Dornier Do 317

The Do 317 was originally designed to fulfil the RLM’s Bomber B specifications of 1939. The Bomber B was to be a twin engined medium bomber, capable of carrying a 8,816lb bomb load to any part of the United Kingdom, and was to be powered by a new generation of new powerful engines.

The original 1940 design for the Do 317 was very similar to the Do 217M. It would have carried a crew of four in a pressurised cabin, but problems with the new engines caused the cancellation of the program. Some features from the Do 317 were then used in the Do 217P.


Dornier Do 317
Dornier Do 317
The Bomber B program suffered from the failure of the new engines it was based around. The Junkers Jumo 222 was a 24 cylinder inline engine with the cylinders arranged in six rows of four, giving it the appearance of a four row radial engine, but none of the advantages. The Daimler Benz DB 604 was another 24 cylinder inline engine, this time with four rows of six cylinders, arranged in an X formation. These engines were expected to produce at least 2,500hp and would have been much more powerful than contemporary German engines. The first prototype of the Jumo 222 was ready in 1939, but despite three more years of development work it was never ready to enter full production. The DB 604 was no more successful.

As a result the prototype Do 317 had to use less powerful engines. Work resumed on the Do 317 late in 1941. The Do 317A was powered by the DB 603A and was very similar to the Do 217M, although did feature triangular fins on the tail plane. Five prototypes of this model were built, with test flights beginning late in 1943, but it was no better than the Do 217M.

The single Do 317B prototype received the 2,870hp DB 610 double engines, which finally gave the aircraft a power plant with the required level of performance. In this form the Do 317B prototype reached a top speed of 372 mph. The new aircraft features a wider 85ft wing, and would have carried one 20mm MG 151 in the tail and three twin-gun machine gun turrets, two of which were to be remote controlled from the pressure cabin.

When the Do 317 program was abandoned, the five Do 317A prototypes were redesignated as Do 217Rs, and used to launch the Hs 293A radio-controlled missile. In this format the cabins were not pressurized.

Span: 67ft 8.5in
Length: 61ft
Max Speed: 348-372mph (top speed with DB 610)
Range: 2472 miles
Bomb load: 8816lb

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How to cite this article: Rickard, J (25 June 2007), Dornier Do 317, http://www.historyofwar.org/articles/weapons_do317.html

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