Sean Dennie wrote:
Thank you for your time Paul. While not being directly related to the
use
of rotaries for aircraft per se, my inquiry deals with the ever present
debate on the true displacement of the engines. I`m sure you have
probably
discussed this to great lenghts with everybody under the sun and have
your
own beliefs, theories and perhaps a convincing method of conveying
those.
As merely a rotary enthusiast, I have not really explored the notion
that
the true displacement of the rotary could be anything other than what
Mazda and the SAE calculate it to be. I am now in such a debate myself
and
am bombarded by opinions and theories (some of which are convincing)
from
other rotary enthusiasts. The problem is that the lack of factual
evidence
from a reputable source makes this debate, in my opinion, a moot point.
Based on the multitude of information you have written of the subject of
the rotay, your many years of experience with them and your close
connections with engineers and other rotary experts, I am hoping you, as
a
field expert on the Wankel rotary engine, can shed some light on this
subject.
The debate centers mostly on the notion that the rotary should be rated
at double the displacement that Mazda and the SAE say it is. Personally
I
always agreed (and even argued until I was blue in the face) that this
was
the correct method but I am nonetheless open to the idea that it might
not. The general opposition is not even unanimous on what the
displacement
should be. Some will argue that it should be doubled and others will
contend that it should be tripled. Then you have motorsports sanctioning
bodies who handicap rotaries based on a factor of 1.5 to one!
My goal here was to simply get your opinion on the subject. Short of
purchasing the SAE paper on the method of calculating this (SAE paper:
930684 : A Study of the Displacement of a Wankel Rotary Engine) I was
hoping to simply find out if there is any engineering basis for not
taking
Mazda and the SAE at their word. I hope I haven`t wasted your time with
a
seemingly trivial question from an ignorant enthusiast. All the best to
you and thanks again for your time.
Sean Dennie
No debate! 1.3 Liter two cycle two cylinder equivalent.
Anything further than that is like debating religions.
Paul Lamar
Yes - Religon it is! And I am holding my cross in front of my face, and
wearing my
garlic garland around my neck as I am saying two stroke is heresy - it is a
four stroke
cycle with each of all 3 chambers completing all four "strokes" in one full
rotation
of the rotor - Vance W Jaqua BSME with over 35 years of design and analysis
experience in aerospace propulsion
That is true Vance. It is a four stroke but just like a two cylinder
two stroke engine it is a two rotor and that fires twice per rev
and displace the same volume just like a 1.3 L two cylinder two stroke
piston engine.
Displacement is bull shit anyway. What matters is HP per pound and
per cubic foot of overall engine size.
Car racing organizations have nothing to say on the matter. What they say
has nothing to do with science or engineering. What they are providing is
closely akin to a circus or entertainment. They have no desire to
prove one way or the other that one engine or car is superior to
another. They are very dishonest about this. You see front drive
car bodies grafted on standardized tube frame rear drive racing cars
in NASCAR. Technically speaking this is about as dishonest as one can get.
Driver celebrities play a major role in bringing in the
money. Not the engineering or the engineers. We need to look elsewhere for that
engineering competition. That is the main reason I got out of car racing.
There are no rules limiting the form or function other than the laws of
physics in experimental aviation. You are allowed to prove
that one engine or airplane is better than another.
Paul Lamar
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