On a Hartzell prop with counterweights, full oil supply would indicate
- on-speed condition.
- overspeed condition.
- underspeed condition.
Explanation from PART66Online
On a counterweighted Hartzell propeller, governor oil pressure drives the blades toward fine pitch to raise RPM. A full oil supply therefore means the governor is fully boosting RPM, which it does when the engine is running below the selected speed, an underspeed condition. At on-speed the governor would hold a balanced oil flow.
M
mwongela asked · 20 Nov 2012
why?
Community Comments (3)
P
PART66Online
20 Nov 2012
The counterweights are the clue here. This is a single acting propeller, therefore if the tank is full the spring must be fully extended to counteract an overspeed condition.
M
mwongela
21 Nov 2012
thanx dimky.will read further
J
Jordi
18 Jun 2020
basically theory says that if the oil is maxed oout the spring with its weights is not pushing much so the blades will rorate slower this is why it is underspeed.I am sorry if i didnt make you understand it well but i saw this in an image in my notes.Oil goes against the movement of the feathering spring.The spring is called feathering.If it was overspeed we would've the opposite.the spring with it's weights whould've pushed oil back (with the piston of course) and we wouldve much quicker rotation.
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