Perry Mick wrote:

Paul,
Here are some photos of the Cosman prop. Tractor, reverse rotation 2.17,
72" diameter, 88" pitch. The blades are carbon, the hub is
hardwood/composite 9" in diameter and 5" thick. The mounting holes still
have to be drilled. The pitch twist is maintained all the way to the
hub, as it is in ducted fans. I will be sending it to you for testing on
your test stand when it is ready.

--
Perry Mick
http://www.ductedfan.com

You do beautiful work Perry.

Paul Lamar

I will second that comment Perry. It is going to take a 3 rotor
AND a rather steep reduction to swing that wheel. If you
like I could do a power/speed prediction if you would
provide some width and verify pitch (ie chordline etc)Vance>

Here is my analysis of it. Chris wants extreme pitch for cruise, without
excessively overspeeding the prop. So it will be stalled and turning
only 1850 RPM static, assuming the engine can produce about 190 HP at
the low RPM of 4000. The black curve at the right is for 200 knots. 2800
prop RPM 6000 engine RPM, takes about 280 HP to do it.

--
Perry Mick
http://www.ductedfan.com

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.