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The Fl 282 was the most sophisticated of all German helicopters of World War II.
Engineer and inventor Anton Flettner was born on November 1, 1885 in Germany. He taught physics and math to high school students, and in 1905 took a job at the Zeppelin company.
During World War I, Flettner developed a device that allowed airplane pilots to raise or lower a plane’s nose for better control. It evolved into a mechanism called the “trim tab” which is still used on all airplanes. Flettner also made several improvements to military tanks, and he apparently designed a guided torpedo which was never built.
In the 1920s, Flettner’s interest in aerodynamics led him to build one of history’s strangest boats: a schooner with two tall rotating cylinders that looked like smokestacks, but were actually sails.
Having turned his attention to the problems of rotary-wing flight in 1930, Anton Flettner first produced a helicopter with two 30hp Anzani piston engines mounted on the ends of two rotors, each turning a two-bladed propeller. While this arrangement eliminated the problems associated with torque (which the Focke Achgelis designs overcame by means of two contra-rotating rotor sets, and which other designers, notably Sikorsky, counteracted by means of a powered tail rotor), it was only marginally successful in other ways. When it was destroyed during tethered testing, it was not rebuilt. Flettner next built a two-seat cabin autogiro for the Kriegsmarine (German Navy) but the single example of the F -184 caught fire in flight and was also destroyed.
THE Fl 185 AND Fl 265
Clearly, Anton Flettner was still searching for a valid way forward, for his next design, designated the Fl 185, was substantially different again, almost a cross between a helicopter and an autogiro, its 140hp Siemens-Halke engine being linked to a single rotor and two variable-pitch pusher propellers located on outriggers. For vertical take-off and landing, the air-craft functioned as a helicopter, the majority of the power going to the rotor, and the two conventional propellers, providing thrust in opposite directions, only counteracting the torque. For forward flight, the rotor auto rotated and the two propellers received all the power and gave forward thrust. The Fl 185 flew only a few times before Flettner abandoned it and turned his attention to a new design using synchronized inter-meshing contra-rotating twin rotors (like those of the Kaman H-43 ‘Huskie’ of the 1960s) with differential collective pitch control.
The single-seat Fl 265 was very similar in appearance to the Fl 185, with its front-mounted radial engine with cowl and cooling fan, enclosed cockpit and stubby tail fin. However, gone were the Fl 185′s outriggers and propellers, and the rotor head assembly, with its paired, inclined shafts, each with a two-bladed rotor, was much more complex. The design was completed in 1937, and the following year, the Kriegsmarine ordered six aircraft for evaluation purposes. The prototype made its maiden flight in May 1939 and was later destroyed when its rotor blades struck each other in flight.
Other Fl 265s were used extensively for operational trials with naval units – cruisers in the main, but also submarines – in the Baltic and the Mediterranean with considerable success, and completely validated the concept of deploying VTOL aircraft with warships. Aircraft also operated with army units, both in the reconnaissance and logistical roles, and a Luftwaffe trial involving a Bf 109 and an Fw 190 fitted with camera guns demonstrated that the helicopter was very difficult to shoot down. The two fighters, amongst the best in the world, we may recall, attacked the Fl 265 for 20 minutes but tailed to score a single hit. The outcome of the various trials was that Flettner was ordered to proceed with volume production. In fact, he had already proceeded with the design of an updated version, the two-seat (some prototypes were single-seat) Fl 282 ‘Kolibri’ (‘Hummingbird’), and it was this aircraft which went into manufacture.
THE Fl 282′KOLIBRI’
The most important modification Flettner made to the design of the new aircraft was to re-locate the engine behind the pilot’s seat, which gave him and the observer a much-enlarged field of view. The drive was taken off the front of the crankshaft through a reduction gearbox and transmitted up and back through a universally jointed drive shaft and a cross-shaft connecting the two rotor shafts, which were set at an inclusive angle of 24 degrees, and inclined forward by 6 degrees. The rotor blades were mounted so that they were parallel when they were at 45 degrees to the aircraft’s centreline. The fin and rudder were much larger than in previous Flettner designs, steering being accomplished by a combination of rudder movement and differential collective pitch control.
The ‘Kolibri’ proved to be very satisfactory indeed, despite a pronounced vibration period as the engine was run-up, with a maximum speed in level flight of 150km/h (93mph), a vertical rate of climb of 91.5m/min (300ft/min), a hover ceiling of 300m (985ft), and a service ceiling of 3290m (10,800ft). Its range, with just the pilot and maximum fuel aboard, was 300km (185 miles). Some 50 pilots were trained to fly it, most of them by Flettner’s test pilot, Hans Fuisting. It was extremely manoeuvrable and very stable and at forward speeds in excess of 60km/h (37mph) could be flown hands-off once the controls were balanced.
SEA TRIALS
From 1942, trials at sea aboard the cruiser Köln demonstrated that the aircraft was usable even in very poor weather conditions, and by the following year, 20 were in service with the Kriegsmarine in the Mediterranean and the Aegean. In 1944, an order for 1000 Fl 282s was placed with BMW, which began tooling up for production at its Munich and Eisenach plants, but before manufacture could begin, both they and the Flettner works at Johannisthal were very badly damaged by Allied bombing. Anton Flettner went on to design a 20-seat passenger helicopter, the Fl 339, but never got beyond the development stage.
Variants
Fl 282 V1/7
Prototypes.
Fl 282A-1
Single seat naval reconnaissance type, for operation from cruisers and other warships. Tested in Baltic, Mediterranean, and Aegean Seas.
Fl 282A-2
Single seat reconnaissance type for submarines equipped with special deck hangar, project only.
Fl 282B-1/B-2
Two seat land reconnaissance-liaison helicopter
Specifications (Fl 282)
General characteristics
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Crew: 1 pilot
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Length: 21 ft 6.25 in (6.65 m)
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Rotor diameter: 39 ft 2 in (11.96 m)
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Height: 7 ft 2.5 in (2.20 m)
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Disc area: 2,418.6 ft² (224.69 m²)
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Empty weight: 1,676 lb (760 kg)
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Useful load: 529 lb (240 kg)
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Max takeoff weight: 2,205 lb (1000 kg)
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Powerplant: 1× Bramo Sh 14A 7-Cylinder radial piston engine, 160 hp (119 kW)
Performance
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Maximum speed: 93 mph (150 km/h)
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Range: 106 miles (170 km)
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Service ceiling: 10,825 ft (3300 m)
Armament
2x 5kg bombs
