Flettner Fl 185

The Flettner Fl 185 was an experimental Nazi German gyrodyne developed by Anton Flettner. It was unique in its operation, which could fly both as a helicopter and as a gyroplane.

Fl 185
General information
Type	Autogyro/helicopter
Manufacturer	Flettner
Designer	Anton Flettner
Number built	1
History
First flight	1936

Design and development

This aircraft was developed in 1936 with support of the Kriegsmarine. It was powered by a 160 horsepower (120 kW) BMW-Bramo Sh 14 A radial piston engine with forced-air cooling, mounted at the nose. The engine drove a 12 m diameter main rotor and two auxiliary propellers mounted on outriggers attached to the fuselage.

At take-off or when hovering, the auxiliary propellers worked in opposition to each other and served to cancel the torque of the main rotor,^[1] a function handled by a single, variable-pitch tail rotor on contemporary helicopters. In forward flight, however, both propellers worked to provide forward thrust while the rotor autorotated, as in a twin-engined autogyro.^[1] The landing gear consisted of a nose-wheel, two smaller stabilising wheels under the outriggers and a tail skid. Only one prototype was constructed.

Specifications (Fl 185)

Data from ^[2]

General characteristics

• Powerplant: 1 × Bramo 314C 7-cyl air-cooled radial piston engine, 110 kW (150 hp)
• Main rotor diameter: 1 3-bladed × 12 m (39 ft 4 in)
• Main rotor area: 113.112 m² (1,217.53 sq ft)
• Propellers: 2 x 2 bladed-bladed fixed-pitch wooden propellers

Performance

See also

• Fairey FB-1 Gyrodyne