The German car manufacturer, Borgward set up a helicopter division in 1956 under the leadership of Prof. Heinrich Focke, whose Focke-Wulf Fw.61 aircraft of 1937 was one of the earliest successful helicopters. The Kolibri I is the first helicopter of German design to have flown since the war.
A light three-seat helicopter, the Kolibri I, was designed with a three-blade main rotor. Blades have steel-tube spar, with plastic-bonded plywood covering. Fully-articulated hub with adjustable friction dampers. Main rotor drive is via two-stage cam-wheel. Tail rotor drive via hollow steel-tube shaft and two bevel-gears. Two tail rotors, inclined at 45° to horizontal, at extremities of tail stabilisers. Tail rotor blades of plastic-bonded plywood.
The uncovered steel-tube girder fuselage had a conventional tail boom and a tricycle type landing gear. Shock-absorption by torsion spring and Borgward hydraulic damper. Fuel tank aft of rear fire-wall.
Normal seating for three persons, with a central seat behind and on a higher level than front two seats, with a forward cockpit enclosed with bubble canopy. Alternative loads can include up to 300kg of freight slung from an under-fuselage hook.
The prototype had a 260hp Lycoming VO-435-A1B engine in the centre section.
The prototype made its first free flight on July 8, 1958, piloted by Herr Ewald Rohlfs, who set up several international helicopter records in the pioneer Fw.61 in 1937. Airworthiness trials were progressing satisfactorily in the Spring of 1959, and plans are being made to put the Kolibri in production.
Engine: 1 x Lycoming YO-435-A1B, 260hp
Main rotor diameter: 9.40m
Main rotor blade area (each) 1.28 sq.m
Main rotor disc area 70 sq.m
Length of fuselage: 8.30m
Height to top of main rotor head: 3.05m
Weight empty: 800kg
Weight loaded: 1200kg
Fuel capacity: 180 litre
Wheel track 1.93m
Wheel base 1.80m
Tail rotor diameter: 1.66m
Tail rotor disc area (total) 4.3 sq.m.
Main rotor/engine r.p.m. ratio 1 : 10
Tail rotor/engine r.p.m. ratio 1 : 6.75.
Max speed (est.): 160km/h
Cruising speed (est.): 140km/h
Rate of climb at sea level (est.): 240m/min
Vertical rate of climb at sea level (est.): 60m/min
Absolute ceiling (est.): 4500m
Hovering ceiling OGE (est.): 600m