Originally Posted by
KurtS
The above issues with the rudder twitching and HH slowly feeding in left rudder only happen when the engine is running. (30cc gas). Engine off and HH keeps the rudder centered unless the fuselage is moved.
Any thoughts as to why or where to look?
thanks
Kurt
You are experiencing 'creep' in heading hold mode.
This used to happen with older gyros when the temperature changed. You would/could use sub-trim to counter the creep.
The 401 recommends that all sub-trim and trim adjustments are zero and that you mechanically center your rudder. Because, the trim changes will cause the creep.
With your problem; it seems as though the gyro is "hearing" noise when the engine is running and it is causing the creep. We would occasionally see this on helicopters and would have to go ground the frame to solve the problem..
So, you may have to look at your options for masking the noise. You may need to shield the gyro signal wire, provide some noise suppression such as a magnet ring (choke), etc.
You can set up a heading hold just fine on an airplane.. Feel free to send me a PM with any questions..
Blue Skies