Systems: Propellers Flashcards
What kind of propellers on the King Air 300/350?
Hartzell
4-bladed
Constant speed
Fully reversing
Full feathering propellers
What holds the prop in the feather position?
Lack of oil pressure
BAS springs
Counter weights
How many governors are there on this engine? (Each engine)
Total of 3
Describe how the primary governor works?
Components: flyweights, speeder spring, Pilot valve
Spinning flyweights seek equilibrium.
At equilibrium, orifice in Pilot valve is covered trapping oil in the propeller husband maintaining constant speed.
When flyweights are disrupted, the oil orifice is opened and oil is either ported into the hub or ported out of the hub.
Prop levers are cable-connected to arm on top of the primary governor, which adjusts the spring tension on the speeder spring, resulting in a set propeller RPM.
How does the overspeed (secondary) governor works?
It is a backup to the primary governor, should the primary governor fail. Factory pre-set to 1768 RPMs.
So when the primary governor fails, the over speed governor kicks in and holds the prop speed at 1768 RPM. There is no cockpit control of the propeller; prop levers do nothing.
How does the fuel-topping governor works?
The fuel-topping governor kicks in when one or more propeller blades fail to rotate. This is a propeller failure mode.
How many idle stops are there?
Two idle stops:
Flight idle at 12 degrees.
Ground idle at 2 degrees.
What makes the propeller pitch go from flight idle stop to ground idle stop?
A 28V ground idle solenoid, which is right squat switch activated.
On the ground, 28V energizes the solenoid which adjusts the beta ring position, moving the prop pitch from flight idle to ground idle, automatically.
When does the prop go from ground idle to flight idle?
Upon power application and N1 acceleration when setting takeoff power.
When would you use ground fine?
Taxiing, to control taxi speed, and landing rollout, to slow down.
