> > I have been monitoring this group for three months now and
     > look
     > forward to
     > > each day's postings. I am an active pilot (P210) and a
     > long-time
     > > subscriber
     > > to Kitplanes, so your discussions surrounding the
     > perfection of
     > the rotary
     > > aviation engine really intrigue me. A 337 running two
     > rotaries
     > would be
     > > one
     > > heck of an airplane!
     > >
     > > I apologize to the aviation purists that my posting is not
     > aviation
     > > related,
     > > but it is rotary related. I own a small manufacturing
     > company in
     > North
     > > Central Montana which has twenty years experience building
     > portable
     > > natural
     > > gas compressors. Our units feature rotary screw compressors
     > driven by
     > > piston engines (natural gas powered).
     > >
     > > I would like to investigate the possibility of utilizing the
     > rotary engine
     > > as a "valve-less" compressor. I am hoping that through this
     > group
     > I can
     > > find individuals who would be willing to provide engineering
     > services for
     > > this concept.
     > >
     > > Ideally, I would like to see the driver and the compressor
     > integrated into
     > > the same rotary engine block--one rotor driving another.
     > >
     > > My major concern is that the stock rotary has too much
     > inherent
     > overlap
     > > between the intake and discharge ports to work properly as a
     > compressor
     > > without the installation of intake and discharge valves. Is
     > there
     > a way
     > > to
     > > re-configure the ports to eliminate overlap?
     > >
     > > Cole T. Chandler
     > >
     > > Sure you put the output p-port just about where the spark
     > plugs
     > > are.
     > >
     > > Wankel rotaries have been widely used as compressors.
     > >
     > > Paul Lamar ...No rotor no motor.
     >
     > Isn't the overlap eliminated in the Renesis, or is it just
     > minimized ?
     >
     > John
     >
     > Yes it is (sort of) but that has nothing to do with a compressor
     > configuration. The compressor config needs an air outlet
     > port near the combustion chamber. If it is anywhere else
     > the engine compresses the air and then lets it expand again
     > and THEN merely escape through the existing exhaust with no
     > pressure change. The difference is there is no fuel and spark
     > to expand the air.
     >
     > Just bore a p-port hole where the lower spark plug hole is
     > and you have a mighty fine, perfectly balanced, 10,000 RPM
     > air compressor capable of horrendous air flow.
     > You don't even have to do that if you want lower flow.
     > Just screw a hose fitting in the spark plug hole.
     > Block the top spark plug hole with a stock
     > spark plug. You will get at least 150 psi.
     > If you fill the depression in the rotors you will
     > probably get close to 200 psi or more.
     >
     >
     > Paul Lamar ...No rotor no motor.
     >
     >
     > As I understand your suggestion, there would be only one
     > compression
     > cycle
     > per rotor revolution? The normal "exhaust" stroke of engine
     > would
     > not have
     > any function and not be utilized? Would this "dead stroke"
     > create wasted
     > horsepower?
     >
     > Cole
     >
     > Yes but if you vented it to the atmosphere it would consume
     > very little power. That part of the cycle could be a used as
     > a vacuum pump with the p-port exhaust as the exhaust port.
     > You would need another intake port below the pressure
     > port on the spark plug side. The pressure output port
     > will need a one way valve. So too the vacuum input
     > port. One problem might be apex seal lube but try
     > self lubricating Rulon apex seals. A mixture of Teflon
     > and Kevlar. What you wind up with is both a vacuum pump
     > and a compressor in the same stroke and in one revolution
     > of the e-shaft.
     > --
     > Paul Lamar ...No rotor no motor.
     >
     > There are in fact rotary compressors and have been for a long
     > time.
     > Most large industrial plants if there is a requirement use
     > rotary
     > compressors. Many air conditioning units use rotary compressors
     > even in
     > autos.
     > R Matt Doody
     >
     >
     > Paul,
     >
     > Is it viable to use one rotor as a supercharger for the other
     > rotors
     > in the engine?
     >
     > If this is feasible, it might make sense In a turbocompund
     > engine
     > where you have an exhaust turbine connected to the engine shaft
     > anyway, so the power to drive the compressor rotor would be
     > deducted
     > from whatever your turbine is putting in.
     >
     > This might have packaging advantages. You could just put your
     > turbine right behind the engine with a gearbox. The output
     > from the
     > compressor rotor would be fed to the remaining rotors.
     >
     > The question is how much power it would take to run that
     > rotor and
     > what would its thermal efficiency be? Also it is pretty heavy.
     >
     > Perhaps use a small single-rotor engine like the Aixro go-cart
     > engine and use that as the compressor?
     >
     > I'm thinking here about a ducted fan turbocompound application
     > where
     > you want the engine to be as cylindrical as possible. This way
     > everything would just go axially on the back of the engine --
     > the
     > compressor, the gearbox and the turbine. The turbine outlet
     > would be
     > facing straight back from the middle of the engine, so you
     > could put
     > a nozzle on it and get thrust at high speed...
     >
     >
     > Regards,
     >
     > Gordon.
     >
     > For some strange reason the engine runs rough on only
     > one rotor. I know not why.
     >
     > Paul Lamar
     >
     >
     > So here's an idea -- get a 20b & a custom e-shaft. Configure the
     > e-shaft such that the configuration of the lobes for 2 of the rotors
     > matches the lobes on a 13b (180 degree opposed). Send gas to the 2
     > opposed rotors. Use the 3rd rotor (the middle one I would guess
    so the
     > thermal effects on the engine are balanced front to back) as a
     > compressor and feed that into the other 2 rotors. Voila - a
     > supercharged engine that should run nice & smooth.
     >
     > Mark Supinski

    This won't work, guys, because the "free air" volume displaced by the
    compressor section must be larger than the displacement of the engine
    section. The supercharger must squeeze a larger volume of air into a
    smaller volume to increase the engine charge.\

    I know we are off the original subject of making a compressor from a
    rotary engine. But, Gordon's comments about the Aixro go-cart engine
    and cylindrical geometry leads me to this idea: use an Aixro engine
    to drive a Rotrex supercharger to pump intake air to a 13b. Boost
    pressure would be easy to control using a model airplane servo on the
    Aixro throttle. The Aixro/Rotrex system could be remotely located,
    thereby simplifying the design of an intercooler system and giving more
    control over weight/balance issues. Bleed air would be available from
    the Rotrex compressor for cabin heat.

    Would this scheme be legal at Reno?

    Aubrey

    Sure. Here are some pictures of a White Lightening
    with something similar. Used a Rotax 2 cycle to drive the
    compressor. The Germans had bombers in WW II that did
    this.

    --
    Paul Lamar ...No rotor no motor.


    That's a neat idea, Aubrey.

    The ability to easily control boost makes this something to think
    about. You could just dial in any manifold pressure you want,
    anytime you want it.

    I would guess that the aixro engine making 40 hp could easily run
    the biggest compressor in the Rotrex lineup. Probably enouhg boost
    there for a 4-rotor...

    Here's a picture of an RC model rotary -- I think it's just good for
    a couple of hp so it would have to be a very small compressor. What
    we need is something in between this and the aixro for a 2-rotor engine.


    Regards,

    Gordon.



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