| 180 km/h|
| 16 m|
June 23, 1971
The Brditschka HB-3, HB-21 and HB-23 are a family of motor gliders of unorthodox configuration developed in Austria in the early 1970s.
Brditschka HB-3 Wikipedia
The unusual design was based on work done by Fritz Raab in Germany in the 1960s. The pilot and passengers sit in a fuselage pod with the engine and propeller behind them. The pod also carries the fixed tricycle undercarriage and the high cantilever wing. The tail is carried on a pair of booms that emerge from the top and bottom of the fuselage pod, the upper of which passes through the propeller hub. The HB-21 has a conventional tail and has two seats in tandem accessed by a sidewards-hinged canopy, while the HB-23 has a T-tail and side-by-side seating accessed via gull-wing doors in the canopy.
The Militky MB-E1 was a modified HB-3 with an 8-10 kW (11-13 hp) Bosch KM77 electric motor. It was the first full-sized, manned aircraft to be solely electrically powered. Flights of 12 minutes duration at up to an altitude of 380 m (1,247 ft) were just within the Ni-Cd battery's capacity. Its first flight was on 23 October 1973.Brditschka HB-3
Single seat powered sailplane, powered by 31 kW (42 hp) Rotax 642 engine, 12.00 m (39 ft 4 in) wingspan.
HB-Flugtechnik HB 21
Tandem two-seat derivative of HB-3 with longer span (16.24 m (53 ft 3 in)) wings.
HB-Flugtechnik HB 21/2400
HB-Flugtechnik HB 21/2400 B
HB-Flugtechnik HB 21/2400 V1
HB-Flugtechnik HB 21/2400 V2
HB-Flugtechnik HB 23/2400
HB-Flugtechnik HB 23/2400 SP
HB-Flugtechnik HB 23/2400 Scanliner
HB-Flugtechnik HB 23/2400 V2
electrically powered version.
Data from Jane's All The World's Aircraft 1990
General characteristicsCrew: one pilot
Capacity: 1 passenger
Length: 8.00 m (26 ft 3 in)
Wingspan: 16.40 m (53 ft 9 3⁄4 in)
Height: 2.45 m (8 ft 0 1⁄2 in)
Wing area: 19.1 m2 (205 ft2)
Aspect ratio: 14:1
Empty weight: 560 kg (1,234 lb)
Gross weight: 760 kg (1,676 lb)
Powerplant: 1 × Volkswagen air-cooled engine, 74.2 kW (98 hp) each
PerformanceMaximum speed: 180 km/h (112 mph)
Range: 800 km (497 miles)
Endurance: 6 hours
Service ceiling: 5,000 m (16,400 ft)
Maximum glide ratio: 20:1
Rate of climb: 3.8 m/s (748 ft/min)
Rate of sink: 1.2 m/s (236 ft/min)