>  > Me too on the mold. I was thinking a spinning on the bell housing part
     > > and welded aluminum tubing on the rest of it along with some machined
     > > aluminum plate (ribs with draft). All tig welded up. I think a
     > > six pinion ring gear held stationary with power out of the planet carrier
     > > on a A4OD 2.17 gear set will yield a 3.15 over all gear reduction
     > > for an RX8 based motor. 8500 takeoff RPM divided by 3.15 is 2700 RPM.
     > >
     > > Lycoming should give up now.  Resistance is futile.
     > >
     > > Paul Lamar

     > Paul do you think the EVOLV engine offers great advantages over the 13B in
     > aircraft application. The little I have read seems to indicates that most of
     > the HP increase comes from operating at a higher RPM. It is my understanding
     > that rebuilding a 13B for operation up to 8200 RPM is not that difficult or
     > expensive. Also could taking the exhaust through the sideplates increase the
     > cooling load in that area and the overall system.
     >
     > Graydon Woods

     I think you mean the RX8 or Renesis engine. Yes most of the HP increase
     does exist from operating it at higher RPM. However we must get rid of the
     subconscious bias against high RPM engendered in most of us by the fact that piston
     engines blow up at high RPM. No such thing happens in a rotary. The
     minimum bearing load in the RX8 motor probably occurs somewhere around
     7000 RPM. This is where the centrifugal loads on the rotor bearings
     are exactly balanced by the combustion loads. In the current 13B engines
     this number is about 6000 RPM.

     This point occurs in the majority of piston engines at 3600 RPM.

     The rotor bearing loads are the limiting factor in the max RPM
     of the rotary engine. The main bearing loads are only a function
     of the combustion pressure.

     How then do we get the potential power out of an RX8 engine? We use a 3:1 gear box
     and run the engine at 8500 RPM (HP peak) for takeoff. Prop RPM is still only
     2800 RPM. The other advantages of the RX8 engine are less fuel burn for
     a given amount of power and a cooler and quieter exhaust.

     Cruise RPM can be anything you want it to be. Particularly if you have
     a variable pitch prop.

     Paul Lamar

Ben Baltrusaitis wrote:

Then what would you suggest for me who wants to use the rotary instead of a 300hp Lycoming I0-540?
I won't be ready for the engine until 2004. Should I figure on a 20B to get at least 300hp or will
I be able to get the ponies from the Renesis (with the "six intake ports and four exhaust ports
located in side housings, providing approximately 30 percent more intake area over previous Mazda
rotary engines. . . sequential dynamic intake system, lightweight dual rotors, a high compression
ratio, and new fuel injectors")?

Ben

You will have to buy a 20B soon as the supply is rapidly drying up.
Unless of course you want to turbo a 13B.

Paul Lamar
 
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