The Si 204 was planned as a small passenger plane with 2 crew and 8 passengers for German airline Deutsche Lufthansa. The development of this all-metal-plane was initiated in 1938. The contractor was, as usual, the RLM, but the development was conducted in close collaboration between Lufthansa and Siebel in Halle. After the beginning of the war the plane was re-designed as a trainer aircraft with a
full "stepless" glass cockpit, with no separate flat windscreen for the pilot (much as almost all German bomber aircraft of the time were being designed with), which seemed to be better for blind flying in the Si 204's case.
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 ((Société Nationale de Constructions Aéronautiques du Nord) 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. In Czechoslovakia 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. In France SNCAC, commonly known as Aérocentre, produced 240 transport NC-701 Martinets and a number (110?) of passenger NC-702 Martinets. The NC-701 and NC-702 were distinguished by three-blade propellers and were powered by 440 kW (590 hp) Renault 12S-00 engines.
The NC-702 had a modified nose similar to the Si 204A.
Crew: one or two pilots
Capacity: up to 8 passengers or up to 1,650 kg (3,638 lb) cargo
Length: 13.00 m (42 ft 8 in)
Wingspan: 21.33 m (70 ft 0 in)
Height: 4.25 m (14 ft 0 in)
Wing area: 46 m² (495 ft²)
Empty weight: 3,950 kg (8,709 lb)
Max takeoff weight: 5,600 kg (12,348 lb)
Powerplant: 2 × Argus As 411 A1, 441 kW (592 hp) each
De Siebel Si 204 (ook wel bekend als Si-204) is een Duits transport- en lesvliegtuig gebouwd door Siebel. De Si 204 is gebaseerd op de Fh 104. Het toestel was eigenlijk ontwikkeld als licht transportvliegtuig voor de civiele markt. Deze ontwikkeling werd opgang gebracht na een reactie op de vraag van het Reichsluftfahrtministerium, het Duitse ministerie voor de luchtvaart, in 1938.
Tijdens en na de Tweede Wereldoorlog is het toestel in Frankrijk door SNCAC (later bekend als Aérocentre) geproduceerd als NC-701 en NC-702 en in Tsjechoslowakije door Aero Vodochody als de C-3 en C-103 (beide uitvoeringen met glazen neus conform de Si 204D).