Hi Paul & Group,

I worked for some years on Rotary engines, development testing and
manufacture.

I am looking for some data, to verify my Excel spreadsheets, formula for
working out the CR on the Wankel engines, combustion pocket capacity in
particular.

We use to (in the early days 1968 ) place plasticine in the rotor combustion
pocket, smooth it level with the flank and they measure the fluid
displacement, form this we would work out the CR , knowing the Rotary engine
geometry of course.

So, if any one can borrow a small amount of plasticine from the little one,
and carry out the experiments, I would be grateful.

Differing sizes of engine would be good (Rotary of course)

The formula that I have converted from GWBasic to Excel takes into account,
flank clearance between housing and rotor, side seal losses due to the rotor
side clearance gap.

Once proven I will gift the Spreadsheet to the group if  you feel that it
could be useful.

I see a lot of comments about Mazda engines and one thing you perhaps
already know is that the combustion pockets changed over the years, from
precision cast to machined.

I visited Mazda for a week when we had our race machine winning (JPS Norton)
Mazda and Norton exchanged ideas, as  we at the time where getting more BHP
per CC than the Mazda 24 hour Engine. I do remember one international
incident!  At Mazda they had beautiful petite young women guides, dress in
white jackets, really smart, and after a few days in Japan for some reason I
also started to bow my head, as you do, as we entered the Lift to go to our
meeting I bowed, She bowed, heads collided, She sat down for a few moments
whilst she regained her composure, the Mazda guys and technicians would not
let me live this down. We dined with the Vice President on the last night of
our meeting and even he had heard about the incident, but after few drinks
all was well.

Anyway I digress back to the CR .

It seems to me that as part of the blueprinting of the engine on assembly,
then the Compression Ratio would be one of the data checks to make, this is
something that we logged on every build, we also did static pressure test,
with the rotor at TDC have air pressure bleed into plug hole (a drilled out
spark plug, was used for the adaptor)

From memory we had two gauges one monitoring incoming pressure and the other
the leak pressure,  compared against a known bleed hole.

However if we had to get the motor back together in a hurry, (race starting
in 55 minutes) we would feel the engine by cranking it around with a
spanner, and our mechanics could sometimes by feel an engines build quality
better than any Technical approach. Oh and we made the start line and after
only one lap warm up, we chalked up another win.

Paul some one did say that CR  request was answered, so I do apologize if I
seem to be repeating myself, but I was not sure how to get the e-mail
replies from you, and now read most of the e-mails.

Robert Rowley

I take it you have the Ansdale book. That is all I know about the subject.

Paul Lamar