The Flettner Fl 282 Kolibri ("Hummingbird") is a single-seat open cockpit intermeshing rotor helicopter, or synchropter, produced by Anton Flettner of Germany. According to Yves Le Bec the Flettner Fl 282 was the world's first series production helicopter.
Design and development
The Fl 282 Kolibri was an improved version of the Flettner Fl 265 announced in July 1940 which had the same intermeshing rotor configuration as the earlier helicopter. It had a Siemens-Halske Sh 14 radial engine of 150-160 hp mounted in the center of the fuselage, with a transmission mounted on the front of the engine from which a driveshaft ran to an upper gearbox which then split the power to a pair of opposite driveshafts to turn the rotors. The Sh 14 engine was a tried and tested design with a proven track record which only required servicing every 400 hours as opposed to the Focke Achgelis Fa 223 which needed maintenance every 25 hours. The Fl 282's fuselage was constructed from steel tube covered with doped fabric, and it was fitted with a fixed undercarriage.
The German Navy was impressed with the Kolibri and wanted to evaluate it for submarine spotting duties, ordering an initial 15 examples to be followed by 30 production models. Flight testing of the first two prototypes was carried out through 1941, including repeated takeoffs and landings from a pad mounted on the German cruiser Köln.
The first two "A" series prototypes had enclosed cockpits; all subsequent examples had open cockpits and were designated "B" series.
In case of an engine failure, the switch from helicopter to autorotation was automatic.
Three-bladed rotors were installed on a test bed and found smoother than the vibrating 2-bladed, but the concept was not pursued further.
Operational history
Model of the 282
Intended roles of Fl 282 included ferrying items between ships and reconnaissance. However, as the war progressed, the Luftwaffe began considering converting the Fl 282 for battlefield use. Until this time the craft had been flown by a single pilot, but now a position for an observer was added at the very rear of the craft, resulting in the B-2 version. The B-2 proved a useful artillery spotting aircraft and an observation unit was established in 1944 comprising three Fl 282 and three Fa 223 helicopters.
Good handling in bad weather lead the German Air Ministry to issue a contract in 1944 to BMW to produce 1,000 units. However, the company's Munich plant was destroyed by Allied bombing raids after producing just 24 machines.
Towards the end of World War II most of the surviving Fl 282s were stationed at Rangsdorf, in their role as artillery spotters, but gradually fell victim to Soviet fighters and anti-aircraft fire.