to the flap control knob. Might take a moment to
>    get used to I reckon.

The big issue here is bumping the know and changing the trim drastically.
I've had it happen on the 347 in the glider stuff and was pleased to find I
could disable the knob.

>    PS to Jim Reith: When I poke at http://www.racores.com, I end up
>    at Ultranet (I think - or was that TIAC). Whatever - one or the other.
>    But there are no actual links to either a "company" account or a
>    personal web page. What's up with that?

Yeah, the www stuff hasn't moved from world yet. All I need is a round tuit
and spare time 8^)

Thanks for the note, Dave. I'll grab a copy and put it on the web pages.
Maybe I can set up the mirror site this weekend...

<         <<< Note 1565.78 by ESB02::TATOSIAN "The Compleat Tangler" >>>
<                   -< Elevons on the Futaba 6VA "SkySport" >-
<
<    Shoot! I wrote this whole thing up, but when I went to exit the editor
<    and save it, it went in the bit-bucket because I had lost the
<    connection to the host...Wouldn't you think that the &$%#@! notes
<    application would at least create a journal file? Sh*t no!
<    
<    Oh well...

Dave - check out help write /last or help reply /last.
The /Last switch is made for exactly what happened to you.

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

Now that you've explained the process in all its gory detail, I can 
understand why Futaba DOESN'T want to put it in the manual.  YES, it can be 
done, but I don't think any manufacturer would want to think someone was 
trimming elevator with the flap knob.  Not only is it very easy to throw this 
critical adjustment off just by brushing gently against the knob, it also may 
be _very_ touchy and give you poor resolution for the trim,ie, it might give 
too much change in deflection per degree of rotation, making it difficult to 
trim it out, if at all.

I'd be Veeerrrrrrry careful with this setup.

But good luck anyway ..  Gremlins are a real BLAST .. who cares if the 
elevator ain't trimmed??

Regards,
Joe

    re: .81
    
    Points taken - although the Flap knob on my sons 6VA is quite "stiff"
    and seems pretty resistant to inadvertent movement. Besides being
    located way up on the top of the unit, where your hands are unlikely to
    be, I tried rubbing my index finger along the knob and it resisted all
    but firm attempts to rotate it.
    
    As for resolution, you can set the rate or sensitivity of this control
    via the backpanel FLAP trimmer. Small settings on the trimmer reduce
    the effectivity of the knob (which is why I set the trimmer just ~30
    degrees from the zero position).
    
    If one was paranoid about it, a piece of masking tape would keep
    everything in check...
    
    Cheers!
    
    /dave

Well, my problems were mostly at contests where transmitters are in an
impound. ALWAYS check your switches and knobs. I've seen people look over Txs
for weight and feel (not as bad now that so many 347s are out there. Newer
radios might be more of a temptation) The 347 knobs are on top as well and
this is where the hands go when passing the radio back and forth. Can you set
the knob to 0% after it's initially trimmed?

    Right now the Flap knob on my sons 6VA is set to the center ("0"
    position) and the control surfaces are centered by "eye". Only a test
    flight will show if I've got nominally level flight established 
    (obviously a matter of linkage settings). Given that I've got at least
    an 1/8" of thread on either side of where the linkage is set at now, it
    should be possible to trim it out with the knob still at "0".
    
    Which provokes the question: with the tank so close to the nose/ahead
    of the CG, would it be wiser to set hands-off-level trim for the
    landing (ie: no fuel left) condition or for the take off (full tank)
    condition? Holding up-elevator during launch sounds tricky if you're
    launching yourself; holding down-elevator on landing sounds easier
    by comparison. But I don't know how much that little 4oz of fuel would
    effect the CG and flight characteristics in either case (yet)...
    
    /dave

You want the top surface of the elevons to be slightly up from flat level.
The wing needs reflexed surfaces to fly level. Some people prefer to trim the
plane so everything is symetrical which gives the same performance
normal/inverted (you have to hold (relative) up in both modes). If you trim
with some up elevon, the upright hands off will be level BUT you'll have to
hold twice as much down in when inverted. It's a matter of taste. Trimming
the elevons level (symetrical) can be a problem on launching since you need
to get on the up elevon right away to maintain level flight. With up trimmed
in it doesn't sink as much so it's less of a hassle self-launching. This is
covered in the trim section and the FAQ inside the front page of the
instructions.

    For take-off, I just dial in up trim.  Once I'm in the air, I set it
    so it flies level. 
    
    Andy
    

My mirror website is now up. It's a copy of the one on world for the moment.

So

http://world.std.com/~racores/    or
http://www.racores.com/~reith/

should work. I'd be interested in hearing comments on relative loading speeds
if anyone notices a diference.

Thanks,  Jim (in the midst of WRAM show mania

    Jim:
    
    The mirror site works just fine. Load time is quick enough (@28.8 at
    home) to not lose interest ;^) Poked around a bit and all the links
    seem to be functional...
    
    I like the idea of "symmetric" trim and using a bit of up-trim for
    launching. Makes the most sense to me, but I reckon only flying these
    critters will prove the tale...
    
    btw: I almost forgot - I caught the "R/C Combat" article in the March
    MAN. It was neat to see you referenced in the article, but why didn't
    they include the Gremlin in their test flight/review?
    
    Cheers!
    
    /dave
    

>    btw: I almost forgot - I caught the "R/C Combat" article in the March
>    MAN. It was neat to see you referenced in the article, but why didn't
>    they include the Gremlin in their test flight/review?

I haven't seen the article yet. I need to check it out. I didn't get a review
kit to them soon enough.

Yesterday I went out and flew frankengrem. This is a .25 gremlin made out of
midaired parts. I used half the RA Cores wing (from the R/C Report ad and half
the electric wing (leaving the servo out in the wing for effect) It seemed to
fly ok and I'll probably use it as a combat plane initially just to see the
reaction as I "Engage!" 8^)

    
    
    
    
    Well we now have 4 Gremlins flying in our club in the UK.
    
    I bought the plans from RCM and two of us produced wing jigs and
    cut our own foam cores. Two of them were built as per plan (a 25
    with 48" span and a 20 with 44" span), and two were built with a
    slightly extended tip cord as recommended by Jim Reith (again a 
    48" span 25 and a 44" span 20). They all fly extreamly well, and all
    of the pilots are very pleased.
    
    I should explain that that the reason for the different implementations
    was more to do with what engines people had to hand, and the fact that
    I forgot to mention the new recommended tip design to the other
    person with the jigs rather than through a detailed aerodynamic
    experiment.
    
    No one has tried the mechanical mixer yet, so far all of the planes
    are controlled by computer radios. However I have a request to build
    one for my son, and will probably use a manufactured mechanical
    mixer that is available for �3.00 ($4.5). One was built with full 
    sized servos, and the builder had to add about 3" to the nose to get it
    to ballance. I have not yet seen that Gremlin fly yet.
    
    We have at least 6 others in advanced stages of construction, and are
    now trying to figure out what rules we lay down for contest flying. We
    would be interested in any pointers to contest organization,
    particularly regarding safety.
    
    So all in all a great plane that is fun to fly, and multiplying like
    flys.
    
    Stewart
    
    

    Stewart:
    
    Jim Reith has a set of basic Gremlin Combat rules listed 
    at http://www.racores.com/~reith/racores/rules.html. 
    
    As for safety: From what I've observed, there only very basic
    considerations given.
    
    1. the "box" should be down-wind from the pilots position
    2. the box should have a minimum altitude (100 feet?)
    3. pilots are ultimately responsible for ensuring their planes are
       structurally sound
    4. the CD should ensure that planes don't have any unusual modifications
       that might jeopardize safety (eg: no metal leading edges ;^)
    
    Don't recall much else...
    
    Have a ball with your Gremlins - Lord knows we do Over Here!
    
    Cheers
    
    /dave

    Way back when dinosaurs roamed the earth and the Gremlin was young I
    tried to get people in my club interested in it. The general comment
    was that we were basically a quarter scale club and no one was
    interested in small planes. I did get one guy to build a kit and he
    loved it.
    
    I saw the guy at the hobby shop the other day and mentioned that I was
    putting together another Gremlin. He wanted me to come out to the field
    on Sunday morning ( a time I'm never there) to show people the Gremlin.
    There's a bunch of the same folks I tried years ago to get to fly the
    Gremlin who are now flying these 1/12 scale combat planes.
    
    I showed up Sunday around 11:00 and by then there had already been
    two planes out of commission. They died during hand launches.  Shortly
    there after a third was trashed during combat when the pilot lost 
    orientation while down low and rolled into the field. 
    
    I fired up the Gremlin for its maiden flight and promptly stuffed it
    into the ground on launch. THEM:"How bad's it broke?" ME:"It's not
    broke, its a GREMLIN" I go back and fiddle with the engine and try
    again. Same thing. Same conversation. Another 1/12th scale fighter
    bites the dust big time as an opposing ME-109 gets its ribbon and then
    chews into the elevator for good measure. 
    
    These guys really like the combat but I'm looking at the broken planes
    wondering how long their going to like rebuilding serious damage every
    time they fly. There wasn't that much combat and four planes were
    trashed.
    
    I decide I need someone else to fly the plane so I can see whats going
    on. The new Gremlin isn't behaving like the Gremlin I remember. We dork
    the Gremlin once more with the same results and then finally got the
    engine going and enough up elevator to get it flying. The guy I got
    helping me is one of the better pilots (he's the guy that got the kill
    chewing into the elevator) and he's worried about the wind which was
    blowing pretty good by this point. Off the the Gremlin goes and the
    guy's worried expression quickly turns to a big smile. He likes it. He
    flew for a while and then the engine quit (new engine) and he ended up
    landing out in the rough. Again, no damage. 
    
    I started the Gremlin back up and was going to just run out the tank to
    break the engine in a bit more but it seemed such a shame not to fly.
    Up it went and then shortly later back down it came with a dead engine
    but no problems on the landing. I fired it up again and then got
    stupid. It was just too much fun diving across the field at low level
    and as I pulled back up after one of the passes the engine quit. I dumb
    thumbed a not so hot turn back to the field and managed to dork it in
    from about thirty feet up.  I went out to get it and came back clearly
    unhappy. THEM:"How bad's it broke"  ME:" I busted the prop"  
    
    There are now several people interested in building Gremlins. With all
    the interest in combat in the club now it should be interesting to see
    what happens when more people get exposed to Gremlins. 

Remember - there is a gremlin contest this saturday at the KVMA field
in Augusta Maine.  See http://www.mint.net/~dfolsom/kvma/ for details.

Bye
Kay R. Fisher