On Fri, 16 May 2008 14:49:06 GMT, Reno wrote:

(Geoff Miller) wrote in news:TvydnR2K2
:

http://blizzard.zmm.com/thunderbird/starboard.jpg

The note says the aluminum prop is the slower prop. It is normal for a
steel prop to have faster top speed than aluminum, all other numbers being
equal, because steel allows for thinner blades and thus less drag.
Yes
The steel prop may have slight efficiencies due to shape as well, such as rake
and cupping, which are easier to do with steel and seldom seen with
aluminum.

Aluminum is easy to machine, not true of stainless steel. Bronze is
easy to work with, and has long been a favorite material for props.
Stainless is quite good, aluminum is cheap.

Casady