Don't you think the r&d will be great for us for aircraft use?

http://www.texasautosports.com/ProCar.html

Ben

Not directly but any experience with the engine helps.
We are unlikely to run ours over 7700 RPM for any length
of time. The highest gear ratio PSRU anybody is using or talking
about building is only 2.85:1. If you impose a 2700 RPM prop
limit (diameter) that converts to a 7700 engine limit.
Paul Lamar

Al Gietzen wrote:

Catto is suggesting limit of 3000 on my 66" 3-blade prop.

Al

I'll also be using a 65-66" prop, but 3,000 rpm @ 75 degrees F is only
0.762 mach (589 mph) tip speed.  This is about 6,500 engine rpm with a 2.17
redrive.  Warp drive (and others) recommend a tip speed up to .88-.92 mach
for maxiumum efficiency.  This requires a considerably higher rpm with this
short of a prop.

Scott Gettings

There can be a significant tip drag increase at .762 mach.

BTW notice the drop in drag when the thickness goes down to 6% from 12%.
It is hard to make a wood or composite prop with a 6% thickness.

Also BTW notice the large increase in drag when the tip angle of attack approaches
10 degrees. This is exactly what a variable twist  IVO prop does when
you increase the "pitch" :)  The angle of attack at the tip is increased
causing higher HP consumption. Interesting.


Paul Lamar
 
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