Thanks!

This is a very interesting case; we would like to learn the results of your test with the tape turbulators.
If the problem continues during the next flights, pay attention to the following:

Does it ever happens at the beginning of the inside loop, where the centrifugal force adds to the weight and the elevator is up?

Is there a big difference in speed entering and leaving the loop?

I assume that it happens at the bottom of the outside loops, while the plane is inverted. Is that correct? Does the yaw happen in the same direction then?

Are the tail and aileron hinges taped?

I have asked all these questions because it seems to me that the tip stall should not ocurr when the elevator is being released while ending the loop (AOA decreases).

May be someting else is inducing the right roll-right yaw-pitch up just before the plane comes out of the loop at the bottom (speed, tail, propeller, wing warp).

May it be a bad coupling associated to down pitch? [sm=confused.gif] Does it also happen leaving a 45 down line?

Best luck!