:Yes, that is all true. The real problem is the rapid decline in the
efficiency of conversion from power to thrust as the propellor rpm
increases. The pounds of thrust per horsepower declines like a capacitor
discharge curve as the rpm increases and you have lost two thirds by the
time the prop rpm gets to 2000!

A ducted fan helps a little, but they are much less efficient than a big old
lazy unshrouded propellor chugging away.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( KPJY )

PS: Pinckneyville rec.aviation flyin is coming up May 20, 21, and 22. See
the article in AOPA Online.
"Morgans" You are missing the point. Take a
small engine, divide the output in half,
and the prop is going to be small. Small props do not mind turning fast.
Also, if you use the belts for the RPM reduction, you have to put the big
pulley out on the pylon, where you want a small one.
--
Jim in NC