Photo ou archives : F-M. Dumas
804
HERCULES
Wankel-Sachs W 2000 - 1973
The fistst production rotary
No more conrods or valves, fewer moving parts, and freedom from vibration! The idea of the rotary engine, developed by Dr. Felix Wankel, proved irresistible to manufacturer the world over. Many of them invested heavily in research programs that never got to production. Sachs-Hercules pulled it off, however, and managed to put a rotary-engined bike on the market.
Shaft-Drive Prototypes
The 1970 prototypes had shaft drive, but the W 2000 offered for public sale in 1973 had chain transmission. It cost some 10,300 francs at a time when a four-cylinder Honda 350 could be bought for 9,600. In 1975, a front disk brake was added, but production was halted in 1978. But Sachs was one of Europe's biggest engine manufacturers and lost no time investigating new opportunities. The rotary proved to be a triumph of hope over experience. Still, the radical bike raised the whole industry's standards.
Spiraling Costs
Eventually, production costs of the complex hypocycloidal combustion chamber spiralled out of control, and the problems of achieving gas-tight seals at the three tips of the trilobite rotor proved intractable. Wonderful in theory, the rotary engine proved unsatisfactory in practice, and the venture was abandoned before the Eighties.
SPECIFICATIONS
Engine: Air-cooled Wankel Monorotor equivalent to 300 cc
Power Rating: 20 hp @ 6000 rpm
Transmission: 4-speed, chain drive
Brakes: telescopic fork (front); swinging fork (rear)
Wheels: 18in wire
Maximum Speed: 80 mph
Higher than expected fuel consumption combined with the advent of anti-pollution laws brought this bold venture at marketing a rotary engine to a sudden end.