The Bücker Bü 131 Jungmann (freshman, young man) is a basic biplane trainer aircraft designed and produced by the German aircraft manufacturer Bücker Flugzeugbau. It was the company's first aircraft, as well as being the final biplane to be produced in Germany. On 27 April 1934, the first prototype Bü 131 performed its maiden flight, which was roughly two years after the company had been founded in Berlin-Johannisthal by Carl Bücker. Anders J. Andersson had led the aircraft's design effort. Comprising both metal and wooden construction, the Bü 131 was designed to be suitable in the trainer role, and even to perform aerobatic manoeuvres. The first deliveries of the Bü 131 occurred in 1934, the Deutscher Luftsportverband (DLV) being a key early customer for the type. Later on, the Bü 131B was selected as the primary basic trainer for the German Luftwaffe. In this capacity, it was operated in large numbers throughout the Second World War. Throughout the 1930s, there had been substantial demand for the Bü 131, multiple large export orders and production licenses were issued as a result. The Kingdom of Yugoslavia was the largest pre-war export customer for the type, flying as many as 400 Bü 131s at one point. Hundreds were produced locally by the Spanish aircraft company Construcciones Aeronáuticas SA (CASA). In excess of 1,300 Bü 131s were operated by the military air services of Imperial Japan under local designations of Kokusai Ki-86 and Kyūshū K9W Momoji. The Bü 131 remained operation with numerous air forces for decades after the conflict, some choosing to retain the type through to the late 1960s. It has proved to be a relatively popular biplane with private pilots, who have often elected to have their aircraft refitted with modern engines for increased performance. The origins of the Bü 131 can be traced back to the work of one man, Carl Bücker. After serving in the Kaiserliche Marine during the First World War, Bücker relocated to Sweden and became the managing director of Svenska Aero AB (Not to be confused with Svenska Aeroplan AB, SAAB). He later returned to Germany with Anders J. Andersson, a young designer from SAAB, and founded a new company, Bücker Flugzeugbau GmbH, in Berlin-Johannisthal during 1932. From the onset, Anderson headed up the company's design team,[note 2] and immediately set about developing the company's first aircraft, out of the efforts for which ultimately emerged the Bü 131. The aircraft was designed to be suitable for aerobatic manoeuvres and training activities. It featured numerous conventional features for such aircraft at that time, being a biplane with two open cockpits in tandem along with fixed landing gear. Both the upper and lower wings were broadly identical in terms of design, to the extent that they could be readily interchanged with on another. Accordingly, all of the wings, which had an 11 degree sweep back and positive stagger, were equipped with ailerons. The wings had a structure largely composed of I-section wooden spars along with a fabric covering. The fuselage of the Bü 131 comprised a structure of welded steel tubing, the covering of which was metal for the front section and fabric around the rear section. Both fuel and oil were accommodated in tanks within the fuselage. Hinged to the side of the fuselage was the twin main legs of the undercarriage, which were furnished with both spring and oil-based shock absorbers, while a spring tailwheel was also present on the underside of the aft fuselage. The mainwheels were outfitted with balloon tyres and brakes. For more details of development, operational history and 13 variants, click here.
