> I am sure many will have seen this already:
>
> There is a paper on the R26b Le Mans engine at www.mymazdarotary.com under
> the `Mazda rotary general' tab.
> This peripheral port motor used a variable intake length and crude scaling
> from the drawings in the above paper suggests an intake runner diameter of
> just over 2 inches and a length of 22 inches at 6000rpm and something
around
> 2 inches shorter at 7k.  Peak torque for this 4 rotor (448ft lb) occurred
at
> 6,500rpm when runner length appears to be about 21inches.
>
> A couple of questions:
> Jerry: why is your inlet port round - in two strokes they are more often
> oval, presumably to maximise flow for a given `valve opening'.  I guess
this
> is convenience for manufacturing???
>
> Anybody: does the PP geometry make it much easier to make Al end plates
and
> is this the easy route to much lighter engines?
>
> Lastly does anyone know where I can get some more information on PPs?
>
> cheers
> mike
Mike
The estimates on the manifold tuned tube are correct!

I'm sure Jerry will answer as well but the answer to most of your questions
is Yes!

The round PP is easier to machine, the square with round corners is slightly
better, but superimposed, there's not a lot in it.

The aluminium end housing are MUCH easier to make with out having to
consider ports.

The aluminium end housing are lighter approx 30 lbs. As both mine ( current
development) and Richard Sohn's have steel wear surfaces ( but different
designs) the savings aren't as great as one would ultimately desire, but the
coating on aluminium aren't all that good. Det Gun is about the best and
horribly expensive.

There isn't a lot on the internet on PP it's a black art!
Basically the inlet tube diameter / router housing diameter, Volumetric
Efficiency is governed a lot by inlet velocity. Jerry has it under control
for you USA chaps. I agree with his assumptions, however there are those who
don't agree.
George ( down under)