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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Paul,
Jeff does run a 6 cylinder, water methanol ADI, water spray on the cylinder
heads for cooling. The long exhaust manifold has the waste gate mounted on
the back (hence the length).

The props actually have a fairly normal life expectancy as long as they do
not see an overspeed event. Also, the engine is not geared.
All of us are fairly certain he runs nitromethane in his fuel (this is not
prohibited) and is something to think about.

Overall, he just has a very clean glass air III and is willing to run his
engine very hard, but has very little problems at Reno. Speaks volumes for
his engine builder and how he manages fuel and cooling.

The mods that can be done on a Legacy can greatly increase their speed.
There is one called "Breathless" that was owned by the late Lee Beile that
was a 340 mph racer without turbo's. Flying in formation with him in a
different Legacy, he was using 10 inches less manifold pressure that us at
the same speed....... that airframe has several mods for drag that really
work. A rotary powered Legacy has the potential to dominate Reno, but it
can't be done with hp alone.
Larry Childs

He must have tons more HP.
In my expedience with them they don't have as much room under the cowl.
That worries me. Is it feasible to move the firewall back?
 Look at these pictures.

I am off to track down a possible 4:1 planetary.


Paul Lamar


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If you want off the list PLEASE let me know and I will
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