ArcaMax

Some of the greets ideas never get fleshed out and remain... great ideas. Mazda's rotary engine, for instance. And the car that was built around it. The RX8.

Well, it began with the RX-7 - which first came to market in 1978. It was the heir-apparent of the Japanese (home market) 1967-'72 Cosmo - Mazda's first production car foray into rotary engine technology. All three were gorgeous cars; great sports cars. Quick - nimble. Technologically advanced. And yet, they failed, each in turn. A triple flop. Why?

They all had a bum ticker. The very thing that defined them, ultimately killed them. The rotary engine - also known as the Wankel engine, after its inventor, Felix Wankel. Like perpetual motion and zero point energy, this unusual engine design has been tantalizing car companies for decades. And disappointing them for just as long.

It all began in the the mid-1960s, when Mazda saw what it believed to be the future - and it was piston-less. The Japanese automaker was one of several that rushed to sign licensing agreements with NSU Motorenwerek AG, the German firm that had been developing Wankel's idea. General Motors, AMC (the Pacer was designed around the rotary engine concept) even Suzuki (for motorcycles) bought in, too. It is not hard to understand why.

The engine was a truly revolutionary design - one that promised more hp and less weight from a smaller,theoretically more efficient engine.

This was achieved - well, promised - by eliminating the conventional reciprocating engine's heavy block, with individual cylinders bored to house pistons that moved up and down in syncopation with the explosive force of internal combustion, their vertical motion translated (after efficiency losses) into rotational motion via a longitudinally mounted crankshaft. Which had to endure tremendous forces as each piston exerted downward pressure and was then - in an instant - pushed back up again. Times however many cylinders the engine had. This arrangement also tended to induce vibration - which had to be tamped down by counterweights and balancers. Which made the engine heavy as well as complex.

Wankel's original design was ingenious.

Instead of pistons going up and down, a kind of rounded-at-the-tips three-sided triangular rotor spins inside the crankcase, the space between each tip serving as the combustion chamber. As the rotor turns, ports are uncovered - admitting air (and fuel) and allowing exhaust gasses to escape. No energy is lost in (up and down) translation. There are no connecting rods, no conventional valvetrain. And virtually no vibration - without any need for counterbalancing.

By getting rid of all those parts, one got rid of a lot of beef. This matters to car designers - especially sports cars designers. The original '67 Cosmo's engine weighed about as much as one large man (225 pounds) and two reasonably strong men could pull one out of the car (and re-install it) by hand.

The reduction in rotating mass (and stresses) also allowed very high engine speeds - 7,000 RPM for the first generation and close to 10,000 RPM by the time of the RX8. Very few piston engines are capable of reliable - and sustained - operation at such speeds. This was just the ticket for a high-performance sports car, where a revvy engine is much desired. As is a compact engine.

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