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Do-217M

Night Bomber

Dornier

Do-217K3

The Do-217M at the Soviet Scientific Research Institute. Our specialists had an opportunity to examine the Messerschmitt DB 603A engine in detail. Single-engine Bf 109G and K variants had different DB 605 modifications with the same 35.7-liter cylinder volume. Thanks to increased piston stroke and cylinder bore, the total cubic capacity of the more powerful 603 engines increased to 44.5 liters. This engine became heavier (from the DB 605A's 745 kg) to 962 kg and its size increased. Problems concerning the reliability of the DB 603A assemblies and aggregates, as well as design changes, were of particular interest because Soviet engine designers headed by B. Ya. Klimov continued to refine the powerful VK-107A engine (displacement of 42.7 liters) even after combat actions ceased.

                                                                                                                                 

It turned out that the Daimler Benz engineers had changed the crankshaft, spark plugs, and the design of the main bearing oil feed; they made the propeller reduction gear casing longer. Engine control became more automated through introduction of a single control lever. The Germans managed to establish precise cross coupling among the main DB 603 operating parameters: rpm, supercharge, fuel-to-air ratio, ignition advance, and impeller rotational speed. In addition, the engine was fitted with automatic units controlling the fuel pump and the supercharger hydraulic clutch. Moreover, the engines operated quite well, without signs of pinking, vibration, and malfunctions. They compared favorably with VK-107A in spooling up, transition from one power setting to another, and start-up at low temperatures.

The focus on German power plants continued when a Do 217M aircraft fitted with two DB 603 engines underwent testing. Except for its powerful engines, the captured bomber generally did not impress leading Air Forces Scientific Research Institute specialists. Its maximum speed of 477 km/h could not be considered sufficient either for the end of the war or for early 1946 when it was first flown in the USSR (lead engineer Engineer-Major P. I. Kuzmin, pilot Lieutenant Colonel V. I. Zhdanov). The Dornier also lagged behind the domestic Tu-2 in rate of climb (it took 15-5 minutes to climb to 5000 meters) and service ceiling (7750 meters). Its defensive armament was less effective as well.

At the same time, the upper DL-13I/ID semi-mechanized gun turret was interesting. It had electrical drive allowina it to move weapons horizontally 360° at a constant speed. This turret was better than the Soviet "purely mechanical" UTK-1 mounted on I1-4 and Li-2 aircraft. However, in general, the defenses were weak and it was almost exclusively confined to performing night missions. In January 1946, study of the Dornier ended.

Specification
Do217K-1 Do217M-1 Do217J-2 Do217N-1
Dimensions
Length, m 17.12 17.12 17.67* 17.67*
Wing span, m 19.0
Wing area without a fus., m² 48.5
Wing area,including a fus., m² 56.7
Height in line of flight, m 4.8
Weight, kg:
Empty weight, kg - 9065 8730 10270
Loaded weight - 16790 13180 13200
Powerplant
Engine (two) BMW 801D DB603A BMW 801ML DB603A
Power, hp takeoff 1700 1750 1580 1750
at alt 1440 1620 1380 1850
m 5700 5700 4600 2100
Performance
Max speed, km/h at alt 515 560 489 515
m 4000 5700 5500 6000
Cruise speed, km/h at alt - 400 465 470
m -     5400
Rate of climb min - 6.7 3.5 9
to alt, m - 2000 1000 4000
Ceiling, m - 7350 9000 8900
Range, km - 2150 2050 1755
Armament
7.92-mm machine guns 3** 3** 4 4
13-mm machine guns 2/3 2/3 2 2
15/20-mm cannon no no 4 4
Internal bomb load, kg 2500 2500 no 400
Bombs, kg 4000 4000 no 400

* - without radar antennas.

** - the nose 7.9-mm twin MG 81Z machine gun was quite often replaced with 13-mm MG 131.

- no data



Photo Description
Drawing Do-217M Drawing Do-217M
Dornier Do-217M The Do 217M was one of the latest captured German Aircraft extensively tested at the Air Forces Scientific Research institute.

Bibliography

  • "Aviation of Luftwaffe" /Viktor Shunkov/
  • "The German Imprint on the History of Russian Aviation " /D.A. Sobolev, D.B. Khazanov/
  • "Encyclopedia of military engineering" /Aerospace Publising/