Bob,
You are right about my error. I should have said "2 revolutions of the e-shaft as is done with reciprocating 4-strokes". Since it is a 4-cycle engine, shouldn't it be measured the same?
Your point about how they measure 2-strokes vs. 4-strokes is well taken. Since the 2-stroke completes a cycle in only 1 revolution of the shaft they only use one revolution of the shaft to compute volume. So as you say, why not apply that technique to the rotary?
My question is to you then becomes: why do you assume that the rotor faces are the "combustion element" that needs to complete its cycle? Shouldn't we be looking at the combustion chamber as the important combustion element? After all, it is the chamber that is determining the amount of displacement, not the rotor. Similarly, in a piston engine it is the cylinder size that determines the displacement not the pistons. As you say, in 2-stroke and 4-stroke engines we wait for all cylinders (not pistons) to complete one cycle. In the rotary shouldn't we be waiting for each rotor assembly (or combustion chamber) to complete one cycle? In that case, to complete a cycle each combustion chamber requires one revolution of the e-shaft, and the 13B is a
1.3 L displacement engine... or is it?
This is where we think outside the box. Inside a rotor housing, yes there are 3 rotor faces, but there are only TWO cumulative 650 cc volumes being moved around (spread between the 3 rotor faces). In one revolution of the e-shaft those two volumes, working together, complete exactly one full Otto cycle!!! Counted together (because those volumes do exist at the same time), those 2 650 cc volumes are
1.3 L per rotor or 2.6 L for the engine.
Hugh? Two volumes? Where did I come up with that you say. How would you measure displacement of a combustion chamber If you could just look at one combustion chamber with its compression element? What would you measure? You would move the compression element to the position where it creates the largest space in the chamber and measure the volume. Then you would subtract out any area that is never displaced by the compression element, and you are left with the displacement. Do this exercise with the rotary using a single rotor and rotor housing, and you are left with
1.3 L displacement per rotor and a completed 4-cycle in 1 revolution of the e-shaft.
But I still think it is best to look at it Ed's way. :-)
On 10/16/05, Bob White <bob@bob-white.com> wrote:
Hi Dave,
OK, one revolution of the e-shaft is 1/3 revolution of the rotors. So
each rotor has had one intake event. Each face has a calculated
displacement of about 650 cc. Two X 650 cc = 1.3L. If you can explain
why it's 2.6L, maybe I can send Paul an apology. Or are you just
trying to get my goat? :)
I'm not trying to create a big discussion on the displacement of the
rotary, I just want to understand where that 2.6L per revolution number
is comming from. I haven't been able to see it. I think Paul gets it
from comparing to a piston engine, and I agree that the 13B compares
closest to a 2.6L 4 cycle 4 cylinder engine.
Bob W.
On Sun, 16 Oct 2005 16:27:59 -0700
David Leonard <wdleonard@gmail.com> wrote:
> Monty, Glad to have you and you know you will always be welcome here.
> However, you are wrong and 'he' is right about the displacement of the 13B.
> It is 2.6L or 159.6 cubic inches to be more exact.
> That is the volume of intake on one revolution of the e-shaft.
> But I think you knew that, you were just trying to get his goat. ;-)
>
> --
> Dave Leonard
> Turbo Rotary RV-6 N4VY
> http://members.aol.com/_ht_a/rotaryroster/index.html
>
http://members.aol.com/_ht_a/vp4skydoc/index.html
>
> On 10/16/05, Monty Roberts <montyr2157@alltel.net> wrote:
> >
> > The doctrine of immaculate ingestion. Whereby molecules of air and fuel
> > magically migrate into a very small, very perfect engine,unsullied by the
> > mere laws of physics, thereby creating the salvation of the world through
> > massive power levels.
> > In the protestant tradition of placing the individual at the front of the
> > line rather than at the bottom of the church hierarchy, I will henceforth
> > place all replies at the TOP of each post.
> > Monty
> > Which doctrine was that Monty?
> >
> > Bob W.
> >
> >
>
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