Yes, I’m still doing research on vintage bikes. Here’s an interesting piece, the Megola, built in Munich, Germany between 1921 and 1925, rare and of unique design interest. The engine is a 640cc 5 cylinder monosoupape (French for single valve) rotary that is mounted inside the front wheel, yes, you heard right, inside the front wheel.
The crankshaft was the front axle, which remained stationary while the cylinders rotated with the wheel. A hand-controlled butterfly valve was located in the hollow crankshaft to regulate throttle. Power output was a meager 14 bhp (10 kW) but was applied directly to the wheel, the machine lacked both clutch and transmission. Starting it required a person to either spin the front wheel while the bike was on its stand, or to push-start. The cylinders could be disassembled without having to remove the wheel spokes. The tires were tubed with the front inner-tube being a circular sausage shape rather than a complete donut so that it could be changed without removing the wheel and engine. The box section frame contained the main fuel tank which fed by gravity a smaller tank mounted on the axle. The front suspension was comprised of semi-elliptical springs. Top speed was 85 km/h (52 mph) resulting in a win at the German Championship in 1924, while later, sportier models were said to be capable of 140 km/h (88 mph). A total of 2000 Megolas were built and only 10 ridable examples remain (via Wikipedia). This bike was included in the Guggenheim’s art of the motorcycle exhibit.
Rotary engines, where the crankshaft is stationary and the cylinder block rotates, are not to be confused with Radial engines, where the opposite is true. The design was originally invented by Lawrence Hargrave in 1889, the first effective rotary was patented by Stephen Balzer for automotive use, circa 1896. In 1908 the Seguin brothers introduced the Gnome Monosoupape for aviation use, the crank would be bolted to the airframe and the propeller attached to the cylinder blocks, in WWI, 80% of the aircraft used rotary engines. Today the term Rotary Engine refers to the Wankel Rotary most commonly used by Mazda in their RX7 and RX8.
Where does this leave me in regards to a project bike? Nowhere really. But maybe a Rotary Engined Monomoto…
