Powerplant - AM.III.M.K4 - Constant speed propeller and governor theory and operation

Question 1

what does the pilot do to change the RPM of an engine equipped with a constant speed propeller when it is operating within the constant speed range?

Answer 1

• pilot moves the propeller pitch control
• this changes the compression on the speeder spring inside the governor which moves the pilot valve
• the pilot valve directs oil into, or out of, the propeller to change the pitch of the blades
• the change in pitch changes the air load ofn the propeller which changes the RPM

Question 2

What is the difference between a controllable propeller and a constant-speed propeller?

Answer 2

• basically the control system
• a controllable pitch propeller uses a manually operated oil valve to control the pitch
• a constant speed propeller uses a governor to control the valve

Question 3

When making a magneto check on an engine equipped with a constant speed propeller, should the propeller control be in the low pitch or the high pitch position?

Answer 3

it should be in the low pitch, high rpm position