King Air E90 Propeller

MEDIUM PITCH

Blade Angle vs. RPM

High Angle – Low RPM

Low Angle – High RPM

Constant Speed PrinciplesProp Governor adjusts blade angles to maintain RPM

On Speed – Blade Angle OK

Blade Angle vs. RPM

High Angle – Low RPM

Low Angle – High RPM

Constant Speed PrinciplesProp Governor adjusts blade angles to maintain RPM

On Speed – Blade Angle OK

Over Speed – Blade Angle increasesHIGHER PITCH

Blade Angle vs. RPM

High Angle – Low RPM

Low Angle – High RPM

Constant Speed PrinciplesProp Governor adjusts blade angles to maintain RPM

On Speed – Blade Angle OK

Over Speed – Blade Angle increases

Under Speed – Blade Angle decreases

LOWER PITCH

Prop Control Power Lever

Speeder SpringFly-Weights

Pilot Valve

Propeller Governor

Beta Ring

Low PitchStop Nut

Beta Valve

Prop Control Power Lever

Propeller Governor

On-SpeedRPM

SettingActualRPM

2000 2000

MEDIUM PITCH

Prop Contro l Power Lever

Propeller Governor

Over-SpeedRPM

SettingActualRPM

2000 2005

HIGHER PITCH

Prop Contro l Power Lever

Propeller Governor

Under-SpeedRPM

SettingActualRPM

2000 1995

LOWER PITCH

Propeller Governor

RPMSetting

ActualRPM

2000 1990

LOWER PITCH

Low Pitch Stop

P rop C on tro l P ow er Leve r

Propeller Governor

RPMSetting

ActualRPM

2000 1990

LOWER PITCH

Low Pitch Stop

Under-Speed

P rop C on tro l P ow er Leve r

Beta Valve Closes

Low Pitch Stop NutPulls Beta Ring Forward

Prop GovTest

Over-Speed Governor

Pre-set: 2288 RPM

Prop GovTest

Over-Speed Governor

Prop Gov. Failed

Prop GovTest

Over-Speed Governor

Prop Gov. Failed

At 2288 RPMOverspeed Governor

Assumes Control

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