<snip>
Dave Arbogast wrote:
I think there is a bias in the debate... Try this paradigm -
Look at the engine as a black box... ignore what is inside and
how it works. Measure the volume the box takes in for one
revolution of the output shaft. In the end, nothing else
matters. Right? End of discussion...-dave>
--
-dave
mailto:dave@arb.net
http://arb.net
I totally and unequivocally agree.
Paul Lamar
Now wait a minute! With a 4 stroke piston engine you are only
measuring 1/2 the pistons in one revolution. With a 2-stroke, one
revolution does it. In other words, I can't make the measurement
without knowing what's in the box.
Bob White
--
http://www.bobwhite-abq.com
N93BD - Rotary Powered BD-4
Sure you can. If x amount of air and fuel goes in in a given time
period x amount of HP comes out in the same time period. Actually the
last statement is redundant as HP is work done in a given time period.
Time period is implied when HP is discussed.
That makes a one cylinder two cycle equivalent to an inefficient two
cylinder four cycle and a one rotor. The only way to tell the
difference is there would be more oil in the exhaust of the two cycle
and the one rotor :) Of course there are efficiency differences in a
narrow range between .45 BSFC and .65 BSFC.
It could be a turbo prop engine in there. In that case it would be
really inefficient at a BSFC of over one for a small turbo prop.
Paul Lamar
Dave's statement is refering to measuring displacement, not HP.
"Measure the volume the box takes in for one revolution of the output
shaft."
No HP, no time period, just volume.
Again, intake volume in one revolution won't measure displacement of a
4-stroke.
Bob White
--
http://www.bobwhite-abq.com
N93BD - Rotary Powered BD-4
OK I missed your point. You are strictly correct but I was referring to the HP out as I
think Dave was implying. Also Dave statement was strictly correct if you consider
the Wankel as a two stroke.
Vance contention was the displacement of the rotary
was somehow more than Mazda claimed so it therefore generated more power.
In fact he claimed it had much more than double the actual two stroke displacement
of the 80 cubic inch rotary and 160 cubic inches when thought of
as a four cycle.
Bill Jepson mentioned that a two stroke actually had another cylinder
in the crankcase so the displacement of the two stroke was double the
number usually attributed to two strokes just like the rotary is
consider a 2.6 L four stroke engine instead of a 1.3 L two stroke engine.
We might want to call it effective displacement.
Paul Lamar
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