The 68 inch diameter prop tip is going 586 FPS at 2000 RPM.

 This assumes zero angle of attack and a forward speed of 400 MPH or
 587 FPS.  This is still not the actually twist as it is desirable
 to have the tip at this angle of attack for low induced drag in the
 transonic region but most of the rest of the blade needs a positive
 angle of attack to generate some thrust.

 That is, as far as I can determine at this moment in time, a
 matter of judgement or experience. If it was ground adjustable only
 several degrees of change would be advisable. I wish I had a good
 CFD program for props.

 The next thing to worry about is blade area to see if this five
 bladed C130 type prop will really absorb 1000 HP.

 BTW The C130 prop twist at the tip does not have to be as great as
 ours as it is not going 400 PH.

 Check my arithmetic I have been known to make mistakes from time to
 time.

 Getting the prop right is probably the most difficult part of this
 project. Up until the C130J it appears that little attention was
 paid to this problem.

 Paul Lamar

 This is our competition.

 I can't believe the GlasAir III aerodynamics are that much worse
 than a Legacy. It is going 400 MPH while all the rest are only
 doing 375 MPH. To do that with HP alone would require an enormous
 amount of additional HP. Top speed is proportional to the cube root
 of HP. Probably well over 200 or 300 HP or more.

 I do think he is using an IA720 A1A The picture looks like a dual
 turbo 720. Hard to beat. Those engines are very very expensive. The
 crankshaft alone is supposed to be $50,000. In 2009 a new
 IO-720-A1B cost $113,621 Stock is 400 HP. We are going to need all
 the HP we can get. The prop is critical.

 Short life of course.  He does have dual turbo's which helps.
 Rumour has it the extra thin  metal props have a 1/2 hour life
 expectancy. They all use the same CS prop more or less.

 Paul Lamar



 I see only three cylinders per side.  Probably a 540 or 580.

 Lewis bjork

See the little white dot (red arrow) and note the length of the tubular exhaust
manifold. With just three cylinders it would not have to be that long.

Paul Lamar

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