Precision machining of propeller blades; Subhuman III Human Powered Record Challenger.
This human powered sub featured
two, twin blade, counter rotating propellers of an extremely sophisticated
design. Variable pitch, variable planform, variable camber, and even that little tiny tip is elliptical. Blades were machined from 6061-T6 billets. The blades fit into a clamped
retention system in the hubs. Also of interest, the entire propeller assembly
including fins could be pivoted to provide vectored thrust for directional