X-Mozilla-Keys:                                                                                 
Paul Yaw wrote:

Vance also tried to convince everyone that the
Wankel two rotor
was really equivalent to a 3.9 liter six cylinder
piston engine.

Even as I am typing, I am wondering why I am commenting on this again.
I think that Vance has arrived at his interpretation through careful
consideration, but really who cares???  Comparing horsepower output
based on displacement is worthless anyway unless you consider rpm.  What
about power to weight ratio?  This is important even in an automobile.

Any engine that is capable of running at high rpm (With reasonable
volumetric efficiency.) will excel in this area because horsepower is a
function of torque and rpm.  

The other thing to consider (Which I feel
is VERY important.) is BSFC. Since the rotary combustion chamber has a
horrible surface to volume ratio it will probably never match the piston
engine in this respect.  The shape of the combustion chamber could
probably not be any worse.  The combustion characteristics are horrible,
and so it makes less power for a given amount of air/fuel ingested.  To
me, that is the ONLY disadvantage the rotary engine has.  Since the
combustion chamber shape is determined by the geometry required to make
it "pump" I do not see a solution to this efficiency problem.  I don't
think it is possible for anyone to win the rotary displacement argument,
because it doesn't mean anything.  We still have the same old rotary.
Great power to weight.  Extremely durable.  Inefficient.

By the way, it was nice to meet you Vance.  I only regret that I didn't
take the opportunity to harass you about the displacement issue just for
the fun of it.  I didn't get into a good argument all day.  If the ghost
of Felix Wankel shows up to tell me that his engine is in fact a six, it
will still be the same engine, pumping the same amount of air for a
given output shaft/rotor rpm.

While I am on the subject, it was Walter Froede of NSU who took Felix's
design and added eccentric motion. The story is that Felix was not too
happy about this because it was no longer a pure rotary.

Paul Yaw

The rumors I am hearing about the new Mazda wankel side exhaust port
rotary 
to be announced next month is that they have the efficiency up to a
equivalent 
piston engine. Even in the low speed car EPA driving cycle.
We shall see shortly.

BTW at high HP levels running lean it is as good as your average
Lycoming
running rich because of exhaust valve cooling necessity. Almost nobody
runs air craft engines lean.

Paul Lamar

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