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Ed,
There is a sealing technique that relies on surface tension that might work,
tolerance would not have to be super accurate.
Visualize a small groove on the inside of the outer tube, and then fill it
with a high temperature silicone oil that is loaded with very fine iron
particles. put a magnet around the tube, and the particles stay in the
location of the magnet, and the surface tension of the oil to the particles
holds the oil where the particles are. Then slip the inner tube into the
outer tube, and the oil-ring acts like an 0-ring, but with very low
friction.
Bill Schertz
----- Original Message -----
From: "Ed Anderson"
Subject: [FlyRotary] Re: DIE the short Answer
>
> Either I am going to have to stop talking with you guys all together or
else
> start talking to you a lot sooner on my projects {:>) Good idea, Jim, if
I
> say so myself.
>
> The two tubes in my newest manifold design (after combining primary and
> secondaries for each rotor) do telescope within one another. There is no
> sealing at this point. IF you use tubing meant for telescoping you can
get
> it so that there is .0045 " clearance between the OD of inner tube and ID
of
> outer tube. Now this does not stop air leaks, but it sure slows it down.
> You can maintain pressure in the tubes just with your breath. However,
what
> I next plan to do is to have the tubes nickle plated (as I did Tracy's
> PSRU). Nickle it turns out has a property that is akin to lubrication
> (Sorry not sure what the mechanism is) in that given Nickle's hardness and
> this "Lubrication" property it would 1. prevent the aluminum from gauling
> and 2. facilitate the tubes sliding and 3. If you coat with the right
> amount you reduce that .0045" clearance even more. Now, my problem is I
> don't know for say a 2" dia tube what clearance below .0045" might be
fairly
> air tight. As I said, the leak is slow enough with the .0045" that your
> breath can maintain pressure in the tube against the leak. So that big
pump
> of an engine might not notice the leak at all except perhaps ad idle. If
> thats not the case, then rubber booties like you suggest would probably
> work.
>
> So my two tubes have the plenum and throttle body with two injectors on
the
> one end and the lower manifold on the other. IF my concept for
> self-alignment of the tubes work out together with my plan on using a ball
> bearing draw-slide (or something a bit more expensive designed for this
type
> of thing) and mount the Plenum to the part that slides and the other end
of
> the drawer slide to the lower manifold. Then a screw driven by a 12V
motor
> would drive a "NUT" fixed to the plenum up and down on this track.
>
> I really would like to use one of those electromechanicam actuators that
> have the screw going throught the middle of the motor, but they are a bit
> expensive.
>
> I think I partially answered your last question, already. My design have
> the two runners from each rotor "merged" into one tube for a total of two
> tubes. In the automobile and with different port timing for primary and
> secondary, the separate runners were just about necessitated. However, if
> like with a turbo block or any block where the port timing is the same,
then
> I can no longer see any great advantage for separate runners. However,
> merged or not, it does not change the pulse timing in the rotary for the
> EDDIE. I don't quite see that your suggestion of a common plenum up close
> and personal to the rotaries would work with the EDDIE. I'll have to give
> it some thought.
>
> Calibrate - based on manifold air temperature, Hummmm. Like I say -
either
> got to stop talking with your guys or talk with you a lot sooner {:>)
>
> Some excellent ideas. Keep 'em coming.
>
> Ed Anderson
>
> Subject: [FlyRotary] Re: DIE the short Answer
>
>
> > 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
> >
> > >> 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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