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 ...

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 ...

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 ...