What is the blade movement for blades of a full-feathering constant-speed propeller that is in the LOW RPM position when the feathering action is begun?

What is the blade movement for blades of a full-feathering constant-speed propeller that is in the LOW RPM position when the feathering action is begun?

• A. From high pitch to feather
• B. From feather to high pitch
• C. From low pitch to feather
• D. From high to low pitch

Answer: (A)

Feathering a full-feathering propeller means driving the blades to the feather angle, the maximum blade pitch, to cut drag when it’s not needed for propulsion. If the propeller is in the LOW RPM position, the blades are already at a relatively high pitch to help keep engine speed down. When feathering begins, the control action drives the blades further toward the maximum feather angle, i.e., from high pitch to feather. This is an increase in blade angle, not a decrease. So the sequence is from high pitch toward the feather position.

Feathering a full-feathering propeller means driving the blades to the feather angle, the maximum blade pitch, to cut drag when it’s not needed for propulsion. If the propeller is in the LOW RPM position, the blades are already at a relatively high pitch to help keep engine speed down. When feathering begins, the control action drives the blades further toward the maximum feather angle, i.e., from high pitch to feather. This is an increase in blade angle, not a decrease. So the sequence is from high pitch toward the feather position.