My plane rolls when I give up elevator??

[jhas]

I have seen this before, but my new scratch built warbird does a big barrel roll when you feed up elevator. Anyone know how I remedy this problem? I try to do a clean loop and it turns into a scary barrel roll/stall.

[Ollie]

One possible cause is a difference in incidence between the left and right wings. This could be caused by a twist or a slight misalignment at the wing mounting. It could also be caused by a slight difference in airfoil camber between the wing halves. If either of these causes are present, it should also show up as a difference in tracking between idle and full throttle. Beginning at idle, gradully advance the throttle. I think your model will veer in the opposite direction to when it tries to loop.

[Tony Oliver]

Unless your wing is warped/ailerons set incorrectly as above, one wing is heavier than the other - try balancing with some weight in the lighter tip.

It's also possible that you have different elevator settings on each side (one marginally different to the other).

Whichever, you should put the model on a flat surface and accurately measure the differences of the surfaces and controls. Make an incidence gauge if necessary, and combined with a spirit level you'll soon find out what's wrong.

Tony

[Haldor]

Most planes will do this if elevator is too much. Try lesser throw.

[pda4you]

Most planes will do this if elevator is too much. Try lesser throw. Haldor is correct. Many planes will snap with too much elevator.

I (used) to fly a Cap and learned many lessions about snap roles. Here is an airplane that did the best snap rolls I have ever seen. You learned (before the days when I could affort a computer radio) to use elevator very judiciously. Would you like to guess how it meet it's demise?:rolleyes: :p :( :eek: , landing and I tried to "flair" just a bit too much!

You have good advice so far - check all those things (In above posts). If all looks good if you have a built up wing you can add some washout - that helps a great deal.

Good luck!

Mike

[pda4you]

By the way - one more thing. On warbirds keep the speed up. The closer to scale wings they have the more this applies. The real ones landed fast - even with flaps.

Mike

[Karl B²]

P-factor at positive angle of attack will induce a yaw, which by itself or by inducing a roll may be causing your symptoms.

Karl

[jhas]

Thanks for replies. I checked the angles and decided to put a little washout in the wing tips. I must admit that I hog the elevator a little too much. Will give it a toss next weekend and let you know if this washout really helps. BTW, I plan on moving more weight forward to see if this also will help.