The Siebel Si 204 was a small twin-engined transport and trainer aircraft developed during World War II. It was based on the Fh 104. Originally designed in response to a RLM development order for a small civil transport plane in 1938, it was eventually produced for the Luftwaffe.
The first two prototypes only were delivered as passenger planes with the old cockpit. The maiden flight of the first prototype was before September 1940, possibly on 25 May 1940, that of the second prototype before February 1941. The third prototype was re-designed as a trainer aircraft for blind flying. As a result of this, the maiden flight was not earlier than the end of 1941 or the beginning of 1942.
At that time Siebel produced the Junkers Ju 88 under licence, and therefore only 15 prototypes were able to be built in Halle. As a result, SNCAN in France produced the passenger plane A-1 and the pre-series A-0 between April 1942 and November 1943. ČKD/BMM in the Czech Protectorate delivered the first blind flying trainer D-0 in January 1943 followed by the production of a further 44 D-0 pre-series planes. The D-1 series was begun in March 1943 by the Aero company, also located in the Czech Protectorate, and by BMM in June or July 1943. In August 1943, SNCAN also delivered the first D-1.
The production of the D-3 was started in October 1944 by the Aero company. The D-3 had wooden wings and a tail plane made of wood and metal. In France, production of the D-1 was ended in August 1944 as a result of the Liberation. All in all 168 Si 204 were built by SNCAN. BMM produced the plane until October 1944 and then changed to the production of spare parts for the Si 204. The Aero company was scheduled to cease production of the D-1 in March 1945 after building 486 planes and then switch to D-3 only. The aircraft, however, was only built until January 1945 with 541 completed. Therefore the total production was 1,216 including the prototypes.
After the war, a production of Si 204 continued in Czechoslovakia and France. Aero Vodochody produced 179 Si 204D, developed into military trainer variants Aero C-3A and C-3B (the later for bombardier training), passenger variant C-103 and military transport variant Aero D-44, until 1949. SNCAC in France produced 240 of transport NC-701 Martinet, and a number (100?) of passenger NC-702 Martinet. NC-701 was distinguished by three-blade propellers.
The use of the Si 204 D was mainly in B- and C-Schools (advanced schools) and by FÜG 1 (delivery wing of the Luftwaffe), probably as a taxi plane for crews who had delivered other planes to fighting units. The utilization in blind flying schools was sporadic; for radio schools there is no evidence of use. The Si 204 A flew mainly with communications squadrons and flying services for senior officers, but also with schools.
In July 1944 five Si 204 were destined to be converted to night combat planes, but no further planes were allotted. They were probably intended for the pre-series Si 204 E-0. There is, however, no evidence that these planes were ever used in combat situations.
Lufthansa received at least four Si 204: The first prototype, D-AEFR, was evaluated from March to May 1941 by Lufthansa Prague. From spring 1942 to spring 1943 the second prototype, D-ASGU, was used on regular routes as a freight carrier. At the end of the war one Si 204 D remained in Berlin-Tempelhof (named “Rhein”). One flew to Enns in Austria, where it was captured by the Allies.
After the war, captured Si 204s flew in a variety of roles in the Soviet Union, including with Aeroflot and TsAGI, but were all quickly phased out of service as local aircraft manufacturing was re-established.
|V1||As 410||Prototype passenger plane, Reg. D-AEFR||25th May, 1940?||Not mentioned in November 1942, scrapped?|
|V2||As 410||Prototype passenger plane, Reg. D-ASGU||Before February 1941||26.02.44 Crash Erprobungs-Stelle Rechlin|
|V3||As 410||Prototype Blind flying school plane||Before February 1942||01.06.42 Crash Erprobungs-Stelle Rechlin|
|V4||As 411||Prototype Blind flying school plane, Reg. KM+GB||Before November 1942|
|V5||For stress testing|
|V6||As 410||Evaluation As 410||December 1942|
|V7||As 410||Weather reconnaissance|
|V8||As 410||General flight evaluation|
|V9||As 410||General flight evaluation||30.06.43 Crash School C-16 Burg|
|V10||As 410||General flight evaluation|
|V11||As 410||General flight evaluation|
|V12||As 410||General flight evaluation||13.03.44 Crash Erprobungs-Stelle Rechlin|
|V13||As 410||General flight evaluation|
|V14||As 411||Prototype D-2|
|V15||As 411||Evaluation As 411|