Dornier Do17

Specification (Z-2)

Type: four-seat medium bomber; Powerplant: 2 x 1,000hp Bramo 323P Fafnir 9-cylinder, radial piston engines; Performance: 255mph / 410kph at 4,000ft / 1,220m (maximum speed), 186mph / 300kph at 13,125ft / 4000m (maximum cruising speed), 26,905 ft / 8200m (maximum ceiling), 721 miles / 1,160km (maximum range); Weight: 11,488lbs / 5,210kg (empty), 18,940lbs / 8,590kg (maximum take-off); Dimensions: 59ft 1in / 18m (wing span), 51ft 10in / 15.8m (length), 14ft 11in / 4.55m (height), 592sq.ft / 55m.sq (wing area); Armament: up to 7 x 7.92mm (0.31in) MG15 machineguns and up to 2,205lbs / 1000kg of bombs; Used: Germany, Finland, Italy, Croatia & Yugoslavia.

History

In response to a Lufthansa specification for a six passenger mailplane issued in 1933, Dornier designed a shoulder-wing all-metal monoplane powered by two 660hp BMW VI engines. Three prototypes were built in 1934 and although the airline undertook an evaluation programme early the following year, the aircraft's slim fuselage provided very limited passenger accommodation and all three were returned to Dornier. The design however had military potential and a fourth prototype (Do17 V4) with twin vertical tail surfaces and a shortened fuselage was flown during summer 1935. Additional development prototypes were built, the fifth was powered by 860hp Hispano Suiza 12Ybrs engines, the seventh mounted a 7.92mm (0.31in) MG15 in a dorsal blister and the tenth was fitted with 750hp BMW VI engines. The initial production models were the Do17E-1, which was developed from the ninth prototype with a glazed and shortened nose and could carry 1,102lbs (500kg) of bombs, and the Do17F-1 reconnaissance model with an increased fuel capacity and two cameras. These models made their operational debut with the Condor Legion during the Spanish Civil War in 1937. Their performance was such that they had little difficulty avoiding the obsolete fighters of the Republican Air Force.

Dornier Do 17P Dornier Do 17P Dornier Do 17Z Dornier Do 17Z Dornier Do 17Z Dornier Do 17Z Dornier Do 17Z Dornier Do 17Z
It was revealed publicly at the 1937 International Military Aircraft Competition held at Dubendorf near Zurich where the Do17 V8 prototype (or Do17 17M V1), powered by two 1,000hp Daimler-Benz DB600A engines, quickly earned itself the nickname of the 'Flying Pencil' due to its slender fuselage. The aircraft was able to better the performance of the fighters appearing at the show and as a result, Yugoslavia expressed an interest with the Do17K being developed, being similar to the Do17M but powered with two 980hp Gnome-Rhone 14N1/2 engines. The aircraft were built under license by Dravazna Fabrika Aviona at Kraljevo with three versions being produced, Do17Kb-1 bomber, the Do17Ka-2 and Do17Ka-3 reconnaissance aircraft with secondary bombing and attack capabilities respectively. The Do17L was a pathfinder version which had two prototypes built but did not make to serial production - it had two 900hp Bramo 323A-1 radial engines due to a shortage of DB 600 engines. the same powerplant was used for the thirteenth and fourteenth prototypes in order to further develop the airframe / engine combination for the production Do17M-1 version that would be able to carry 2,205lbs (1000kg) of bombs. A photo-reconnaissance version of the Do17M, designated Do17P, went into production with two 875hp BMW 132N radial engines and carried one of two sets of cameras, either the Rb20/30 and Rb50/30 or the Rb20/8 and Rb50/8. Two aircraft were built as engine testbeds, designated Do17R one having 950hp Daimler-Benz DB600Gs, the other with 1,000hp Daimler-Benz DB601As. These were followed by three Do17S-0 prototype, high-speed reconnaissance aircraft equipped with DB600G engines that featured a glazed nose and an airframe incorporating a bulged section on the underside of the forward fuselage accommodating a gunner lying in a prone position to operate an MG15 firing aft. The experimental machines were followed by a small production batch of fifteen pathfinder aircraft, comprising three Do17U-0 and twelve Do17U-1 aircraft with five man crews that included two radio operators to handle the comprehensive navigational and communications equipment.

The major production version was the Do17Z of which some 1,700 were built between 1939 and 1940,  appearing in several versions. The Do17Z-0 featured two 900hp Bramo 323A-1 engines and was armed with three MG15 machineguns but was otherwise similar to the Do17S. The Do17Z-1 had an additional MG15 mounted in the nose but was underpowered and could only carry a 1,102lbs (500kg) bomb load. The Do17Z-2 rectified the situation with 1,000hp Bramo 323P engines, carrying 2,205lbs (1000kg) worth of bombs and up to eight MG15 machineguns. The Do17Z-3 was a reconnaissance variant of which twenty-two were built, each equipped with Rb50/30 or Rb20/30 cameras, followed by the Do17Z-4, a dual-control trainer. The Do17Z-5 was the final bomber variant, which while similar to the Do17Z-2 differed by having floatation bags in the fuselage and at the rear of the engine nacelles. Do17 production ended with a single Do17Z-6 Kauz I long-range intruder and night fighter which incorporated the nose from a Junkers Ju88C-2 with a 20mm MG FF cannon and three MG15 machineguns. However, for the nine Do17Z-10 Kauz II aircraft that followed a new nose was developed which housed four MG FF cannon and four 7.92mm (0.31in) MG17 machineguns - when developed as night fighters they were equipped with Lichtenstein C1 radar and Spanner-II-Anlage infra-red detection equipment. Dornier Do17 aircraft played a major role in the early stages of the Second World War, taking part in the invasion of Poland, Denmark, Norway, the Low Countries and France. They also featured during the Battle of Britain, the invasions of Greece and Yugoslavia and finally Operation Barbarossa but by then had begun to be withdrawn from frontline service.

Do17 Variants

Export versions of the Do17Z were designated Do215, the first being the Do215A-1 with 1,075hp Daimler-Benz DB601A engines being ordered by Sweden in 1939. On the outbreak of World War II, the eighteen aircraft were embargoed and converted to Luftwaffe specification under the designations Do215B-0 (four-seat bomber) and Do215B-1 (reconnaissance), while the Soviet Union was sent two examples of the Do215B-3 while the Do215B-4 was a reconnaissance version similar to the Do215B-1 but equipped with Rb20/30 and Rb50/30 cameras. The final variant was the night fighter / intruder Do215Z-5 which had an unglazed nose, similar to the Do17Z-10 but housing two 20mm MGFF cannon and four 7.92mm (0.31in) MG17 machineguns.


Dornier Do 217
Dornier Do 217E

Dornier Do 217E
Dornier Do 217E
A major variant of the Do17 was the Dornier Do217, essentially an enlarged version, first flown as a prototype in August 1938, powered by two 1,075hp Daimler-Benz DB601A engines. Dornier had issued Manufacturing Specification No. 1323 recognising the need for a twin-engined bomber or long-range reconnaissance aircraft, as well recognising that the Ju88 was superior to the Do17 in every way. Although the original aircraft crashed a few weeks later, the programme was continued by three prototypes equipped with two 950hp Jumo 211A engines. The third prototype carried armament and enlarged vertical tail surfaces and modified dive brakes. A further three Jumo-engined aircraft were followed by two with 1,550hp BMW 139 engines in an attempt to improve the aircraft's performance but the advanced BMW 801 was eventually adopted (with a similar output) for the eight pre-production Do217A-0 reconnaissance aircraft. These carried two cameras and three 7.92mm (0.31in) machineguns and entered service with the Aufklarungsgruppe Oberbefehlshaber der Luftwaffe in 1940. The A series was followed by five aircraft of the Do217C bomber version, the first (Do217C V1) being equipped with the Jumo 211A engines but the remainder (Do217C-0) had the BMW 601A engines although all were armed with one 15mm MG151 cannon and five 7.92mm (0.31in) machineguns plus a bomb load of 6,614lbs (3,000kg). The first major production variant was the Do217E which appeared in 1940 having modifications such as a deeper fuselage and an enlarged bomb bay that could accept bombs or a torpedo. The Do217E-1 was able to carry 4,409lbs (2,000kg) of bombs, one 15mm MG151 cannon and five 7.92mm (0.31in) machineguns. This was followed by the Do217E-2 with a revised armament of one 13mm (0.51in) MG131 machinegun in a dorsal turret, another placed ventrally, three 7.92mm (0.31in) machineguns in the forward fuselage and a 15mm MG151 cannon in the nose. The Do217E-4 came out in 1941 and featured BMW 801C engines and had cable-cutters in the leading wing edges while the E-3 was an anti-shipping aircraft used over the Atlantic, carried additional armour plating, two additional fuel tanks in the bomb bay and armed with seven MG15s and a single 20mm MGFF cannon in the nose. Series production of this version began with the Do217E-5 of which about sixty-five were built that had underwing racks for the addition of Henschel He 293 missiles. There was a single Do217H variant that was a high-altitude experimental aircraft developed from a Do217E and equipped with Daimler-Benz DB601 turbocharged engines. The Do217J-1 (fighter-bomber) and Do217J-2 (night fighter) began production in 1942. The J-1 had the same nose as the Do17Z-10 and was armed with four 7.92mm (0.31in) MG17 machineguns and four 20mm MGFF cannons and a pair of 13mm (0.51in) MG131 machineguns in the ventral and dorsal positions. The J-2 had a 20mm MG 151/20 cannon instead of the MGFF and a FuG 212 Lichtenstein radar. In autumn 1942, Dornier introduced the Do217K-1  bomber with a new glazed nose and an un-stepped cockpit. The K-2 carried two SD 1400X (Fritz X) missiles underneath the wings and had FuG 203a and FuG 230a guidance equipment installed. In fact it was a SD 1400X missile that sank the Italian battleship Roma when on 14 September 1943, the Italian fleet sortied out of La Spezia to join the Allies. The K-3 could carry either the SD 1400X or Hs 293 missiles but this was not the last word in these advanced missile carriers. Two aircraft designated Do217L were developed from the K series to test revised cockpit and defensive dispositions, followed by the Do217M-1 which was a Do217K-1 with Daimler-Benz DB603A engines while the Do217M-5 was a K-1 with underwing racks for Hs 293 missile. The Do217M-3 was a Do217K-3 with DB603A engines while the Do217M-11 was an extended wingspan, missile carrying version of the Do217K-2. The last operational variant of this bomber was in fact the Do217N night-fighter, appearing as the Do217N-1 combining the nose of the Do217J-2 with the Do217M airframe. It was replaced in production by the Do217N-2 which had the dorsal turret removed but the limitations of this aircraft in the night-fighter role meant that it more-or-less replaced in that role by the more effective Bf110 or Ju88. The remaining versions include the Do217P, which first flew in June 1942. It was developed as a high-altitude reconnaissance aircraft with a pressurised cabin, powered by two 1,750hp DB 605T engines which were boosted by a two-stage supercharger driven by a 1,475hp DB 605T engine mounted in the bomb bay. Weapons included four MG81 machineguns along with one Rb20/30 and two Rb75/30 cameras. Pressurisation had been a feature Dornier had originally proposed back in 1939 but received little official interest. The concept was resurrected in 1941 under the designation Do317 (see below) which saw the first of six prototypes built. Pressurisation must have been too complicated however as the remaining five prototypes were completed without this feature and were built as normal Hs 293 missile carriers under the designation Do217R. Overall, some 1,730 Do217 aircraft were built and were last used in a large-scale bombing campaign against targets in the UK in early 1944.


Dornier Do 317
Dornier Do 317
The Dornier Do317 was planned as a heavy bomber, essentially a development of the Do217, outlined in plans produced in June 1940. It featured a pressurised cabin and more powerful engines (DB 604 or Jumo 222). The Do317 was one of the proposals submitted to the RLM (Reichsluftfahrtministerium - German Air Ministry) for the 'Bomber B' project, a requirement for an advanced medium bomber to be powered by two twenty-four cylinder piston engines, to replace the Heinkel He111 and Junkers Ju88. The new aircraft had to have the range to reach any part of the British Isles from bases in France, have a maximum speed comparable to the best fighters then around and carry a bomb load of 8,820lbs (4,000kg). Four companies produced designs, of which the Focke-Wulf 191 and Junkers Ju288 were awarded full development contracts, the Arado Ar 340 was abandoned and the Dornier Do317 retained as an insurance against the other two failing and was given a low development priority. Two versions of the Do317 were proposed. The first was a simplified Do317A equipped with 1,750hp DB 603 engines and a conventional weapons layout, while the second was a more advanced version, the Do317B, equipped with 2,870hp DB 610 engines, remotely controlled defensive barbettes, a heavier bomb load and an extended wing span. Six prototypes of the Do317A were ordered and the first (Do317 V1) commenced its flight test programme on 8 September 1943. The Do317 V1 was very similar to the Do217 but featured a pressurised cabin and triangular tail fins. Tests revealed no real performance advantages over the Do217 and so the remaining five aircraft were completed without cabin pressurisation as Henschel Hs 293 missile carriers. In this form the prototypes were re-designated as the Do217R. The Do317B project was cancelled at this point due to changing wartime conditions.

Bibliography

Green, W. Warplanes of the Third Reich, Galahad Books, London, 1986.
Kay, Antony & Smith, J. German Aircraft of the Second World War, Putnam Aeronautical Books, London, 2002 (Rev Ed).
Mondey, David. The Hamlyn Concise Guide to Axis Aircraft of World War II, Bounty Books, London, 2006.
Gunston, Bill. The Illustrated Encyclopedia of Combat Aircraft of World War II, Salamander, London, 1978.
Wikipedia. Webpages on the Dornier Do17, Do217 and Do317.

Photos courtesy of the website of Professor Lluís Belanche Muñoz:
http://www.lsi.upc.es/~belanche/personal/do-17.html
Do317 picture is an artist's rendition.

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How to cite this article: Antill, P. (30 July 2007), Dornier Do17, http://www.historyofwar.org/articles/weapons_do17_peter.html

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