I just finished putting together my H9 AT-6 Texan and hope to fly it next weekend. I mentioned to one of the instructors in my club that I programmed in flaperons and he told me NOT us do that! He said that it would make the airplane more succeptable to tip stalling. I thought that if would provide more lift at the wing tips. Anyone else have any experience with using flaperons with outboard aileron wings?

I fly a TF AT-6 which is similar in size to your H9. I wouldn't use flaperons as this plane doesn't need it. I've noticed that the big cowl and also lower pitch prop (14X6) provide enough drag when landing so flaps aren't neccessary. My AT-6 is a nice plane to fly but it will drop a wing on landing if it gets too slow. At least mine will as this happened to me when I first built and flew it 5 years ago.

Flaperons work fine on full span ailerons, but on "barn door" ailerons like the T-6 has, they are the same as wash-in at the tips. Tip-Stall-City

Jim

I fly the H9 AT-6, have been now for about 1.5 years. Don't dial in flaperons, they're not needed and will make it more likely to tip stall. It'll probably land slower than you think without any problems. On the first few landings though, keep the speed up a bit until you get used to it. Good luck.

well, I have it with flaperons (small movement, about 5mm) and yes it helps slowing it down and decreasing the take off length, and no it does not hamper the plane flight characteristics.
one thing is theory, the other is practice....I do it (as well as on my P-51 MA and P-40) and yes, it helps.
What I avoid, is putting too much deflection, that's all

Your instructor is right. Either use flaps or none. Avoid using flaperons. You do not want more lift at the wing tips so they stall first (tip stall). You want the inverse - more lift near the center section. This is why some wings have washout (less angle of attack at the tips) to decrease the chance of tip stalling. Using flaperons will increase the angle of attack at the tips.

It's not that I didn't believe what the instructor was telling me, I just like to understand the theory behind it. I think I understand now that it's the change in the angle of attack that the flaperons create at the wing tips that will likely cause a problem. Thanks for the responses!