Our plane will be heading for the annual fairly soon. Couple of questions:
1. The propellor governor ‘hunts’ in flight. It never sits exactly at the selected rpm, but rather fluctuates slightly around it. Can this be fixed at a non-eyewatering cost? The engineers have always said ‘fine during ground test’ and of course it is, but then that’s not the same as in flight.
2. The prop control seem to be spring-loaded. If you fully unwind the friction lock, then rather that it just being loose and easy to move it actually springs to the fully-fine position. You have to have a fair amount of friction lock set, otherwise your prop control won’t stay where you put it. Is this normal?
Fairly obviously the prop governor should not oscillate. It probably needs to be overhauled. There is no adjustment for the loop gain etc.
The prop governor lever is indeed spring loaded; this is to ensure that if the cable snaps it goes to fully-fine so you can land, climb, etc.
If the cable is so slippery that the rpm lever drifts, my guess is that somebody lubed it with some slippery stuff; maybe wd40? It should be a teflon lined cable which, for a long time at least, needs no lubrication, IIRC.
I agree with Peter, the only reason for the governor to hunt is because of mechanical problems ( I assume the engine has good oil pressure) , sorry but it’s time to overhaul.
I’ve experienced that issue in a TB10 and would not like to live with it. Start with the governor….
