Originally Posted by birddog486
I'm not exactly sure what your saying here but If you have a constant speed Hartzell and you haven't adjusted the low pitch stop on the prop, the governor is controlling your RPM on takeoff.
If your climbing out at 2700 and the governor fails with a correctly set low pitch stop you wont notice any RPM change until you reduce the climb rate or gain speed both of which will increase RPM.
On the other hand, If your climbing out and the governor fails and you haven't adjusted the low pitch stop, the engine over revs and can destroy itself.
My new hartzell was so far off in adjustment if my governor would have failed the engine would have potentially been close to 3800 RPM in the climb. I cant imagine what the RPM could climb to in cruise at that setting with a governor failure but I'm betting if you dont catch it in time the engine is junk.
The low pitch stop is an easy adjustment and I believe it's recommended in the manual for all new installations
The Hartzel manual has a procedure for confirming that the low pitch stop is set correctly, but it only needs to be adjusted if that check shows that it is not within spec (This should be checked on every new installation). I think I have only had to adjust one propeller out of many installations on RV's... they are usually spot on.
As others have said, the test / adjust procedure is setting the stop relative to a static
RPM. Once the airplane begins to gain airspeed the RPM would increase if it was only the low pitch stop controlling RPM in climb (just like a fixed pitch prop does). Because of that, it is not the low pitch stop regulating the RPM once the airplane is moving. That is handled by the gov.