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

[jackiewilson]

Go and buy one when you get back Jackie. https://www.mazda.co.uk/cars/mazda-mx-30-r-ev/ it will change your life

ME—im just an old fashioned regular motorist who runs a simple trusty LEXUS 450 H SPORT. I get 35 mpg with a range of over 450 miles per tankful .
whilst i bow to your superior engineering knowledge —i simply have to rely on common sense !!!!
Nowhere in the ad for the Mazda SUV with a rotory Hi-brid does it tell me the distance i can travel on a tankful of fuel and a full charge [ tells me i can travel 53 miles on a full electric charge — which hardly fills me with confidence if i want to travel the continent, niethr could i find the final price ????
Nah— think i will stick to the trusty Lexus — while it didnt change my life ,i enjoy driving it and i do have every confidence in its performance and reliability with enough filling stations to satisfy my needs both at home and abroad.

[techteam]

Nowhere in the ad for the Mazda SUV with a rotory Hi-brid does it tell me the distance i can travel on a tankful of fuel and a full charge. "I get 35mpg"

Its horses for courses Jackie. Whats your average journey distance, bet its less than 53 miles. How much does your 450 mile tankful cost ?

Mazda MX 30 REV 282.5 mpg Total Range Electric and onboard fuel over 400 miles. Starts at 31K which for a range extended EV is pretty good. Would I buy one, NAH I'll stick with the diesel Porsche.

[jackiewilson]

Its horses for courses Jackie. Whats your average journey distance, bet its less than 53 miles. How much does your 450 mile tankful cost ?

Mazda MX 30 REV 282.5 mpg Total Range Electric and onboard fuel over 400 miles. Starts at 31K which for a range extended EV is pretty good. Would I buy one, NAH I'll stick with the diesel Porsche.

Honest to murgatroyd i did try with due diligence to find figures on the Mazda rotory—- but failed miserably.
i do apologise for not believing there was any car manufacturers anywhere fooling with a rotory—— i was wrong [often am -but loathe to admit it].
if it comes anywhere near 400 miles using under 2 gallons of fuel i would buy one tomorrow although the fact that you would not buy one and prefer the diesel Porky does not exactly fill me with confidence.

[Rotary John]

I'm afraid it's the decal on the front and has nothing to do with the diesel or rotary.

[techteam]

I'm afraid it's the decal on the front and has nothing to do with the diesel or rotary.

You know Ann, John. When I suggested one she said Mazda? They make light bulbs don't they........

[techteam]

Old Old Newspapers but still readable

[Rotary John]

OMC Rotary Race Engine
I reflect back now; some 50+ yrs. later; on what I would have down differently to improve the engine durability and performance. The two major issues affecting durability were the thru bolt breakage and rotor bearing failure. We also saw an occasional premature apex seal wear. We had solved the broken thru bolt issue with the 4 pc. crank design. I had developed apex seal materials that showed no measurable wear after 100 hrs. continuous WOT. in addition, they cost less the $.05 each. A fraction of the cost of the Torrington supplied seals. I still have one in my desk drawer. The rotor bearing was always a potential problem. The engines were adjusted a rich as possible before losing HP and was run at 20:1 mix ratio. I had developed a unit cage design with INA bearing that consistently ran 100 Hrs. on the Snowmobile engine test cycle w/o failure. Never got a chance to run them in a race engine. Another significant improvement would have to add oil injection thru the crank. Rotor bearing failure was a result of heat generated between the cage and the outer race due to lubrication breakdown. According to SKF Research, failed bearings demonstrated outer race temps in excess or 1800 F. This was far in excess of the 458 F tempering temperature causing the race to shrink to the point is would seize on the crack and all hell broke loose. The failure always started on the downstream side of the bearing due the "C" section design's ability to get sufficient oil in that interface. Direct oil injection thru the crank along with the unit cage bearing design would have eliminated durability. problem #2.
Several areas to improve performance were on the list but never got fully explored. Titanium rotors would have reduce the rotor weight by about 50%; around 20 lbs. for all 4 allowing higher speeds w/o increased loads. The increase in Hp between 7000-9000 was in excess of 40HP. Titanium also has several thermal properties that are advantages over cast iron. I knew the rotor combustion pocket design had potential to affect power, fuel consumption and emissions. Previous development testing had shown an 8% power increase when a trailing spark plug was added; upping power 20/25 HP. Adding the trailing plug caused thermal cracking on the rotor housing and was never run on the race engine. We had just started to explore alcohol. Alcohol would lower the air temp going thru the rotor, improving the engine specific air consumption and helping the bearing issue.
Overall, my vision for the future of the race engine was 400HP at 9000RPM. When the 2L issue was being raised to run ON, I was all set to grind off a little on the housing and the rotor. OZ suddenly came back into vogue, so it became a mute issue. The last year of the program I was the only engineer working on the race engine with a part time designer so my too due list was overshadowed by fix the problem from the last race so we could go to the next race.
Strang had achieved his objective of beating Merc and was pushing V-6 development hard. He felt with 150 CI V-6 he could continue to do battle with the 2L Merc, so the rotary programs were but on the back burner and I was assigned various 2-stroke projects.

[techteam]

It may be 50+ years ago but you are still spot on. In our earlier engines you could not get a standard bearing to last more than a few hours even with oil injection so we made our own in house of exotic materials. Pictured is our bearing taken from an engine in for a 500hr TBO customer engine. Interestingly our latest 20hp engine has a standard INA bearing in an oil cooled rotor and is yet to have a failure upto 10,000 rpm. We did have a bearing failure early on but when it was stripped it was discovered our supplier had switched the INA bearing for his "high quality" alternative that lasted 2hrs. The engine was cleaned we removed all the jingly bits left over and fitted an INA and that engine has been fine ever since. We designed a titanium rotor for that engine but the customer wouldn't pay for testing so it remains a CAD/Drawing dream for now. We used as you know to run ceramic apex seals but they just got too expensive to manufacture at our size of engine so we swapped and make our own from more available material.

[Rotary John]

It may be 50+ years ago but you are still spot on. In our earlier engines you could not get a standard bearing to last more than a few hours even with oil injection so we made our own in house of exotic materials. Pictured is our bearing taken from an engine in for a 500hr TBO customer engine. Interestingly our latest 20hp engine has a standard INA bearing in an oil cooled rotor and is yet to have a failure upto 10,000 rpm. We did have a bearing failure early on but when it was stripped it was discovered our supplier had switched the INA bearing for his "high quality" alternative that lasted 2hrs. The engine was cleaned we removed all the jingly bits left over and fitted an INA and that engine has been fine ever since. We designed a titanium rotor for that engine but the customer wouldn't pay for testing so it remains a CAD/Drawing dream for now. We used as you know to run ceramic apex seals but they just got too expensive to manufacture at our size of engine so we swapped and make our own from more available material.

Try 440c SS. High carbon stainless with very high chrome content. Heat treat 58/60 RC and black nitride. I'm giving away all my secrets. I hope by now you have switched to nodular cast iron. I saw you were testing some at the machine shop when I was there and didn't realize you weren't already using it. It works for rotors and apex seals also.
You need to push for the titanium rotor. Not only is the rotor lighter, the ct. wts. are also reduced. I would think weight savings in your applications would be paramount. After all, why are they using a rotary in the first place? Do you hear from Fisher anymore?

[techteam]

Hi John, Happy Christmas. Nobody wants to spend money anymore, so development is paused unless you have some supposedly "revolutionary" rotary engine technology which in reality is nothing new. Not heard from Fletcher since I left years ago apart from a few friend requests. Anyway keep well and we can speak in the New Year.