Unwanted interference mix

[Dave180]

Hi. I have a weird problem with my radio. I've been flying off and on since the '80's. I have an AMA 1991 gold label FM World engines Expert radio which has worked great till now. Currently, I'm flying a HOB Super Decathlon converted to electric.(10 years old) Everything works ok on the pre-flight ground check. I handlauch as it has a glider skid on it. It climbs great and flys great.

Here is the problem: At altitude, If I pull back more then 1/2 way on the stick, it immediately snap rolls to the right. It does it every time. Even with the motor turned off at speed. Less then 1/2 way, its just fine. Its like its a controlled mix. Its crazy.. I won't be flying it again till I figure this out. Actually I've done 3 flights with it like this. No more flights.

Any ideas of what could be causing this???

[rcers]

Yes - it is too much elevator control deflection. How much does the elevator surface move?

[Dave180]

Thanks for the reply. It moves 5/8" at full throw. I turned down the dual rate adjustment so its like 3/8" now. Somehow I don't remember it doing this before but its been awhile.

[rcers]

Give that a shot - many airplanes will do a high speed snap with too much elevator.

Mike

[newjak]

I'd also take a look at the structural integrity of the horizontal stab and the elevator itself. You said the plane is old. Some glue joints may have worked there way loose.