Mr. Lamar:

I have greatly enjoyed your Aircraft Rotary Engine Electronic Newsletter and have read (or saved for later reading) almost all the information the site has to offer.  I have especially been interested in the stratified charge idea you offer below.  I have been thinking of a portable source for the air supply without the use of turbo chargers.  What about a couple hollow tubes doubling as wing spars (ala BD-4) or fuselage longerons?  The weight is partially offset by using the tubes as part of the airframe and the pressure can be as high as 3000 psi for .1 thickness of 200ksi AL/carbon wall. (Hoop stress = PD/2t.)  A 6 ft long tube 12 inches dia. will weigh about 27 lbs. assumming the mandrel turned Al/carbon tube is the same weight as Al by itself.  The part I do not know is how long the boost will last.  An additional benefit is the cooling imparted to the engine with the expanding compressed air through the flow restrictor or expansion valve...  Maybe if the cooling is great enough, extra fuel could also be introduced thereby extending the boost time.  This could be of great interest to VTOL builders since they require very high power for short lengths of time with much lower power requirements for cruise.  How much percent increase could be expected with a statified charge/boost?   By the way, this set up could be very usefull for the Power Recovery Turbine as well.  Please reply at your convenience to let me know of your thoughts on this idea.

Thank you for your time and attention to this idea.

Norman DeBoer

Interesting idea. I had some sort of on line compressor in mind putting out 150 PSI.
It would be cheap and fun to try this on a dyno.

Paul Lamar
 
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