barit1 - 1) Beech D95A, 2) Lycoming IO-360-B1B, 3) Hartzell HC-C2YK-2CUF/FC7666C(B)-4 propeller, 4) Woodward 210360 governor.
The prop specs: high pitch (feather) = 82 degrees, low pitch = 14 degrees, start locks = 19.5 degrees.
aerobat77 -
hey ! a piston engine will not feather. you can see this on a normal shutdown where also oil pressure is gone finally. the prop will remain in low pitch wich is useful for low drag on next startup .
in general you can expect on a piston to force springs the prop in low pitch and oil pressure to high pitch- when oil pressure is gone the prop moves to low pitch.
We're talking about a piston multi-engine airplane. A single will normally go to low pitch with a loss of oil pressure. Start locks prevent the prop feathering on shutdown with a multi engine airplane. As you can see above, the start locks are greater than the low pitch stops. When running the engine above ~1000RPM, the engine will be at the low pitch stops. When you shut down, the RPM decreases to ~700-800RPM at which time the start locks will slide in and stop the prop from moving beyond the start lock pitch. You'll notice that the engine doesn't really lose oil pressure until you're below ~500 which will then allow the props to go towards high pitch but will be stopped at the start lock pitch.
Back to my question at the beginning - I'm basically looking for someone who has some maintenance diagrams/schematics with detailed descriptions about the operation of specific governor and propeller models.