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Subject: Re: [FlyRotary] Re: Fw: Different Rotary Port configurations
Date: Tue, 19 Jun 2007 12:16:55 -0400
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Tracy I only partially agree. One of the reasons diesels do well is=20
direct injection with NO butterfly in the intake at all! As engine=20
management systems get better we should be able to do the same thing=20
with a gasoline engine. I heard a Mecury engine running in the test=20
cell using this system. It was a 2 cycle which sounded really wierd=20
since it didn't miss at idle (which is typical). Since the engine=20
didn't "4 cycle" it sounded like it was running twice as fast! The new=20
direct injection system running in Audis and others may be the best=20
thing to ever happen to the rotary. I would love to work with you on=20
it, in your "spare" time LOL.
Bill Jepson


-----Original Message-----
From: Tracy crook <lors01@msn.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, 19 Jun 2007 8:13 am
Subject: [FlyRotary] Re: Fw: Different Rotary Port configurations


The very best (economy wise) piston engine designs today use variable=20
overlap. The Prius engine may not have this feature because I think it=20
operates at a very narrow rpm range so it is a different case. The BMW=20
(straight 6s) vary both intake & exhause timing to make good power and=20
economy(for a performance car) across the rpm range. Laura's 330i gets=20
32+ mpg at 65 -70 mph.=A0
=A0
>"getting the engine to pump the most air at a given RPM is "THE WAY."=A0
=A0
There is absolutely no arguing this (correct) point but it only applys=20
at WOT (where the 26B and most all race engines) operated. This is=20
where the best SFC happens due to minimum pumping losses. But I think=20
the pumping losses argument goes out the window as soon as you back off=20
the throttle and manifold pressure goes down. Sucking air past that=20
damn butterfly takes energy. You can operate at WOT and get good SFC=20
but this ignores the real world factor that the aerodynamic losses on=20
the airframe go way up at the higher airspeed. This is the dominant=20
factor so in reality, all these BSFC arguments are sort of moot unless=20
you are racing. But fun to discuss none the less.=A0
=A0
Tracy=A0
=A0
=A0
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