A quadcopter only needs the collective portion, which is similar to a traditional helicopters tail rotor mechanism, or a variable pitch prop on an airplane. These new quadcopters are using a much ...

But this supersonic propeller design produced such intense ... drive shafts spinning beside the pilot, and variable pitch blades optimized for transonic airflow, the Thunderscreech pushed engineer ...

the latter with a 210-horsepower engine and a variable-pitch propeller. The Air Force and Naval academies used the T-41 to train cadets, while the U.S. Army used it for reconnaissance. Beginning ...