HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 29, 2011, 08:45 AM
Call me Frosty
TheRealFrosty's Avatar
Lawton, Oklahoma - USA
Joined Sep 2004
397 Posts
common location is at the leading edge of the wing... as in looking down on the wing from the top you can barely see the landing gear structure. The wheel will poke out a little.
TheRealFrosty is offline Find More Posts by TheRealFrosty
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 29, 2011, 09:38 AM
Registered User
JohnsPop's Avatar
LaGrange, GA
Joined Jun 2009
1,816 Posts
I'm with Frosty.... at or a touch in front of the LE. If you put it back near the CG, you'll be doing nose-overs all the time. Here's a pic from the Dominator build: http://www.spadtothebone.com/SPAD/Do...ding_gear.html I wouldn't put the bolt heads inside like they show, though. I like a wooden block inside with the wooden holes tapped and hardened with CA or blind nuts inside and I run nylon bolts through from the outside. Easier to change out that way. The nylon will also snap off in case of a rough landing without ripping out your fuselage.
JohnsPop is offline Find More Posts by JohnsPop
Reply With Quote
Old Sep 01, 2011, 12:18 AM
Registered User
United States, HI, Kailua
Joined Jun 2010
227 Posts
Thank you for your help. had some time today so I got it together again. If I can get some time this weekend I'll give it another go. This time I deleted my model profile and created another one just in case the elevator problem was my programming. I also moved the elevator servo to an extra channel in case it is my receiver.
Kalikikopa is offline Find More Posts by Kalikikopa
Reply With Quote
Old Sep 01, 2011, 10:38 AM
Registered User
JohnsPop's Avatar
LaGrange, GA
Joined Jun 2009
1,816 Posts
Looks awesome! Makes me want to get back in the shop something aweful. I haven't had much spare time here lately. Good luck with it and let us know how it goes.
JohnsPop is offline Find More Posts by JohnsPop
Reply With Quote
Old Sep 01, 2011, 03:58 PM
Registered User
draftman1's Avatar
central CA
Joined Aug 2002
347 Posts
awesome! good luck on the flight!!
draftman1 is offline Find More Posts by draftman1
Reply With Quote
Old Sep 03, 2011, 08:00 PM
Registered User
United States, HI, Kailua
Joined Jun 2010
227 Posts
One more Flight Report

Ok, Took it to the field. gave it a go. I'm glad to report it was a great day. Many great flights. The new wing dimensions work flawlessly. It flies a lot faster than before. Take offs are in the 15 to 20 ft range now. Flies like a decent trainer. It is my first tail dragger( literally, there is no tail wheel). With the .61 engine it's fast enough now that I can see elevator flutter. Guess there's always room for improvement. Happy flying
Kalikikopa is offline Find More Posts by Kalikikopa
Reply With Quote
Old Oct 30, 2011, 08:23 AM
Registered User
Joined Aug 2009
233 Posts
Im no expert and this is totally random and out of my own head. I learned that aeleron flutter can be cured by tapering them so that they are thicker near the center of the wind vs the outer edges. perhaps this would work for elevators? It also seems that if there is flutter then it is because of turbulence most likely coming from the wings. would changing the angle of attack divert that turbulence or minimize it so that it doesnt drift back to the tail feathers? Like I said, this is just speculation. I know a more efficient angle of attack reduces the turbulence behind the wing, potentially sparing you from elevator flutter. If I am wrong, please educate me. If Im right, it was a lucky guess.
DEBAY777 is offline Find More Posts by DEBAY777
Reply With Quote
Old Oct 30, 2011, 10:27 AM
Envies his own avatar
rockyabq's Avatar
Albuquerque, NM
Joined Apr 2008
581 Posts
Debay,
I think what you're suggesting when you say "change the angle of attack" is a change of the decalage angle--the relative angle between the wing and the horizontal tail plane, including the elevator. Right? If so, the result would be the same as just changing your elevator trim neutral position significantly. If you increased the decalage angle, it would be the same as flying with lots of "up" elevator trim--necessitating the addition of more nose weight to compensate and allow you to fly straight and level again. If you decreased the angle, you'd have to reduce nose weight. If the plane's flying well, neither of these solutions would enhance its performance.

Flutter is caused by a harmonic vibration that sets in when the velocity of the air over the surface pulls it one way and then the other with a frequency that builds on itself given the nature of the structure. Stiffeners, the addition of weights, changing the trailing edge so the airflow exits differently may all reduce flutter. Your thought about tapering the ends of the elevator is certainly worth trying, provided the surface area of the remaining elevator is sufficient for control.
rockyabq is offline Find More Posts by rockyabq
RCG Plus Member
Old Nov 01, 2011, 02:32 AM
Registered User
United States, HI, Kailua
Joined Jun 2010
227 Posts
I wasn't having aileron flutter. I fixed that with balsa ailerons. I was having elevator flutter. This was caused by not putting skewers under the control horns. I fixed this by making two squares of pvc and gluing them to the elevator under the control horn. Of course now I've had a wing joint separate. probably from leaving the plane in the bed of my truck for about 3 weeks. It's glued up now. Just have to pick up some rubber bands, and install a rx, since I pirated the rx in it for another plane. I had been flying a Supra Fly 25 for a bit, but pulled out of a knife edge the wrong way, then applied substantial elevator straight into the ground, proving that I am TRULY my own worst enemy.
Kalikikopa is offline Find More Posts by Kalikikopa
Reply With Quote
Old Nov 18, 2011, 03:34 PM
Registered User
Joined Nov 2011
33 Posts
Hello Kalikikopa I think Debay almost solved your problem. You have your elevator mounted on the same plane as your wing. Your wing is blanking out the airflow over your elevator. The faster you go the worse it gets.

Mount your horizontal stab on the bottom of the fuse and make sure your servo pulls up on the control horn and is not pushing just in case you have some control rod flex. In the design book I read you should never put the wing and stab in the same path unless you have a really long fusealage.

Its just like when you drive too close behind an 18 wheeler on the the freeway and your truck gets buffeted around from the disturbed air rolling around the back of the trailer.

I have only built one SPAD, A Debonair and its a really fun plane to fly. I have enough Coro to build about 3-4 more planes. I like how cheap they can be built. I will make a better effort to make my next plane lighter in weight. Mine weighs 6.25lbs and still flies very well with a TT plain bearing 40.
burlesontom is offline Find More Posts by burlesontom
Reply With Quote
Old Nov 18, 2011, 03:43 PM
Registered User
Joined Nov 2011
33 Posts
If I did this correctly you will see my SPAD. I have since lost the nose weight and now have duel aileron servos and that solved my aileron flutter problem.
burlesontom is offline Find More Posts by burlesontom
Reply With Quote
Old Nov 19, 2011, 02:11 AM
Registered User
United States, HI, Kailua
Joined Jun 2010
227 Posts
Quote:
Originally Posted by burlesontom View Post
Hello Kalikikopa I think Debay almost solved your problem. You have your elevator mounted on the same plane as your wing. Your wing is blanking out the airflow over your elevator. The faster you go the worse it gets.

Mount your horizontal stab on the bottom of the fuse and make sure your servo pulls up on the control horn and is not pushing just in case you have some control rod flex. In the design book I read you should never put the wing and stab in the same path unless you have a really long fusealage.

Its just like when you drive too close behind an 18 wheeler on the the freeway and your truck gets buffeted around from the disturbed air rolling around the back of the trailer.

I have only built one SPAD, A Debonair and its a really fun plane to fly. I have enough Coro to build about 3-4 more planes. I like how cheap they can be built. I will make a better effort to make my next plane lighter in weight. Mine weighs 6.25lbs and still flies very well with a TT plain bearing 40.
I appreciate all the help. And I'm sure there is some effect to having the elevator and wings in the same plane, however my problem was the weakness of the old campaign sign coroplast that I used for the elevator(actually for most of the plane). The elevator was moving independent of the control horn. Cutting a couple of squares of gutter pipe and gluing them to either side of the elevator and attaching the control horn to those pieces did the trick. It flies really well now. I've got the wing reglued. Just haven't had time to put a rx back in it and take it to the park. Thanks again for all the advice. It's a great plane to fly. My bigger problem is I crashed my SupraFly now. It's about all back together. Just need to put on a wheel, the cowl, and a couple of screws and it'll be up for a test flight. If it doesn't fly as well as it did, it will probably become a corostang.
Kalikikopa is offline Find More Posts by Kalikikopa
Reply With Quote
Old Nov 21, 2011, 09:19 PM
Registered User
Joined Nov 2011
33 Posts
Hello Kali. I didn't catch that your plastic was soft. Glad you got it figured out and flying correctly.

My SPAD is not a true Debonair. I made my wing like on the Spad Stik with 2mm coro on the top. I read about half the builds on spadtothebone and once you see the principle of the design its easy to take the features you like best and sorta roll yer own.

I sure wish these were around when my dad was alive. I would build him one so he would go fly with me again. He killed his favorite plane and never flew again.
burlesontom is offline Find More Posts by burlesontom
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Help! What do I do wrong with my Radian? nph Electric Sailplanes 14 Jul 28, 2011 09:35 PM
Discussion Using Traxxas connectors, what did I do wrong? smoking_rubber Batteries and Chargers 12 Jul 10, 2011 10:34 PM
Careful! Close call...what'd i do wrong? penderperson Batteries and Chargers 12 Jun 23, 2011 08:15 AM
Are these lipo's shot/what did I do wrong.... OUAndy1807 Batteries and Chargers 8 Feb 01, 2005 01:19 PM