The document describes how a propeller governor system regulates propeller speed during over-speed and under-speed conditions. During over-speed, accelerating rotation pulls fly weights outwards, reducing spring pressure and opening a valve to allow high-pressure oil to the prop hub. This increases pitch and slows rotation. During under-speed, decelerating rotation moves fly weights inwards, increasing spring pressure to open the valve and release oil from the hub. This decreases pitch and speeds up rotation.

2. Over-speed: Level to Descending (or unscrewing prop knob)
1. Accelerating rotation
pulls fly weights outwards

3. Over-speed: Level to Descending (or unscrewing prop knob)
1. Accelerating rotation
pulls fly weights outwards
2. Levers attached to fly weights
reduce spring pressure

4. Over-speed: Level to Descending (or unscrewing prop knob)
1. Accelerating rotation
pulls fly weights outwards
2. Levers attached to fly weights
reduce spring pressure
3. Valve opens allowing high-
pressure oil to prop hub.

5. Over-speed: Level to Descending (or unscrewing prop knob)
4. High pressure oil presses
the piston that forces
increased pitch which
slows rotation.
1. Accelerating rotation
pulls fly weights outwards
2. Levers attached to fly weights
reduce spring pressure
3. Valve opens allowing high-
pressure oil to prop hub.

6. Over-speed: Level to Descending (or unscrewing prop knob)
4. High pressure oil presses
the piston that forces
increased pitch which
slows rotation.
1. Accelerating rotation
pulls fly weights outwards
2. Levers attached to fly weights
reduce spring pressure
3. Valve opens allowing high-
pressure oil to prop hub.
5. Slowing rotation makes
fly weights close the valve.

7. Under-speed: Level to Climbing (or screwing-in the prop knob)
1. Decelerating rotation
moves fly weights inwards

8. Under-speed: Level to Climbing (or screwing-in the prop knob)
1. Decelerating rotation
moves fly weights inwards
2. Levers attached to fly weights
increase spring pressure on valve

9. Under-speed: Level to Climbing (or screwing-in the prop knob)
1. Decelerating rotation
moves fly weights inwards
2. Levers attached to fly weights
increase spring pressure on valve3. Valve opens allowing high-
pressure oil to be released
from hub to sump.

10. Under-speed: Level to Climbing (or screwing-in the prop knob)
4. Less pressure on the
piston allows prop to
decrease pitch which
speeds-up rotation.
1. Decelerating rotation
moves fly weights inwards
2. Levers attached to fly weights
increase spring pressure on valve3. Valve opens allowing high-
pressure oil to be released
from hub to sump.

11. Under-speed: Level to Climbing (or screwing-in the prop knob)
4. Less pressure on the
piston allows prop to
decrease pitch which
speeds-up rotation.
1. Decelerating rotation
moves fly weights inwards
2. Levers attached to fly weights
increase spring pressure on valve3. Valve opens allowing high-
pressure oil to be released
from hub to sump.
5. Speeding-up rotation
makes fly weights equalize
and close the valve.