Dornier Do 17 The Dornier Do 17 , sometimes referred to as the " Fliegender Bleistift " ( " flying pencil " ) , was a World War II German light bomber produced by Claudius Dornier ' s company , Dornier Flugzeugwerke . It was designed as a " Schnellbomber " ( " fast bomber " ) , a light bomber which , in theory , would be so fast that it could outrun defending fighter aircraft . The Dornier was designed with two engines mounted on a " shoulder wing " structure and possessed a twin tail fin configuration . The type was popular among its crews due to its manoeuvrable handling at low altitude , which made the Dornier capable of surprise bombing attacks . Its sleek and thin airframe made it harder to hit than other German bomber s , as it presented less of a target . Designed in the early 1930s , it was one of the three main " Luftwaffe " bomber types used in the first three years of the war . The Do 17 made its combat debut in 1937 during the Spanish Civil War , operating in the Condor Legion in various roles . Along with the Heinkel He 111 it was the main bomber type of the German air arm in 1939 – 1940 . The Dornier was used throughout the war , and saw action in significant numbers in every major campaign theatre as a front line aircraft until the end of 1941 , when its effectiveness and usage was curtailed as its bomb load and range were limited . Production of the Dornier ended in the summer of 1940 , in favour of the newer and more powerful Junkers Ju 88 . The successor of the Do 17 was the much more powerful Dornier Do 217 , which started to appear in strength in 1942 . Even so , the Do 17 continued service in the Luftwaffe in various roles until the end of the war , as a glider tug , research and trainer aircraft . A considerable number of surviving examples were sent to other Axis nations as well as countries like Finland . Few Dornier Do 17s survived the war and the last was scrapped in Finland in 1952 . On 3 September 2010 , the Royal Air Force Museum London announced the discovery of a Dornier Do 17 buried in the Goodwin Sands off the coast of Kent , England . On 10 June 2013 , the salvage team successfully raised the airframe from the seabed . Development . In 1932 , the Ordnance Department ( " Heereswaffenamt " ) issued a specification for the construction of a " freight aircraft for German State Railways " , and a " high speed mail plane for Lufthansa " . The factory at Friedrichshafen began work on the design on 1 August 1932 . When the Nazi s took power in 1933 , Hermann Göring became National Commissar for aviation with former Deutsche Luft Hansa employee Erhard Milch as his deputy , soon forming the Ministry of Aviation . The Ministry of Aviation designated the new aircraft Do 17 , and on 17 March 1933 , just three months after taking office , Milch gave the go ahead for the building of prototypes . At the end of 1933 , the Ministry of Aviation issued an order for a " high speed aircraft with double tail , " and for a " freight aircraft with special equipment , " in other words , a bomber . The original design ( the Do 17 V1 ) configuration in 1932 had sported a single vertical stabilizer , and Dornier continued developing that model . The Do 17 was first demonstrated in mock - up form in April 1933 . The " special equipment " was to be fitted later , to disguise its offensive role . In April 1934 , the Dornier works at Manzell began project " definition . " During this month , the defensive armament was designed and the bomb release mechanism details ironed out . Production of these prototypes began on 20 May 1934 and , on 23 November 1934 , the Do 17 V1 , with a single fin and powered by two BMW VI 7 . 3 motors , took off on its first flight . Testing was delayed by a series of accidents , with V1 being damaged in landing accidents in February and April 1935 . The twin - tailed V2 ( powered by low - compression BMW VI 6 . 3 engines ) first flew on 18 May 1935 and was evaluated together with the V1 by the Ministry of Aviation at Rechlin in June . During the tests , the single fin proved to be only marginally stable , resulting in the V1 being modified with a twin tail . The aircraft was destroyed in a crash after an engine failure on 21 December 1935 . The V3 , also fitted with a twin tail , was originally planned to be powered by Hispano - Suiza 12Y brs engines , but as these were unavailable , it was fitted with BMW VI 7 . 3 engines like the V1 and flew on 19 September 1935 . The V1 prototype remained the only built machine with the single stabilizer . It is claimed that , unlike the Heinkel He 111 series , whose military use was planned from the start , the Do 17 V1 was contracted as a fast six - passenger mail plane to compete with the smaller Heinkel He 70 monoplane It has been suggested that it was rejected by Luft Hansa , as the cramped cabin was too uncomfortable for passenger use and the operating costs also were too high for a mail plane . According to the story , the three prototypes remained unused in the Dornier factory in Lowental for almost six months , until Flight Captain Untucht of Luft Hansa came across them . After receiving permission to fly one of the machines , he proceeded to put it through an almost stunt flying routine . After landing , he said that " the machine is as nimble as a fighter , give it more lateral stability and we ' ll have a high speed bomber ! " Untucht ' s comments prompted Dornier to redesign the tail unit and revived interest in the type . Dornier was then ordered to produce the V4 prototype . Some sources state this differed from the V3 in that the passenger portholes were removed and the single fin was replaced with two smaller ones . Photographic evidence demonstrates the V3 had twin stabilizers from the start of its construction . The tests of the " twin - tailed " V4 , V6 and V7 prototypes were positive and more prototypes like the V8 emerged as the forerunner of the long - range reconnaissance version , while the V9 was tested as a high - speed airliner . The V9 machine was still flying in 1944 . Design . The cockpit and forward fuselage had a conventional stepped cockpit , and its nose was fully glazed . Early variants had been labelled the " flying pencil " owing to its sleek and continuous " stick - like " lines . As a result of the lessons learned in the Spanish Civil War , the cockpit roof was raised and the lower , or bottom half , of the crew compartment was a typical under - nose " Bodenlafette " , abbreviated " Bola " , inverted - casemate design ventral defensive armament position , a common feature of most German medium bombers . The " Bola " was extended back to the leading edge of the wings where the lower - rear gunners position and upper - rear gunner position were level with each other . As with contemporary German bombers , the crew were concentrated in a single compartment . The cockpit layout consisted of the pilot seat and front gunner in the forward part of the cockpit . The pilot sat on the left side , close up to the Plexiglas windshield . One of the gunners sat on the right seat , which was set further back to provide room for the MG 15 machine gun to be traversed in use . The Do 17 usually carried a crew of four : the pilot , a bombardier and two gunners . The bomb - aimer also manned the MG 15 in the nose glazing and " Bola " - housed rear lower position . The two gunners operated the forward - firing MG 15 installed in the front windshield , the two MGs located in the side windows ( one each side ) and the rearward firing weapon . The cockpit offered a bright and panoramic view at high altitude . The standard ammunition load was 3 , 300 rounds of 7 , 92 mm ammunition in 44 double - drum magazines . The wings were of a broad 55 m² ( 590 ft² ) area and had a span of 18 m ( 59 ft 0⅝ in ) with a flat leading edge which curved in a near - perfect semicircle into the trailing edge . The positions of the wing roots were offset . The leading edge wing root merged with the top of the fuselage and cockpit . As the wing extended backwards , by roughly two - third , it declined downwards at a sharp angle so that the trailing edge wing root ended nearly halfway down the side of the fuselage increasing the angle of attack . This design feature was used on all future Dornier bomber designs , namely the Dornier Do 217 . The trailing edge was faired into the round fuselage shape . The engine nacelle was also faired into the flaps . The extreme rear of the nacelle was hollow and allowed the flap with an attached vertical slot to fit into the cavity when deployed . The fuselage was 15 . 80 m ( 51 ft 9⅝ in ) long . It was thin and narrow , which presented an enemy with a difficult target to hit . The fuselage had twin vertical stabilizers to increase lateral stability . The power plant of the Z - 1 was to have been the Daimler - Benz DB 601 but , owing to shortages , it was allocated Bramo 323 A - 1 power plants . The Bramos could only reach 352 km / h ( 220 mph ) at 1 , 070 m ( 3 , 500 ft ) . The limited performance of the Bramo 323s ensured the Do 17 could not reach 416 km / h ( 260 mph ) at 3 , 960 m ( 13 , 000 ft ) in level flight when fully loaded . The range of the Do 17Z - 1 at ground level was ; this increased to 1 , 370 km ( 850 nm ) at 4 , 700 m ( 15 , 500 ft ) . This gave an average attack range of . The introduction of the Bramo 323P increased the Z - 2 performance slightly in all areas . The Dornier had self - sealing fuel tank s to protect fuel stored in the wings and fuselage . This reduced the loss of fuel and risk of fire when hit in action , and often enabled the aircraft to return . Twenty oxygen bottles were provided for crew use during long flights above 3 , 660 m ( 12 , 000 ft ) . Communications usually consisted of FuG X , the later FuG 10 ( " Funkgerät " ) , navigational direction finder " PeilG V " direction finder ( PeilG - " Peilgerät " ) and the FuG 25 IFF and FuBI 1 blind - landing devices . The crew communicated by EiV intercom . A primitive autopilot device , the Siemens K4Ü , was installed and could maintain bearing using the rudder ' s control surfaces . The bomb bay accommodated four bomb racks , the No . 5 for SC50 bombs and two ETC 500 racks to carry heavier loads of up to each . A " Lotfe " A , or B bombsight was issued together with the BZA - 2 aperture ( a modernised optical lens system ) . The aircraft ' s bomb bay allowed two options . The first was to carry four 250 kg ( 550 lb ) bombs for a load of 1000 kg ( 2 , 200 lb ) , which reduced aircraft range . With half the maximum load , ten 50 kg ( 110 lb ) bombs , additional fuel tanks could be placed into the forward part of the bomb bay to increase range . The bomb aimer would deploy the bomb load via the Lotfe ( A , B or C 7 / A , depending on the variant ) bomb sight which was in the left side of the nose compartment directly under and forward of the pilot . When fully loaded , the Z - 1 weighed 7 , 740 kg ( 17 , 200 lb ) . Variants . Early Daimler - Benz - powered variants . The initial production variants were the Do 17E - 1 bomber , which was tested with two Daimler - Benz DB 600 , and Do 17F - 1 reconnaissance aircraft , powered like the early prototypes with BMW VI engines , which entered production in late 1936 . The first Luftwaffe units converted to the Do 17 in early 1937 . The Do 17E - 1 was equipped with two BMW VI 7 . 3D inline engines of 750 PS each . The crew numbered three . The radio operator manned the two 7 . 92 mm MG 15 machine gun s within a B - Stand pod in the rear cockpit . They had 750 rounds of ammunition . The bomb bay was divided into two compartments . Each had five bomb racks with individual capacity of . A single ETC 500 / IX bomb rack could be mounted externally underneath the aircraft to carry a 500 kg bomb . A Do 17 E - 1 with the designation D - AJUN was tested with an unusual configuration , two SC 500 bombs mounted side by side under the fuselage . It showed a notable performance reduction due to the increase in weight and drag , this configuration was not used operationally . The E - 1 continued to carry low bomb loads into the Second World War . The performance of the E - 1 enabled it to reach a speed of 330 km / h ( 205 mph ) at 3 , 000 m ( 9 , 842 ft ) . Conducting a shallow dive the light frame of the Do 17 could reach 500 km / h ( 310 mph ) . Its maximum ceiling was 5 , 500 m ( 18 , 044 ft ) . Several E - 1s were rebuilt as E - 2 or E - 3 , at least three E - 2 and one E - 3 were used by DVL and Hansa - Luftbild GmbH ( Hansa Aerial Photography Ltd ) in a secret military reconnaissance role prior to the war . The Do 17F - 1 was a long - range reconnaissance aircraft based on field modified Do 17Es . The Do 17 prototype V8 was used to test the configuration of the F - 1 and V11 for the F - 2 . The defensive armament consisted of a MG 15 in the B - and C - Stand ( B - Stand - an upper rear firing position , C - Stand — lower gun emplacement ) . The fuselage had two cameras along with six ejector tubes for flashlight cartridges . The F - 1 would see service until replaced by the Do 17 P in 1938 . Only one F - 2 was ever built , it was designated D - ACZJ and was used by Zeiss - Jena Company as a factory aircraft . Conversion of two E - 2 series aircraft with two BMW 132F radial engines led to the Do 17 J - 1 and J - 2 . These aircraft served as flight testing machines to evaluate the BMW 132 for usage in the Do 17 . The aircraft were the V18 ( " Wrk Nr " , or " Werknummer " meaning works / factory number , 2021 ) and V19 ( Wrk Nr 2022 ) prototypes . Trials began in late 1937 . A similar conversion , but with Bramo 323 radial engines , led to the designation Do 17 L - 1 and L - 2 . Two Do 17 ( Wrk Nr 2031 and 2032 ) were renamed as V20 and V21 prototypes and used to evaluate the Bramo 323 fur usage in the Do 17 . The test were satisfactory and all future production models would be equipped with this engine . After seeing the Do 17M V1 at the Zürich air races in 1937 , the Yugoslav Royal Air Force bought license rights for production at the " Drzavna Fabrika Aviona " factory in 1938 . They equipped it with the more powerful Gnome - Rhône 14N radial engine ( although the French exaggerated its performance ) Dornier designs were delivered to the " Pomorsko Vazduhoplovstvo " ( Naval Aviation - PV ) in 1926 , namely the Dornier Komet and Dornier Do Y heavy bombers . The Yugoslavs were familiar with Dornier designs , and on 19 November 1935 Yugoslav pilots test - flew the Do 17 V - 3 prototype , D - ABIH , W . Nr . 258 . They decided to select the Do 17 for service , despite it being more expensive than any other aircraft , because of the German willingness to deliver them quickly without limitations on numbers . The Do 17L - 0 and Do 17M - 0 were developed in parallel as replacements for the earlier E and Fs , the L being the reconnaissance version . Both were designed around the more powerful DB 600A engines , delivering about 746 kW ( 1 , 000 hp ) . Two L and one M versions were built as prototypes , both with another MG 15 in the nose . The first prototype of the revised version , the Do 17M V1 ( D - ABVD ) was powered by two DB 600s , and demonstrated impressive performance , including a maximum speed of 425 km / h ( 264 mph ) . At the International Military Aircraft Competition at Zürich , Switzerland in 1937 , the Dornier Do 17M V1 proved a leader in its class and was faster than the fastest foreign fighter , the French Dewoitine D . 510 . The Do 17 , along with the Messerschmitt Bf 109 , won many prizes , demonstrating the prowess of German aviation design . The radial variants . Despite its success , owing to shortages in the supply of the Daimler - Benz engine , the production Do 17M was fitted with the Bramo 323 engine , with the corresponding reconnaissance aircraft , the Do 17P , being powered by BMW 132Ns to give better range . The supply of the DB 600 remained extremely limited as production was soon switched over to the fuel - injected DB 601 , which was reserved for the Messerschmitt Bf 109 and Messerschmitt Bf 110 fighters . Therefore production versions of the basic Do 17M model airframe were fitted with the new Bramo 323A - 1 Fafnir engines of 670 kW ( 900 hp ) , which gave reasonable performance and raised the bomb load to 1 , 000 kg ( 2 , 200 lb ) . The resulting Do 17M - 1 was produced in small numbers and operated until 1941 . The prototypes for the M - 1 series were Do 17M V1 ( Wrk Nr 691 ) and Do 17M V2 ( Wrk Nr 692 ) which were tested with bomb loads of a medium bomber . The third prototype , Do 17M V3 was evaluated as a fast bomber . The MV1 was fitted with two Daimler Benz DB 601 inline engines while the MV2 and MV3 had the Bramo 323 A and D respectively . The Ministry of Aviation favoured the widespread use of the DB 601 , but demand for the DB 601s in fighter aircraft and the lack of production forced the use of the Bramo . The Do 17M - 1 started its service as a medium bomber and was able to carry of bombs . It was equipped with two air - cooled Bramo 323 A - 1 or A - 2 . The defensive armament consisted of two , and later three , MG 15 machine guns . The first was operated in an A - Stand pod operated by the navigator through the windshield . The position was allocated 370 rounds of ammunition . The rearward firing B - Stand was operated by the radio operator and allocated 750 rounds . The rear position in the lower fuselage was allocated 375 rounds in a C - Stand pod . The Do 17M could carry a bomb load of either 20 SC50 or two SC250 bombs or 10 SC50 and a single SC250 bomb . The speed of the M was superior to that of the E variant . The Do 17M could reach 420 km / h ( 250 mph ) at altitudes of 3 , 500 m ( 11 , 500 ft ) and could achieve a maximum service ceiling of 5 , 790 m ( 19 , 000 ft ) and a range of . Reconnaissance aircraft based on the M - 1 , the under - surfaces of the wing were covered with duralumin and it had a wider engine axis and longer engine nacelles . The demand for a reconnaissance aircraft based on the M - 1 led to the development of the P - 1 variant . The L version would not be able to enter production with the DB 600 owing to its use in the Bf 109 , and the Bramo engine was rather thirsty on fuel and left the M models with too short a range for reconnaissance use . BMW 132 N radials of 865 PS were selected instead , which had lower fuel consumption for better range . Another two prototypes with DB 600 engines were produced as the Do 17R - 0 , but did not enter production . During reconnaissance missions the P - 1 was armed with four MG 15s in the A , B and C — Stands . One machine gun was located in the rear of the cockpit , another in the lower rear " Bola " mount , one facing forward through the windscreen and the other in the nose glazing . In earlier variants the B - Stand ( the gun position in the upper rear cockpit ) was open to the elements , but the P - 1 now provided an enclosed bulb - shaped mount protecting the radio operator from the weather . The P variant had similar features to the Do 17M - 1 , with added blind flying and camera equipment for reconnaissance work . The Do 17P - 1 was powered by two Bramo 132 N radial engines with a maximum performance of 865 PS ( 853 hp , 636 kW ) each . The machine was fitted with several radio variations . The FuG IIIaU radio ( " Funkgerät " ) , the PeilG V direction finder ( PeilG - " Peilgerät " ) and the FuBI 1 radio blind - landing device ( FuBI - " Funkblindlandegerät " ) . The crew of three communicated with each other via the EiV intercom ( EiV - " Eigenverständigungsanlage " ) . The P - 1 was equipped with either Rb 20 / 30 and Rb 50 / 30 or Rb 20 / 18 and Rb 50 / 18 cameras . The P - 1 / trop was fitted with filters and protection for the cameras . The cameras were controlled remotely by the crew from the cockpit . Due to a shortage of night fighters , at least one Do 17P - 1 was assigned to this role . A smooth metal sheet was installed in place of its glass nose and it was armed with three MG 151 / 20 cannon s . The machine operated under " Luftflotte " 1 . The Do 17P - 2 was identical to the P - 1 , with the additional installation of an ETC 500 bomb rack under the fuselage . These aircraft were designed for night reconnaissance . It is assumed that Dornier converted most , if not all , P - 2 models from existing P - 1 production aircraft . Unlike the P - 2 , the Do 17R - 1 did not see series production . The experiences of the Spanish Civil War proved that unarmed aircraft were easy prey for fighter aircraft . The R - 1 was to be a fast long - range reconnaissance aircraft with two additional fuel cells inside the fuselage aft of the bomb bay . Two variants were suggested , the first ( variant I ) had a single Rb 50 / 30 and two Rb 20 / 30 cameras , while variant II had a third fuel cell to replace the rear Rb 20 / 30 . The aircraft had a gross weight of but could be overloaded to in emergencies . The crew usually numbered three , but a fourth was added depending on the missions to be flown . To achieve a high performance at increased altitudes two DB 600 Gs were to be used . The power plants were tested in the Do 17RV1 prototype registered D - ABEE . The second , the RV2 , registered D - ATJU , received the even more powerful DB 601 Aa engines . The power plant of the R - 1s that did exist are not known . The lessons from the Spanish Civil War had led Dornier ' s designers to incorporate more defensive machine guns . Battles with Soviet - built fighter aircraft had demonstrated that the Dornier was not as fast and invulnerable as was first thought . To cope with this , a completely new pod - like cockpit was designed to give the crew more room and better visibility . The roof was extended upward over the line of the fuselage , sloping down to meet it just in front of the wing . The dorsal gun was moved to the rear of the pod where it had a considerably better field of fire . Likewise , the floor was dropped under the fuselage as a " Bola " casemate - style defensive armament emplacement , and the ventral gun moved to the back of the " Bola " , allowing it to fire directly to the rear . The changes in the roof and floor made the whole front of the aircraft much larger . The rest of the airframe remained the same . The new cockpit design was nicknamed " Kampfkopf " ( German : " Battle head " ) . Three S variant prototypes with the DB 600 G inline engines were tested . The S - 01 ( designation D - AFFY ) , 03 and 04 were flown . The inverted V - 12 engines were constructed as the Do 17 S - 0 reconnaissance version , but it did not go into production . An additional 15 Do 17 U - 1 pathfinder models were built , similar to the S - 0 but adding an additional crewman ( taking the total to five ) to operate the extra radio equipment . The U models were to fly ahead of other bombers on night missions , using the radio equipment to locate the target and drop flares on it . They were personally requested by KG 100 as experimental models for this role . The U - 1 had a maximum speed of 265 mph ( 424 km / h ) and a combat ceiling of 4 , 500 m ( 15 , 000 ft ) . The U - 1 had a cruising speed of 384 km / h ( 240 mph ) and a maximum reachable height of 5 , 700 m ( 19 , 000 ft ) , owing to the " rather low performance of the Bramo 323 A - 1 engines " . The three prototypes ( U - 01 - U - 03 ) and twelve production aircraft were built by 1938 . Dornier Do 17Z : The main variant . The Dornier Do 17Z series was the most recognised and mass produced variant , and saw more combat service than the E - U types . The type was modified as a result of combat experience during the Spanish Civil War . The forward fuselage was redesigned , with the cockpit area being " dropped " , or extended further to enable a rear firing gunner position to be installed , and the canopy extended aft , until it was nearly parallel with the leading edge and wing root . To test the design , the Do 17S and Do 17U were produced , both to be powered by the DB 600 power plants . However , a call for all DB 600 series engines to be reserved for fighters led to the variants being fitted with Bramo Fafnir 323 A radial engines . The bomb load was increased to 1 , 000 kg ( 2 , 200 lb ) and a fourth crew member was added . It proved to be underpowered , so Bramo 323 P engines were then fitted . Only three Do 17S and 15 Do 17Us were built . With the updates , the Dornier , with a full bomb load , had a combat radius of 322 km ( 200 mi ) . Later variants , in the Do 17 Z - 3 , Z - 4 and Z - 5 , which were fitted with cameras , dual trainer controls and flotation aids ( for maritime operations ) respectively , still could not solve the problems with range and bomb load . At first , a batch of Z - 0s were built with the Fafnir for testing , the DB 600 again proving to be too hard to obtain . These were quickly replaced with the Z - 1 model , which added another gun for the bombardier , but the additional weight of the nose and guns meant the bomb load was reduced to 500 kg ( 1 , 100 lb ) . The Luftwaffe , not being satisfied with the test outcome of the Z series , immediately ordered performance and design studies to increase the overall performance of the bomber . These resulted in very optimistic speeds and altitudes for all future Z variants , especially for the Z - 5 aircraft . Planned performance altitudes of up to 7 , 620 m ( 25 , 000 ft ) at a maximum speed of 418 km / h ( 260 mph ) with an aircraft weight of 8 , 100 kg ( 17 , 800 lb ) were planned . Unfortunately , production aircraft never reached these optimistic performances during the service career of the Do 17Z . At 7 , 740 kg ( 17 , 200 lb ) , the heavy Do 17Z - 1 used two Bramo 323 A - 1 engines with self - sealing fuel cells in the fuselage and wings . The crew of four consumed approximately 20 bottles of oxygen during long flights above . The Do 17Z - 1 had a speed of 352 km / h ( 220 mph ) at 1 , 100 m ( 3 , 500 ft ) . However , the performance of the Bramo 323s did not permit the Do 17 to reach 416 km / h ( 260 mph ) at 3 , 900 m ( 13 , 000 ft ) and level flight when fully loaded . Range of the Z - 1 at ground level was while at 4 , 700 m ( 15 , 500 ft ) this increased to . This gave an average range of . The introduction of the Bramo 323P increased subsequent performance in the following sub variants . This was addressed in the major production model , the Do 17 Z - 2 . The Z - 2 mounted the new 323P - 1 version of the Fafnir with 746 kW ( 1 , 000 hp ) , which was specifically tuned to the performance needs of the Do 17 by decreasing supercharger power at lower altitudes and thus improving low - level performance . The increase in takeoff power allowed the bomb load to be increased from 500 kg ( 1 , 102 lb ) to 1 , 000 kg ( 2 , 200 lb ) . However the combat range with a full 1 , 000 kg ( 2 , 200 lb ) bomb load was a very short 330 km ( 200 mi ) . The armament was further upgraded by adding an additional pair of guns firing out of the sides of the upper part of the pod , but as the three guns were all fired by a single gunner , only one of them could be fired at a time . From May 1940 , 422 Do 17 Z - 2s flew with " Kampfgeschwader 2 " , " Kampfgeschwader 3 " , " Kampfgeschwader 76 " and " Kampfgeschwader 77 " . The upgrades of the Z - 2 had its overall weight increased from 17 , 600 lbs to 17 , 920 lbs ( 7 , 983 to 8128 kg ) . After heavy losses of Do 17s during the Battle of Britain it was decided to replace the MG FF cannon with the more powerful MG 151 / 15 . Losses had mounted in spite of an increase of up to eight machine guns in some Dornier ' s . The standard MG 15 machine guns were retained . These features were present in the next variant the Z - 3 . The Z - 3 formed part of the bomber versions of the Z series , it was , however , also used as a reconnaissance aircraft by the staff flight of the particular unit . The engines and the general equipment were identical to the Z - 2 standard ; however two cameras — the Rb 50 / 30 and Rb 20 / 30 - were incorporated into the crew entry hatch . A handheld camera was issued to the crew to validate the success during bombing missions . Autopilot equipment was added later . The Z - 2 and Z - 3 were identical visually , and could only be distinguished from each other by the altered crew hatch on the Z - 3 . Owing to spacing problems because of the added camera equipment , the ammunition supply was reduced from 44 to 42 magazines . The power plant of the Z - 3 was upgraded to the Bramo 323P - 2 . The Bramo P - 2 remained the engine of all the remaining Z series variants . The Z - 4 was designed as trainer . Although nearly identical to the Z - 2 and Z - 3 , it featured several equipment changes optimised for blind flying training . The four - seat aircraft had a single control column with dual steering , which was achieved by a jib protruding to the right . Rudder pedals were in front of both seats . The defensive armament and bomb racks were reduced , or in most cases omitted to reduce weight . The Z - 5 was similar to the Z - 3 with a weight of . Designed as an anti - shipping aircraft , the Z - 5 , was fitted with flotation cells in the fuselage and engine nacelles in case it was forced down on water . Usually the flotation devices took the form of inflatable bags stored in the rear of the engine nacelles and in bulges on either side of the nose , just behind the front glazing . Later variants of the Z model were developed . The Z - 6 was to be a reconnaissance aircraft , although it was only built as a prototype . During the war only a few were converted from existing combat variants . The type was selected for weather check flights . It was identical to the Z - 1 / Z - 2 variants , but offensive armament was omitted and extra fuel cells fitted . This increased the fuel load to 2 , 890 l ( 578 Imperial Gallons ) . As flights required higher altitude , the oxygen supply was increased from 20 to 24 bottles . For long - range flights over water , the larger dinghy of the Z - 5 with its updated emergency escape equipment was mandatory during operations . The Z - 6s were also used for night fighter operations . Some of the few converted Z - 6s had the Ju 88C - 6 nose installed and were equipped with machine guns and cannons . The nose proved to be unsatisfactory , and it was redesigned . In the tip of the new nose was an infrared spotlight which was soon made redundant after the introduction of Lichtenstein radar which was fitted to some of the Z - 6 . The Z - 8 " Geier " was not produced . It was intended as a ground attack aircraft and reached the first planning phase but was given up due to lack of performance and protective armour allocation against anti - aircraft artillery . An increase in armour would have meant a decrease in speed which would have exposed the aircraft further to enemy fire . The Z - 9 , which was fitted with special bomb release equipment , and delayed release gear for low - level attack missions . Its purpose was to suppress enemy air defences . Therefore it was designed to fly over anti - aircraft positions and drop Butterfly Bomb s , an early form of cluster bomb munitions . This could only be done with air superiority , as the Z - 9 was unarmoured . The airframe and equipment was identical to the Z - 1 / Z - 2 version . Only the bomb bay was altered to accommodate 16 bomb - dispenser systems . The maximum weight of the Z - 9 was . The design did not reach serial production . After bomber production ended in 1940 , the Z model was modified with a " solid " nose from the Ju 88C , fitted with one 20 mm MG FF cannon and three 7 . 92 mm ( . 312 in ) MG 17 machine gun s , to be used as night fighters . Three prototypes were converted from existing Z - series airframes to the Do 17 Z - 7 Kauz I ( " screech - owl " ) configuration . The standard Z - 7 was fitted with Bramo 323P - 1 radial engines and had a crew of three airmen . In comparison to the standard bomber version , the fuel load arrangement was altered by subdividing into cells . Two cells were in the wings , with a capacity of 770 litres ( 154 imperial gallons ) each . A third cell was placed in the bomb bay within the main fuselage , having a capacity of 895 litres ( 179 imperial gallons ) . The oxygen supply for the three man crew was reduced to nine bottles , as intercepts at high altitudes were not anticipated . Add - on armour in the form of heavy steel plates was bolted to the nose bulkhead to protect the crew against frontal fire . Originally , it was planned to completely armour the crew compartment . This idea , was given up again as the increased weight would have reduced flight performance of an already slow aircraft . The ammunition loads for the three 7 . 92 mm MG 17 amounted to 3 , 000 rounds and 400 rounds of ammunition for the 20 mm MG 151 cannon ( although some Do 17Z bombers carried a single 20 mm for ground attack missions ) . Later , the design was further modified to the Do 17 Z - 10 Kauz II , the solid nose now containing an infra - red searchlight for the " Spanner Anlage " infrared detection system . The infrared lamp in the nose was used to illuminate the target while the display unit in the windshield made the reflection visible to the target . The Z - 10 was armed with four 7 . 92 mm ( . 312 in ) MG 17 machine gun s grouped above the IR light and two 20 mm MG FF in the lower nose . The crew could reload the 20 mm cannon internally . The Z - 10 contained an IR searchlight ( " Spanner - Anlage " ) for the Spanner infrared detection system . A single " Kauz II " was equipped with and tested the Lichtenstein radar . Only 10 of these Kauz II designs were converted from existing Z - series airframes . The " Spanner " system proved to be essentially useless and many Z - 10 were left without any detection system . At least one Z - 10 , coded CD + PV , was used as a flying test bed to help developing the early low - UHF band B / C version of the Lichtenstein radar system in late 1941 – 1942 . When the Z - 10 was stripped of all non - night fighter equipment , it had a maximum weight of . Armament fit was similar to that of the Z - 7 , with an added MG 17 and an additional 1 , 000 rounds of ammunition in the nose section . Defensive gun positions included the B and C stand , each equipped with a single MG 15 . Do 215 . The Do 215 was developed as an export version of the Do 17Z series , and was used as a bomber , reconnaissance and night fighter aircraft . Production . German . Official figures state 2 , 139 Do 17s were built on German assembly line s . At the Dornier factory at Oberpfaffenhofen , 328 Do 17Es were built along with a further 77 Do 17Fs and 200 Do 17M variants . Do 17Z production figures for Oberpfaffenhofen stand at 420 . At Friedrichshafen , 84 Do 17Ks were built , some of which were sold to the Yugoslav Royal Air Force . Do 17P production was spread out over different factory lines . At Siebel / Halle , eight were built . At the Henschel factory at Berlin - Schönefeld 73 were constructed . At the HFB plant in Hamburg 149 were built . Henschel also produced some 320 Do 17Zs , HFB contributed to construction of 74 at its Hamburg plant , and another 73 were built at Siebel . Some 105 examples of the Dornier Do 215 B was later built at Oberpfaffenhofen . By 19 September 1938 , the Luftwaffe had received 579 Dornier Do 17s . These were mostly Do 17E , F , M and P variants . During 1939 – 1940 , some 475 Dornier Do 17Z bombers , 16 reconnaissance aircraft and nine night fighters were built . Another 100 Dornier Do 215s , an updated variant of the Do 17 , were built during this period also . Yugoslav . Other governments were interested in the Do 17 . In June 1936 , the Yugoslav government ordered 36 Do 17E variants from Germany . The negotiations for a licence were completed on 27 June 1938 for 36 Do 17Ka ' s at the cost of 1 , 829 , 825 " Reichsmark " ( RM ) . On 18 March 1938 , Yugoslavia ordered 16 complete Do 17 Ka - 2 ' s and Ka - 3 ' s at a cost of 3 , 316 , 788 RM . They received the last on 21 April 1939 . The machines were from 72 - 96 % complete . The Dorniers were devoid of German equipment , including engines . The Yugoslavs found a French manufacturer to supply the powerplants instead . Gnome et Rhône was the supplier chosen , and the Gnome - Rhône Mistral Major engine was to be used in the Dornier . The French had inflated the performance data of the engine , claiming it to have 649 kW ( 870 hp ) and a speed of 420 km / h ( 261 mph ) at 3 , 850 m ( 12 , 320 ft ) . The constant - speed propellers were also poor , and delivered late . This led to trials with Piaggio Aero and Ratier propellers . Only one of the Do 17s delivered was fitted out complete with German equipment . The rest of the Dorniers were equipped with Belgian FN 7 . 9 mm ( . 31 in ) machine guns , Czech camera equipment and eventually Telefunken radio sets . Altogether , 70 Do 17s were produced by Yugoslav factories . Survivors . Until 2007 none of the Dornier twin - engined bomber variants were thought to have survived intact , but various large relics of the Do 17 and Do 215 are held by public museums and private collectors . In September 2007 a Do 215 B - 5 ( variant of Do 17Z ) was found largely intact in the shallow waters off Waddenzee in the Netherlands . Dornier Do 17Z " Werknummer " 1160 . On 3 September 2010 , the RAF Museum announced that a Do 17 had been discovered in of water off the coast of England . The aircraft had been discovered in September 2008 on the Goodwin Sands , a large sandbank off the coast of Kent , but the discovery was kept a closely guarded secret . The Dornier Do 17Z - 2 , " Werknummer " 1160 , built under license by Henschel with the full " Geschwaderkennung " ( combat wing aircraft ID code ) of 5K + AR , was operated by 7 " Staffel " , III " Gruppe " , " Kampfgeschwader " 3 ( KG 3 ) . On 26 August 1940 , " 5K + AR " was taking part in a raid by KG 2 and KG 3 , targeting the RAF stations RAF Debden and RAF Hornchurch . While flying over clouds , the aircraft became separated from the bomber formation and lost its bearings ; it was then attacked by Boulton Paul Defiant fighters of No . 264 Squadron RAF . One of the Dornier ' s engines was disabled and the other damaged , so the wounded pilot , " Feldwebel " ( Flight Sergeant ) Willi Effmert , elected to make a crash landing on the Goodwin Sands . He and another crew member survived and were taken prisoner . The other two crew were killed ; one is buried at Cannock Chase German war cemetery and the other in the Netherlands . The identity of the Defiant that shot down the Dornier is unknown – it may have been one of three 264 Squadron aircraft that was shot down soon after in a battle with Bf 109 fighter escorts of the German fighter wing JG 3 . This aircraft is one of at least fourteen Dorniers that are known to have crashed in the area , and crew from another Do17 , call sign U5 + DM , designating it as being from the 4 . " Staffel " / KG 2 , are buried in the local Hamilton Road Cemetery , Deal as well as at Cannock Chase . In June 2010 diving operations were carried out and the survey report indicated that the aircraft was largely complete , although " 5K + AR " lay inverted on the seabed , indicating that it ground - looped on landing . The port rudder , starboard stabiliser , forward nose glazing , undercarriage doors and engine cowling were missing , but the discovery of a small debris field associated with the wreck indicates that some or all of those parts may still be present at the site . After completing fund - raising and devising a plan for recovery and conservation , the Royal Air Force Museum announced that the wreck would be recovered in May 2013 . The recovery was originally planned to take around four weeks , using a specially - constructed lifting frame to raise " 5K + AR " from the sea , but this approach was altered as costs escalated with delays due to bad weather . The aircraft was eventually raised on 10 June 2013 . It will be taken to the Michael Beetham Restoration Centre at the Royal Air Force Museum ' s Cosford site , where metallurgists from Imperial College London will have a significant role in the post - recovery conservation of the aircraft . Current plans are to use Citric acid to remove encrustation and chloride from the aluminium airframe . Dornier Do 17M - 1 ( Hansakollen , Norway ) . On 2 July 1942 , a Dornier Do 17M - 1 crashed in Hansakollen in Maridalen , outside of Oslo , Norway . The Do 17 was heading to the airport at Gardermoen , but crashed into a mountainside . All three German aviators on board were killed . They are buried at the German war cemetery at Alfaset . The wreck is well preserved and remains clearly visible , well over 60 years after the accident .