Message-ID: <3F71D335.187C68BB@frontiernet.net>
Date: Wed, 24 Sep 2003 13:24:05 -0400
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: DIE the short Answer
References: <list-2601739@logan.com>
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I was just yanking John's chain, but as long as we're here,
let's progress a little.  So you have to use something more
substantial than a condom.  Big deal.  What if you made a
telescoping section in the intake runner (much easier to do if
the runner is straight :o) and a jack screw actuator (something
like an electric pitch trim)  to slide the upstream side of the
runner out over the telescoping section.  You could make it
pretty loose so it wouldn't bind and then cover the telescoping
area with rubber "accordion" tubing to prevent leaks.  If you
had an indication of how telescoped the intake runners are, you
could calibrate it in Manifold Air Temp and adjust the length to
match the MAT you're looking at at any given time.

Tuned exhaust headers on 2-stroke motorbikes are tuned to an rpm
and length so that a pulse will travel the length of the pipe at
the local speed of sound during the period from one exhaust
pulse to another.  EGT and racing rpm in motorbikes is pretty
stable, so one length will work.  Intake temp is much less
stable in a rotary engine, so variable length runners
would be a must if you mean to avail yourself of the DIE effect
under anything even remotely like typical operating conditions.

Would it be possible to have an intake plenum at the block so
that both rotors draw from the same runner?  That would shorten
the runner to half what it needs to be now, and make it easier
to expand since you're varying the runner length by a percentage
of itself.  What is the engineering rationale for four intake
runners to serve two rotors?  Is it more important than DIE?

But I've already told you more than I know ... Brain farts have
that effect ...
Jim S.

Ed Anderson wrote:

> Hey!  I like it! Jim
>
>     Has the appeal of simplicity, low cost and easily adjustable.  Did I, by
> chance, ever mention that "Concepts are easy... the Devil is in the
> details"?.  Well, the first prong of the pitch fork I see with the idea -
> is - 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{:>)
>
> Ed Anderson
>
> ----- Original Message -----
> From: "Jim Sower" <canarder@frontiernet.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Wednesday, September 24, 2003 10:12 AM
> Subject: [FlyRotary] Re: DIE the short Answer
>
> > <... a way to adjust ...>
> > Like an india rubber segment in the intake tubes.  Attach to a big lever
> and
> > stretch the intake out a little longer when the air is warmer :o)
> >
> > John Slade wrote:
> >
> > > >  That is indeed the conceptual underpinnings of the EDDIE.
> > > Cool. So all we need now is a way to adjust that timing on the fly, that
> way
> > > we can have our cake and eat it while not having to worry about precise
> > > calculations and configuration issues that prevent us from implementing
> the
> > > theory.
> > >
> > > >>  Homepage:  http://www.flyrotary.com/
> > > >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
> >
> > --
> > Jim Sower
> > Crossville, TN; Chapter 5
> > Long-EZ N83RT, Velocity N4095T
> >
> >
> >
> > >>  Homepage:  http://www.flyrotary.com/
> > >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html

--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T