Dornier Do 32

In the early 1960s, the German Army had an interest in a small helicopter for observation and communications duties that could be folded up compactly enough to be carried in a trailer pulled by a jeep. The Do 32, like several other light helicopters of the time such as the Fairey Ultra-light Helicopter and the Sud-Ouest Djinn, used rotor tip jets to drive the rotor blades. The advantage of tip drive is the absence of torque reaction, making a tail rotor unnecessary, saving weight and simplifying control of the aircraft. Dornier used a small gas turbine to drive a compressor, which fed air out through tubes in the rotors to the tips.[1]

The Do 32 was structurally very simple, with a square section, tapering fuselage behind the pilot. The BMW 6012L turbine and compressor were placed on top of the fuselage, immediately behind the rotor pylon. Its exhaust impinged upon a large rectangular rudder, built to resist thermal stresses, for yaw control. The horizontal tailplane was swept. The pilot sat in front of the rotor pylon, on a simple seat, carried on the lower longerons. He controlled the plane of the two-bladed rotor directly with a long curved hanging arm, and its pitch with a conventional collective pitch lever by his left side. The rudder pedals were almost straight out in front of him on a strut that also carried, beyond his feet, some simple instruments. This member also formed part of the simple three-legged undercarriage, each strut ending with an unsprung foot.[1]

The Do 32 first flew on 29 June 1962,[1] and much flight testing was done with this aircraft and two further prototypes. The aircraft was also stowed in a trailer, transported, unfolded and flown. The heavy rotor could be spun up before takeoff with zero pitch, containing enough energy for a rapid initial vertical climb or jump start, autogyro fashion.[2] All three were eventually lost in accidents with different causes. Though Dornier had hopes of large Army orders, none followed. Agricultural applications were considered, and there was a design project for the Do 32Z, a two-seat version with a bigger engine,[1] but no more manned Do 32s flew. The unflown fourth prototype is on display at the Deutsches Museum, painted as the first prototype D-HOPA. The Do 32U was a pilotless version of the Do 32E, very similar, apart from the missing seat. The Do 32K, developed into the Do 34, was also an unmanned drone with compressed air-driven rotors, but without a fuselage.

 Germany

• Luftwaffe

Fourth prototype at the Deutsches Museum

Data from Green 1964, p. 255

General characteristics

• Crew: one
• Length: 3.42 m (11 ft 3 in) fuselage
• Height: 1.89 m (6 ft 2 in)
• Empty weight: 147 kg (325 lb)
• Gross weight: 270 kg (596 lb)
• Max takeoff weight: 321 kg (707 lb)
• Powerplant: 1 × BMW 6012L gas turbine driving compressor, 67 kW (90 hp)
• Main rotor diameter: 7.5 m (24 ft 7 in)

Performance

• Maximum speed: 119 km/h (74 mph, 64 kn)
• Cruise speed: 100 km/h (62 mph, 54 kn)
• Range: 90 km (56 mi, 49 nmi)
• Endurance: 50 min
• Rate of climb: 4.0 m/s (780 ft/min) maximum inclined rate

Related development

• Dornier Kiebitz

Aircraft of comparable role, configuration, and era

• Gyrodyne Rotorcycle
• XH-26 Jet Jeep