The trouble with any kind of wear coating on bare aluminum is there
are only a couple of molecules between you and disaster. It is
extremely sensitive to any kind of foreign particles. The only kind of
tried
and true, robust and reliable wear surface for piston engines and rotary
engines is a hard steel steel liner.
Paul Lamar
Paul, earlier you said that the steel liner increased thermal
efficiency, would putting a 2 or 3 times thicker liner in, make a
significant
difference?
Dave James
I think it would as heat transfer is a function of the distance it must
travel. Everything I have learned on this subject in regard to the
rotary
has to do with keeping the oil working between the apex seal and
the wear
surface. That is what the cooling system is required to do.
In that case just using synthetic oil should cut the cooling
requirements. I discussed this with the Mazda factory several times
and their
attitude was we did not try Mobil One so it is not endorsed one
way or the other.
However the large Japanese oil company Idemitsu sells synthetic oil
for the Mazda. I use it in my RX8.
So far I have not seen a tech paper on this subject where synthetic
oil was tried back to back. It should be investigated with both
iron and
silicon nitride seals. The question is: What temperature can the wear
surface be and still work?
Perhaps Frank Herfert can help in regard to a tech paper on this
subject.
Here is some info from Rotary Engine.
This is relevant to piston engines as well.
Paul Lamar
This is an interesting chart from Heinz Heisler book
Advanced Engine Technology. You can see how the oil film would cool
the apex seal. Organic oils break down around 250 F so the OMC was
designed
around that factor. Synthetic oils help a lot.
The apex seal takes the brunt of the heat as it sweeps all the hot gas
stagnant film in front of it. The steel wall temperature is quite
low. My guess is 300 F.
Silicon Nitride seals are a major advance and should be used in all
rotary aircraft engines as they will tolerate 1000 F.
Paul Lamar
Paul,
Mazda went trough hell and high water to solve the chatter problem.
Since then 2.5 million steel lined chrome plated rotary engines have
been sold. All others have failed.
Henry Ford said : "Show me a pioneer in technology and
I will show you candidate for bankruptcy" . Or words to that effect.
I agree with Henry :-)
If it were me I would copy Mazda with regard to the wear surface.
Paul Lamar
Nice Paul, good info on the apex seals.
The chrome plating of the rotor housing is the same technique used
for Chrome plated piston cylinders?
David Mikesell
Yes. I would think any chrome shop could do it. I think they
reverse the current for a short
while after it is done to get a bit of porosity on the chrome layer
to enhance oil wetting.
This would be far less expensive than any other kind of effective
coating on aluminum.
2.5 million rotary engines prove it works.
I think they can mask off the surfaces that do not need to be chromed.
My name for the all steel new design is "Unsymmetrical Rotary"
Copyright Paul Lamar 2016
I will scale it up to Mazda size and determine the weight.
I'll bet it is not much more than a stock Mazda rotor housing.
----------------------------------------------------------------------------------
I was right! The stock Mazda ( mostly aluminum) rotor housing
weighs 6.5 pounds. The Unsymet all steel water cooled weighs 7 pounds.
Plus or minus a few ounces.
It is all that useless junk on the cold side of the Mazda rotor
housings.
The air cooled Mazda version would be about the same weight.
The way to make the aluminum heat sink fins is gang slitting saws.
This is the way P&W and CW did it in the old days on radial engine
cylinders.
The way to get rid of most of the material in the big block of
steel is drill a trochoide pattern roughly in the center. Then band
saw it out.
That is the way the Wright brothers built their first crank shaft.
They drilled a
big block of steel then they sawed it to rough shape.
Anybody for an air cooled one rotor Mazda size rotary engine weighing
70 pounds and putting out 130 HP ?
E-shaft and rotor the same Mazda parts. Of course :-)
Paul Lamar
Build your own housing, maybe some ideas hear !
http://www.rx7club.com/old-school-other-rotary-63/tegheim-home-made-4-rotor-wolvo-project-892879/page32/
Steve Carlisle
Wow!! This guy is doing what we need to do. If you are a member see if
you can get an email for him. He might sell us steel rotor housings.
If it was not winter it is almost worth a trip over there :-)
---------------------------------------
The guy's name is Tony Tegheim I think. I also think he owns a company
called Mooseville Performance. I have been able to find an email
address or phone number yet.
Paul Lamar
Unsymmetrical Rotor housing:
I will order plate stock 1/4" thicker than needed for my motorcycle
engines. Using milling center cut the outer diameter complete, clean up
cut the end face, then cut down into the block forming the rotor cavity
complete. Eat my
Wheaties and gently turn it over with a hoist. locate from the same
corner that was zero point at start. Use a wider end-mill to cut the
face to OAL housing finished dimension thus freeing it from the plate. I
believe a hollow rectangle can be bought from a company like this. (Much
lighter).
http://www.benedict-miller.com/content.cfm/4130-E4130-Alloy-Steel/AISI-4130-E4130-per-AMS-6350-6351-Plate/category_id/102/page_id/123
My shop will have a plasma/water jet cnc and will cut the center of the
plate for the rotor and stationary gears or other small parts.
Being thick material it may be quicker to mill the blanks out and have
the same operator place them in the Hardinge turning center to turn/cut
the gears. I grew up making machine parts from age 12 in a family shop
that specialized in monthly runs of 100-1000 pcs ea. for blanket orders.
When hired by Coors you had to qualify in 3 journey trades. 3500
applied...I was 1 of 40 hired for a new plant start up in Virginia. A
working knowledge of complex mechanical processes and growing things in
our 300' aquaponic greenhouse is my entertainment now.
In a few weeks an investment I made should mature. Moving ahead in the
1st. Quarter of 2017 is my hope. Provided my being paid does not get
kicked down the road for the umpteenth time. If payment is made soon it
will be my pleasure to work on marketing aviation engines of several
sizes with you and the remarkable others on this thread.
The corporation that owns everything does nothing...the corporation that
does everything owns nothing. Both held in a trust offshore.
Our CPA was an ex IRS field agent.
Sincerely yours,
Michael Nash
The Rotary Engine free News Letter. Powered by Linux. If you want off
the list PLEASE let me know and I will remove you. ACRE NL web
site.
http://www.rotaryeng.net You Tube
http://tinyurl.com/beqqxas
Copyright 1998-2016 All world wide rights reserved.