OMC's 4-Rotor Wankel Racing Engine - The Real Story

**E-tec1** · 07-30-2009, 09:13 AM

Im not gonna say that maybe that wastn part of what happened,,,,,the engineer that went to infinite that brought me worked on the 2 rotor sea drive, i believe George Miller was chief engineer at stern drive at that time and thats why that project existed, ive gone on infinites websight a few years after i was canned and they still showed doing rotatry work, i wonder if the 2 rotor was not part of that deal????, i dont remember alot, was too busy makin parts all day long to get too involved in the politics............

do u remember Jerry Crichton??? Mike Roepanack??? I talk to Ziggy once in a while... I lost contact with Mouse a while ago.....I dont know if u knew but Jim Nettles passed a couple years ago .....

**powerabout** · 07-30-2009, 01:34 PM

They are still workig on it
http://www.moller.com/files/Breakthrough.pdf

John
when you rebuild one is that simple to do and fast?
How does a rebuild compare to a piston engine

Powerabout

**mercmack** · 07-31-2009, 02:37 PM

I want to thank john sheldon and others for this great story..
Its not going to be to long before all this is going to be lost in history...i know i am just a old retired ob mack of 52 years..but i still enjoys how the bus was developed over time..stock and racing both...99.9 percent will never know about the rotor eng and how it influenced the industry..:d:d

**Rotary John** · 08-05-2009, 05:52 PM

The History of the OMC Rotary Program
By John Sheldon

Part 4; Additional Rotary Programs
In the 70’s, OMC owned several non-marine companies. Among
them was Cushman Vehicles. Cushman was using a B&S 12 hp
4-cycle engine in their golf cart. The engine actually
produced 9 to 10 hp. I was asked if I could develop a true
15 hp engine for a golf cart application. To expedite
things, I used the snowmobile engine, detuned to produce 15
hp at 3600 RPM. This was accomplished by removing the
peripheral intake port and using only a small downstream
side port. The engine was built, dyno tested and sent to
Cushman for installation in a golf cart. The only report I
ever got back was, “the acceleration was beyond
exhilarating, it was down right frightening”. Seems the
detuned engine with a large displacement gave considerably
more torque than the B&S engine had. When you nailed the
throttle, it picked the front wheels off the ground. Even
though Jim Briggs was responsible for Cushman, they decided
it was just too much engine for a golf cart and they
didn’t want to fund a completely new engine for their
application.
Pioneer Chain Saw was another OMC company. Vibration was
becoming a major issue with chainsaws. Long-term exposure to
chainsaw vibration caused Reynolds disease in the hands of
the user. Some manufactures chose to use vibration isolation
to help reduce the problem, but this added considerable cost
to the unit. Pioneer wanted to use a rotary as it was
dynamically balanced with only torsional inputs. As a side
note, nobody figure out at the time that the vibration input
from the chain cutting wood was equal in vibration to the
piston engine. I was assigned the project to design and
develop a 5 hp air-cooled engine for a chainsaw. Pioneer
engineering would incorporate the engine into a new saw
design. Knowing 1 hp per ci was feasible, I decided on 5 ci
for the displacement and copied the snowmobile cooling
arrangement. This meant a very high performance fan to be
able to cool the engine properly. Normally chainsaws had the
starter on the left side, but because of the airflow
restriction caused by the starter, I told Pioneer, the
starter could not be in front of the fan. The starter on the
left was to allow closer clearance from the ground to the
bar and chain. Pioneer didn’t want to give up this
feature, so they designed a swing arm starter like some of
the outboards used. To use this type starter and get back to
the crank resulted in a 2 to 1 reduction in cranking speed.
I know now this is not something you want to do with a
rotary. Many design innovations were used on this engine.
The stationary gear, rotor, buttons and apex seals were made
with the powered metal process (sintered metal). The
trochoid was chrome plated. The side housings were
hi-silicon aluminum requiring no addition wear surfacing.
Prototypes were made and assembled. Dyno testing confirmed
5hp at 7000 RPM, but cooling was an issue. No failures
resulted from the high temps, but performance tapered off as
the temps rose. It was felt that chainsaw typically didn’t
run at WOT for extended periods and thus this may be
acceptable. The day came to install the engine into the new
saw. After a couple of tweaks, it was ready to try cutting
wood. After pulling on the starter for God knows how long,
it became apparent the swing arm reduction starter was not
going to crank the engine fast enough to start. We did what
all good engineers would do. Cut a hole in the starter
housing and get out the electric drill with a socket. The
engine started, but threw the socket beyond retrieval. The
saw performed well and cut wood like a banshee. That’s
when I learned what sawdust coupled with tree sap did to
cooling fins. It didn’t take very long before temperatures
started rising beyond acceptable levels. We also learned
very quickly what saw chain induced vibration meant. At this
point in the development, it was apparent vibration
isolators would be required to tame the saw chain vibration
and thus the advantage of the rotary was diminished because
of the cost of the two together. The project was stopped.
We changed directions and used the same hardware for a
water-cooled version. 6 HP was the target. New parts were
designed and made to water cool the engine. A cast in
sintered metal insert was used for the trochoid surface. The
goal was to sinter to size and no addition trochoid
machining would be required. The engine produced the target
6 HP but would not consistently idle below 2500 RPM. Idle
speed on the 2-strokes was 300/500 RPM. Starting was also an
issue. Most of the small 2-strokes would start with a flick
of the flywheel. This was not the case with the rotary and a
significant pull on the starter rope was required. Many
100’s of hours were run on this engine with no mechanical
problems. We mounted the engine to a 6HP mid-section/lower
unit and went boating. Idling and start ability continued to
be a problem. The guys at research came up with an ingenious
invention that took some charge from the compression cycle
and put in back into the intake cycle. This solved the
idling and starting issues. The engine would consistently
idle at 500 RPM and would start with a modest pull of the
starter rope. It was at this time the 4 rotor race engine
came into being and I was reassigned to that program. The 6
HP engine was assigned to Doug Betts; a relatively new
engineer at OMC. The program floundered with redesigns to
increase displacement and HP. The demise of the engine was
part of the OMC direction to shelve the rotary programs. Ken
Finely has my only picture of the engine. Maybe he would be
kind enough to post it.

**Rotary John** · 08-05-2009, 05:58 PM

Originally Posted by Rotary John

If I remember the story correctly, Moller got The OMC 650 as part of his deal with OMC. He sold the rights and tooling to Infinite Machine. They got in a huge lawsuit ,which Infinite lost ,with a many million $ judgement against them. Moller settled for the return of his stock and all the 650 stuff.
John
ps:
who says hi?

I did some more checking and Moller did not get the 650 engine as part of the original OMC deal. The rights to the engine along with all the tooling for the engine was sold to Infinite Machine. They indeed did go thru an IPO, but ran into contract problems with Moller. The law suit and the rest of the story is correct. Moller now has the 650 engine and the tooling to produce it.
John

**Rotary John** · 08-05-2009, 06:06 PM

Originally Posted by powerabout

They are still workig on it
http://www.moller.com/files/Breakthrough.pdf

John
when you rebuild one is that simple to do and fast?
How does a rebuild compare to a piston engine

Powerabout

I guess a lot depends as to why you are rebuilding it. Taking it apart is fairly simple and fast. Undue all the thru bolts and wala its apart. Now comes the fun part. If the housings are damaged, they generally have to be replaced. It takes very specialized machinery to repair them. Seals are like piston rings, except there are no over size parts. The rotor and stationary gear are usually not hurt and can be reused after cleaning. That is unless something went thru the engine and got into the gearset; then both have to be replaced. Same story with the crank. If the bearing is shot, replace both. I guess to be fair, a piston engine is most likely easier to rebuild because of oversize parts and machining round holes is readily available.
John

**Rotary John** · 08-05-2009, 06:09 PM

Originally Posted by E-tec1

Im not gonna say that maybe that wastn part of what happened,,,,,the engineer that went to infinite that brought me worked on the 2 rotor sea drive, i believe George Miller was chief engineer at stern drive at that time and thats why that project existed, ive gone on infinites websight a few years after i was canned and they still showed doing rotatry work, i wonder if the 2 rotor was not part of that deal????, i dont remember alot, was too busy makin parts all day long to get too involved in the politics............

do u remember Jerry Crichton??? Mike Roepanack??? I talk to Ziggy once in a while... I lost contact with Mouse a while ago.....I dont know if u knew but Jim Nettles passed a couple years ago .....

Yeh I remember all those guys. Wasn't Jim Nettles the dyno operater that almost lost his head when a flywheel came apart?
John

**Rotary John** · 08-05-2009, 06:17 PM

Originally Posted by Old fiberglass

They made a major mistake on that one....it's easy to be a Monday morning quarterback though.

Why did the rotary EGT get so high ??? A/C turbine APU's could get up to 1800F on start up on some applications, but usually max EGT at full load was 1000~1200F.

We did a lot of development work on a passive non-mechanical oil cooler for aircraft turbine APU's. It is called a eductor and took the exhaust airflow creating a vacuum to pull air through the oil cooler. It got rid of the mechanical cooling fan. I always wondered if that could somehow work in other applications.

The rotary has continual exhaust. The exhaust port in the rotor hsg. is uncovered when the apex seal passes over it and continues to exhaust thru the posititve exhaust cycle. But remenber while that rotor face is exhausting the next rotor face is combusting. Thus when the apex seal closes the first face it opens the second face; thus continious exhaust. It doesn't have a valve in its way like a 4-cycle or being diluted but the next charge like a 2-cycle to cool it down
John

**Rotary John** · 08-05-2009, 06:18 PM

Originally Posted by E-tec1

Im not gonna say that maybe that wastn part of what happened,,,,,the engineer that went to infinite that brought me worked on the 2 rotor sea drive, i believe George Miller was chief engineer at stern drive at that time and thats why that project existed, ive gone on infinites websight a few years after i was canned and they still showed doing rotatry work, i wonder if the 2 rotor was not part of that deal????, i dont remember alot, was too busy makin parts all day long to get too involved in the politics............

do u remember Jerry Crichton??? Mike Roepanack??? I talk to Ziggy once in a while... I lost contact with Mouse a while ago.....I dont know if u knew but Jim Nettles passed a couple years ago .....

Mouse is somewhere in Fl.
John

**jackie wilson** · 08-09-2009, 02:15 AM

John, the story so far has made for some fascinating reading, and now maybe someone,somewhere will put it all on record. The facts so far though, only substantiate my views on the rotary. Every twist and turn of development filled the engineers with hope of a breakthrough, only to create another problem which sent them down heartbreak alley. Hats off to all those clever and gifted guys that tackled the problem head on, made inroads, and developed that damn motor still further, before going back to a sane world where problems could be solved and development brought just rewards.
I will be the first to shout "Bloody Hooray " for a successful rotary, but it 'ain't going to happen in my lifetime. I bet you right now, at this moment in time there is a guy somewhere who is convinced he's 'cracked it '--------probably funded by Virgin or Murdoch where the odd mill or so doesn't matter much.
Meanwhile, the damn thing should be documented every inch of the way until someone has the balls to put it in it's rightful place-----'THE SKIP'.
Will wait for the flak from rotary buffs every where. I have a broad back and a thick skull, so bring it on.
I apologise most sincerely to all the OMC guys who worked the project, and to "Rotary John' for his info, i did not mean to belittle anyone's effort, it's just the viewpoint of a cranky old 78 year old EX whatever.

**powerabout** · 08-09-2009, 03:06 PM

Hers's one for jackie
give your Cosworth job a run for its money
( from another site)

Here is one of them from some, gotta love em, crazy Aussies I think.

20B Ski Boat
- Hull - Kevlar 1850 bullet, Bravo 1 XR leg
- Engine – X-Treme Rotaries 1962cc 20B (3 rotor) rotary engine, bridge ported, turbocharged, fuel injected, NRS Ceramic Power Seals
- Horsepower – 800hp 9500rpm 615 ft/lbs torque (@ 22 psi)
- Speed – max 120mph 9650rpm (top speed is now 142 mph)
- Tuning – by Anthony Rodrigues, Maztech of Melbourne
- Turbo – Garret GT42 1000hp
- Intercooler – PWR barrel water to air

http://www.xtremerotaries.com/

I think it is a ski racing boat, theres a vid on the net somewhere
Cheers
Powerabout

**jackie wilson** · 08-09-2009, 05:16 PM

PLEEEEZE Just give me the FACTS. Did it ever finish. Did it ever Win? Like all rotaries the spec is brilliant, power awesome. speed phenomenal, and it uses just a thimbleful of paraffin to help it along it's almost silent environmentally friendly way. The only Aussie to ever do it right was Warby.[in boating of course] and he did not even mention the damned word rotary.

**powerabout** · 08-09-2009, 11:31 PM

i'll find out

**jackie wilson** · 08-10-2009, 01:58 AM

The beauty of the Cosworth was it's total reliability. Run within the parameters laid down by Duckworth and it would run until eternity. These were very simple ie.
Le mans spec-------400 hp @ 7,500 injected 3 litre. = 24 hrs non stop [ 8,000 max allowed]. Ran the rig for 18 months without a single [even minor] glitch.
would run 125 mph all day long.
Compare the 800 hp rotary @ 9,500 and 142 mph + 40 years heartbreak R&D to the modern day Cosworth 1,000 hp @19,000 Rpm, and the damn thing didn't move very far down the road did it? The faithful old 'Cossie' does have about 150 formula 1 wins to it's credit, and a few hundred Indy car wins. How does the rotary stack up against that i wonder. Case closed.