Dornier Do 317

In June 1940, Dornier produced plans for a development of the Do 217, which would have a pressurized cabin and more powerful engines (DB 604 or Jumo 222). Designated Do 317, it was one of the proposals submitted to the RLM for the “Bomber B” project. Two versions of the Do 317 were proposed: the simplified Do 317A, powered by two DB 603A engines and featuring conventional defensive armament, and the more advanced Do 317B with the heavy 1.5 tonnes apiece, counter-rotating DB 610A/B “power system” engines, remotely aimed Fernbedienbare Drehlafette (FDL)-style gun turrets, heavier bomb load, and an extended wing.

Six prototypes of the Do 317A were ordered, and the first of these, the Do 317 V1, commenced its flight test program on 8 September 1943. The Do 317 V1 was very similar in appearance to the Do 217K and M models, with a visually reframed slight variation of its multiple glazed-panel “stepless cockpit”, fully glazed nose design that accommodated a pressurized cabin provision, and triangular tail fins. Trials with the Do 317 V1 revealed no real performance advance over the Do 217, so it was decided to complete the remaining five prototypes without cabin pressurization equipment and fit them out with FuG 203 Kehl radio guidance transmitting gear to employ them as Henschel Hs 293 missile launchers. In this form, the prototypes were redesignated Do 217R. At this time, the Do 317B project was abandoned due to changing wartime conditions.

General characteristics

Crew: four
Length: 16.8 m (55 ft 1 in)
Wingspan: 20.63 m (67 ft 8 in)
Height: 5.44 m (17 ft 10 in)
Wing area: 68 m² (730 sq ft)
Gross weight: 20,140 kg (44,401 lb)
Powerplant: 2 × Daimler-Benz DB 603A inverted V-12 liquid-cooled piston engine, 1,300 kW (1,750 hp) each

Performance

Maximum speed: 560 km/h (350 mph, 300 kn) at 6,000 m (19,685 ft)
Cruise speed: 420 km/h (260 mph, 230 kn)
Stall speed: 133 km/h (83 mph, 72 kn)
Range: 3,980 km (2,470 mi, 2,150 nmi)
Service ceiling: 9,800 m (32,200 ft)

Armament

Guns:

3 × 13 mm (0.512 in) MG 131 machine gun in upper turret, rear dorsal, and rear ventral positions 2 × 7.92 mm (0.312 in) MG 81 machine gun in nose 1 × 15 mm (0.591 in) MG 151 cannon in nose