Bertin

   By 1899 Leonce Bertin, known earlier as a long-distance bicycle roadracer and trainer, had designed and built an air-cooled motor for his bicycles (probably a V2), and became the first motor-bicyclist to reach a speed of 100 kmh. He also built a small air-cooled flat twin, later developed into a flat 8, as well as an 8-cylinder in X-form and another 8 in twin-X; at the same time he was working on a heavier-than-air flying machine, a helicopter.
   It was built in 1907 at Puteaux with the help of a mechanic named Bouline; the 150 hp flat 8 drove with direct drive a 1.7-meter tractor propeller at 2500 rpm, and at the same time, through a reduction gear, a horizontal 2-blade 2.4-meter rotor at 1200 rpm. This unsuccessful machine weighed c 300 kg. His second design, also unsuccessful, was called a helicoplan; the same engine higher in a smaller airframe drove 2 propellers, but in this version the tractor was 2.2 m in diameter and the rotor was 2.5 m. Both propellers were Voisin-style, with aluminum plates and a steel-tube axis. The airframe was mounted on 4 wheels and fitted with a pair of folding biplane wings behind the tractor propeller; and a large swallowtailed tailplane with a large rudder and 2 elevators was underneath. Only the horizontal surfaces were covered, and the lower wing may have had variable incidence for use as elevators. After much testing the machine was converted to a monoplane through the removal of the horizontal rotor.
   His third helicopter was a simpler design done with Lieber for exhibition on cycle-racing tracks where Bertin was already famous as a champion. The Bertin-Lieber consisted of a tetrahedral frame on 4 wheels with a 55 hp 4-cylinder Bertin radial at the top, driving 2 horizontal rotors, the smaller one 1.3 m in diameter driven directly at 1000 rpm, and the larger, fabric-covered, clutch-driven at 120 rpm. The drive-shaft ran vertically through the center of the high cylindrical fuel tank. The rig stood c 3.5 m high.