The first product of
Bücker Flugzeugbau GmbH, established at Johannisthal, Germany during
October 1933, was a two-seat light trainer known as the Bücker Bü 131
Jungmann (Young Man). Designed by Anders J. Andersson, the company's
Swedish chief engineer, it was a conventional single bay biplane with
fabric-covered wooden wings, a welded steel-tube fuselage that, with
the exception of light alloy around the engine and cockpit, was also
fabric-covered, and a wire-braced tail unit of similar construction to
the fuselage. The tailwheel type landing gear had rather stalky main
units, and power for the prototype (D-3150), was first flown on 27
April 1934, and was provided by an 80 hp (60 kW) Hirth HM 60R inline
A Swiss operated Bücker Bü 131B (HB-UUA) Jungmann "Young Man"
The Bü 131A, as the
initial production version was designated, proved to be very
successful, being manufactured not only for civil flying schools in
Germany but also for the Luftwaffe, although production figures do not
appear to have survived. They consisted not only of the initial
production Bü 131A, but also an improved production Bü 131B which had a
more powerful Hirth HM 504A-2 engine. An experimental BU 131C was
built, powered by a 90 hp (67 kW) Cirrus Minor engine, but following
testing this version was not put into production. Bücker exported
production aircraft for service in some eight European countries with
the largest numbers going to Hungary (100) and Romania (150), and in
addition 75 were licence-built in Switzerland. The most extensive
licence-construction was in Japan, where 1,037 were built for the
Japanese army as the Type 4 Primary Trainer (Ki-86A) by Kokusai. This
followed the initiation of production on behalf of the Japanese navy
for which it was licence-built by Watanabe (later Kyushu) as the Navy
Type 2 Primary Trainer Model 11 (K9Wl). Production figures for the
Japanese navy version differs according to source, varying from 217 to
339, but it seems reasonably certain that more than 200 were used as
the navy's standard primary trainer.
Used throughout World
War II by the Luftwaffe, the Bü 131 was later displaced by the improved
Bucker Bü 181 Bestmann, and many saw service with auxiliary ground
attack squadrons. Carrying 2.2 lbs (1 kg) and 4.4 lbs (2 kg) bombs,
they were used by night to maintain nonstop harassment over Soviet
lines. Like other classic trainers, many Bü 131s survived the war, and
they were even built by Aero in Czechoslovakia during the 1950s under
the designation C.4.
Bücker Bü 131 Prototype
(D-3150) - The prototype was first flown on 27 April 1934 powered by an
80 hp (60 kW) Hirth HM 60R inline 4-cylinder engine.
Bücker Bü 131A - The
intial production version produced both for civil flying schools
(Luftsportverband) and the Luftwaffe. Powered by an 80 hp (60 kW) Hirth
HM 60R inline 4-cylinder engine. Heavily exported with Switzerland and
Japan both acquiring licences for production.
Bücker Bü 131B - An
improved version with a 105 hp (78 kW) Hirth HM 504A-2 inline
4-cylinder air-cooled piston engine which added about 8 mph (12.9 km/h)
to the top speed and gave a much improved rate of climb.
Bücker Bü 131C - A
single experimental version powered by a 90 hp (67 kW) Cirrus Minor
inline 4-cylinder engine. Flight testing showed no real performance
gain so further work was abandoned.
Tatra T-131 - This
aircraft was produced in Czechoslovakia during the war under licence
based on the Bücker Bü 131B design.
Type 4 Primary Trainer
(Ki-86A) - Produced in Japan by Kokusai under licence for the Japanese
Army based on the Bücker Bü 131A design (1,037 aircraft).
Navy Type 2 Primary
Trainer Model 11 (K9Wl) - Produced in Japan by Watanabe (later Kyushu)
under licence for the Japanese Navy based on the Bücker Bü 131A design
(217 to 339 aircraft - exact figures are unknown).
Aero C.4 - Built by
Aero in Czechoslovakia during the 1950s.
Bü 131B Jungmann "Young Man")
Type: Two Seat
Primary Trainer & Auxiliary Ground Attack
Pilot/Instructor and Student sitting in open cockpits in tandem with
Designer Anders J. Andersson as Chief Engineer of Bücker Flugzeugbau
GmbH. (Formerly from Svenska Aero AB in Stockholm).
Bücker Flugzeugbau GmbH formed in October 1933 at Johannisthal with
Carl Clemens Bücker as Managing Director and owner of the Company. In
1935 the company was moved to a new factory at Rangsdorf, near Berlin.
Carl Clemens Bücker was the former Managing Director of Svenska Aero AB
in Stockholm. Also licence built by CASA at Cadiz, Spain and by Dornier
at Altenrhein, Switzerland. Watanabe (later Kyushu) and Kokusai also
built the type under licence in Japan.
105 hp (78 kW) Hirth HM 504A-2 inline 4-cylinder air-cooled piston
Maximum speed 114 mph (183 km/h) at sea level; cruising speed 106 mph
(170 km/h); service ceiling 9,840 ft (3000 m); landing speed 51 mph (82
km/h); climb to 6,560 ft (2000 m) in 12 minutes.
Fuel Capacity: A
single welded Aluminium fuel tank in the fuselage with a capacity of 11
Imperial gallons (50 litres).
Range: 404 miles
(650 km) with internal fuel.
Weights & Loadings:
Empty 836 lbs (380 kg) with a maximum take-off weight of 1,474 lbs (670
kg) and a disposable load of 638 lbs (290 kg). Wing loading 9.49 lbs/sq
ft (46.3 kg/sq m); power loading 13.75 lbs/hp (6.25 kg/hp).
24 ft 3 1/4 in (7.40 m); length 21 ft 8 in (6.60 m); height 7 ft 4 1/2
in (2.25 m); wing area 145.32 sq ft (13.50 sq m).
131A, Bü 131B, Bü 131C, Tatra T-131 (Czech built), Ki-86A, (Japanese
Army), K9W1 (Japanese Navy). C.4 (Postwar Czech version built by Aero)
Standard communications equipment only.
Unit: The wings are of the single bay biplane type with
interchangeable upper and lower wings. Incidence (lower) 0°, (upper)
1°. Dihedral (lower) 4.5°, (upper) 2.5°. Sweepback 11°. No lift or
anti-lift wires attached to lower rear spars. "I" section wooden spars,
wooden ribs and conventional drag bracing, all with fabric covering.
Steel struts with ailerons on all four wings. The fuselage was of
welded chrome-molybdenum steel tube construction with fabric covering,
with the exception of metal sheeting used around the engine and
cockpit. The tail unit was also of welded chrome-molybdenum steel tube
construction with fabric covering with wire bracing. Divided elevator
with trimming flaps in trailing-edges and an unbalanced rudder. The
aircraft was stressed to an immensely strong +/- 12 g's and was a
superb aerobatic aircraft with excellent handling qualities.
The landing gear was of the divided type. Shock Absorbers with steel
springs and oil-damping were hinged to the sides of the fuselage with
the axles hinged to a pyramidal structure beneath the structure.
Balloon type tires equipped with brakes. Sprung tailwheel.
flight (D-3150 prototype) 27 April 1934; first delivery (Luftsportverband)
late 1934; first delivery (Luftwaffe) 1935.
Germany (Luftwaffe), Hungary, Romania, Finland, Netherlands, Spain,