----- Original Message -----
From: "Charlie & Tupper England" <cengland@netdoor.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, September 24, 2003 2:49 PM
Subject: [FlyRotary] Re: DIE the short Answer


 

Russell Duffy wrote:

   

We somehow have to keep the lower pressure in the manifold (at idle for
example) from sucking the rubber tubes closed.  So the concept is
..err great, err, but needs some more  work on the details{:>)


Two words- slide trombone :-)

Rusty (I'll just turn up the boost)

     

Mazda did the slide thing on the LeMans winner. Remember, car engines
must produce torque over a much wider range than a/c engines. I'm
looking forward to seeing a VE plot vs RPM using Ed's formulas &
manifold. How much detuning is there between 5000 & 6000 RPM?

Charlie

   

Hi Charlie

Mazda did something that appears similar in some respects.  They did indeed
have pipe intakes that they could vary the length of to get better airflow
matching with RPM.  This was an excellent example of "Organ Pipe" tunning.
However, that engine did not use the EDDIE.  It had 3 spark plugs, 10:1
compression rotors, unrestricted intake (I think they even used a "slide"
throttle body so at WOT there would be nothing in the way of air flow)  With
4 rotor it had no problem getting to 6000 rpm against any load that little
race car body weight might have produced {:>).

I would love to provide a Ve plot vs rpm. However, I think we would have to
put the system on a dyno to get the data.  One way of looking at the EDDIE
is that it does, in effect, increase Ve (Volumertic efficiency).  My
calculations indicates max increase is around 115%.   And for that
particular figure it was for around 5700 rpm.  I would expect approx the
same through at least 6500 rpm.  Some things start to happen above that rpm
that makes me leery of hazarding any further extrapolation.

Not quite certain exactly what you are referring to by detuning between 5000
and 6000 rpm?  If you mean the "bandwidth" of the EDDIE then it depends on
several factors.  Most of the effect falls in a region below the EDDIE rpm.
There are things you can do to broaden the bandwidth.  However, when you do
that,  you are diluting the EDDIE by spreading the resulting energy over a
wider band.  Same amount of total energy, so if you spread it you reduce the
energy at the peak.  Now reducing the "Peakiness" for an non racing
automobile may be benefical, but for a  racer and aircraft use, we might be
more interested in keeping the EDDIE at the "sweet spot" rpm.  I think that
is one reason they didn't use the EDDIE on the LeMans.  Also, using the
"Organ Pipe" approach you don't have to have tubes sliding inside of tubes
to keep the effect on the rpm {:>).

At least that is my take on it.  Could be wrong, have been before and will
be again.

Be seeing you in about 1 1/2 weeks, Charlie (provide the Wx holds good)

Ed Anderson