Focke-Wolf Kolibri

The rotors had the same synchropter configuration as the earlier Fl 265. The radial engine was mounted in the center fuselage, with a small propeller to draw in cooling air. A transmission was mounted on the engine crankcase front. It ran a driveshaft connected to an upper gearbox that split the power into two opposite rotating driveshafts that turned the rotors.

By this time, however, Flettner had developed the idea of counter-rotating, intermeshing twin rotors. Many of his advisers thought that the airflow disturbed by the intermeshing blades would make this system less efficient than one using a single rotor; but Flettner believed that any problems thus encountered would be more than offset by the reduced drag resulting from having no external rotor-carrying structure. He proved his point by installing such a system in the Fl 265, whose prototype (D-EFLV) flew in May 1939. At this time encouragement for the development of small helicopters came mostly from the German Navy, on whose behalf six Fl 265's had been ordered in 1938 with a view to developing a machine suitable for shipboard reconnaissance and anti-submarine patrol. Service trials of the Fl 265 were more than satisfactory, and plans were made for series production; but by this time work was well advanced on a later model, the Fl 282, which could carry a men and was more versatile. The RLM therefore agreed to wait for the Fl 282, to hasten whose development it ordered thirty prototypes and fifteen pre-production aircraft in spring 1940. Maiden flight was made in 1941. The first three prototypes were completed as single-seaters and had fully enclosed cabins made up of a series of optically flat Plexiglas panels, faired-in rotor pylons and well-contoured fuselages. The Fl 282V3 was fitted with endplate auxiliary fins and a long underfin beneath the rear fuselage. Later machines had more utilitarian bodies and some had semi-enclosed cockpits; others, like the example illustrated, had a completely open pilot's seat. Like the Fl 265, the Fl 282 underwent exhaustive service trials, and several were used operationally from 1942. Usually they flew from platforms above the gun turrets of convoy escort vessels in the Baltic, Aegean and Mediterranean, often in extreme weather conditions, and revealed control and performance qualities well above expectations. By VE-day, only three of the twenty-four prototypes completed by Flettner at Johannisthal still survived, the others having been destroyed to prevent capture. Two of these, the V15 and V23, were taken to the United States, and the other to the Soviet Union. The RLM had placed an order in 1944 for one thousand Fl 282's from BMW, but Allied bombing attacks prevented production from being started. At least two other Flettner helicopters were under development when the war ended. These were the Fl 285, another fleet spotter with an Argus As.10C engine, capable of making a 2-hour flight and carrying two small bombs; and the Fl 339, a large transport helicopter project powered by a BMW 132A engine.