Thursday, November 03, 2011


Dr. Felix Wankel with the first prototype of his rotary engine in 1957, which had a rotating inner chamber, unlike all later Wankels
Dr Felix Wankel (born 1902 in Lahr, Germany) had the vision for his remarkable rotary engine at the age of 17, began working on prototypes 5 years later, and gained his first patent for this remarkable engine in 1929.  His work on the motor was slow in the following two decades as he developed rotary-valve applications for piston engines.  By 1957, working in conjunction with NSU, he had a fully functional rotary engine prototype, and immediately began licensing the engine, which had many theoretical advantages over a typical piston motor.  First to take up this new design was aircraft engine builder Curtiss-Wright, who licensed the design on Oct.21, 1958.  Curtiss-Wright has a long and deep motorcycle connection, via founder Glenn Curtiss, but their Wankel engines were mostly used in aircraft.  The first motorcycle applications for this promising engine appeared shortly after the first rotary-powered automobiles, the Mazda Cosmo and NSU Spider of 1964.  [A more in-depth story of Felix Wankel and his Lindau research institute will be told shortly]
The world's first Wankel-engined motorcycle, the 1960 IFA/MZ 'KKM 175W'
Motorrad Zschopau (MZ)/ IFA:
The first motorcycle application of the Wankel engine emerged from the IFA/MZ factory, from 1960.  MZ took out a license from NSU in 1960, to develop Wankel engines as possible replacements for their two-stroke engines in both motorcycles and the 'Trabant' 3-cylinder two-stroke car.  Within 3 months, a single-rotor, watercooled engine (using the thermosyphon principle rather than a water pump?) of 175cc, was installed in an IFA chassis (the 'BK 351' of 1959) which formerly housed a flat-twin two-stroke engine.  The development team included engineer Anton Lupei, designer Erich Machus, research engineer Roland Schuster, plus machinists Hans Hofer and Walter Ehnert, who deserve credit as the first to build a Wankel motorcycle.
Details of the water-cooled MZ engine; twin spark plugs, single (tiny) carb, radiator, neatly mated gearbox.
The Wankel motor is neatly mated to the existing IFA gearbox (with shaft drive - similar to the BMW R25 gearbox), and developed 24hp, twice that of the comparable 175cc MZ two-stroke engine.  The prototype appears to have been extensively tested, and currently has over 38,000km on the odometer.  It lay in obscurity for years, before a 1994 exhibit of MZ history at Neckarsulm brought it back to light.
The second prototype MZ, using an air-cooled 175cc Wankel motor; the KKM 175 L
A second prototype was built in 1965, using a new 175cc air-cooled, single-rotor engine, also producing 25hp, considerably more than the ES250 'Trophy' engine normally installed in this chassis.  This engine appears very much based on the Fitchel and Sachs engine, which was well-developed by 1965 and being sold under license worldwide.  Despite the success of both MZ engines, inevitable problems with rotor tip seal failure and high engine/exhaust temperatures meant lots of development money would have been required to replace their reliable two-strokes... money which MZ didn't have.  Their incredibly successful race program (all two-strokes, designed by the genius engineer Walter Kaaden) was practically created out from the factory scrapheap, with little help from the Socialist functionaries controlling industry in the GDR.

The KKM 175L used an extremely compact Wankel engine.
The idea of a simple, robust, and compact rotary engine was very appealing in the early days of Wankel development, but the dream proved unrealistic, as it became clear production machines required terrible complexity for acceptable road use.  East German engineers created several prototype engines for the Trabant and Wartburg autos, but none were developed beyond the prototype stage, and the NSU license was allowed to expire in 1969.

The 1972 Yamaha RZ201
Yamaha licensed the Wankel design in 1972 and quickly built a prototype, showing the 'RZ201' at that year's Tokyo Motor Show.  With a 660cc twin-rotor water-cooled engine, it gave a respectable 66hp @6,000rpm, and weighed 220kg.  While the prototype looks clean and tidy, the lack of heat shielding on the exhaust reveals the Yamaha was nowhere near production-ready, given the searing heat of the Wankel exhaust gases, and subsequent huge, double-skinned, and shielded exhaust systems on production rotaries.
The Yamaha rotary in exposed display
During this period, Yamaha was looking for alternatives to its small-capacity two-strokes, developing large rotary, two-stroke, and four-stroke engines.  With 'shades of George Brough' (ie, showing prototypes to 'wow' show-goers), another never-manufactured Yamaha design was shown in 1972, a 4-cylinder two-stroke - the TL750.
The original 1974 RE5, with futuristic touches
One year after Yamaha introduced, but never manufactured, their rotary, Suzuki introduced the RE5 Rotary at the 1973 Tokyo Motor Show.  Suzuki licensed the Wankel engine on Nov.24, 1970, and spent 3 years developing their own 497cc single-rotor, water-cooled engine, which pumped out 62hp @ 6500rpm. Styling of the machine was reportedly entrusted to Giorgietto Guigiaro, a celebrated automotive stylist and advocate of the 'wedge' trend in cars, who leaked into the motorcycle world via several projects, notoriously the 1975 Ducati 860GT. Guigiaro's touch extended only to the cylindrical taillamp and special instrument binnacle for the RE5; a cylindrical case with novel sliding cover, meant to echo the futuristic rotary engine... the rest of the machine looked nearly the same as Suzuki's GT750 'Water Buffalo'.
The more 'conventional' 1975 RE5
The modest power output of the engine, combined with the 550lb wet weight, meant performance wasn't exciting, with a top speed of 110mph; no better than the two-stroke T500 series it was meant to displace, and far more complex, heavy, and expensive. Unfortunately, the release of the RE5 coincided with the Oil Crisis of '73, and customers suddenly became wary of the rotary's reputation for poor fuel economy.  This combined with motorcyclists' typical skepticism of anything too new, meant sales of the RE5 were far lower than required to recoup their investment.  With millions at stake in the project, Suzuki were determined to carry on production.  Blaming Giugiaro's binnacle, in 1975 the styling was more conventional, but sales didn't improve, and by 1976 Suzuki had swallowed their losses, and shut production.  Around 6,300 were built.
The 1974 Hercules W-2000
Hercules / DKW:
Fitchel and Sachs were the second licensee of the Wankel engine, on Dec 29, 1960, and the first with a motorcycle connection, with 'Sachs' the largest European maker of two-stroke engines.  Sachs built their rotary as a small, light accessory motor for applications as diverse as lawnmowers, chainsaws, and personal watercraft.
The W-2000 Sachs air-cooled engine
The first two-wheeled mass-production of the Wankel engine was the 'Hercules' W-2000 of 1974, with a 294cc/20hp (later 32hp) air-cooled engine, with a single-rotor, which had previously been used in a snowmobile. The prototype machine used a BMW R26 gearbox and shaft drive, but production W-2000s used a 5-speed gearbox and chain final drive.
Hercules also built an Enduro using a rotary engine
The Hercules was good for 82mph (later 94mph), and was the first production motorcycle using a Wankel motor. The first models used a two-stroke mix in the petrol to lubricate the engine, which was later upgraded to an oil injector; smoky in either case!  About 1800 were sold under both Hercules and DKW badges between 1974-76.  In 1977 they sold all their production tooling to Norton...

The original BSA test mule, with A65 cycle parts; note the compact motor, and doubled-up 'cigar' silencers - rotaries are Loud!
BSA / Norton:
BSA felt, in common with most of the automotive industry, that the Wankel was the engine of the future, and in 1969, hired David Garside, a gifted young engineer, to begin exploration of Wankel engines for a motorcycle.  Market research indicated the motorcycling public would accept the Wankel engine on fast sports machines, and Garside's small team began experimenting with a Fitchel and Sachs single-rotor engine, and with significant changes to the intake system, gained a staggering 85% more power, to 32hp.   Suddenly the experimental engine looked appealing.
David Garside in his kitchen, explaining the function of his air-cooled Wankel motor, which he is still developing for aircraft use.  Many Norton-based rotaries are used in military drones!
Economic catastrophe at BSA meant development was immediately stalled.  1973 was the end of BSA, as the British gov't formed NVT - Norton-Villiers-Triumph...BSA was dropped from the title, even though it had owned Triumph since 1951! Still, under Dennis Poore's thoughtful leadership, the rotary project continued, and it was Norton who licensed the Wankel design on July 25, 1972.
Fan-cooled Sachs motor in BSA Starfire running gear
 David Garside and his team began physical research with the installation of a Sachs fan-cooled single-rotor motor in a BSA 'Starfire' chassis; this was the first of a long line which led to the famous Norton rotaries.  The 294cc engine gave 32hp at 5500rpm, and evidenced significant problems with heat - with twice the combustion events per revolution compared with a piston engine, and a physically much smaller engine unit, heat is a significant issue with Wankels.  Sachs dealt with heat by routing the incoming air through the rotor itself, but this heated up the incoming mix, which reduces power.  Garside redesigned the intake route, so that it still cooled the rotor, but then passed into a plenum chamber to cool off again.  Air passing through the engine entered the plenum at 100ºC, but was cooled to 50º by the chamber and atomized petrol.
Norton-built twin-rotor, air-cooled engine, installed in a Triumph 'Bandit' chassis
In this work, Garside was helped by Bert Hopwood, retired BSA and Triumph designer (a protogé of Edward Turner, and author of the excellent 'Whatever Happened to the British Motorcycle Industry'), and the pair added a second rotor to the Sachs engine (giving 588cc), with many times the original finning area, plus that redesigned intake.  The engine was installed in several chassis over the years, from a Triumph 'Bandit' to a Norton Commando, but eventually an entirely new chassis was developed, as the engine showed considerable promise during development.
Norton rotary, Norton Commando chassis...the compact rotary engine looks tiny compared to the original 750cc vertical twin.  Note plenum chamber above the engine.
The first twin-rotor engine was installed in a Triumph 'Bandit' chassis in 1973, which was never shown to the public.  With nearly 70hp, about twice the 'spec' of the original dohc Bandit twin-cylinder piston engine, this prototype must have been a lively ride!
The 1973 'spine' frame with Triumph Trident tank; this machine has been restored, and can be found at the Hockenheim Motorsport Museum
It was clear a new chassis was needed, and later in 1973 the Wankel appeared in a new frame, with a large spine tube which held oil; various iterations can be seen with Norton or Triumph tanks, as the engine was developed, in 1973/4: these were code named the 'P39'.
The Norton 'P42' prototype of 1978
After the merger of Norton and BSA/Triumph in 1973, another chassis was created for the rotary Norton, with box-section frame tubes - still holding oil - and an integrated airbox; the 1978 'P42'.  With a Triumph T140 5-speed gearbox, this wholly new Norton was intended for production, and enough material collected for a first batch of 25 machines, but the project was halted suddenly, even after brochures were printed and journalists (notoriously, Cook Nielsen of Cycle World) invited to test it. 
The Norton Interpol II police motorcycle
It took until 1984 for Norton to gear up production, but the 'P42' model was never sold to the public; it became the 'Interpol II', a police motorcycle; Norton had a long history of supplying the police, with the original Interpol Commando built from 1970-77. The Interpol II used Norton's well-developed 588cc air-cooled twin-rotor engine gave 85hp, and was in production from 1984-89, with around 350 built.
The 'Classic' of 1987, air-cooled, a naked Interpol II.
The first Norton civilian rotary was the 'Classic', built as a limited edition of around 100 machines in 1987, which sold out quickly.  It was essentially an Interpol II in civilian garb, with a traditional Norton silver-and-black paint scheme.  With all the bodywork removed, the 85hp engine gave sporting and smooth performance, very reliably, having been de-bugged using feedback from police agencies.  The engine weight was low, making for easy handling.
The water-cooled Commander tourer, with Krauser bags
As Norton continued to develop their rotary, water-cooling was a natural next step to deal with heat issues, and in 1988, an Interpol II with a radiator was introduced, the 'P52'.  The civilian version, essentially a re-painted Interpol, was the p53 'Commander', produced from 1989, with 85hp on tap. Norton hoped to repeat the success of the Classic, but the machine was criticized for using merely adequate Yamaha wheels and suspension, and not the sporting items one might expect of the Norton marque. Around 300 Commanders were built.
The discreet Norton F1 ad campaign...
Such disappointments were rectified in 1990, when Norton finally lived up to its heritage and introduced the lovely 'F1' ('P55'), based on their RC588 racers, then in the midst of a terrific run of success on the racetrack; in 1989 they won the British F1 championship.  Only one color scheme was offered, in race sponsor 'John Player' livery of black and gold. Power was bumped to 95hp@9500rpm, from the water-cooled engine. The F1 had issues with heat buildup, as the bodywork almost sealed the engine unit within plastic, and lost quite a few hp when ridden hard. Around 145 F1s were built.  Built with a Spondon aluminum twin-spar frame, White Power upside-down forks, a Yamaha 5-speed gearbox, and stainless exhaust, the F1 sold for an expensive £12,000.
The last Norton F1 Sport of 1992, in rare blue
In 1991, Norton rectified the heat issues by introducing the F1 Sport ('P55B'), which was effectively a F1 Replica, using the same bodywork as the racers, with more air flow possible around an open fairing, which resulted, curiously, in a less expensive sportsbike. Some consider the F1 Sport the finest of all the rotary Nortons.  66 were built, before Norton's eternal financial troubles put an end to rotary production...for now.

Henk van Veen with his OCR 1000
Van Veen:
In 1976, Henk vanVeen, the Dutch Kriedler importer, saw potential in the new rotary Comotor engines, which were compact and developed good power.  Comotor was a joint venture of NSU and Citroen, who invested huge sums developing a new Wankel engine for the Citroen GS Birotor.  The prototype of this engine had been extensively tested between 1969 and '71 in the Citroen M35, which was never officially sold, but 267 were given to loyal customers for beta-testing. The M35 engine used a single rotor rated at 47hp, whereas the later GS engine had two rotors, and produced 107hp from a 1,000cc. Van Veen saw this powerful and compact engine as the basis of a new superbike, and created the VanVeen OCR 1000.
The Comotor twin-rotor, watercooled rotary, rated at 107hp
The OCR was a heavy machine at over 320kg, but had good performance, with a top speed of over 135mph, and could hit 125mph in under 16 seconds.  The water-cooled engine was housed in a Moto Guzzi chassis, used a gearbox designed by Porsche, and sold for $15,000, the same price as a Lotus Elite!  38 VanVeen OCRs were built before Comotor went into liquidation, as the GS Birotor was an utter flop, a gas-guzzler appearing exactly during the 1973 oil crisis, and worse, it was more expensive than the venerable Citroen DS, and slower.  Citroen even tried to recall and destroy all examples, but a few survive.  The VanVeen OCR, on the other hand, has always been a coveted and expensive collector's motorcycle.

Housed in a CB125 chassis, with a 125cc air-cooled single-rotor Wankel engine.  Clearly a test-bed to see if Honda was missing out on the Next Big Thing, this prototype looks to have been built between 1971-73, given the paint job and spec of the CB125 'mule'.  Honda never bought a license to build Wankels, and also never 'bought in' engines, so this little motor is curious indeed...

The 'X99' prototype had a twin-rotor engine, water-cooled, which purportedly developed 85hp. Kawasaki Heavy Industries, Ltd, purchased a license to built Wankels on Oct. 4, 1971; the chassis of the X99 appears to be based on Kawasaki's Z650, introduced in 1976, which suggests the date of this prototype.

The Motoprom RD501B, with Sachs-derived fan-cooled rotary in the venerable BMW R71-clone chassis
The Soviets are coming!  The city of Serpukhov, 100km from Moscow, was one of many 'secret' towns in the Soviet Union, where research into new technology was conducted (plus manufacture of the AK-47), far from prying eyes.  VNII-Motoprom was an auto and motorcycle research institute, which created quite a few interesting machines, most notably Soviet racers such as the Vostok-4, and a few Wankel-engined bikes, completely unlicensed.  The story of the Soviet motorcycle industry is little known in the West (and the East!), and deserves exploration...
The fan-cooled engine of the RD-501B
In 1974, the RD501B used the ubiquitous BMW R71-based chassis (from a Dnepr MT-9), with a fan-cooled engine, clearly a copy of the Sachs rotary.  With 495cc, it developed 38hp @6300rpm, and used shaft drive.  It is claimed two were built.
The RD-660 with air-cooled twin-rotor engine
The RD-660 prototype was built in 1985, using a 660cc air-cooled twin-rotor engine, with chain drive. The engine is very similar to the BSA/Triumph/Norton prototypes built since 1973...a little Cold War industrial espionage not doubt, but methinks the Soviets bit off more than they could chew with the Wankel motor, as none were produced in series, in cars or motorcycles.
The RD-515 with a water-cooled version of the Sachs engine
The RD-515 of 1987 used a water-cooled twin-rotor engine, driving through a Dneper gearbox and shaft drive.

Little-known outside the Eastern Bloc, Izh is the oldest Soviet/Russian motorcycle manufacturer, founded in 1929 in Izhevsk (on the banks of the Izh river) as part of Stalin's enforced industrialization of the agrarian economy, begun in 1927 with the rejection of Lenin's 'New Economic Policy', which allowed producers of grain or goods to sell their surplus at a profit - very similar to China's first moves toward Capitalism in the 1990s.  Stalin's successful effort at creating an industrial power, where none existed previously, actually decreased the standard of living, caused widespread famine, and meant imprisonment or death for millions...although it did create an automotive and motorcycle industry. Not that 95% of Soviet citizens could afford it in those early days, although Izh sold something like 11 Million motorcycles before 1990.

One of the last hurrahs for Soviet-era Izh was this Wankel-engined prototype of surprisingly contemporary, if clunky, aesthetics.  The 'Rotor Super' was under development at the end of the Soviet era, and shown just after the fall of the Berlin wall in 1989, when the Russian economy was in relative chaos.  Suddenly without the state business subsidies and guaranteed incomes of potential customers, all Soviet-era businesses were suddenly faced with the need to make a profit, and rash ventures such as Wankel superbikes were out of the question.  Izh is still in business, making inexpensive small-capacity motorcycles.

[If any reader has more information or photos of these obscure machines, please contact me!]
Some of my sources:


GuitarSlinger said...

Brilliant article !

Nuff said .

Anonymous said...

Dear Paul,

Your article was very interesting; and surprisingly accurate and comprehensive. I congratulate you!

In relation to BSA / Triumph / Norton there were a few errors ref dates etc. But nothing very important.
I could list them if you wish.
It is true that a Russian delegation did visit us at Norton in about 1983, and no doubt took some ideas away.

The SAE Paper which I wrote in 1981 (SAE 821068 ) gives a detailed description of the technology of the twin-rotor air-cooled motorcycle engine.

It would be nice if you were to add that the work on the rotary engine at BSA and Norton for motorcycles then led to the development in the UK of the Wankel -type engines for UAVs, and their extremely successful (and profitable) usage in that application.

But the best is probably still to come for the Wankel.
Two recent (patented) big-step-forward innovations (by me) are likely to lead to the rotary engine being by far the best engine type for powering the genset in Series-Hybrid Electric Vehicles.
And these same improvements would now enable a superb motorcycle engine to be created. The power output of the UAV engines today is some 33% higher than the final production Norton m/cycle engine; and it can run at that power continuously, not just for a short burst.

Are you an engineer ?
If so I perhaps could send you further information.

I will send a little more history, particularly ref the 1992 MBO from Norton of the rotary engine technology for the UAV application .

Best regards

David Garside

Formerly Director of Engineering at Norton Motors Ltd

The Vintagent said...

Hi David,
I welcome your input! As I have been essentially traveling the past 18mo's, I've had no access to my library, which included work on Wankels/motorcycles, so did all my research on the web, from memory, and parsed the junk from the jewels. Thus, getting dates correct and making some semblance of an event sequence was very difficult; I'm glad the result approaches accurate.

During my research, I did note many further developments of the Wankel engine, by yourself and even Brian Crighton's current rotary racer, and would be very interested to hear more on your current activities, and opinions on the future of these amazing engines.

Perhaps an interview with you, or an article by/about you, is in order; I do cover 'future' issues in The Vintagent, but there's such a direct and short line from BSA to the hybrids you mention, my readers would be fascinated I'm sure.

I'm not an engineer, but have an ability to translate the highly technical into readable prose. I've been following with interest several strains of engine development, from compact steam generators to wave pulse turbines, and would very much enjoy a conversation about your current research.

And please, detailed corrections on my dates, or any additions you think are important, are most welcome.

As an aside: It is my opinion that the Great Lens of History shifts its focus depending on what it relevant Today. Thus, many motorcycle writers have for decades considered steam and electric motorcycles irrelevant, and even dismiss the very first powered two-wheelers as 'not motorcycles' because they used steam in 1862, and not internal combustion! I have argued with Kevin Cameron of Cycle World, an educated and thoughtful man, about this very point. 'Discarded' technology like the Wankel, compact steam generators, and electric motors, will come again to relevance in they eyes of the public and historians...clearly electrics already have.
This article on Wankels is my attempt to drag history's lens back toward the Wankel (I've already done one on Steam), as we are coming out of a long period of technical doldrums, in which the hegemony of the piston engine was undisputed, and other research barely funded or noticed. It becomes clear to all that an engine of much greater efficiency will of necessity dominate future transport, as resources dwindle and demand grows, and it is my sincere hope that shedding light on such projects, even as a historian, will bring awareness to and support of these efforts. The power of the media should not be underestimated in this regard...

all the best, Paul

Hairy Larry said...

Very interesting article. My only Wankel experience was borrowing my brother in laws Mazda RX3 for a week in the 70's. Very impressed by the power. Have never worked on or ridden a Rotary bike, and had no idea that so many companies had looked into building them.
For some reason I googled world's largest and smallest wankel and came up with the following. will bring you to an article about an engine Curtiss-Wright built in 1960. It's a 31.5 liter single rotor that made 750 hp.Ingersoll Rand further developed this design into single rotor 550 hp, and double rotor 1100 hp motors. They were used for gas compression and power generation. brings you to a press release about a micro rotary that runs on hydrogen or propane, I believe, and are extremely small. They are supposed to last longer than batteries of the same weight.Very interesting subject.

Anonymous said...

Nice work on the Wankel motorcycle feature, well done indeed. A couple of comments: Cook Neilson was editor of Cycle, not Cycle World. Not sure what you mean by “notorious” in the context of Cook’s Norton Rotary article. The mule he rode for the piece on the roads near Kitts Green was, by his admission, still quite a way from production spec. He was fairly full of praise for the bike’s performance potential, describing it as “capable of jerking the headlights out of a good-running Trident [which was along for comparison], and the Trident is no slouch.” His caveats came from his view of NVT’s ability to pull off this program, given their financial straits at the time. (Cycle’s UK columnist, Jim Greening, was posting columns about NVT’s survival regularly during this period.)

The Honda concept rotary chassis shown isn’t a CB125—the TLS front brake and fuel tank are too large for the period 125. Looks to be a CB175.

As I recall from factory documents I have in my home archive (I’m writing this from the office), BSA bought its rotary rights from Curtiss-Wright. C-W demonstrated much success with direct-injected, stratified-charge rotaries, showing diesel levels of fuel consumption and multi-fuel operation. Emissions in tests were encouraging. But C-W’s interest in the rotary license ranged far beyond its own light aircraft propulsion and aero APUs. Very quickly C-W began extending license agreements to the auto industry, including GM and American Motors, plus Mercury Marine (outboards), John Deere, Ingersoll-Rand, and others including BSA. This was a gravy train for C-W. Then the U.S. Clean Air Act came.

For Vintagent readers, it might be useful to have included some reasons why the rotary failed to live up to its promise (apex seal issues, rotor-tip sealing), as well as mention that Mazda recently threw in the towel on its RX rotary program. Besides powering military drone aircraft, the rotary’s future may be in running within a very defined rpm map, powering series-type hybrid cars.

Plus, it just looks silly in a motorcycle frame!

Keep up the great work.


SAE International

The Vintagent said...

Hi Lindsay,
thanks for your comments!

I still think the Honda is a CB125, as that paint scheme wasn't found on the CB175 - the 'swoosh' stopped below the tank bottom.
Compare this:

With this:

Not that it matters much; what I'd like to know is, from whom did they get the right to build this motor? Or was it a 'graft' job with an existing engine (ex-snowmobile?) appears to be straightforward...check here:

According to my research, BSA did indeed buy their rotary rights from Felix Wankel's 'holding company' in 1972; we can ask David Garside if this is correct. It's also possible that Norton was in contact with Curtiss-Wright for some of their experience developing the engine, and licensed this as well. C-W patented many improvements of their own on Wankel's design.

I'll get to the whole advantage/disadvantage discussion of the Wankel motor in another post on Felix Wankel himself, and discuss the development difficulties.

yours, Paul

Anonymous said...

Hi Paul.

Very fine post. And what a grand litany of posters.

There is a Vincent connection to the rotary.

In his later years Philip Vincent was working on a rotary-type engine. Robin Vincent-Day, who began a romance with Dee, PCV’s only daughter, in 1974 and married her a little later, assisted PCV in preparing drawings for the rotary concept, as he worked in the then embryonic photo-copy industry.

His recollection of the work is here -

Robin had also just bought himself a Rapide. Later, Dee and Robin were blessed with a son, Philip, whom remains active in the Vincent Owners Club.

It seems Vincent was very alive to the potential of the rotary engine but the determination which saw him produce such fine motorcycles during his most productive period, did not, perhaps, serve him as well in the years after. PCV’s idea was that his engine would be manufactured from Silocan Nitride, a ceramic material.

His rotary engine is chronicled in LKJ Setright’s book Some Unusial Engines, (1975) .

Having ridden the Norton F1 JPS production bike, I can confirm that with its Sponden frame, and smooth, smooth engine – more than a match for its rivals – it was a stunning machine. But why would a buyer with 150bhp on offer now, think of a rotary engine?

Dave Lancaster

Ward said...

Great article. An interesting point about the heat and noise that took me years to realize is that piston engines have a brief time between the explosion and the valve or port letting the gasses out. A Wankel lets those gasses escape, essentially, while it is still exploding! Thus the heat and noise.

Anonymous said...

I read and enjoyed your blog on the rotaries.

If you'd like to to an expanded version on the history of the Norton rotaries I also suggest you talk to Joe Seifert, owner of Andover Norton. As you probably know, Andover Norton is the supplier of authentic Commando AND Rotary parts. They also have an extensive quantity of documentation from the former Norton factory.

Joe Seifert

-Dave F

The Vintagent said...

Hi Dave,
I'm going to interview David Garside in a few days! I'm off to London on Thursday, and will catch up with him on the 9th...very excited to meet an unsung hero of the bike industry. Yes, I'd like to meet Joe Siefert, and Brian Crighton too. I hear Crighton has recently built a 175hp/120kg super-rotary...after researching them, I'd love to own a hotrod Norton rotary; talk about rare...

Anonymous said...

The first Wankel-powered motorcycle, an MZ of 1967


nice article!
But the first Wankel-powered MZ (175cm³, 24PS) was built in 1960 on basis of a MZ BK 351 (built in 1959, also a prototype as follow-up for the legendary IFA/MZ BK 350 ). The prototype you've shown is on a basis of a MZ ES 250/2, built in 1965.
You can read more about it on the following websites:


PS: MZ had a license for the Wankel-engines until 1969!

The Vintagent said...

Hello 'M',
many thanks for your information; it will be incorporated into my article, with credit of course.
I find no record of MZ/IFA taking out a license for Wankel development - this is curious; I do note that one of these sites claims an expiration of a Wankel license in 1969. In my research, no Eastern or Soviet license was sold...but of course, there may be more to the story!

kamagra said...

From old to new, cool! Vintage motorcycles to a new model, as time change design changes too. Good job!

Anonymous said...

Can I have the right article for the Ingersoll Rand Biggest Wankel Engine (IR-2500)

The Vintagent said...

Here's the info on the Ingersoll Rand IR 2500 engine, the largest Wankel motor produced to date:

Stephen said...

Some corrections regarding Soviet usage of Wankels.

The Dnepr MT-9 chassis is not R71 based as it uses a swingarm rear suspension and is modelled loosely on the post-1955 BMW chassis. The RD-501B engine and the later RD-515 engine were also trialled by IMZ (Ural) in their motorcycles but never went beyond prototypes.

VAZ (Lada) actually produced a couple of series of production engines See

The Izh factory was actually founded by Alexander I in 1807 and constructed it's first prototype motorcycles with sidecar drive in 1929. See and

The IZH "Rotor Super" (actually IZH Lider - Leader) was designed for Government use - KGB (now FSB), GAI (now GIBDD) and Militsas (now Politsas - Police). It used a production VAZ twin rotor engine, probably the VAZ-413 or VAZ-4132.

The Vintagent said...

Stephen, many thanks, I'll update the post. Finding good info (in English) about Soviet motocycles is improving, albeit slowly. Interest is growing though, especially as Russians begin to re-value their history.

Interestingly, there was an article on Izhmash in the NYT today, about the popularity of Kalashnikovs (actually their civilian counterpart, the Saiga) in civilian markets, with sales having increased 50% in the US in 2011.

Anonymous said...

Dear Sir,

If you send an e-mail me, I will send you information about my work on the Wankel rotary engine.

I am an inventor and I have no particular material, look for a research center to put into practice my work in a newly developed rotary engine with the ideas of my project BRUNTOR. My job, I've put into practice in a rotary engine that got SACHS with outstanding results that will send you.

After verifying the outstanding results achieved with my work, develop a new rotary engine may be the best internal combustion engine invented by man and also a motor "green."

The most important idea of my project - called NEW DESIGN - ensures permanent seal between the chambers of the motor, this idea is patented.

With the idea - NEW DESIGN - The rotary engine is best suited to consume hydrogen.


========== =============== ==================

The IMAGINATION can build the knowledge,
the knowledge can LIMIT the IMAGINATION.

Anonymous said...

A very interesting article and tremendously good work!
Some thoughts: maybe it was a wrong decision to use the Fichtel & Sachs engine as a basis for a motorcycle. The F & S engine was conceived as motive power for position independent devices like chainsaws where a pressure lubricated engine would not have worked – there is not much use in an oil sump when the engine is operating upside down. This led to the Hercules and Norton motorcycle engines being fed by two stroke mixture where proper purpose-designed engines have an oil sump. For Fichtel & Sachs and their Hercules subsidiary it was a quick and cheap hack to use an existing engine mated to an existing gearbox to create a nasty motorcycle but Norton bet their existence on it. Hmmm.
Herules did one bike much better than the "vacuum cleaner" W2000 and this is lacking from your otherwise comprehensive list. For ISDT type sports events Hercules created a Wankel bike heavily based on their successful competition bikes. They used the lower parts of a 250cc F & S six speed two stroke engine, replaced the crankshaft with a bevel drive and put the trochoid on top of the crankcase in a horizontal position, mating the eccentre shaft to the bevel drive below. This bike looked pretty conventional except for the exhaust exit position at the side of the engine. Otherwise it could have been any two stroke engine guided by its looks. There are photographs in the internet showing these bikes (,
. In the German press a production of this bike was heavily rumoured at the time but of course nothing came from that.
When talking about hot exhaust gases from a Wankel engine, I remember a dark summer night with a fast blast along a deserted Autobahn where I followed an early Mazda RX7. This car had an exhaust silencer immediately at its rear bumper and two short exhaust pipes protruding from there, giving a sight of the innards oft he silencer. The guy in the Mazda was really driving hard and you could tell the throttle position by the colour of the visible interior of the exhaust silencer. Everytime he went truly fast the two exhaust pipes showed a bright yellow, under slowing down this turned orange first, a dark red then and invisible shortly afterwards. As soon as he used his right foot again the exhaust heated up from red to yellow within five to ten seconds. I followed that car for about fifty miles, continuously watching this glowing exhaust. It was a truly amazing sight that I never forgot. This is the price you pay for a vibration-free engine having a combustion chamber that is disastrously inefficient from a thermodynamic point of view, allowing a tremendous amount of heat to escape through the exhaust instead of being used for creating motive power.

Anonymous said...

What a great, informative article! Enjoyed it tremendously, thank you Paul!!

I recall a comparison test of the Suzuki RE-5 versus its sibling GT750 and others, including a Harley, all under the guise of seeking out the best touring bike at the time (1975).

The RE-5 outhandled every last one of the test bikes, perhaps due to a more favorable weight distribution.

As I recall, Suzuki had significant issues with their dealers' service network - to support the RE-5, some $5000 of diagnostic equipment was necessary, the cost of which came directly out of the dealers' pockets.


Pete Causer said...

Hi Paul,

Having spent some time working on the NRS588 racers in 1992 I am surprised that you have omitted the fact that one of these machines won the Senior TT in 1992 in the hands of the Late Steve Hislop, who also set a race record which lasted quite a few years. This was the first time a British bike had won a Senior TT for 31 years.

The Racers were initially developed by Brian Crighton in his spare time and first appeared at Darley Moor in 1987, ridden by Malcolm Heath to a creditable third place. John Player sponsorship was secured for the next few years and the machine was ridden by quite a number of top men, ultimately by Ron Haslam and the late Robert Dunlop in a team that was managed and led by Barry Symmons until 1992. Unfortunately the JPS sponsorship was due to end at the end of this year and, as you mentioned, financial problems that had been highlighted in a television programme put paid to any new deal and the team folded at the end of the season.

In 1992 a new team was formed independently by Brian Crighton and Colin Seeley which ran until 1994, taking the British Supercup championship with Ian Simpson on board.

Crighton has continued to develop the machine in a small way with the support of Stuart Garner at the reformed Norton factory and had a brief and unsuccessful outing at the TT in 2009 when it failed to complete a lap in practice. It seems to have slipped into obscurity again since then.

An interesting piece just the same!

Pete Causer

Anonymous said...

Dear Paul, great article and one of interest to me, I have always had a soft spot for the rotary waited for the day that the last of the problems got sorted and at last see the potential was seen. Well I was fortunate to work with the great Brian Crighton ex-Norton over the last 2-3yrs and last year the CR 700P was born. Worked. and was a fantastic launch at Mallory Park where ex-British champion and TV BSB presenter tested it...WOW... I had the job of tech drawings and visual design. It's worth a look and if you haven't seen it can do so here:

Thank you


internetexplorer said...

never thought cars could be this pretty. no wonder men would go crazy over them haha! I am starting a new Pinterest board of motorbike pictures and I wish to include this. Please let me? Cheeeeeeers!!
Halloween recipes 2014

Jose Gros-Aymerich said...

Nice to know that mr David W Garside is active and with the same ingenuity as before. I'd always like having more feed-back about his results with Reed-valves, I had a letter from him in the 80s, and also a reference to find about the intake ducts, intake duct plate hole, intake ports, and out of rotor incoming mix temperatures. Regarding the Ingersoll-Rand huge engine, the info I'm aware of is: 'Detonation Characteristics of Industrial Natural gas Rotary Engines', T N Chen et al. SAE paper 860563. I still ignore if this T N Chen is the same T Chen heading Wankel research in China. If you provide with a workable e-mail address for this site, I can send a small list of what I consider basic RCE references. I'm not an engineer, I collected Wankel documents the same others collected movie stars pictures, and own some engines in different sizes.