Hey Paul,

   I heard about a material called Titanium Aluminide. It can be forged
   and machined. It's light and can withstand high temperatures.
Maybe it   would be a good material to make some 20K RPM rotors from?


http://en.wikipedia.org/wiki/Titanium_aluminide
   http://www.precast.com/

   Mark LaPierre

   It is higher density than aluminum at .144 pounds per cubic inch.
   Aluminum is .1 pound per cubic inch. Iron is .3 pounds per cubic inch.
   The really trick alloy for rotors is beryllium aluminum at .07
   pounds per cubic inch. Half the weight of Titanium Aluminide.

   Paul Lamar

   It's BA is probably much easier to fabricate than TA too.

   Mark LaPierre

  Titanium aluminium is more readily available, it would be Worth
while to  try it (M.H.O).  Maybe those guys who were looking to do
something innovative with the  rotary engine  could build a gama
aluminide one rotor ;proof of concept FWF for a  Ran's s-19 for example.
   P.S. what's up with them anyway?

  -clifton younger-

  You won't get 20K unless the density is much less than aluminum.

  Paul Lamar

Probably wouldn't need to go 20k. just needs to be at lest the same
weight as the rotax FWF, 130 hp and close to the rotax price,read no
more expensive than a rotax installed.

clifton younger

Rotax's are $20,000. HP is barely 115 for 5 minutes max. Installed
weight is 166 pounds. TBO is 1200 when your throw away most of the
moving parts like crank, rods and pistons.

A 125 HP all aluminum turbo one rotor could be had for less than
half that and would not need to rev past 7500 RPM.

Paul Lamar



A gamma aluminide rotor would help reduce the engine weight. What would the
lighter rotor do for the stresses that you say are minimal at 6K for a stock
engine (Fe) rotors? Maybe you could use a higher TO RPM and cruise at 7K.
How well would BeAl rotors take the combustion heat? Then there is the
expansion to deal with. A turbo p-port with Al end housings and BeAl rotors
would be light as well as powerful.
How light are Jeff's custom rotors? What kind of cost Jeff?
A 3 rotor with RB and RX7 Specialties Al end housings, Jeff's rotors,
p-ports, Cermet coated housings like the Le Mans engine and power recovery
would be a potent performer. I think with the turbo and PSRU the FWF could be
close to 250#. 450 to 500HP would be easy. Turn up the wick in a Lancair and
the Reno speeds could be blindingly fast.

Dale Davies