FEATHERING - CONSTANT SPEED - SELECTIVE PITCH
Here the first experimental Curtiss-Electric four-bladed variable-pitch propeller is seen fitted to a standard USAAC P-36A in 1939.

FEATHERING - CONSTANT SPEED - SELECTIVE PITCH
Here the first experimental Curtiss-Electric four-bladed variable-pitch propeller is seen fitted to a standard USAAC P-36A in 1939.