By providing power to a propeller it can impart motion to the air and can therefore couple human power output to provide propulsion for an airplane. For boats, a propeller used for propulsion can ...

The use of a bicycle power train in conjunction with a large air propeller also became the favored mode of power transfer in the record setting Decavitator hydrofoils. The photograph and diagram show ...

In a bubble test, air is blown in front of the spinning propeller to visualize the flow ... to figure out exactly how close someone at home with a 3D printer and some spare time can get to those ...