WordNet
variable-pitch propeller
n. propeller for which the angle of the blades is adjustable
Wikipedia
Variable-pitch propeller
A controllable-pitch propeller (CPP) or variable-pitch propeller is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can also create reverse thrust for braking or going backwards without the need to change the direction of shaft revolution.
Usage examples of "variable-pitch propeller".
It had flaps which permitted slow landings and short take-offs, and it had retractable landing gear and variable-pitch propeller.