Everett Hatch was not entirely infallible. Look at his incorrect
position
on the torsional vibration issue. Neither is Jim Mederer.
Compared to the engineering resources of Mazda they are fleas on
the back of an elephant.
It always amazes me how people are in complete denial on the Lemans
engine. It is a big mystery to me. Do you think Mazda was lying
about 240 HP at 6000 RPM? Do you think the drawing Mazda published
in the SAE paper showing the P-port to be at least two inches in
diameter
to be a cartoon? Have you read what I wrote and looked at all the
pictures
of the Lemans engine? Do you not believe that the 3rd gen ports are
larger
than the 2nd gen ports and that the RX8 ports are larger than the
3rd gen
ports by 20%? Do you not believe the bigger the pipe the more the
flow
at the same velocity? What's up? I don't get it. Am I to be
completely
discounted? Are you people being contrary just be contrary and create
a controversy? :-) As my wife is found of saying; "what does logic
and
reason have to do with it"?
I'll tell you what is probably fooling more than one cottage
industry
rotary engine tuner. And that is this. The diameter of the pipe also
affects
the tuned length. Surprise! Have you been to church lately and seen
an organ?
If you are not trying all combinations of pipe
length and diameter on your dyno you are fooling yourself. See
the chart below. Lets say you want to try only 3 different diameters
and 3 different pipe lengths and 3 different timings. That is 27
different
combinations and dyno runs. Did Everett or Jim do this? I don't think
so. OK lets say you make three different pipe diameter variable
length tuned
intake manifolds. Or start small and tear the engine
down each time you increase the size of the p-port.
You will also need six sacrificial rotor housings with different
p-port timings. Did Everett or Jim do that? I don't think so.
This sort of trial and error applied research is economically
beyond the average cottage industry or shade tree rotary engine
tuner.
Just copy the Leman engine for *&^%$#@ sakes!
Paul Lamar
Paul,
I sure dont want to get into a debate with you trying to defend
another
man's position. And I agree that Everett Hatch (like all folks, me
and you
included) probably wasnt infallible.
Yes, I've read all the stuff you've written the past couple of
years on
the subject of peripheral ports because its a subject that interests
me. It
amazes me that the example you continually cite as the benchmark
reference
for an aircraft application of PP tech is the Le Mans 4 rotor engine.
It is
a very impressive piece of work. But I dont know of anyone on here
who is
building a 4 rotor with tunable runner lengths.
Why does that amaze you?
What does four rotor have to do with it? It is the HP per rotor
that counts. Divide the HP numbers by two and you get 240 HP at
6000 RPM. If you run it at a steady 6000 RPM the runner length
remains fixed. The slides do not move in and out at a steady
6000 RPM. What is the problem with understanding that?
So I dont consider it as
applicable to the discussion as Everett's work. It strikes me as quite
simplistic to assume that simply cutting the Le Mans HP number in
half is
appropriate. And I question whether an eyeball engineered copy will
produce
the often quoted 240HP @ 6000 RPM.
You went to a lot of trouble to explain that the combination of
runner
size and length both contribute to optimize power for a given RPM. I'd
certainly agree with that. Unless I'm mistaken (its possible; I am
fallible) I believe its only length that is tunable in the Le Mans
engine
isnt it? So presumably the fixed runner diameter was chosen to
optimize
output at a given runner length and RPM (not likely 6000 RPM).
It's not even remotely possible that Everett Hatch tested all
possible
combinations of runner length and diameter. But in his presentation at
Copperstate 95 he stated that he did experiment with a number of
combinations of runner length, diameter, and port timing. And while he
didnt have the resources of Mazda his focus was on an aircraft
application
tuned for operation at our desired RPM range. As such I will give more
weight to his data than you seem to be willing to.
I hope someone else actually builds and tests a 2 rotor engine
operating
at 6000 RPM using your theories that proves Everett wrong. Maybe
Jerry is
the guy that will do that. Nothing would please me more than being
able to
assemble a cheap PP engine that is proven to produce 240HP.
Mike Wills
IT IS NOT MY THEORIES! @#$%^%$#@! MAZDA HAS DONE IT!
Everett did a very good job. He got 210 HP. Ray Richardson and folks at
the current Power Sport got another 5% by merely adding bell mouth
intakes
to what Everett did for a grand total of 215 to 220 HP. I say if you
copy
Mazda exactly with larger runners and ports you can get up to 240 HP
at 6000 and much much more with a 2.85:1 gear box and 7500 RPM.
Yes, I agree the optimum diameter, for 6000 might be different and
even more
than 240 HP might be possible. So far nobody, nada, no one else,
except Mazda,
has come even close to 240 HP at 6000 RPM.
Paul Lamar
This is some interesting discussion, I just want to remind everyone
that the vertical dimension of the peripheral ports affects timing, so
when you increase diameter you are mixing effects of timing and port
size. This is why the factory ports are squared off, you get more port
area without affecting timing by squaring off the port.
Paul, I think you are on the right tract with the idea that the intake
tract is more important than the area of the port, not counting timing
effects. What I mean is if you had a 13B with x HP and round ports,
you could square off the ports, increasing their area without changing
the timing and you would have more power than before.
Hans
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