1. King Air E90
Propeller

2. Constant Speed Principles
Blade Angle vs. RPM
High Angle – Low RPM
Low Angle – High RPM
Constant Speed Principles
Prop Governor adjusts blade angles to maintain RPM
On Speed – Blade Angle OK

3. Constant Speed Principles
Blade Angle vs. RPM
High Angle – Low RPM
Low Angle – High RPM
Constant Speed Principles
Prop Governor adjusts blade angles to maintain RPM
Over Speed – Blade Angle increases
On Speed – Blade Angle OK

4. Constant Speed Principles
Blade Angle vs. RPM
High Angle – Low RPM
Low Angle – High RPM
Constant Speed Principles
Prop Governor adjusts blade angles to maintain RPM
Over Speed – Blade Angle increases
On Speed – Blade Angle OK
Under Speed – Blade Angle decreases

5. Propeller Governor Fly-Weights Speeder Spring Pilot Valve Beta Valve
Beta Ring
Low Pitch Stop Nut

9. Propeller Governor
RPM Setting
Actual RPM
On-Speed
2000
2000

10. Propeller Governor Over-Speed 2000 2005 RPM Setting Actual RPM Pr op Con t ro l
Power
Lever
RPM Setting
Actual RPM
Over-Speed
2000
2005

11. Propeller Governor Under-Speed 2000 1995 RPM Setting Actual RPM Pr opon t ro l
Power
Lever
RPM Setting
Actual RPM
Under-Speed
2000
1995

12. Propeller Governor
Low Pitch Stop
RPM Setting
Actual RPM
2000
1990

13. Low Pitch Stop Nut Pulls Beta Ring Forward
Propeller Governor
Low Pitch Stop
RPM Setting
Actual RPM
Under-Speed
2000
1990
Beta Valve Closes
Low Pitch Stop Nut Pulls Beta Ring Forward

14. Over-Speed Governor
Pre-set: 2288 RPM

15. Over-Speed Governor
Prop Gov. Failed

16. At 2288 RPM Overspeed Governor
Prop Gov. Failed
At 2288 RPM Overspeed Governor
Assumes Control

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