Ed Anderson told me he will make a presentation on intake manifold
design using this theory at the up coming Shady Bend Rotary engine
powered airplane fly in on October 24th, 25th and 26th.
It appears at this time major improvements in intake
manifold tuning MIGHT be possible using this theory.
One of the best internet references I have found so far
is this one.
http://www.ae.gatech.edu/~comblab5/Publications/RobEJASAApril2003.pdf
There may be other good ones. If you find a better one please let me know.
Read up on the theory so you can ask Ed intelligent questions.
I am sure Ed will jump on here and fill us in some more
before Shady Bend.
Paul Lamar
Thanks Paul, (I think {:>))
Finite-Amplitude-Waves (FAW) are indeed at the heart of the Dynamic
Intake Effect (DIE) or "Dynamic Supercharging" as the Mazda Marketers often
refereed to it. Found on the NA 13Bs from around 1884 through at least 1992
or so. Fortunately, to understand the DIE effect which makes use of the
characteristic features of a FAW, you do NOT have to understand the higher
theoretical basis of FAW. Original solutions of FAW reactions in a
tube/duct involved Hyperbolic Partial Differential Equations (which are just
about analytically impossible to solve for real world applications) which
only became solvable with Numerical Techniques (the digital computer). Now
you may feel comfortable with Hyperbolic Partial Differential Equations, but
they are pretty tough animals and I, for one, intend to avoid them. No,
you won't have to bring your computer either {:>).
So, certainly read all that you are interested in reading about FAW - BUT,
if you come expecting anything close to the study done in Paul's reference
above - YOU WILL be disappointed {:>}. The highest math that you will need
to understand what I am going to present is high school algebra. Even that
is probably not absolutely necessary - but it makes it a bit easier.
Paul makes a good point, the DIE will not make a "silk purse out of a sow's
ear". If you don't have a basically good induction/exhaust system to start
with then DIE won't pull the fat out of the fire. The Mazda engineer's spent
a lot of time getting a good basic induction system developed to provide the
characteristics they desired. Available information I have (mostly
provided by sources from Paul, thanks, Paul) indicates that somewhere around
a 15% increase is probably the maximum obtainable. My own calculations also
indicate that 15% approximate power increase over that produced by a good
induction system.
For those of you pursuing "Forced Induction" designs this information will
be of limited interest. For those of you which hope to eke out every last
HP residing in the NA rotary, this will probably get your attention. Right
now the Analysis only addresses the two rotor engine - sorry you 20B guys.
I do have some initial thoughts on DIE and the three rotor, but they require
some more investigation.
The main focus of my presentation is to show the derivation of the
significant variables that affect the DIE operating points and their
interrelationships (via some simple algebraic equations). Some of it will
come as no surprise to many of you, but I think other areas will be eye
opening. The bottom line is that I have used parametric equations derived
from my analysis to show the relationship between manifold length and these
other variables of the DIE and have produced graphs of these parametric
curves and compared the results with what little specific we have from Mazda
on the DIE. So you will be able to judge the validity of the analysis for
yourself.
So ED's DIE presentation (as contrasted with something Mazda might own up to
{:>)) will consist of three parts:
A very short lead-in on what got me started down this path
I. A short overview of the DIE as implemented by Mazda to bring everyone up
to a minimum level of understanding of the DIE system
II. The analysis and derivation of the variables and equations that govern
the DIE (this is where the algebra comes in)
III. The comparison of the results of these equations with what we know from
Mazda about DIE
The presentation consists of approx 65 slides at this point, so bring your
pillow - this may be the most relaxing time you'll have at Shady Bend.
For those of you who can not make the Shady Bend flyin. This information
will be make available to you (assuming that I survive the tomatoes {:>))
after Shady Bend. If Paul becomes convinced (yet to be determined) that the
results are meaningful - who knows, they might even show up on his Web page.
If they do not then, you will have Paul's de facto assessment of my Analysis
{:>)
That is all that will be revealed before Shady Bend - thanks for the
announcement, Paul.
Best Regards
Ed Anderson
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