"Rogers, Bob J." wrote:

Based on all that I have read in available literature and from comments

on

this forum, it appears that the use of peripheral port intakes provides

a

significant advantage in power for the rotary engine.  Because of the
agressive timing on a peripheral port, however, it seems that a major
problem associated with this type of intake is very poor idling
characteristics.  How bad is it really?  I know that Powersport is using

a

butterfly valve at the port opening to improve air  flow characteristics

and

velocity at low engine speed.  They also have intake tubes that are less
than 1 and 1/2 inches in diameter, which increases airflow velocity and
improves idle characteristics, when compared to the huge port openings

that

Racing Beat offers.

Before I spend a lot of money on the modifications necessary to convert

a

Mazda 13B to a peripheral port intake engine, I would like to get a more
thorough discussion of the pros and cons, along with the technical

aspects

of what effect the peripheral port has on overall engine performance.

Does

anyone know of a book, treatise, technical paper or other comprehensive
discussion on the subject, including actual data on just how poorly the
engine really idles?  I am hoping that someone has already been down

this

road and has written extensively on peripheral port engines.  Is anyone
currently flying with a peripheral port engine, other than Powersport?

Any suggestions would be appreciated.  If you know of a technical paper

or

book, I would like to know how to get it.  Thanks.

Check our web site below for a list of books and papers.

Paul Lamar

"Rogers, Bob J." wrote:

I had already looked at the impressive list of technical papers shown as a
link on your web site, but none of them seemed to address the questions
posed above, nor did the titles of any of those papers appear to deal with
the effects of a peripheral port intake on rotary engine performance.  If

I

missed one, a specific reference would be appreciated.  Surely, this issue
has been analyzed and reported on somewhere.

Bob Rogers

A couple of papers that discuss the subject of P-ports are SAE 920309
amd SAE 841017.

We have had extensive discussions on here about P ports. You might try the
CD. Ken Powell and I are in the process of building a P-port engine as we
speak.
We will report its idle characteristics. When Everett and Allan Tolle
were racing the Power Sport engine in Fl at Sun & Fun the idle sounded
OK to me.

Are you building a sea plane?

Paul Lamar

Thank you for the specific references. Comments from Lynn Hanover were also
very helpful and encouraging.  I am building a Mustang II and am just about
ready to start on my engine installation.  I want to build a normally
aspirated engine using a turbo block with N.A. high compression rotors, much
like Tracy Crook has done.  If I can get them, the 3rd Generation rotor
housings seem to be a little better than the 2nd Generation housings,
because of the improved carbon-graphite coating on the housing wear surface
and the machined water passage around the spark plugs for cooling.  I really
like the idea of a P-port intake, but was concerned about the idle
characteristics.

I think that is a teflon coating on the housings. It was mentioned in
one of those SAE papers as I recall. The six port timing is as
radical as any P-port that I have seen. So far nobody that I have found
so far has ground out the partition between the two ports on the 6port end 
housing and I suspect that might give more power than just running
them as is or the four port. If you do build a four port make sure you 
take max advantage of the porting templates out there.

Paul Lamar
 
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