In
response to a Lufthansa specification of 1933 for a six-passenger mailplane,
Dornier designed a shoulderwing all-metal monoplane to be powered by two 660-hp
(492-kW) BMW VI engines. Three prototypes of this Dornier Do 17 were built in
1934, but although the airline carried out an evaluation programme early in the
following year, the aircraft's slim fuselage provided such limited passenger
accommodation that all three were returned to the manufacturer. The design had
military potential, however, and a fourth prototype (Do 17 V4) with twin
vertical tail surfaces and a shortened fuselage was flown in the summer of
1935. Among development prototypes, the fifth was powered by 860-hp (641-kW)
Hispano Suiza 12Ybrs engines, the seventh mounted a 7.92-mm (0.31-in) MG 15
machinegun in a dorsal blister, and the tenth was fitted with 750-hp (559-kW)
BMWVI engines. The initial production versions were the Do 17E-1 which,
developed from the ninth prototype, had a glazed and shortened nose, and
carried a l,102-lb (500-kg) bombload, and the Do 17F-1 reconnaissance aircraft
with increased fuel capacity and two cameras.
Both of these models made their
operational debut with the Legion Condor in Spain during 1937. Their
performance was such that they had little difficulty in avoiding contact with
the obsolescent aircraft then serving with the Republican air force. Introduced
publicly at the 1937 International Military Aircraft Competition held at
Dubendorf, near Zurich, the Do 17 V8 prototype (or Do 17M V1) powered by two l,000-hp
(746-kW) Daimler-Benz DB 600A engines soon gained the nickname 'Flying Pencil'
because of its slender fuselage. More significantly, it was able to better the
performance of international fighters taking part in the contest. Following
this demonstration at Dübendorf, Yugoslavia showed interest in the type and the
Do 17K was developed for that nation, being similar to the Do 17M but powered
by two 980-hp (731-kW) Gnome-Rhone 14N1/2 engines. The type was to be
licence-built by Drazavna Fabrika Aviona at Kraljevo, the three versions,
produced being the Do 17Kb-1 bomber, and the Do 17Ka-2 and Do 17Ka-3
reconnaissance aircraft with secondary bombing and attack capability
respectively. Two prototypes of a proposed pathfinder version which did not
enter production were built under the designation Do 17L, these being powered
by two 900-hp (671-kW) Bramo 323A-1 radial engines because of a shortage of
Daimler Benz DB 600s. The same Bramo powerplant was used for the thirteenth and
fourteenth prototypes to develop the airframe/engine combination for the
production Do 17M-1, which could carry a 2,205-lb (l000-kg) bombload and was
armed with three 7.92-mm (0.31-in) MG machine-guns.
A photo-reconnaissance
version of the Do 17M entered production under the designation Do 17P, powered
by two 875-hp (652-kW) BMW 132N radial engines and carried Rb20/30 and Rb50/30,
or Rb 20/8 and Rb50/8 cameras in the Do 17P-1 production series. Two aircraft
were built as engine test-beds under the designation Do 17R, one with 950-hp
(708-kW) Daimler-Benz DB600Gs, and the other with l, 000-hp (746-kW)
Daimler-Benz DB 601As. They were followed by three DB600G-powered high-speed
reconnaissance aircraft which had the designation Do 17S-0. Used for test
purposes, these had an extensively glazed nose and the airframe incorporated a
bulged section in the underside of the forward fuselage, accommodating a gunner
in a prone position to operate an aft-firing MG 15 machine-gun. These
experimental reconnaissance machines were followed by a small production batch
of 15 pathfinders, comprising three Do 17U-0 and 12 Do 17U-1 aircraft, the
five-men crews of which included two radio operators to handle the new and
comprehensive communications and navigation radios.
Major
production version was the Do 17Z, which appeared in several variants and was
built to a total of some 1,700 between 1939-40. They included the Do 17Z-0
which, powered by two 900-hp (671-kW) Bramo 323A-1 engines and armed with three
MG 15 machineguns, was otherwise similar to the Do 17S. The Do 17Z-1 had an
additional nose-mounted MG 15 but was underpowered and restricted to a 1, 102-lb
(500-kg) bombload; this situation was rectified in the Do 17Z-2 which with 1,000-hp
(746-kW) Bramo 323P engines could carry a 2,205-lb (1000 kg) bombload and up to
eight MG 15 machine guns. Some 22 examples of the Do 17Z-3 reconnaissance
aircraft were built, each equipped with Rb50/30 or Rb20/30 cameras, and they
were followed by the Do 17Z-4 dual-control conversion trainer. Final bomber
variant was the Do 17Z-5 which, generally similar to the Do 17Z-2, differed by
having flotation bags in the fuselage and in the rear of the engine nacelles.
Do 17 production ended with a single Do 17Z-6 Kauz I (screech owl I) long-range
intruder and night-fighter which incorporated a Junkers Ju 88C-2 nose housing a
20-mm MG FF cannon and three MG 15 machine-guns. However, for the nine Do 17Z-10
Kauz II aircraft that followed a new nose was developed which housed four MG FF
cannon and four 7.92-mm (0.31-in) MG 17 machine guns; when deployed as
nightfighters they were equipped with Lichtenstein Cl radar and
Spanner-II-Anlage infra-red detection apparatus.
Export
versions of the Do 17Z were planned under the general designation Do 215, the
first to be developed being the Do 215A-1, with l, 075-hp (802-kW) Daimler Benz
DB 601A engines, which was ordered by Sweden in 1939. With the outbreak of
World War II the 18 aircraft were embargoed and following conversion to
Luftwaffe requirements were delivered for use as four-seat bomber/reconnaissance
aircraft under the designations Do 215B-0 and Do 215B-l. Two examples of the Do
215B-3 were delivered to the USSR during 1940, and the Do 215B-4 was a
reconnaissance version, similar in configuration to the Do 215B-1, but carrying
Rb 20/30 and Rb 50/30 cameras. Final variant was the night-fighter/intruder Do
215B-5 which had an unglazed nose, similar to that of the Do 17Z-10, but
housing two 20-mm MG FF cannon and four 7.92-mm (0.31-in) MG machine-guns.
Dornier Do
17s played a significant role in the early phase of World War 11, used first on
1 September 1939 when the invasion of Poland began. They played only a small
part in the Norwegian campaign, but were used extensively in the invasion of
France and the Low Countries, against Allied convoys in the English Channel and
targets in England during the Battle of Britain. Deployed in the invasion of
Greece, Yugoslavia and the Soviet Union, most had been withdrawn from
first-line service by late 1941.
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