I have a twinstar, slightly modified, enlarged control surfaces (including rudder) extended nacelles, etc.

Both engines still have about the same amount of out-thrust as in the original version.

The rudder works as expected when I use rudder only to turn left. When I put in right rudder, I get some yaw, but the plane banks left. Therefore I can not complete any turn with rudder only. To date this has not been a problem, but if I ever have a problem with the ailerons, there is no way I could possibly land it with rudder only. I have only tried this at full throttle (OS 25 FX engines).

Any advice or suggestions? Twinman, I am the guy from Nebraska that saw you fly in Katy this summer, could you please make some suggestions on if there is a way to "fix" this potential problem?

Thanks,

Tim

Hi Tim.
Bet it is cooler up there now.
Wow..got to think on this one. Will will have to watch for this on the weekend. I can only guess that perhaps there is TOO much rudder throw and that is a guess. I am into big rudder throws, but if it pushed the top of the plane hard enough at high speeds, I guess that it could and would cause the fuse to rotate to the left, similar to losing on half of the elevator will cause a plane to roll. The would occur as an opposite movement to the intended direction of the turn. I am sitting at my desk playing with my hands as a "Plane" and office workers now are calling the padded cell guys!! Bunch of worms!!
Keep us posted, but will try this myself this weekend..on students new Stick...Tee Hee.
Twinman

Twinman,

You hit the nail right on the head. When I modified the rudder, I made it taller than the vertical stabilizer, I also extended the portion above the vertical stabilizer ahead of the hinge line. (similar to my Funtana 40). I thought more rudder surface would be a good thing, if a little is good then a lot must be better... ha ha ha.

I cut the top section off, bringing it back to the same height as the vertical stabilizer. Opposite banking issue solved. It really won't bank the plane at all, but it will force the plane to yaw and I can turn that way if needed.

Wow! you really know your stuff

Thanks again,

Tim

Something to consider is that the fin is just another wing - only vertical..it will try to roll the plane in the opposite direction that you are trying to yaw it...ie right rudder will induce a roll to the left......as well, you have those two gyroscopes running at full blast out on the wings trying to yaw it to the left ... try taking the power off and see how the airplane flies

Tim Years ago I had a Sig Cougar that did the same thing at hi speeds, at lot speeds it worked right. I never did figure that one out. Crashed it on about the tenth flight. so it didn.t matter. Rich