Flettner Fl 282

https://en.wikipedia.org/wiki/Flettner_Fl_282

The Flettner Fl 282 Kolibri ("Hummingbird") is a single-seat 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.

The Fl 282 Kolibri was an improved version of the Flettner Fl 265 announced in
July 1940, which pioneered the same intermeshing rotor configuration that the
Kolibri used. It had a 7.7 litre displacement, seven-cylinder 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 drive shaft ran to
an upper gearbox, which then split the power to a pair of opposite-rotation
drive shafts to turn the rotors.

The Sh 14 engine was a tried-and-true design that only required servicing every
400 hours, as opposed to the nearly 27 litre displacement, nine-cylinder
BMW/Bramo Fafnir 750 hp radial engine powering the larger Focke Achgelis Fa 223
helicopter, whose outdated design required maintenance every 25 hours.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 tricycle 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-blade rotor, but the concept was not pursued further. The hover
efficiency ("Figure of Merit") was 0.72 whereas for modern helicopters it is
around 60%.

Intermeshing rotors were not used on a mass production helicopter until after
World War Two.

Role
Helicopter

Manufacturer
Anton Flettner, Flugzeugbau GmbH

First flight
1941

Introduction
1942

Retired
1945

Primary user
Luftwaffe

Number built
24

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 by then a position for an observer was added at the
very rear of the craft, resulting in the B-2 version.Later the B-2 proved a
useful artillery spotting aircraft and an observation unit was established in
1945 comprising three Fl 282 and three Fa 223 helicopters.

Good handling in bad weather led 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.

Specifications (Fl 282 V21)

General characteristics
Crew: 1
Length: 6.56 m (21 ft 6 in)
Height: 2.2 m (7 ft 3 in)
Empty weight: 760 kg (1,676 lb)
Max takeoff weight: 1,000 kg (2,205 lb)
Powerplant: 1 × Bramo Sh.14A 7-cyl. air-cooled radial piston engine, 119 kW (160
hp)
Main rotor diameter: 2× 11.96 m (39 ft 3 in)
Main rotor area: 224.69 m2 (2,418.5 sq ft)

Performance
Maximum speed: 150 km/h (93 mph; 81 kn) at sea level
Range: 170 km (106 mi; 92 nmi)
Service ceiling: 3,300 m (10,800 ft)

Hover ceiling: 300 m (984 ft)
Rate of climb: 1.52 m/s (299 ft/min)

Rotor loading: 8.84 kg/m2 (1.81 lb/sqft)




*