Rotary engines made their largest influence in Mazda sports activities vehicles, however a current episode of “Jay Leno’s Storage” delves into the rotary’s earlier historical past.

Earlier than it was popularized by Mazda, the rotary engine entered manufacturing with German automaker NSU (an Audi predecessor). The NSU Spider launched in 1964—three years earlier than Mazda launched its first rotary automobile, the Cosmo 110S. A type of early NSU rotary vehicles is now a part of Jay Leno’s assortment.

The rotary engine was invented by German engineer Felix Wankel after which licensed to automakers. It will get its title from the truth that, as a substitute of pushing pistons, the power from the combustion of gas and oxygen is used to spin a rotor (or generally two, as was the case with later Mazda engines).

The rotor has a triangular form however is mounted in a roughly spherical housing. The corners of the triangle are designed to seal towards the housing (one thing that proved troublesome for engineers to attain) permitting open areas on the perimeters to function the combustion chamber. The fuel-air combination (ignited by only one spark plug within the NSU) pushes towards the perimeters of the rotor, spinning it.

The benefits of rotary engines have been clean operation and compact measurement. The NSU Spider’s engine is so small that it sits beneath the rear baggage compartment, giving this convertible each a traditional trunk and a frunk that assist make up for its small measurement. The air consumption is positioned on the rear trunk lid; air is directed down into the engine by means of a pipe within the trunk.

Disadvantages included larger oil consumption than standard piston engines, and a self-destructive eagerness to rev. The NSU can simply rev to eight,000 rpm, Leno notes within the video, however that can put on out the rotor’s seals. The tachometer even has a inexperienced zone ending at about 5,500 rpm to encourage extra conservative driving habits.

The NSU Spider was additionally pretty costly for its time. It price round $3,500 in 1964, greater than different small sports activities vehicles just like the MGB. And it solely had 54 hp, despatched to the rear wheels by means of a 4-speed handbook transmission. Even with the Spider’s roughly 1,500-lb curb weight, that made for a driving expertise that required a little bit of endurance.

Rotary engine

After constructing a rotary sedan known as the R080, NSU was acquired by the Volkswagen Group within the late Nineteen Sixties and folded into what grew to become Audi.

Rotary engines lived on, with Common Motors and Mercedes-Benz experimenting with them within the Nineteen Seventies and Mazda making them an everyday characteristic in its lineup, notably within the RX-7 and RX-8 sports activities vehicles. The rotary-powered Mazda 787B grew to become the primary Japanese automobile to win the 24 Hours of Le Mans in 1991, however Mazda rotary manufacturing finally resulted in 2012.

Mazda introduced the return of the rotary engine early this 12 months, albeit as a spread extender in a brand new R-EV model of the MX-30 electrical crossover. The MX-30 R-EV will not be coming to the U.S., however Mazda unveiled an electrified rotary idea known as the Iconic SP on the 2023 Tokyo auto present. That ought to hold hopes for the return of the rotary sports activities automobile alive.