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Hi Alex,
Mark and I were discussing non-EDDIE intake tracts which I should have pointed out - thanks for identifying this for the other guys; your comments are entirely correct. I'm afraid that I will end up just like everyone else, i.e., building several manifolds. I would like to try the idea that I just identified as well as an EDDIE intake on a peripheral port engine. The only way to know for sure is to build and test differnet ideas.
I would like to remind everyone that if your engine uses different intake port timing for you primary and secondary ports then you have multiple timing events which will make building an intake manifold for max power more difficult.
Ken Powell
> EDDIE tuning and Helmholtz operate on different principals. EDDIE
> tuning uses the pressure wave from one intake closing to force air into
> the second intake. Helmholtz uses a reflected low pressure wave
> (reflects into a high pressure wave) to force air into the same
> cylinder. A resonant chamber will change will flip low pressure waves to
> high pressure waves. You do not want this for the EDDIE tuning.
>
> Alex Madsen
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of kenpowell@comcast.net
> Sent: Wednesday, May 12, 2004 11:56 AM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] PP variable intake
>
> Hi Mark,
> Yes, I also considered the resonant chamber (also used on some
> motorcycles, which is my real background). The resonant chamber would
> be lighter and maybe easier to build but I liked the 'tunability' of the
> separate runners for each rpm range. If I need either shorter or longer
> runners I can change the length by inserting a longer runner connected
> with hose & clamps. Also, I have the formulas (I used Ed's formulas) to
> calculate the tubing lengths and I don't have any idea on how to
> calculate the needed volume of a resonant chamber. It is also
> interesting that some off road 2 strokes use a resonant chamber on the
> exhaust as well. I haven't ruled this out yet but the butterfly would
> be living in a harsh environment ideed! Maybe we should consider a
> resonant chamber on the exhaust in an effort to get the overall length
> shorter. This would definitely be a research project for AFTER I get my
> RV-4 built and flying (which will be NEVER at the rate I'm going!).
>
> Ken Powell
>
>
> > Ken,
> > This is directed at the engineer types in the group... What I was
> thinking
> > is would you actually need two separate runners, or could you add a
> > resonance chamber to the shorter intake so as to fool it into thinking
> it
> > was longer than it actually was? A butterfly valve could open and
> close
> > the chamber. I got this idea from studying the intake on my LS1 Chevy
>
> > pickup. It uses a resonance chamber in the intake between the air
> filter
> > and the TB. Not sure why, but though this same idea may work here
> too.
> >
> > Mark S.
> > (back to lurking)
> >
> >
> > At 02:19 AM 5/12/2004 +0000, you wrote:
> > >Rusty,
> > >I just gotta ask - why don't you just copy Tracy's intake and be done
> with
> > >it???
> > >
> > >I calculated intake runner length for a PP engine last year but
> > >unfortunately I don't have the results here in sunny Florida (playing
>
> > >tourist, much to the chagrin of the natives). So these numbers mean
> > >nothing, but I THINK that I calculated that a 16" runner length for
> 7400
> > >RPM (2.85 redrive) and 24" for either 5600 or 6000 RPM. The problem
> we
> > >are all seeing here (and Ed is addressing) is that we need several
> > >distinct lengths to correspond to the differing engine RPM. Since I
> am
> > >dealing with a PP engine I am sorta on my on but Ed's work has been a
>
> > >great help because his formulas will allow you to calculate the
> length for
> > >a given RPM. My thought on the solution to this is a little
> different
> > >from Ed's infinitely variable length but simpler to build - since a
> PP
> > >engine only needs 2 runners (1 per rotor) the idea is to have a short
>
> > >runner (16") for high rpm and a long runner (24") for cruise; a
> butterfly
> > >valve will be used to switch between the two. I hope that this setup
> will
> > >not need to be automated - set the butterfly to 'long' for takeoff,
> climb
> > >and low altitude cruise and 'short' for WFO and high altitude cruise.
> > >
> > >Ken P.
> > >
> > >
> > > >> 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
>
> >> 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
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