Efficient Propellers

Boat propellers are rotating foils.
Efficiency is strongly related to the aspect ratio of the blades:
- higher aspect gives better efficiency.
Efficiency is strongly related to the inlet and outlet velocity ratio of the prop:
- lower ratio gives better efficiency.

Aluminium Propeller Milled by Rohmec to CAD file supplied
- Prop shown used to set 24 hour record

V11J with Fabricated Steel Prop On Curved Spring Steel Shaft