Props Flashcards
Barrel Assembly
1) Supporting Structural member of the prop
2) Holds Prop Blades
3) 2 Halves (front and Rear): Pair balanced for lifetime of prop
What is the general nature of the Props
1) 1100 lbs
2) 13.5’ diameter
3) Aluminum blades
4) hollow shafts (for weight)
Dome Assembly
1) Mounted to Front of barrel
2) houses and protects pitch change mechanism and low pitch stop.
Control Assembly
1) 2 parts, located behind prop, mounted on real barrel
2) valve housing assembly
- on top of pump housing assembly
- houses mechanical linkage and Cams
3) Pump housing assembly
- Oil reservoir
- HOuses 5 pumps: Main, scavenge, standby, electrically-driven, double element aux pump.
4) Cooling fins direct air through nacelle and around assembly.
Spinner
1) Improves aerodynamic capabilities, protects dome.
2) 2 parts (front and real barrel)
3) Hole in front allows ram air to flow over dome and barrel, over cooling fins, vents through nacelle
Synchorphaser
1) Used to keep all props turning at the same speed.
- Lowers sounds level adn vibration
- highest noise levels on aircraft are the prop.
2) 1 Master (#2or3), 3 slaves
3) Adjustable up to 2 degree resynching removes adjustments - gives 4-6% improvement.
What does the Mechanical Governor Do?
1) 2 Position switch
2) In norm - prop controlled electrically and mechanically.
3) Mech Gov
a) Removes electric control
b) can still be used as master for synch
c) removes throttle anticipation and speed stabilization
d) speeder springs want to overspeed.
e) flyweight want to underspeed.
Prop Brake
1) Keeps prop from reverse ration after feathering.
2) Located on 1st stage of RGB
3) Gearbox oil px keeps brake engage when RPM above 23%
NTS
1) Engages at -1260 +/- 600
2) prevents prop from driving the engine.
3) Normally seen in descent, aircraft tends to YAW in these situations.
4) Acutator in prop Valve Housing
5) Signaling assembly in RGB.
Safety Coupling
1) Drag Limiter
2) Disconnects prop from engine if torque reaches -6000
3) Connects at 1st stage of RGB
4) backs up NTS
Pitchlocked Regulator
1) Prevents prop overspeed by preventing blad ange decrease
2) Engages at 103% RPM keeps blade from Flattening out
3) Locks pitch between 25 - 55 degrees.
4) Located in barrel
If Pitchlocked prop what do you see?
1) Corresponding changes in RPM with throttle movements.
2) Increase Throttle - high RPM and Vise-a-versa.
Pitch Lock operation involves what?
1) 96-98% RPM
- Provides good range between bogging the engine down and overspeeding.
Low Pitch Stop
1) Located in Dome
2) prevents prop from decreasing below 23 Degrees
3) Be prepared to only go into reverse on only two engines or none at all when landing.
Prop Feathering
Two ways to do so
1) Fire Handle
2) Condition Level
