Bücker Bü 131 Jungmann variant
Bücker Bü 131 Jungmann Bü 131D
Final German production version, from 1938: the same 105 hp Hirth HM 504A-2 with minor improvements, recognisable by its larger tailwheel. It was the version Aero built in Prague and the one Hungary received.
History
The Bü 131D replaced the B version on the Rangsdorf line from 1938. The Air Britain Digest describes it as "the final German production version, introduced in 1938 with minor improvements"; the German Wikipedia adds that it was outwardly distinguished by a larger tailwheel and kept the 105 hp Hirth HM 504A-2. The RLM tally does not separate the D from the B: it groups 1,356 aircraft with the HM 504 engine for both series.
The D was also the version built outside Rangsdorf during the war years. After the occupation of Czechoslovakia, the Aero factory in Prague was assigned to build the Bü 131D-2 for the Luftwaffe at a rate that reached 24 aircraft per month, until in September 1940 the plant switched to the Focke-Wulf Fw 189; about 300 Jungmann are thought to have left the line there. In Spain, the CASA Jungmann Research Team recalls that the first 200 aircraft built under licence by CASA were Bü 131-D2s, before the CASA 1.131E introduced the Tigre engine. And Hungary received 151 Bü 131Ds from 1939 onwards; most were destroyed during the German retreat, although the Hungarians managed to rebuild 42 with salvaged parts and new wings before the lack of spares grounded the last one in 1953.