> 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
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