Hovering around Atlanta
My Posts: All Forum Topic
Look at vibration...Since each time you said the trim changed was at a higher rpm, I'd investigate the effect vibration has on the 3G. I've seen this happen countless times using other FBL systems and it can drive one crazy looking for the drift cause. If you can look carefully at the servos' neutral position at the lower speeds and then the higher speeds, and you KNOW 100% the trims are identical in all flight modes, you'll have the basis of your problem. Moving the FBL unit to a different location or providing softer mounting could be the fix.
I've seen this happen with both Skookum and CSM gyros.
So many heli's - too little time...