<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
VJ - I will repeat again! the out put shaft is not the definative time base
for a Wankel -
What exactly do you mean by "the out put shaft is not the definitive time base"????????
Does it rotate in x number of revolutions per minute or does it not?
ANY time base is definitive because all parts are geared together.
AGAIN..... HP IS EXPLOSIONS PER MINUTE!!!!!!!!!!!!!!! That is the definition
of HP. MORE EXPLOSIONS PER MINUTE MORE HP. LESS EXPLOSIONS PER MINUTE LESS HP
the reason that it takes 3 turns to complete a four stroke cycle is
because it is chasing the the working surfaces -
YOU HAVE IT WRONG!!!! "it" the one rotor Wankel output shaft takes only ONE!!! 1!!!
UNO!! revolution to complete a four stroke cycle. ONE EXPLOSION per revolution!!!!
NOT THREE REVOLUTIONS!!!!!!!!!!!!!!
Apparently you don't know or are unaware of that FACT. Come to my hangar and hold on to
the spark plug wire while I turn the engine over :)
the rotor which is turning
that
extra turn - the crank (and it is a crank) makes the classic 2 revs per four
stroke
RELATIVE to the rotor which is the pumping/expanding element for the
extraction
of the power. Another case where you cannot use the output rotation is for
the
Dyna- cam where one turn takes all the pistons through all four strokes.
Who cares? We are not talking about the dynacam engine.
This
provides a useful 2:1 reduction for swinging big props and also provides
cross balancing for the pistons on the opposite side. I do not think that we
count
it as twice as big because of this ratio - AGAIN the cycle is the time line
!-
not the rotation of some mechanical part of the machine!
Vance - if someone missed the web page address it is
www.geocities.com/vjaqua
Paul Lamar
Dear Paul,
With all due respect, the shaft of the Wankel needs to turn three (3) !!!!!
times for one chamber to complete the four stroke cycle.!!
Again who cares how long it takes one chamber to complete the four
stroke cycle? The ENGINE completes the four stroke cycle in one
revolution of the output shaft. As I said before all three chambers
cooperate to achieve that end.
Since there are three chambers, one ignition occurs at every single shaft
revolution. Three revolutions divided by three chambers = 1 revolution
per chamber.
Nobody is arguing that. Vance is saying the engine operates like a
three cylinder four cycle piston engine and nothing could be further
from the truth. Obviously when you focus on the three chambers of
the Wankel you can confuse yourself and be misled as Vance is confused
and misled.
Also,
The RX-7 compares to a 240 in 3 four cycle RPE, where it does not matter
how many cylinder are used with regard to total displacement and throughput.
However, the shaft has to turn 1.5 times faster.
Using equal shaft speed, which is an incorrect comparison, we can only talk
about "similarities" between the Wankel and the RPE. With equal shaft speed,
the equivalent displacement is 160 in3. If the RPE should be a six cylinder
or a four cylinder is another debatable issue.
I was working at NSU in Neckarsulm, in the 60's during the Wankel
development years.
Rolf P.
I am surprised. For somebody that worked at NSU you too appear to be misled
and confused as well. Forget the RPM. RPM is only another way of keeping time.
The number of explosions of a given size per second, per minute, per day
per year is all that counts. There is absolutely no doubt
the one rotor Wankel takes in one chambers worth of air and fuel and fires
once per output shaft revolution no matter how long that takes.
EXACTLY THE SAME AS A TWO CYLINDER FOUR STROKE PISTON ENGINE OF TWICE THE DISPLACEMENT!!
EXACTLY THE SAME AS A ONE CYLINDER TWO STROKE PISTON ENGINE OF EXACTLY THE SAME DISPLACEMENT!!
I AM GETTING TIRED OF WASTING MY TIME ON THIS SUBJECT.
END OF THREAD!!!!!!!!!!!
Paul Lamar
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