On Jun 3, 10:18 am, "Ken S. Tucker" wrote:

I wonder if ram scoops were ever installed near the
prop tips. Probably too expensive for GA, but a WW2
A/C with tips spinning at what(?) 500-600 mph would
give a nice pressure boost.
I've read dual phase superchargers were used in recon
A/C to get the speed and altitude.

Airspeed off the tips is the same as the speed off the inner
blade areas, due to the pitch washout across the blade span, so
there'd be no advantage to having scoops behind the tips. The
propeller's blades are flying at an AOA of between 2 and 4 degrees in
cruise flight, anywhere between the tips and hub, because of that
pitch variation.
See Figure 6-4 of this page:
http://www.allstar.fiu.edu/aero/flight63.htm

Dan