mike h wrote:

Just a heads up, one of the stress engineers and I are going to try to

build

a computer model of the intake path of the rotary (probably start with

just

one port, the end housing, and work from there) to maximize volumetric
efficiency. IE, we want to solve for the changes in velocity and airflow

for

various changes made to say, a stock 88 NA intake.

Anyone able to CC me any relevant SAE papers (I'm not a member) or point

me

to other data sources? Anything I need to watch out for? This guy is

very

good at aircraft but he's not too car savvy, so I need to guide him

along

here a bit.

Mike Harrington

You can buy the papers without being a member Mike. Also some library's
have them on microfiche and they will let you copy them.
See the SAE paper list on the ACRE NL web site.

Mike,

One good book that I have used is Scientific Design of Exhaust & Intake
Systems by Smith and Morrison ISBN 0-8376-0309-9. Mostly empirical stuff,
some theory. All recip stuff, no rotary. A bit dated, but most of the really
useful stuff was done before 1970 anyway. Might help with model validation.
As much as I like computers for design work, I am still a bit cynical when
it comes to computer models of complex systems. Especially CFD
(computational fluid dynamics for the fortunate souls unfamiliar with this
acronym). I have been involved in the design of fans for both noise, flow
etc and have come to rely almost exclusively on empirical data. We tried the
CFD stuff but found that 1 test is worth a thousand models. Tests and
scaling laws are hard to beat. Models like you are talking about work great
for refining designs after you have some initial test data, or for playing
what if games. All the same I wish you great luck and hope that it is a
resounding success. Please keep us posted.

Monty

Chart from Advance Engine Technology by Heinz Heisler.

Paul Lamar

As a computer modeling professional for over 25 years, all I can say is
AMEN.   There are enough difficulties modeling relatively simple
systems that I absolutely cringe at some of the "computer modeling"
that is "done".  OTOH, I have done some work that absolutely amazed
the hell out of me when I did the validation tests.  I have gotten some
fairly complex systems right within less than 1%, but it surprised even
me.  If you have no test data for validation of your model, your model
is an interesting exercise, but little more.

A pet peeve is the "climate models" that tell us what the global climate
will be in 100 years.   Ha!  These are the same people that can't tell
you reliably whether it will rain TOMORROW.  Their "fine" model
uses a 250 km square "element".   Gotta stop before I turn blue!   :-)

Bill Freeman
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

If its for an airplane Mike just copy this intake and make it 18-22 inches long.
You will get 240 HP at 6000 RPM.

Paul Lamar

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