I think Jeff (jeff.doddridge@gmail.com) cut these down for Mazdatrix.
It does away with the round oil seals which I suspect we don't need.
The oil seals have unavoidable friction which in theory burns slightly
more
fuel.
My guess, based on these enclosed charts, is a 33% reduction in rotary
engine friction. The engine will generate more power at the same RPM as
well.
Furthermore the side seals will get more oil for possibly lower side
housing
wear.
It also cuts the weight of rotors so the counter weights are slightly
lighter and the load on the rotor bearings is reduced at any given RPM.
My Mazda Cosmo had melted oil seal O-rings and I drove it for years.
It smoked like a radial engine when you started it up but then it stopped
after a few seconds. I never noticed higher oil consumption.
Mazda mentioned this when they were talking about the first rotary engine
they
built. It ran fine but they had to add the oil seals to solve the start
up smoke
problem.
I think they will work fine in a p-port aircraft or racing car engine.
Sorry about the cell phone pictures. I forget my good camera when I
visited
Mazdatrix.
Paul Lamar
Paul,
Best idea I have seen in a while. as long as the side seal gaps are done
very well, this should work fine. I once worked a an engine that a school
had rebuilt and the oil seals were installed upside down. Smoked like a
navy
smoke layer.... but the side seal gaps were big as well. I like the
increase
in corner seal oiling.... I think I might have to build one of these to
try....
Larry
Great minds.........:)
Paul Lamar
Paul,
for anyone doing this, make sure you radius off all the sharp corners left
by the end mill...... unless you like cracks
Larry
I just had another idea. The amount of oil retained in the rotor after
the engine
stops depends of the size of the large oil drain back oil in the center
housing. This
oil will leak down and get to the bottom of the engine to create smoke on
start.
Making the large drain back hole even larger will reduce the quantity. It
will also
cut a bit of weight out of the center housing.
Another possibility is a tiny .032" dia. drain hole drilled in the bottom
of the
rotor housings letting the accumulated oil slowly drain back to the oil
pan.
This may eliminate the smoke on start up.
Paul Lamar
Hi Paul,
You guys are always coming up with something new
for rotaries, as I have said before I think that if even a fraction of
the effort that has been put into
piston engines into rotaries the rotary would not be on the bottom of
"joe blow" wanna list. The big factories do not have all the answers.
John Burey.
Paul, I would be concerned about opening up the size of the center
housing where the E-shaft passes thru. The shaft and rotors operate in a
semi-flooded condition to remove heat from the rotor. Enlarging the hole
would reduce the oil volume in this area. Also the "dogleg" in the
E-shaft appears to me to pump any oil that gets to the center housing back
to the pan and with a lower oil level foaming of the oil could be a
possibility. The removing of this much surface area would also reduce the
amount of heat that can travel thru the center housing to the water
jacket. A small (.090?) hole at the bottom of the red line in the
attachment would vent to an area of nearly equal pressure and lower the
retained shut down oil level slightly.
It would seem that the real issue is oil that finds it's way past
the rotor side combustion seals which is an area lower than the drain. I
see in the other attachment an idea to vent the bottom of the rotor
housing. This area is under constant combustion pressure from the
continuous expansion strokes and would vent into the oil system
both exhaust gasses and some particulate residues. This could however be
made to work. Rather than going thru the water passage it would seem better
to go through the clearance between the tension bolt and it's hole which is
relatively large in the rotor housings, moreso than the side housings which
are drilled holes. These holes run between the water jacket seals and are
therefore not intended to be sealed from coolant, however "O" rings similar
to those around the hollow dowels could isolate a bolt hole. The oil port
would need to be sealed during operation but open at shut down. I might
suggest a plunger ported to be closed by the exhaust pressure or by engine
oil pressure on a differential area spool as used in a balanced pressure
hydraulic relief valve. The large area side overcomes the smaller area side
because they see the same pressure..
When we get done chewing on this bone how about a thread dealing
with exhaust headers. So far it seems that 32" long is the only advice.
How about diameter and is the diameter constant or increasing slightly.
Also I read something about an inverted cone a few inches from the end of
the header which reflects a sound wave back up the pipe to cancel the
outgoing wave sound. Apparently having it at a distance still allows some
exhaust scavenging because the pressure wave reflects back from the end of
the pipe similar to the intake runner at 18" length. With parts from
Jeff and RWS we can get the engine bolted to the airframe with a prop,
the EFI and ignition. We now have a handle on the cooling thanks to your
book so might it be time to tinker with the exhaust side a little.
george grimes
Due to the complex orbiting motion of the rotor the cooling oil, what there is of it,
stays out near the apex seal slots. It is less oil than most people think.
There is not going to be a lot of exhaust gases coming through .032 dia. hole.
The hole is drilled in a vertical rib in the bottom of the rotor housing. It does not
intersect cooling passages.
Paul Lamar
Did some playing with a 12A rotor to see what impact it could have on my single rotor
work.
The impact would be significant, if it works.
The rotor in the picture weighs 3,500g versus 4357 in original configuration. Running
this weight through balancing analysis shows less balancing moment required on the
balance weight than on a two rotor. This alone is worth pursuing this for the single
rotor.
Machining the rotor on the CNC is a no-brainer.
Who came up with that idea anyway? Probably the most significant one in a long time.
The only technical issue still open is demonstrating rotor balancing. If MazdaTrix
can do it, I would put that rotor in my test engine and see what happens.
Anyway, thanks to the guy who came up with this.
Richard Sohn
N2071U
http://www.fairpoint.net/~res12/home.html
It was Jeff as far as I know.
Paul Lamar
This last jpg is of a Wankel AG rotor. No oil seals.
Paul Lamar
------------------------------------------------------------------------
It occurred to me that is now possible to make a billet rotor out of stainless steel.
Thermal conductivity of Stainless Steel is 16 while that of Cast Iron is 55.
W/(meter.degree C)=0.5779 Btu/(ft.hr.degree F). What this might mean is less heat
will be lost to oil cooling and possibly a higher compression ratio will be
possible. AKA a shallower bathtub in the face of the rotor. This could result in
lower fuel burn. In Rolex GT racing the slightest increase in gas mileage can make a
major difference in results as cars are only seconds apart at the end of 2 hours.
Less time in the pits refueling.
The recent Speed Source RX8 results at Road America improved the championship point
result to third place behind Ferrari and Camaro. Of course this does not mean much
in terms of engine power to weight ratio as the rules about minimum weight and max
engine RPM are adjusted race to race. The old Can Am road racing rules are far better
IMHO.
Therefore the organizers determine who is going to win opening the door to serious
corruption and qualification sand bagging.
It would be far more fair if all cars had the same rules as such as minimum weight to
displacement ratio and/or displacement to frontal area ratio. For example the
Porsche's are allowed a 4 L engine while the RX8's are limited to 3.9 L.
The Porsche's and Ferrari have lower frontal area and drag being only a 2 place cars
while the RX8 and 5 L Camaro are 4 place cars. No RPM limits.
Without these types of minimum weight rules the RX8's would dominate due to the
superior engine weight to power ratio of the rotary. The minimum weight of the
racing car should be a performance based on what the roll cage will support both
vertically and horizontally. Sort of the same as aircraft rules.
Paul Lamar
Great minds think alike.... EJ and myself had that same conversation middle of last
week....MazdaTrix better get ready to do a bunch of balancing!
Larry
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