The Wankel engine is the greatest automotive engine story that never was. It was the way of the future, a simpler engine for an easier life. And today, not one single car is being made with one. Mazda gave it a go for a few years with greats like the 787B and the RX-7, but they weren't the only ones.
In these halcyon days of motoring, when we have hybrid motors that produce almost 1,000 horsepower and our engines of the future have no camshafts, we still rely on a piston in a cylinder moving up and down so that we can move forward. That's the system that's been in place since the 19th century, and that's boring. Surely we can do better.
A man named Felix Wankel thought so as well, so he created his own engine that featured a rounded triangle spinning inside of a housing that was, in theory, much simpler and much more efficient for their size. Matt already posted this video once before, but it's probably the best way to explain how the whole thing works:
Unfortunately the engines also tend to gulp down fuel and burn oil like Saddam trying to get out of Kuwait, which means horrible emissions. And in today's world, that just ain't gonna fly. So back to the up-and-down piston it is, while we get on with our boring lives and our boring reciprocating engines until the next dreamer with a great idea comes along.
In the 1960s and 1970s, though, everyone was still convinced of the genius of the Wankel design. With super-cheap gasoline, too, and ice caps intact, it looked as if there was no conceivable reason not to switch over to the engine of the future. Many manufacturers accordingly submitted their entries to the Pantheon of the rotor-powered engine, and not just the bold men and women at Mazda.
These cars, then, represent not a future that was, but a future that could be. In a world where the planet took care of itself and the black gold lasts forever, this is how the automotive landscape would look today.
Chevrolet XP-895 (aka the Aerovette)
There once was a time when GM didn't just claim the Corvette was the car of the future, it actually was the car of the future. Powered by a 4-rotor engine that produced 420 horsepower mounted in the middle, the XP-895, also known as the Aerovette when Chevy finally got around to putting a V-8 in it, showcased a lot of styling cues seen on later Corvettes. The engine itself was made from two two-rotor engines originally installed in some 1973 Chevy Vega prototypes. A thirst for petroleum wasn't the only thing that killed this one off, however. Corvette fans like eight cylinders up front powering the rear wheels, and this is one of many Corvette concepts that never actually got off the ground.
Photo credit GM
While Chrysler went about rewarding loyal customers with turbine-powered curiosities, Citroen decided they would reward their loyal customers with this, the M35. It wasn't actually sold to the public, but rather was used as a test vehicle to see if this whole Wankel thing would work itself out. Citroen handed out 267 M35s out to its biggest fans to find out whether or not they liked it, and, unsurprising for Citroen fans, they thought it was weird and wonderful and just perfect.
It was so perfect, in fact, that when Citroen actually put a Wankel-engined car on sale in the form of the Citroen GS Birotor, that the company only sold 867. It tanked so hard that Citroen actually tried buying back and scrapping all the GS Birotors it could get its hands on so that they wouldn't be forced to maintain them, and nowadays very few of perhaps the weirdest of the weird Citroens exist.
Photo credit Ruizo
The C111 wasn't so much a concept car as a concept platform that led to all the Mercedes-Benz engines we have today. Diesels? Check. Twin-turbo V8s? Check. Four-rotor engines producing 370 horsepower? No dice. The rotor segment of the Mercedes C111 program is perhaps the only one that never saw some descendant hit production, despite hinting at all the wonderful things that could be. In fact, the C111 program as a whole is kind of a disappointment, in that none of it ever left the company. With a super-slippery body giving a drag coefficient of only .191, the aforementioned twin-turbo variant, producing 500 horsepower, made it all the way to 250 miles per hour. Granted, it probably had such little downforce as to be downright terrifying, but seeing one on the streets would be pretty neat. The Mercedes C111 almost looked production-ready with a fully-built interior, but then decided they just didn't feel like making it.
Photo Credit Cees Dirijk
NSU Ro 80
The NSU Ro 80 was actually one of the first rotary-powered cars available to the general buying public when it went on sale in 1967. It's also one of the few cars to have brought down an entire company single-handedly.
The Ro 80 was a zippy little car with an incredibly smooth engine for the time, but it was doomed from the start. Like many European manufacturers of the era that hit upon a good idea, they got so excited about said idea that they just put it on sale before getting all the kinks worked out. One of those kinks involved the seal between the tips of the rotor and the rotor housing itself, and the two parts would grate against each other and would eventually caused the engine to kill itself if left untreated. Mazda eventually solved the problem by coating the offending pieces in graphite, but before that could happen NSUs rapidly acquired a reputation as incredibly unreliable. Used NSUs were practically being given away, and sales fell off a cliff.
Within two years of the car going on sale, NSU was bought by Volkswagen.
Which car do you think would be better with a smooth and high-revving rotor? Leave your suggestion in the comments below!
Photo credit Wikicommons. Topshot credit Mercedes-Benz.