I just got back from the maiden flight of my Hobby Hangar Gee Bee Model D. All I have to say is, it was nothing like I expected, except for the power, a Magnum .36 with an APC 9/6 which took it away like a bat out of hell. BTW, it was keeping up with a Stinger 40 with the throttle around 1/3.

There is a problem with the rudder though. When I push right it has the normal slight roll coupling but when I push left, even just a little, it falls out of the sky like the wing fell off. What could cause this? Evering thing apears to be straight.

The plane flies very well in all other aspects of flight. It's slow speed characteristics amazed me for this sort of plane. It slowed down to just about the speed of my Great Planes Stik. Ground handling will take some getting used to, well, a lot of getting used to.

Why would you voluntarily buy and attempt to fly a Gee Bee. People were killed in those things. Just kidding (sort of)

The only thing I can think of is that you have severe left yaw induced by engine torque. When you add left rudder, it's just too much for the stubby tail. Trimming your ailerons can mask the effect of torque induced yaw. You can check it by flying straight up. If it yaws left, and gets worse as you slow, you probably need to add some right engine thrust angle. You can also get a clue when taking off. If you have to hold hard right rudder, like I did on my GP Extra, during take-off, this may also indicate right thrust needed.

Also check your C.G. An aft C.G. can lead to abrupt stalling.

Good luck.

Things that could cause this;

- The stuff that ilikeplanes suggested
- different rudder throw left/right - check it with resistance.
- warped wings
- different airfoil shapes of the wings
- different gaps in the aileron hinges - seal both left and right aileron.

Thanks for the replies. I'll be gone for the weekend so I'll check everything Monday and get back to you.

and I'm sure you've already checked...
but make sure there's no unintentional coupling of left rudder and down elevator.
(could be in the form of binding control linkages/rods, or mixed from the transmitter)

I don't think thrust angle is causing this as the rudder is trimmed straight and it flies straight. Rudder throw is equal both ways (with resistence) and all the hinge gaps are sealed. Also the wings have equal dihedral. I doubt I will get a chance to fly again anytime soon since I start school tomorrow. Next time I fly I'll give everyone an update.

Try it at different power settings, see if it's related to the slipstream somehow? If that doesn't make much difference, then maybe the airplane is not trimmed in yaw? Even though the rudder has the same throw in both directions, the plane could be flying with a yaw angle. Since we don't sit in the cockpit with a turn and bank indicator, there's no way to know if it's off a little bit? Maybe try using the centerpoint adjustment to offset the rudder to the right, retrim the ailerons and repeat the experiement? Or maybe the engine thrust line might have the same effect.

You can't trim thrust angle by flying straight and level. You will simply compensate with aileron. Trimming thrust angle is one of the most difficult precision trimming tasks you can do. It take a variety of "tests" to really get it nailed down.

BTW, my GP Extra flew perfectly straight out of the box. But, during certain parts of an aerobatic sequence, it would not hold a line. I ended up adding over two degrees of right thrust before it would behave. I used techniques that the pattern guys use for precision trimming.

Good luck.