The Flettner Fl 282 Kolibri (“Hummingbird”) was the world’s first series production helicopter. It was a single-seat intermeshing rotor helicopter (synchropter), produced by Anton Flettner of Germany. 24 helicopters have been built in 1942-45.
The first ever practical, functional helicopter – Focke-Wulf Fw 61 – was also developed in Nazi Germany. It was first flown on June 26th 1936 with Ewald Rohlfs – the German test pilot – at the controls. One year later he took the same helicopter to an altitude of 1,130 feet (344 m) and then idled the engine, using its spinning rotors to descend safely to the ground.
Intermeshing rotors on a helicopter are a set of two rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding.
The arrangement allows the helicopter to function without a tail rotor, which saves power. However, neither rotor lifts directly vertically, which reduces efficiency per each rotor.
Currently, the only synchropter in production is the K-MAX helicopter designed and manufactured by US-based Kaman Aircraft Corporation based in Bloomfield, Connecticut. K-MAX is optimized for external cargo load operations, and is able to lift a payload of over 6,000 pounds (2,722 kg), which is more than the helicopter’s empty weight.
The initial user of Fl 282 Kolibri (first deployed in 1942) was the Kriegsmarine – the Nazi Germany 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, with repeated takeoffs and landings from a pad mounted on the light cruiser Köln.
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 helicopter had been flown by a single pilot, but by then a position for an observer was added at the very rear of the craft.
It proved a useful artillery spotting aircraft and an observation unit was established in early 1945. The unit was equipped with three Fl 282 and three Fa 223 helicopters (I will cover the latter in the next section of the book).