Subject: Torque and bmep
From: ACRE
Date: 7/2/2003, 11:48 PM


<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
 
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