Wankel

Wankel (pronounced wahng-kuh)

A type of rotary internal combustion engine, first produced 1961, named after its inventor, German engineer, Felix (aka Fritz) Wankel (1902-1988).

The Wankel engine is a type of internal combustion rotary engine, one of many based on the a rotary principle, the Wankel using an eccentric drive to convert pressure into rotating motion.  The design was conceived by German engineer Felix Wankel, an eccentric, though clearly gifted, self-taught engineer who was an early convert to National-Socialism (linked with a right-wing political movement in 1921) who joined the NSDAP (the National Socialist German Workers Party which would become the Nazi Party) the following year.  It’s important not to make too much of that, the party in its early days an aggregation of factions which were, literally more nationalist and socialist in character than anything like the racist and ultimately genocidal thing into which the Nazis evolved under Adolf Hitler (1889-1945; Führer (leader) and German head of government 1933-1945 & head of state 1934-1945). 

But an enthusiastic Nazi Wankel certainly was although that didn’t protect him from falling victim to the internecine squabbles which would beset the party to the very end, expelled from the party in 1932 after feuding with his Gauleiter (the regional party boss) who, after Hitler came to power in 1933, succeeded in having Wankel jailed although, under less unpleasant conditions that those tossed into concentration camps.  Indeed, while in prison, he was able to continue working on his rotary engine, a patent for which had been granted to him in 1929.

Felix Wankel admires a shaft.

Wankel though had friends in the party, one of whom approached the Führer, stressing the importance of the amateur engineer’s contribution to German industry and that proved enough to secure his release.  He worked on a variety of projects during the 1930s, some on contract for BMW but mostly for the military including on seals, something which years later would absorb much of his energy at that of many others.  Despite his efforts for the Reich, his attempts to rejoin the party were rebuffed but his friends did gain him the honorary rank of Obersturmbannführer (Lieutenant Colonel) in the Schutzstaffel (The SS (Security Squad or Section), originally Hitler's personal security detail which evolved into a vast party security apparatus and later a parallel army almost a million strong) although his career in the "black mist" wasn't long, Wankel expelled within two years.  The records were lost in the confusion of war so the reasons aren’t known but while it’s tempting to wonder just how ghastly one has to be to be thought too evil for the SS, given the lack of any subsequent punitive action against him, it’s likely he just lost out in another of the squabbles that were so common in the Nazi system, the structures of which actually encouraged internal conflict.

It didn’t stop the Nazi state funding his research including what he was then calling his “rotary motion engine” although progress was slow and slow for a reason, the fundamental flaw in the design not resolved until the 1950s when another engineer, less visionary but more practical, rectified the fault.  Wankel's rotating cul-de-sac was far from unique in wartime Germany, the interest of the regime in technical innovation and the gullibility of party officials drew cranks, con-men and inventors inspired and otherwise.  Among the projects which received interest and sometimes cash from the state was a “non-combustible” material called durofol (which would catch fire), a scheme to create liquid fuel from the roots of fir trees (which consumed three times as much energy as it produced), the production of alcohol from bakery fumes (apparently that one was quickly rejected), a “death ray” championed by notorious drunkard Reichsleiter Robert Ley (1890–1945; head of the German Labour Front 1933-1945), which turned out to be impossible to build or even test, a plan to turn the atmosphere into a conductive element using ionization (which at least has a theoretical basis even if impossible) and the mysterious “Gerloff miracle pistol”, the records for which were lost.  Compared to some of these, Wankel’s engine (which didn’t work) probably appeared quite promising.

Gleitkufenboot (skid boat).

Wankel had other projects too, one of which he would, like his engine, later revisit.  This was the Zischboot (Hiss boat), intended as a small, high-speed torpedo-boat for the navy, a kind of hydrofoil that used clusters of skis.  In the 1970s, Wankel would display a prototype (now called the Gleitkufenboot (skid boat)), powered by an impressively powerful Mercedes-Benz four rotor Wankel engine.  Wankel claimed not only was it impossible to capsize the boat but that it was unsinkable, a notable feature said to be borrowed from certain sea creatures, air-intake "nostrils" with flaps controlled by sensors to ensure no water could penetrate when driving through waves.

Wankel survived the war and suffered not greatly in the denazification process the allied occupation authorities ran to weed out the worst of the worst, his work as an engineer suggesting someone unpolitical and being expelled both from the party and the SS probably helpful in mitigation.  In that he was lucky; had the investigators dug deeper they would have discovered Nazi-era Wankel held some fairly unsavory views and had expressed them more than once.  In the new Germany, those opinions he either no longer held or kept to himself, in 1951 obtaining a position with NSU as a technical consultant.  NSU were interested in his rotary motion engine.      

1957 NSU Prinz (the front of the car is to the left).

NSU (the name an abbreviation of "Neckarsulm", the city in which the factory was located) began in 1873 as a knitting machine manufacturer which in 1886 branched out into the production of bicycles and so successful did this prove that by 1892, the knitting machines were abandoned, the factory converted wholly to the building of bicycles.  The first NSU motorcycles appeared in 1901 and were both popular and profitable, encouraging the company in 1905 to enter the potentially even more lucrative market for cars.  Between then and the end of World War II (1939-1945), there were ups and downs but NSU survived and, in December 1946, resumed building bicycles and motorcycles, commercial vehicle production starting in 1949.  These efforts proved successful and the company, by now a significant beneficiary of Wirtschaftswunder (the post-war German "economic miracle"), was by the mid-1950s the world’s largest maker of motorcycles and profitable enough for car production to resume in 1957.  Wholly unrelated to knitting machines, motor-cycles & cars, NSU (non-specific urethritis) was the old term for NGU (non-gonococcal urethritis), an inflammation of the urethra not caused by gonorrheal infection.  In post-war Germany, it's used also as the initialism of Nationalsozialistischer Untergrund (National Socialist Underground), a general term for neo-Nazism and other fascist organizantions & movements.     

1958 NSU Prinz Sport.

The car was modest enough, tiny and powered by a 600 cm³ (37 cubic inch) air-cooled twin cylinder powerplant which was essentially two motorcycle engines joined by a common crankcase.  As was fashionable in small European cars of the era, the engine was at the rear, something which would prove a cul-de-sac, most manufacturers outside the Warsaw Pact soon convinced to abandon the idea.  That disenchantment actually extended to Porsche which had the 911’s replacement in production by the mid-1970s, only to find out just about every soul left on the planet who still thought rear-engined cars a fine idea were Porsche 911 buyers who insisted nothing else would do.  The customer being always right, the 911 survives to this day and that a rear-engined machine can be as well-behaved as 911s now are will be no surprise to those familiar with modern electronics but Porsche, remarkably, had engineered a high degree of predictability into its behavior even before computers were robust and fast enough to do the job.  In 1958, NSU didn’t face the same issues of high-speed handling, the new Prinz (Prince) having but 20 bhp (15 kW).  It was wholly utilitarian but suited to the times and sold well, national success (and growing incomes) meaning within a year, the idea of a more profitable up-market version became attractive.  Although little more than an Italian-styled body atop the existing underpinnings and never a huge seller, the Prinz Sport remained in production for a decade and its lightweight and slippery shape made possible an impressive top speed of 75 mph (120 km/h).  By 1968 over twenty-thousand had been built and it was the Prinz Sport NSU used as the basis for the world’s first Wankel-engined car.

The rotary engine, light, powerful and with few moving parts had interested NSU which saw the potential for motorcycles but they also quickly identified the fundamental flaw in the design which Wankel had never resolved: both rotor and rotor housing rotated, each on different axes, creating an assembly almost impossible to keep in balance as well as necessitating an additional housing.  While Wankel proceeded along his path, publicized by NSU in 1954, another NSU engineer, Hanns Dieter Paschke (1920-1999), unbeknown to Wankel, was developing his own version (KKM 57), displayed in 1957 as the DKM 54 at the NSU Research & Development Department in Versuchsabteilung.  Before long, the concept would be refined in that the single housing became static and only the rotor rotated, Wankel’s original vision intriguing but perhaps, even now, impossible to build as a practical working device and NSU devoted some years to making their version exactly that.  In 1964, it was released to the public.

1967 NSU Spider.

In 1964, the Western world was not so laden with rules and restrictions (for good and bad) and it was possible to sell for use on the public highways what were essentially prototypes in development and that the NSU Spider certainly was.  It was also a seen by NSU as an advertisement on wheels, a showcase not only for their upcoming models but also to encourage other manufacturers to buy licenses to produce their own Wankels, an option that would be exercised by many, including Alfa Romeo, Curtiss-Wright, General Motors, Daimler-Benz, Rolls-Royce and Mazda.  For whatever reason, BMW, Felix Wankel's Nazi-era employer, declined.  Citroën, an outfit with a reputation for the quirky, were enthusiastic enough to set up with NSU a Swiss co-venture to pursue the technology.  More than most, the French would come to rue the day they ever heard Wankel’s name.

A NSW spider, the Sydney funnel-web.

The NSU Spider should not be confused with NSW’s spiders of which there are quite a few.  Of the order Araneae, spiders are air-breathing arthropods (the usual reference to them being arachnids is a bit vague) and Australia is home to many, the most venomous of which is the Sydney funnel-web (Atrax robustus), found in New South Wales (NSW) in forests as well as populated urban areas.  They prefer to burrow in humid sheltered places but it’s not uncommon for them to wander into suburban backyards and sometimes they have to be rescued from swimming pools.  Human encounters are however relatively rare but they’re noted for their aggression if a threat is perceived so caution is recommended, their highly toxic venom produced in large amounts and the remarkably large fangs (larger than a brown snake, another of Australia’s many dangerous species) can be deployed with sufficient force to pierce human finger & toenails.  Although measuring only 15-35 mm (.6-1.4 inch), their venom contains a compound which attacks the human nervous system & internal organs, a strike from a male able to kill an adult although since anti-venoms became available in 1981, no fatalities have been recorded.  The Sydney funnel-web is the deadliest spider in Australia.

Skoda (rear) engine bays, the conventional (piston) engine (left) vs the single-rotor Wankel (right).

Although the project never progressed beyond the prototype stage, the Czech manufacturer Skoda was apparently the first to have running vehicles with a rotary engine installed (a complete engine said to have been running as early as 1961) but in 1964, the NSU Spider was the first to go on sale.  It used a single-rotor, water-cooled engine and was easily distinguishable from the Prinz Sport because it was a soft top cabriolet, apart from which it was substantially the same car with only detail differences in styling and specification except it was offered only in red or white.  One other change was definitely apparent however, power had jumped to a heady 50 bhp (37 kW) at a surprisingly low 5,500 rpm, enough to propel the Spider to close to 100 mph (160 km/h) for anyone on the autobahn prepared to push the little machine to the limit.  Never expected to be a big seller, fewer than 2500 were built between 1964-1967, its purpose more to whet the public appetite for what NSU intended to be their entry into the burgeoning middle-class mass market.  Additionally, though not at the time discussed, the Spider’s engine, while at a stage of development beyond being a prototype, was not ready for release to a public using it in a wide variety of ways in different climates in different countries.  The Spider’s customers unwittingly were also NSU’s development test team, something which later in the century would become a handy business model for many software companies.

Given the specifications of the Wankel NSU would produce in the future, it may that the Spider’s single rotor powerplant wasn’t an ideal a test bed for the customers to debug but problems in design and the choice of materials were identified and, where possible, within the limits of metallurgy and the realities of economics the lessons learned were applied.  Nor was the Spider’s specification static, the experiences of the customers applied to improve not only longevity but also power, the later cars enjoying a slight increase in capacity, output now 54 bhp (40 kW) at 6,000 rpm, 4 bhp perhaps not impressing all but it was close to 10% more and although the factory didn’t claim any increase in attainable speed, the most recent Spider owners presumably got there a little more quickly.

1967 NSU Ro 80 (1967-1977).

If the spider had generated interest, the NSU Ro 80, released in 1967, was a sensation.  Even without the novelty of the rotary engine (without which all concede it would doubtless have been a success), it would have made quite an impact.  The body, which does not look out of place even in the twenty-first century, was a modernist masterpiece, trendsetting in a way the 1955 Citroën DS (often called the déesse (literally "goddess")) was just too extreme to be yet more aerodynamically efficient, the Ro 80’s drag coefficient (CD) of .354 just a fraction better than the French car’s .359.  Beneath the skin, the futurist vision continued, the efficient front-wheel-drive packaging in the vanguard of adoption by larger vehicles, four wheel disk brakes (inboard at the front), a semi-automatic transmission, power-assisted rack and pinion steering and all independent suspension.  Reviews upon release were sometimes ecstatic, the only criticism from some who found the interior austere but it was era in which only the most expensive German cars were fitted-out with much beyond the starkly functional; NSU’s designers looked to Le Corbusier and Gropius, not the Jaguar Mark X.

The Ro 80 won the 1968 European Car of the Year award and buyers seemed as impressed as the many journalists who voted NSU.  Out on the autobahns, the twin-rotor engine was a smooth, quiet and a delight to use, the slippery shape meaning the 113 bhp (85 KW) it generated from a comparatively small 995 cm³ (61 cubic inch) displacement allowed it to match the speed of cars with even three times the capacity, the turbine-like feel encouraging a disregard for the 6500 rpm redline which it seemed to exceed without complaint.  The honeymoon didn’t last.  Critics began to notice it was good to match larger six cylinder cars in performance but it came at the cost of a thirst many V8 owners didn’t suffer.  Nor was the Ro 80, so at home cruising at 100 mph (160 km/h) on the autobahn, quite as happy in the stop-start urban conditions where the modern German motorist was now spending much time, some finding the previously admired semi-automatic transmission clumsy to use, the experience jerky.  The Wankel engine didn't deliver much much low-speed torque and drivers had to adjust their technique; those used to the more effortless performance of the 2-3 litre engines most often found in this class of car found negotiating their commute through a succession of red traffic-lights harder work than before.    

Nothing is perfect and such was the appreciation of the Ro 80’s virtues these drawbacks may have been overlooked or at least endured but what couldn’t be forgiven was that the Wankel engines were frequently, numerously, rapidly and expensively failing and, being within the warranty period, it was NSU which bore the cost to repair or replace.  That was bad enough but the car was quickly gaining a reputation for unreliability and sales were falling, exacerbating the financial strain NSU was suffering from all the warranty claims.  Nor was the once profitable motorcycle business there to subsidise the four-wheel venture, production having ended in 1968 to allow the company to focus on the Ro 80.  The problems hadn’t been wholly unexpected, just underestimated; NSU’s engineers had warned the board the engine wasn’t yet ready for production and needed at least months more durability testing and development but, perhaps remembering the relatively smooth introduction of the Spider, and certainly seeking cash-flow, approval was given for a debut in 1967.

It wasn’t difficult to work out where the problems lay which was mostly in the high wear of the apex seals and consequent damage to the rotor housing.  Essentially, the seal failure destroyed the engine, necessitating a replacement and it was not uncommon for replacement engines also to fail and require replacement, again under warranty.  For a small company with limited resources, it was unsustainable and NSU was soon unviable, the takeover by Volkswagen in 1969 said to be a "merger with Audi" only an attempt to glue a veneer of corporate respectability on what was the takeover of a distressed competitor.  It was unfortunate.  In just about every way except the flawed engine, the Ro 80 was years ahead of its time and deserved to succeed.  Had it been powered by a 2.8 litre flat-eight and configured with all-wheel drive (AWD) it would have been worthy competition for Mercedes-Benz and Jaguar (in this class BMW & Audi not yet a thing) and more advanced than either. 

1967 Mazda Cosmo.

The issue was the engine at that stage of its development given the metallurgy of the time rather than NSU because Mazda, which had in 1961 purchased a licence to produce the Wankel, were suffering the same problems in the Cosmo sports car, introduced also in 1967.  The Cosmo however, was a low-volume model and Mazda had other, profitable ranges on sale and so could absorb the cost of fixing failed Cosmos.  Mazda did seem to learn from the NSU experience however.  When they put the Wankel into volume production, the vehicles initially were offered either as a rotary or with a conventional piston engine, an approach which seemed promising but such was the fragility of the Wankel, even that had to be abandoned.  Mazda, after putting Wankels even into small trucks and busses, realised that for consumer vehicles, it was a niche product and restricted it to specialist sports cars.  The problems didn’t go away, but, for a while, they became manageable.

Mazda RX-7 (the Porsche 924-928 inspired second generation (1985-1992) model) in Lindsay Lohan's music video clip First (2005).

The Cosmo's spiritual replacement was the RX7, a two door coupé (there was a short run of roadsters in the second generation) built over three generations between 1978-2002.  With over 800,000 produced, it's probably still the machine most identify with the Wankel engine and was the car which came closest to gaining the mainstream acceptance which had eluded earlier models such as the RX-2 (Capella), RX-3 (Savanna) & RX-4 (Luce), probably because reliability had significantly improved and those buying relatively expensive sports cars were more tolerant of the higher fuel bill and in fairness, much of the competition offering similar performance returned fuel consumption which was little different.  It was replaced by the RX-8 which proved (thus far), the swansong for the Mazda rotary on the streets.     

1972 NSU Prinz 1200 TT.

Remarkably, Audi-NSU, although axing the outdated rear-engined Prinz range, maintained the troublesome Ro 80 in production and despite its thirst it survived even the first oil crisis which killed off so many others.  Although most of the old NSU manufacturing capacity had long been given over to the Audi production line, it wasn’t until 1977 the last Ro 80 was built, the decade’s total production of 37,000-odd a disappointment for a car expected to ship more than that every year.

Despite NSU’s takeover in 1969 in the wake of the problem, even in the early 1970s, many major manufacturers were still convinced the Wankel's many advantages would render the piston engine obsolete and embarked on large, and expensive, development programs.  In this they were encouraged by the legendary optimism and confidence of engineers who so often think any engineering problem can be solved with enough time and money.  However the problems, seal wear, emissions and high fuel consumption proved insoluble and the projects which hadn’t been abandoned didn’t survive the first oil crisis.  Apart from the odd small-volume independent, only Mazda persisted. 

Notable Wankel Moments

1974 Mazda Rotary Parkway 26 Minibus (1974-1976).

The Mazda Cosmo was shown only weeks after the NSU Spider. Twice the capacity of the NSU, it was much more ambitious and though also troubled, its low volume meant the rectification was manageable.  Only Mazda has produced Wankel engines in large quantities and they've offered the power-plant in sports cars, racing cars, sedans, coupés, station wagons, pick-up trucks & buses, the last two perhaps a curious place to put an engine not noted for its prodigious torque.  Others, with varying degrees of success, have put them in automobiles, motorcycles, racing cars, aircraft, go-karts, jet skis, snowmobiles, chain saws, and auxiliary power units.

1976 Mazda RX-5.

Even Mazda, which has at least partially solved most of the problems, currently don't have a Wankel in production; the last, used in the RX-8, unable to meet the latest EU pollution standards.  Despite this, Mazda claim to be committed to the Wankel and the factory say development is continuing, in 2016 showing the RX-Vision, hinting it could be on sale as early as 2020.  The COVID-19 pandemic put that at least on hold and concerns about CO₂ emissions may mean the Wankel's historic automotive moment, which lingered for so long, may finally have passed so whether Mazda really solved the problem of toxicity may never be known. 

1975 HJ Mazda Roadpacer (HJ & HX, 1975-1977).

Most Holden fans, as one-eyed as any, don’t have fond memories of the HJ (1974-1976) Premier.  Usually, all they’ll say is its face-lifted replacement, the HX (1976-1977), was worse.  With its chassis not including the "radial tuned suspension" (RTS) which lent the successor HZ (1977-1980) such fine handling and with engines strangled by the crude plumbing used in the era to reduce emissions, driving the HJ or HX really wasn’t a rewarding experience (although the V8 versions retained some charm) so there might have been hope Mazda’s curious decision to use the HJ (and later the HX) Premier as their top-of-the range executive car, complete with a smooth two-rotor Wankel, might have transformed the thing.  That it did but the peaky, high-revving rotary was wholly unsuited to a relatively large, heavy car.  Despite producing less power and torque than even the anaemic 202 cubic inch (3.3 litre) Holden straight-six it replaced, so hard did it have to work to shift the weight that fuel consumption was worse even than when Holden fitted their hardly economical 308 cubic inch (5.0 litre) V8 for the home market.  Available only in Japan and sold officially between 1975-1977, fewer than eight-hundred were built, the company able to off-load the last of the HXs only in early 1980.  The only thing to which Mazda attached its name not mentioned in their corporate history, it's the skeleton in the Mazda closet but does have one place in history, the footnote of being the only car built by General Motors (GM) ever sold with a Wankel engine.

Mercedes-Benz C-111 (1968-1970), the three-rotor (upper) and four-rotor (lower) Wankel versions.

Although the C-111 would have a second career in the late 1970s in a series of 5-cylinder diesel and V8 petrol engined cars used to set long-distance speed & endurance records, it's best remembered in its original incarnation as the lurid-colored ("safety-orange" according to the factory) three and four-rotor Wankel-engined gullwing coupés, sixteen of which were built.  The original was a pure test-bed and looked like a failed high-school project but the second and third versions were both finished to production-car standards with typically high-quality German workmanship.  Although from the school of functional brutalism rather than the lovely things they might have been had styling been out-sourced to the Italians, the gullwings attracted much attention and soon cheques were enclosed in letters mailed to Stuttgart asking for one.  The cheques were returned; apparently there had never been plans for production even had the Wankel venture proved a success.  The C-111 was fast, the four-rotor version said to reach over 300 km/h (190 mph), faster than any production vehicle then available.

Herr Wankel’s personal R107 (350 SL) fitted with 4 Mercedes-Benz Rotor Wankel (KE-413).

Less conspicuous than the C-111s in lurid safety orange were the roadsters which Mercedes-Benz used as Wankel test-beds.  The first used the W113 (1963-1971) platform, remembered now as the first “pagoda” and while it would never have been suitable as a production car, it apparently wasn’t as unbalanced as the sole W113 fitted with the 6.3 litre (386 cubic inch) M-100 V8 (used in the big 600 Grossers and the 300 SEL 6.3) which test drivers described as "exciting but unstable".  Still, the Wankel W113 proved quite a bit faster than the 280 SL and as a proof of concept was judged a success.  The W113 though had never been intended to use anything but a straight-six whereas the successor W107 (1971-1989) was designed from the start with an engine bay and transmission tunnel which would accommodate either a V8 or the Wankel with its high central power take-off.  The W113 had used a three rotor unit (M 50 F) but R107 had four (KE-413) and delivered considerably more power than the 3.5 litre (215 cubic inch) & 4.5 litre (275) V8s used in the production models and not until the adoption of 5.0 (305) & 5.5 (339) V8s in the 1980s would the performance be matched.

Four rotor Wankel engine (KE-413, left) and the unit installed in Herr Wankel’s 350 SL.

Yet however successful the proof of concept may have been, the early skepticism mentioned by the combustion chamber specialists was vindicated because as they pointed out the chamber was "...the central feature of the combustion engine.  The priority is to produce an optimum design so as to achieve the most favorable thermodynamic efficiency."  By that they meant "...as complete combustion of the fuel as possible” and not only was this not happening with the Wankel, their point was that fundamental aspects of the design meant it could not happen, something which manifested in high fuel consumption and difficulties in meeting the exhaust emission standards due to all the non-combusted hydrocarbons.  Modest in their demands in the early 1970s, the US regulators had already provided a decade-long roadmap which would make the rules so onerous there was then no realistic prospect the Wankel could ever be made to comply.  The engineers were confident they could produce a smooth, reliable and powerful Wankel, albeit a thirsty one, but knew they could never make it clean.  All of the factory’s W113 & R107 test-beds were scrapped when the project was cancelled but Felix Wankel’s personal R107 SL survives.  He obtained a four rotor unit from Mercedes-Benz, had it installed by technicians at his institute and in 1979, the trade journal Auto Motor und Sport published their road-test of the unique machine, reporting a 0-200 km/h (120 mph) time of 25.9 seconds and a top speed of 242 km/h (150 mph).

Citroën GS (GX) Birotor (1973-1975) on the stand at the Frankfurt Motor Show, August 1973.

Sometimes one gets lucky, sometimes not.  In the US, Ford introduced the new, small and economical Mustang II a few weeks before the first oil shock in 1973 and had a big hit (something sometimes forgotten by those who so decry the Mustang II and condemn it a failure).  In Australia, about the same time, Leyland announced the big new P76, a selling point its V8 engine.  The P76 wasn’t without faults and may anyway have failed but the timing didn’t help and it didn’t last long, shortly taking with it whatever remained of Leyland Australia.  In France, in October 1973, the very month in which events in the Middle East triggered the first oil shock, Citroën's thirsty GS Birotor went on sale.  Shown at the Frankfurt Motor Show in August, the reception had been generally positive, most complaints being about the aesthetic; all the Birotors appeared to be painted in shades of brown, a color which seemed to stalk the 1970s.

Mechanically though, even before going on sale, some with high hopes for the Wankel were disappointed, the Birotor not realising the promise of smaller, lighter packages.  Despite the compact size, the engine would fit in the GS’s engine bay only transversely so Citroën’s signature inboard disk brakes couldn't be used for the first time since the pre-war Traction Avant. That necessitated a different subframe, a wider track, and bigger wheel arches than the standard GS.  Combined with other detail differences, it bulked the rotary-powered GS up to 690 lb (290 kg) more than the standard GS, compelling the addition of anti-roll bars to reduce the increased propensity towards body roll.  Another mechanical aspect not much discussed at the time was the Wankel's high exhaust emissions.  In one of many possible illustrations of how the politics of the matter has changed, it was a time when the exhaust pollution rules imposed by the United States appalled Europeans because of the way they made the detoxed cars behave.  Not wishing to sacrifice power, in Europe, drivers for years enjoyed un-emasculated engines and accepted the higher emission of CO₂ and other pollutants as part of life.  Widespread interest in climate change, then the concern of a handful of specialists looking at what was called the "greenhouse effect", was a generation away.  Despite cubic money being spent, it was one aspect of the Wankel that was never fixed and was the final nail in the coffin of Mazda's RX8.    

Known also as the GZ, the Birotor replaced the noisy but robust and economical air-cooled flat four used in the GS on which it was based and cost about 70% more.  The Wankel engine was the first fruit of the NSU-Citroën joint venture and, being of small capacity, attracted lower taxes than a similar piston-engined car.  However, it suffered the problems endemic to the Wankel: ruinously high fuel consumption and chronic unreliability caused by wear of the rotor seals and the damage this caused to the housing walls.  Citroën had looked at the Ro 80's issues and had included an additional oil pump to improve seal lubrication but the problems persisted.  Internal documents later revealed that just as at NSU half a decade earlier, there were those within Citroën who understood, long before the release, that a disaster was impending but a combination of corporate inertia, an unwillingness to admit failure and a number of contractual obligations meant the Birotor went on sale.  Within months the extent of the problem was realized.  Although only a few hundred had found buyers, broken ones were being towed to dealers around the country and owners were irate.  Early in 1975, Citroën dropped the model, offering to buy back all the 847 made, running or not, customers given a full-refund.  Most agreed and Citroen scrapped every one they could, hoping everyone would forget they ever existed.  A remarkable third of owners declined the offer and many survived in private hands; among Citroën aficionados they’re a collector’s item though probably more displayed as a curiosity than driven.

A twelve-rotor motor intended for marine applications.

The low weight, compact profile, small number of moving parts and very high specific output of the Wankel has always attracted engineers.  The Wankel turned out to be well suited to applications where it could be maintained at a constant speed for long periods, the problem of unburnt fuel in the exhaust substantially resolved, improving emissions and fuel consumption.  Wankels lose efficiency dramatically when they are revved up and down as they are in the normal use of a passenger car but in boats and aircraft where engine speed tends to be constant for long periods, they can work well.  In airframes especially, where weight is so critical, the inherent advantage of the vastly superior power to weight ratio can be compelling.

1989 Norton 588.

One of the many companies to purchase a licence from NSU was English motorcycle manufacturer BSA (British Small Arms) and this became the property of Norton when it absorbed BSA in 1973.  Norton’s troubled history in the 1970s had little to do with the Wankel but after bankruptcy, it was revived on more than one occasion and during one of those escapades, it made almost a thousand Wankel motorcycles.  Other manufacturers dabbled with Wankels and Suzuki actually made some 6000 RE5s between 1974-1976 but the best of the breed were thought to be the Nortons, even though they were admitted to be early in the development cycle.  The Wankel was a more reliable thing by the time the Nortons were made but they suffered the underlying problem of all road-going applications: the advantages just weren’t enough to outweigh the drawbacks, added to which, piston engines continued to improve.  Norton allowed the project to die but did use the Wankel technology to develop a line of UAV (unmanned aerial vehicles, sometimes called drones) engines that proved successful; weighing only 22 lb (8.2 KG) yet producing 38 bhp (28 kw) they proved ideal for the task.

1972 Chevrolet Corvette XP-895 Prototype.

In 1972, spooked a bit by the news Ford would be offering the mid-engined De Tomaso Pantera through Lincoln-Mercury dealers, to steal a bit of the thunder, Chevrolet dusted-off and displayed a mid-engined Corvette prototype, production of which had been cancelled because of the cost.  It was shown again in 1973, this time with a four-rotor version of the Wankel GM had been developing in a number of configurations.  After the Wankel project was aborted, there were plans to use the body with a V8 to replace the existing Corvette, a release penciled in for 1980 but again, costs and concerns about sales potential aborted the idea.  It meant the already long-serving Corvette stayed in the line for fifteen years, not replaced until 1983 and not until well into the next century was a mid-engined version released.

Triple

Triple (pronounced trip-uhl)

(1) Threefold; consisting of three parts (matching or not).

(2) Of three kinds; threefold in character or relationship.

(3) Three times as great; multiplied by three (numbers or quantities in general).

(4) In international law or international relations, as triple entente, triple alliance etc, a treaty or some state of arrangement between three states.

(5) In baseball (also called the three-base hit), a hit which enables the batter safely to reach third base.

(6) In (ten-pin) bowling, three strikes in succession.

(7) In basketball, a three-point field goal.

(8) In curling, takeout shot in which three stones are removed from play.

(9) In musical time or rhythm, having three beats in each bar

(10) As triple crown, in various sporting competitions (Rugby Union, thoroughbred racing, motor sport et al), a (sometimes informal) acknowledgement of victory in three specific events (use based on the triple crown (sometimes as triple tiara) once used for the coronation of the Roman Catholic Pope).

(11) In internal combustion engines (ICE), an engine with three pistons or rotors.

(12) One of three; a third (obsolete and the source of some misunderstandings when found in historic texts).

(13) In programming theory, as Hoare triple, a description of how the execution of a piece of code changes the state of the computation in Hoare logic, consisting of (1) a command to be run, (2) a pre-condition that holds true beforehand, and (3) a post-condition that holds true afterwards.

(14) In mathematics, a sequence of three elements or 3-tuple.

1325-1375: From the Middle English triple (there was also þripell), from the Old French triple or the Medieval Latin triplare (to triple) from the Latin triplus (threefold, triple), from the primitive Indo-European tréyes.  Triple is a noun, verb & adjective, tripled is a verb, tripling is a noun & verb, triply is an adverb and triplet is a noun; the noun plural is triples.

In English, the Latinate multiplier “triple” is but one of many ways the value three (3) is in some way expressed or applied.  “Three” is the highest value, single digit cardinal number, as an ordinal it’s “third” (the Latinate ordinal is “tertiary”), the adverbial form is “thrice” (or the more mundane “three times”, as a multiplier the term is “threefold” (also as “three-fold”), the distributive is “triply”, the collective “tripartite”, “trio” or “threesome” (ménage à trois a popular version which has tended to limit the utility of “threesome” for other purposes), the multiuse collective “triplet”, the Greek or Latinate collective “triad”, the collective prefix (from both Latin & Ancient Greek (the latter also had “trito”)) was “tri”, the fractional expression is “third” (the Latinate fractional prefix was “trient-”, the elemental “thrin” & “triplet” and a period of three years is a triennium.  However, while there are weeks, fortnights & months, there’s no accepted term which express a measure of 21 days although three months is often described as “a quarter” although in the context of the nine month gestation associated with human pregnancy, the three month blocks are "trimesters" (first, second & third).  The use in obstetrics extended to education and in systems where academic years exist in four semesters (or terms), there is also the "fourth trimester".

Boss & Co SxSxS 16-bore triple-barrel shotgun #4690.

Originally an adjective, the noun emerged in the early fifteenth century.  The use in baseball dates from 1880 while the various uses of triple-deck, triple-decker etc (a development of the earlier double-decker) for cakes, sandwiches, bunk-beds etc all came into use in the early 1940s.  Triple-barrel carburetors were rare but did exist, Porsche for example using them on their flat sixes.  Rugby Union in 1883 was the first to use “triple crown”, awarded in the UK to the side which won the three “home countries” (England, Ireland, Scotland & Wales) matches.  That was based on the use of the papal triple crown (sometimes as triple tiara) then used for the coronation of the Roman Catholic Pope and was later picked up in US thoroughbred racing: The Kentucky Derby, the Preakness Stakes, and the Belmont Stakes comprise the Triple Crown which was first officially awarded in 1919 although the term didn’t become widely used until the 1930s.  In motorsport, despite the popular perception, it’s never been an official award and many branches of the sport have their own triple crowns, most barely known outside of the small circle of their cognoscenti.  The three events which comprised the classic triple crown were (1) the Indianapolis 500 (first run in 1911), the 24 Hours of Le Mans (first run in 1923) and the Monaco Grand Prix (first run in 1929) and it’s been achieved only once.  That was by Graham Hill (1929–1975) who completed the set at Le Mans in 1972 and although he and others have suggested the Formula One World Championship should be included instead of the Monaco Grand Prix, the original arrangement seems still the accepted triple crown.

The Triple Alliance and Triple Entente were diplomatic arrangements formed in Europe in the decades prior to the First World War (1914-1918).  The Triple Alliance between Germany, Austria-Hungary & Italy was signed in 1882 as a defensive system directed entirely against France.  It was an integral part of the series of treaties and agreements variously negotiated or imposed by Otto von Bismarck (1815-1989; chancellor of the German Empire (the "Second Reich") 1871-1890) and needs to be understood in the way it interacted with other cogs in the Bismarck machine.  That machine, a collection of inter-locking treaties and agreements (some of them secret) worked to further the interests of (1) the German Empire and (2) a general peace in Europe and was a good device in Bismarck’s capable hands but it proved lethal when less competent practitioners (who didn’t fully understand the implications) inherited the tool.  The Triple Entente was between France, Russia and the UK and was formed in 1907; in the narrow technical sense it was not a formal military alliance but an “understanding” between the three to counter the growing power of Germany and the Triple Alliance.  The Ottoman Empire and Bulgaria would become attached to the Triple Alliance with the onset of war although Italy initially remained neutral before (in what would continue to be an Italian tradition) switching sided in 1915 to join the Alliance.  Both the Alliance and the Entente played their parts in the escalating tensions which culminated in the outbreak of hostilities which would trigger the chain reaction of declarations of war.  Had Bismarck still been in Berlin, it’s unlikely things would have been allowed to assume their own momentum.

Six-pack: Lindsay Lohan re-imagined as one of identical triplets.

The word is used also as a modifier as required such as triple-barreled (used with three-element surnames and in various manufactured items but best known in shotguns), triple-headed (again widely used but probably still most associated with creatures from mythology, tripledemic (a term used in public health and epidemiology to describe the simultaneous outbreak of three epidemics or pandemics), triple fault (in computing a third (and fatal) error instance in a CPU attempting a graceful recovery from a double fault, triple jump (an athletic (track & field) event involving three different types of jump), triple goddess (a female deity who is either three goddesses in one or one who is triune (both three and one at the same time) and triple X syndrome (a chromosomal variation characterized by the presence of an extra X chromosome in each cell of a human female).

The papal triple tiara

Pius XII (1876-1958; pope 1939-1958) in the papal triple tiara, at his coronation, 12 March, 1939.

The papal triple tiara is a crown which has been worn by popes of the Roman Catholic Church since the eighth century.  Traditionally it was worn for their coronation but no pontiff has been so crowned since Saint Paul VI (1897-1978; pope 1963-1978) in 1963 and he abandoned its use after the Second Vatican Council (Vatican II, 1962-1965).  The name tiara refers to the entire headgear and it has used a three-tiered form since a third crown was added during the Avignon Papacy (1309–1378).  It's also referred to as the triregnum, triregno or Triple Crown.  In a piece of one- (or perhaps four-) upmanship, Suleiman I (Süleyman the Magnificent, 1494-1566, Sultan of the Ottoman Empire 1520-1566) commissioned from Venice a four tier helmet to show, in addition to the authority claimed by popes, he could add the symbol of his imperial power.  Often put on display as the centrepiece of Ottoman regalia to impress visitors, there's no documentary evidence the sultan ever wore the four layer tiara, crowns not part of the tradition and, fashioned from gold and gemstones, it would anyway have been extraordinarily heavy.

A representation of the triregnum combined with twocrossed keys of Saint Peter continues to be used as a symbol of the papacy and appears on papal documents, buildings and insignia.  Remarkably, there’s no certainty about what the three crowns symbolize.  Some modern historians link it to the threefold authority of the pope, (1) universal pastor, (2) universal ecclesiastical jurisdiction and (3) temporal power.  Others, including many biblical scholars, interpret the three tiers as meaning (1) father of princes and kings, (2) ruler of the world and (3) vicar of Christ on Earth, a theory lent credence by the words once used when popes were crowned:  Accipe tiaram tribus coronis ornatam, et scias te esse patrem principum et regum, rectorem orbis in terra vicarium Salvatoris nostri Jesu Christi, cui est honor et gloria in saecula saeculorum (Receive the tiara adorned with three crowns and know that thou art father of princes and kings, ruler of the world, vicar on earth of our Savior Jesus Christ, to whom is honor and glory for ever and ever).

Lindsay Lohan triple-pack DVD offer.

Documents in the Vatican Archive suggest by 1130 the papal tiara had been modified to become a conventional (and temporal) symbol of sovereignty over the Papal States.  In 1301 during a dispute with Philip IV (Philip the Fair, 1268–1314, King of France 1285-1314), Pope Boniface VIII (circa 1230–1303; pope 1294-1303) added a second layer to represent a pope’s spiritual authority being superior to an earthly king’s civil domain.  It was Benedict XII (1285–1342; pope 1334-1342 (as the third Avignon pope)) who in 1342 who added the third, said to symbolize the pope’s moral authority over all civil monarchs, and to reaffirm Avignon’s possession.  A changing world and the loss of the Papal States deprived the triple crown of temporal meaning but the silver tiara with the three golden crowns remained to represent the three powers of the Supreme Pontiff: Sacred Order, Jurisdiction and Magisterium.

Not since 1963 has a pope worn the triple crown.  Then, the newly-elected Pope Saint Paul VI, at the end of his coronation, took the tiara from his head and, in what was said to be a display of humility, placed it on the altar.  In a practical expression of that humility, the tiara was auctioned; the money raised used for missionary work in Africa although, keeping things in house, the winning bidder was the Archdiocese of New York.  Popes Benedict XVI (1927–2022; pope 2005-2013, pope emeritus 2013-2022) and Francis (b 1936; pope since 2013) received tiaras as gifts but neither wore them.  Benedict’s, in a nice ecumenical touch, was made by Bulgarian craftsmen from the Orthodox Church in Sofia, a gesture in the name of Christian unity.  Benedict would have appreciated that, having always kept a candle burning in the window to tempt home the wandering daughter who ran off to Constantinople.

The Mercedes-Benz triple rotor Wankel

The original (although there was a prototype rendered in the tradition of functional brutalism) Mercedes-Benz C111 with triple rotor Wankel engine (1969).

Triple cylinder engines in cars were something of a niche in the early post war years but of late they’ve achieve a new popularity, improvements in electronics and combustion chamber design meaning three cylinders can now achieve what once required four and even with an equivalent displacement their efficiency is inherently greater because of the reduction in internal friction.  Obviously compact, they’ve proved an ideal power-plant in hybrid vehicles.  One quirky triple was the Mercedes-Benz C111 which first appeared in 1969 with a 1.8 litre (110 cubic inch) three-rotor Wankel engine, something then thought to have a great future; it seemed a good idea at the time.  The C111, although produced in a small run and finished in some cases to production car standards was only ever a test bed, not only for the doomed rotary engine but also developments in suspension design, anti-lock braking (ABS; Anti-Bloc System) and safety engineering.  The gullwing body really was designed by an Italian-born stylist but so long had he been in Germany that Teutonic ways had entered his soul so the C111 was less lovely than what might have emerged from a studio in Turin but at the time it still caused a stir, even though finished in what the factory called “safety orange”, their standard high-visibility paint for prototypes and test-beds.  Later versions were fitted with a four-rotor Wankel, a variety of diesels and even a 4.8 litre (292 cubic inch) V8, the fastest of the rotaries said to be capable of 300 km/h (188 mph) while the V8 version (C111-II-D) in 1976 set a new closed-course record on the Nardò Ring in Italy, clocking in at 403.978 km/h (251.815 mph).

Triple carburetors

1966 Ferrari 275 GTB/C (Gran Turismo Berlinetta Competizione (denoting a grand touring coupé built to competition-specification)).

When submitting to the Fédération Internationale de l'Automobile (the FIA; the International Automobile Federation) the application to homologate the 275 GTB/C for sports car racing, there was some glitch in the factory’s administrative processes because the document certifying the existence of a six-carburetor option for the 275 GTB wasn’t part of the paperwork enclosed.  That meant the 275 GTB/C could appear on the grid only with triple carburetors so to compensate, Ferrari had Weber produce a run of 40 DF13 units which in addition to their higher flow-rate featured lightweight magnesium bodies instead of the aluminium housing and were distinguished also by the distinctive, rearward-facing inlet trumpets.  As might be expected, original Weber 40 DF13s now command a premium price.  Twelve 275 GTB/Cs were built and the model was a turning point in being the last Ferrari built for racing to use the classic Borrani wire wheels.  Such had been the advances in tyre technology that by 1966 the grip generated transferred stresses so acute that in extreme conditions the spokes could break, a tendency exacerbated by the wheels’ additional width (7 inch front 7½ rear); there were accidents.  Such was the concern the two 275 GTB/Cs built as road cars were factory-fitted with aluminum-alloy wheels although the lovey Borranis continued to be made available for the later and much heavier 365 GTB/4 (Daytona, 1968-1973) and 365 GTC/4 (1971-1972).  In truth, using a 275 GTB/C on the road was a dubious proposition because as, a weight-saving measure, the body panels had been fabricated in thin 20-gauge aluminium; about half the thickness of the metal used for the road cars, it could be dented just by being touched and the dainty bumperettes (which offered at least some protection on the standard other variants of the 275 GTB) were wholly fake and merely affixed to the panels with no underlying structure.

1960 Jaguar XK150S 3.8 (left) and schematic of typical installation of Jaguar's auxiliary enrichment thermo-carburetor (right).

The last in the XK series (XK120 (1948-1954), XK140 (1954-1957) & XK150 (1957-1961)), the Jaguar XK150 was introduced in 1957 with a version of the twin carburetor 3.4 litre XK-Six used since 1948.  Increased weight had blunted the XK150's performance, something not wholly off-set by the slight increase in power coaxed from the engine and in 1958 the option of an "S" specification was made available as the XK150S, restoring the pace of the earlier cars, the raised output achieved with a revised cylinder head and triple carburettors (seen earlier in the 1950son the C-Type, D-Type & XKSS).  The final and fastest of the species was the 3.8 litre version of the XK150S, introduced in 1960; the engine in essentially this configuration would later be shared with the early E-Types (XKE) and Mark X, the triple carburetor arrangement carried when the 4.2 litre versions were released in 1964.  The triple carburetor engines were in 1968 withdrawn from the US market because the anti-emission regulations made the cost of certification prohibitive although, while in North America buyers had to be content with twin-carburetor units, the triples continued for RoW (rest of the world) vehicles exported to other places or sold in the home market.  When the last of the six-cylinder E-Types was made in 1971, that was the end of the line for the triple carburettor Jaguar.  It is however misleading to suggest the XK150S, E-Type and Mark X/420G were the only series-production Jaguars with triple carburetors because on some cars during the 1950s & 1960s, the factory fitted a smaller electromagnetically controlled “auxiliary carburetor” the main pair of carburettors.  The unusual arrangement acted as a choke but it was a complicated solution to a simple problem and, while performing faultlessly in testing, in the real world with gas (petrol) of varying quality and in different climatic conditions, it sometimes proved troublesome and there were owners who gave up and installed a conventional choke.

1966 Pontiac 2+2 421 HO Tri Power.

The early carburetors were all single throat (later also as “choke” or “barrel”) device and almost all were gravity-fed and it wasn’t until the 1930s the first two-barrel (then called a “duplex”) units appeared.  That design was such an advance because the duplexing allowed “fuel separation” manifolds which more accurately sent the mixture to the most distant cylinders; the adoption if this technology in 1934 allowed the output of Ford’s then new “flathead” V8 to rise from 60 to 85 horsepower (HP).  Buick in 1941 created what was, in effect, the first four-barrel system by installing two two-barrel units, the second becoming active only when the throttle had been opened far enough to operate the progressive linkage. The advantage being economy of operation in most circumstances, the additional fuel-burn required only on demand; it was an approach Detroit would use until 1971.  Four-barrel carburettors which operated on the same model appeared at scale in the 1950 and became an industry standard, some even installed in pairs on the highest-performance vehicles.  Ideal in many ways for the V8 layout, the problem for the manufacturers was the engines grew at a much greater rate than the carburetors and while the dual four-barrel configuration was suited to some, a better compromise for many was to use triple two-barrels.  Pontiac and Oldsmobile chose that path in 1957 and Chevrolet and Cadillac followed in 1958.  Ford flirted only briefly with the triple two-barrel before switching for a few years to dual four barrels for their high performance V8s and in 1958 three were bolted onto even the big, heavy 430 cubic inch (7.0 litre) MEL V8 although in that form it appeared only on one Mercury for that single season.  As higher-volume four-barrel carburetors became widely available, the rationale for the triple option faded and Chevrolet ceased use for all but the full-sized line and the Corvette; the last triple carburetor corvettes were built in 1969.  Chrysler was last to adopt the idea and the last to offer it, Trans-Am themed 340 cubic inch (5.5 litre) Plymouth ‘Cudas and Dodge Challengers made in 1970 while the 440 cubic inch (7.2 litre) (advertised variously as “Six Pack” by Dodge and “Six Barrel” by Plymouth) was available in several models between 1969-1971 although its last appearance was in the Jensen SP, the last of which was built in 1973.

"Triple" is used of many things: Lindsay Lohan and her lawyer in court, Los Angeles, December 2011.

Of taillights and exhaust tips 

1957 DeSoto Adventurer Convertible.

DeSoto's signature triple stacked taillights were a footnote in Detroit's macropterous era of the late 1950s, the style making possible the distinctive vertical arrangement.  Chevrolet would for years make triple taillights a trademark of their more expensive lines (although, apart from the odd special built for the show circuit, they resisted the temptation to add a third to the Corvette (the additional rear apertures on the abortive 1963 Corvette Grand Sport (GS) were for air extraction)) but they appeared always in a less memorable horizontal array.  DeSoto's motif was Chrysler's most successful use of the fins but it wasn't enough to save the brand  which was crowded out of the mid-priced market, not only by competition from General Motors (GM) and Ford but also by intra-corporate cannibalization, squeezed from below by Dodge and from above by Chrysler's new Newport line.  Demand for DeSotos collapsed and that so many were built in 1960 was simply to use up the large inventory of the few parts still exclusive to the brand.  The last of the line, heavily discounted, were not sold until well into 1961.

More sharing of stuff than before: 1960 DeSoto Fireflite four-door hardtop (left) and 1960 Chrysler New Yorker four-door hardtop (right).  Note the New Yorker's larger rear window.  Remarkably, the 1960 Chryslers offered two different designs of rear glass, the more panoramic described in the brochures as “Extra large rear window” which was standard on all two-door hardtops & New Yorker four-door hardtops and optional on the Saratoga and Windsor four-door hardtops.  It was a time when such a flourish was at the whim of designers whereas now it would require a separate programme of crash-testing several vehicles.

By 1959 the writing was on the wall for the once popular DeSoto and the 1960 range would prove its swansong, the last of the breed barely modified Chryslers and the only real hint of the past was the taillight's triple frets.  On the DeSoto the ridges were a modest attempt to retain brand identity but in optics such things have a purpose and are known as “Fresnel lenses” or “Fresnel ribs”, the name from French civil engineer Augustin-Jean Fresnel (1788–1827), remembered for his research into optics which led eventually to the near-unanimous acceptance of the nature of light being a wave (he was half-right but light was later proved to possess a wave-particle duality).  His more enduring Fresnel lens used the catadioptric (reflective/refractive) principle and what the “stepped” design did was extend the reach of lighthouse beams, doubtlessly saving the lives of many seafarers.  Fresnel’s invention was a refinement of the dioptric (refractive) stepped lens, a concept first published by the French cosmologist and mathematician Georges-Louis Leclerc, Comte de Buffon (1707-1788) and Fresnel’s enhancements better distributed and directed the light, improving visibility from longer distances and a greater range of angles.

By 1960 (left) the DeSoto's taillights were a shadow of the way the triple-stack motif had been defined in 1959 (right): This juxtaposition is DeSoto Red Tail Lights in Black and White by Paul Ward.  Many designers probably will prefer the later interpretation but there's a charm to the triple stack. 

1969 Dino 206 GT by Ferrari in Azzurro Metallizzato (left), 1974 Ferrari 365 GT4 in Rosso Corso (centre) and 1975 Ferrari 365 GT4 BB in Verde Germoglio.

Unexpectedly, in the early 1970s, Ferrari had a flirtation with triple taillights and they doubled-down for the 365 GT4 BB (better known as the Berlinetta Boxer), adding a pair of triple tail-pipe apparatuses (thus a count of six rather than the usual four) for the 4.4 litre Flat-12.  Before the decade was out it must have been decided four of either was enough and the factory decided for a while (mostly) to stick to the classics: as designs like the Dino 206 GT illustrate, less can be more.  Since the BB however, Ferraris have also appeared with two and three tailpipes (some in the 1970s had but one) and in the twenty-first century many cars come with just a minimalist pair of taillights.  Ascetically, no arrangement works as well as the traditional template: four lights, four pipes.

The fetish of motorcycle exhaust systems

1980 Laverda Jota 1000 (3-into-2, far left), 1973 Suzuki GT750 "Water Buffalo" (3-into-4, centre left), 1972 Kawasaki 750 Mach IV (H2) (3-into-3, centre right) and 2017 MV-Augusta Dragster 800Rc (3-into-3, far right).

Triple cylinder engines have been a feature of motorcycle engines for decades and different manufacturers have taken various approaches to the exhaust systems, an item which exerts upon riders a special fascination.  It’s not unusual to fit single systems (3-into-one) but there are also some which “siamesed” the central header pipe, the derived pair joining the two outer pipes to duct into two mufflers.  Unusually, Suzuki for a while offered 380, 550 & 750 cm³ machines with 3-into-4 systems, the central header again “siamesed” the central header but had the novelty of terminating the two pipes in separate mufflers thereby emulating the appearance of a four-cylinder machine.  It was a curious arrangement which Suzuki abandoned and other manufacturers choose not to follow (although there had been after-market suppliers which concocted 2-into-4 systems which exchanged the "advantage" of "the look" for the drawback of additional weight and needless complexity).  Greatly at the time, Suzuki must have valued symmetry.

1973 Kawasaki H2 Mach IV 750 (left) and 1975 Triumph X-75 Hurricane (right).

Somewhat earlier, asymmetry hadn’t frightened Kawasaki which used pragmatic 3-into-3 engineering for their range (250, 350, 400, 500 & 750 cm³) of charismatic, highly strung two-strokes, one pipe to the left, two to the right and it was a distinctive feature which, although sometimes seen on the track, remains rare on the road.  In the same era, Triumph on their X75 Hurricane took 3-into-3 asymmetry to its logical conclusion, its three pipes arranged in a radically upswept stack on the right.  It looked dramatic and was much admired but didn’t catch on although there’s the odd revival, the Italian house MV-Augusta engineering a particularly aggressive interpretation on their Dragster 800Rc.

1969 Triumph Trident T150.

So there have been triple-cylinder motorcycles with exhaust systems configured as 3-into-1, 3-into-2, 3-into-3 & 3-into-4 but the early versions of the Trident and BSA Rocket 3 (1968-1975) offered a unique take on things with a design which had the three headers ducted into two mufflers, each of which terminated with three exhaust stubs so it can be described as a 3-into-2-into-6 which seems at least one layer of complication too many.  The styling on the early Trident and Rocket wasn’t well received and was revised for 1971.  Neither motorcycle was a commercial success because they arrived too late; had the pair been released in 1966 as was planned, things might have been better because genuinely they were fast and offered a level of refinement beyond the parallel twins which for years had been a mainstay of the British industry.  As it was, within weeks of their debut, Honda’s epoch-making 750-Four was on the market, a generation (or more) advanced compared with the competition and when the Kawasaki 900 later followed, even the (slight) performance advantage enjoyed by the British triples vanished.

2022 Triumph Rocket 3 GT in triple black.

When Triumph announced the Rocket 3 in 2019, most attention was on the numbers, the 2458 cm³ (150 cubic inch) triple being the largest displacement engine available in a motorcycle and the (163 ft-lb) (221 N⋅m) torque generated also industry leading, topping even the big Ducatis and the straight-six BMW.  Triumph since 2004 been at the top of the displacement tree with the Rocket III’s 2294 cm³ (140 cubic inch) engine and the updated model was very much a modernization exercise, something which may account for the decision to switch from the traditional Roman numerals to a digitally compliant “3”.  Being a triple there were of course options for how to handle the exhaust ducting and for the GT model Triumph opted for the asymmetric on the model of the old Kawasaki two-strokes rather than reprise its own X-75 Hurricane of nearly half a century earlier.  Unlike Kawasaki, Triumph didn’t make asymmetry a signature feature, choosing to route the third exhaust, almost inconspicuously, just under the swing-arm on the left side, a curious juxtaposition with the visual statement of intent made by the two on the right.  Doubtlessly the engineering behind the decision was sound and to add a bit of high-tech bling, some Rocket 3’s had carbon-fibre exhaust tips and most conspicuously they were carbon-fibre.