Dornier Do 17

The Dornier Do 17, sometimes referred to as the Fliegender Bleistift ("flying pencil"), was a light bomber produced by Dornier. It was designed as a Schnellbomber, a light bomber, which in theory, would be so fast that it could simply outrun defending fighters. It was used in the first three years of World War II with some success by the Luftwaffe. The type was popular among its pilots as a manoeuvrable low altitude light bomber, capable of surprise bombing attacks. Its sleek and thin airframe made it harder to hit than other German bombers, as it presented less of a target. The Dornier was used in every major campaign in significant numbers until the end of 1941, when its limited bomb load and range became too much of a problem, and its effectiveness and usage was curtailed. The Do 17 continued in Luftwaffe in various roles until the end of the war, as a transport, test and trainer aircraft, while a significant number of Do 17s were sent to other nations. A small production run of an updated version known as the Do 215 was also produced for export, but ended up in Luftwaffe service. The successor of the Do 17 was the Dornier Do 217.

Design and 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".^[1] The factory at Friedrichshafen began work on the design on 1 August 1932.^[1]

When the Nazis had taken power in 1933, Hermann Göring became National Commissar for aviation with former Lufthansa employee Erhard Milch as his deputy, soon forming the Reichsluftfahrtministerium (RLM - Air Ministry). The RLM 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 RLM 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.

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 single vertical stabilizer, powered by two BMW VI7.3 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 RLM at Rechlin in June. During the tests the single vertical stabilizer proved to be only marginally stable, resulting in the V1 being modified with a twin tail, being destroyed in a crash after an engine failure on 21 December 1935.^[3] The V3, also fitted with a twin tail, was originally planned to be powered by Hispano-Suiza 12Ybrs engines, but as these were unavailable, was fitted with BMW VI 7.3 engines like the V1, flew on 19 September 1935.^[4]

It is claimed, unlike the Heinkel He 111 series, whose military use was planned from the start, that the Do 17 V1 was contracted solely as a fast six-passenger mail plane to compete with the smaller Heinkel He 70 monoplane^[5] According to this version of the story, it was rejected by Lufthansa as the cramped cabin space was too uncomfortable for passenger use and the operating costs also were too high for a mail plane.^[6] The three prototypes remained unused in the Dornier factory in Lowental for almost six months, until Flight Captain Untucht of Lufthansa 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.^[7] Dornier was then ordered to produce the V4. This differed from the V3 in that the passenger port holes were removed and the single vertical stabilizer was replaced with two smaller ones.^[8] The tests of the "twin-tailed" prototypes Do 17 V4, V6 and V7 were positive and more prototypes like the V8 emerged as the forerunner of long-distance reconnaissance version, while the V9 was tested as a high speed airliner.^[9] The machine was still flying in 1944.^[8]

The initial production variants were the Do 17E-1 bomber, which was tested with two DB 600 engines,^[10] and F-1 reconnaissance aircraft, powered like the early prototypes with BMW VI engines, entered production in late 1936 with the first Luftwaffe units converting to the Do 17 in early 1937.^[11] Dornier, meanwhile, planned a more advanced version of the Do 17, with more modern and powerful engines. A prototype was tested with the Hispano-Suiza 12Ybrs engines intended for the third aircraft, while other aircraft flew with BMW 132 or the Bramo 323 radial engines. The first prototype of the revised version, the Do 17M V1 (D-ABVD) was powered by two Daimler-Benz DB 600 engines, and demonstrated impressive performance, including a maximum speed of 425 km/h (264 mph).^[12] At the 1937 international airshow in Switzerland, the Dornier Do 17 M V1 proved a leader in its class, and was faster than the fastest foreign fighter, the French Dewoitine D.510.^[7] The Do 17, along with the Messerschmitt Bf 109, won many prizes, demonstrating the prowess of German aviation designs.^[9] Despite this, owing to shortages in the supply of the Daimler Benz engine, with priority in supply going to fighters, the production Do 17M was fitted with the Bramo 323 engine,^[13] with the corresponding reconnaissance aircraft, the Do 17P, being powered by BMW 132 engines to give better range.^[14]

The Dornier Do 17Z

The Dornier Do 17Z series saw more combat service than the E-U types. The type was modified due to combat performance 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 Daimler-Benz DB 600 powerplants. However, a call for all Daimler-Benz engines to be reserved for fighters led to the variants being fitted with Bramo Fafnir 323 A radial engines. The bomb load was extended to 2,205 lb (1,000 kg) and a fourth crew member was added. It proved to be underpowered, so Bramo 323 P engines were then fitted. Only three Do 17 S and 15 Do 17 Us were built. With the updates, the Dornier, with a full bomb load, had a combat radius of 200 miles (320 km). Later variants, in the Do 17Z-3, Z-4 and Z-5, which were fitted with cameras, dual trainer controls and floatation aids (for maritime operations) respectively, still could not solve the problems with range and bomb load.^[15] 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. The Z-8 "Geier" was not produced. The Z-9, which was fitted with special bomb release equipment, and delayed release gear for low-level attack missions. The last Z variants, the Z-7 Kauz I and Z-10 Kauz II were nightfighter versions, which were used in that role until late 1940-1941.

Operational history in the Luftwaffe

Bomber

The First Dornier Kampfgeschwaders

In late 1936 the Do 17 E-1 began to be mass produced. The first Luftwaffe units to be receive the bomber were Kampfgeschwader 153 (KG 153), and KG 155. Aufklärungsgruppe (F)/122, a reconnaissance unit, began converting to the Do 17 F-1. In early 1937 KG 255 was formed, also to be equipped with the Dornier Do 17 E-1.^[16] KG 153 received its first Do 17 E-1s on 20 September 1938 (note the significance of the date)^[17] KG 155 converted on to the type in early 1938. KG 252 was also equipped with the Do 17 M, at this time to meet the threat of the Sudeten crisis. By December 1938 it had 26 Do 17s and 17 crews. On 1 May 1939 the Kampfgeschwader was redesignated "Kampfgeschwader 2".^[18]

Spanish Civil War

The Do 17's baptism of fire came during the Spanish Civil War (1936–39), where it outpaced most enemy fighters and performed well. The Spanish nicknamed the Dornier the Bacalaos, (Codfish). In early 1937, mass production began on the Do 17E and Do 17F series. The Do 17F-1 was to replace the Heinkel He 70 as a high-flying fast reconnaissance aircraft, while the Do 17E-1 was to supplant the Condor Legion's aging Heinkel He 111B bomber.^[19] However, more modern Soviet-supplied Republican aircraft were capable of intercepting the E and F variants, which prompted an upgrade of the Dornier's defensive armament. Among the units committed to the Franco's cause was Hauptmann Rudolf Freiherr Von Moreau's 4.K/88. On 6 January 1937, it was decided by Erhard Milch, Albert Kesselring and Ernst Udet that the "Legion" should have more modern aircraft. Soon 12 Do 17 E-1s, as well as He 111 B-1s and Ju 86 D-1s were dispatched to serve in Spain. The unit was named VB/88 (Versuchsbomben Staffel, meaning Experimental Bomber Squadron).^[20] VB/88s Dorniers were involved in a strike around Guernica, but that particular units objective was a bridge, rather than civilian areas. VB/88 dropped eight tonnes of bombs, while K/88 added 37 tonnes over the city itself causing the deaths of circa 1,500 people. The bombing of VB/88 straddled the bridge, the only other target hit by the German bombers that day was the rail station, no other military target was hit.^[20] On 8 July 1937 the Dorniers flew multiple sorties to protect Nationalist forces now threatening the capital, Madrid. At this point the Junkers Ju 86s had been withdrawn and replaced with the Do 17 Fs. In the spring of 1938 another unit, 1.A/88, equipped with Do 17s also arrived in Spain.

Polish Campaign

A series of new models introduced the new enlarged nose, greatly increasing defensive firepower, finally settling on the Z models, which were widely available by 1939. During the first phase of World War II, the Do 17, along with the He 111, formed the backbone of the Luftwaffe's Kampfgruppen. From 1939 to 1940, four of the Luftwaffe's bomber groups, KG 2, KG 3, KG 76 and KG 77 operated the Dornier. KG 76 and KG 77 operated the first generation Do 17 E, with the other two Kampfgeschwader operating only the Do 17 Z on the outbreak of war.^[21][22][23] On 1 September 1939, 533 Dorniers and 705 Heinkels were combat ready.^[24] Its reliability and robustness afforded it great popularity in the Luftwaffe.^[25]

During the campaign Do 17s of I./KG 2 took part in the Battle of Bzura in which it used incendiary bombs against Polish forces consisting of Army Poznań and Army Pomorze. These raids caused a huge amount of Polish casualties, who by now had retreated to dense wooded areas, contributing to their vulnerability.^[26]

Battle of France

The first German aircraft shot down over France during the war was the Dornier Do 17 P of 2(F)123, brought down by No. 1 Squadron RAF Hawker Hurricanes on 30 October 1939 by a Pilot Officer Mould. The Dornier, Wrk Nr. 4414, constructed at Blohm and Voss, crashed near Vassincourt killing all three of its crew, Hauptmann Balduin von Norman, Oberleutnant Hermann Heisterberg and Feldwebel Friedrich Pfeuffer.^[27][a] The Do 17 saw its usefulness diminish during the French campaign. The design continued to be favoured by the Luftwaffe aircrews, as it was more manoeuvreable than the He 111 or Ju 88, and due to its ability to perform low level strikes well. An example of this was a raid carried out by KG 2 against the RAF-controlled airfield at Vraux on 10 May. Six Bristol Blenheims and two Fairey Battles of No. 114 Squadron RAF were destroyed, with many more damaged.^[b] However Allied fighter resistance on the first day was severe, and KG 2 and KG 3 of Fliegerkorps II lost a total of 19 Do 17s between them on the 10 May, the highest single daily loss of any Fliegerkorps over France.^[28] Only two weeks into the campaign, KG 2 and 3 suffered fuel shortages, keeping the Dorniers grounded, and forcing some attacks to be aborted.^[29] By the beginning of June the Dornier Geschwader were encountering less opposition and losses declined sharply, as the Armée de l'Air was no longer a sufficient threat. However, over Dunkirk, the RAF fighters were inflicting a high loss rate. On 2 June, 30 German aircraft were destroyed, including 16 Do 17s, (4 from KG 2 and 12 from KG 3), and despite dropping some 320 tonnes of bombs, the Allies kept a toehold on the continent.^[30]

Battle of Britain

During the Polish campaign, the Do 17Z could use its 265 mph (427 km/h) maximum speed to stay away from most enemy fighters, and its light armament was effective. It also fought with success during the Battle of France and losses were relatively light, although when facing modern fighters like the Hawker Hurricane, the bomber proved slower and more vulnerable. When it faced British fighters during the Battle of Britain, it was shown that fast, well-armed monoplane fighters had changed the balance between bombers and fighter decidedly in favour of the latter. The Do 17 suffered in early raids.

A significant action the Dornier took part in was the raid against RAF Kenley on 18 August 1940. Nine Do 17s of KG 76, supported by a high-level force of 27 Do 17s and 12 Ju 88s which were covered by 20 Bf 110s and nearly 60 Bf 109s were to carry out a low-level attack, in the wake of the high-level forces attack. The high-level force consisted of Dorniers from I. and III./KG 76 while 9 Staffel of III./KG 76, a specialist low-level attack unit, struck at low altitude. The unit, led by Hauptmann Joachim Roth, were issued with steel Helmets to protect them from shrapnel and the Dorniers had been fitted with a 20 mm cannon in the nose for hitting ground targets. However the high-level raid, which was supposed to attack first to spread disorganisation, was late, and the British were waiting for the attack. As soon as the Dorniers reached the airfield, rocket powered parachute and cables were fired into the air to drag aircrat from the skies. Despite the added heavy anit-aircraft fire, the Dorniers managed to destroy three hangars and eight Hawker Hurricanes, killing nine RAF personnel. One of the Dorniers was seen to hit a cable, while already on fire and it crashed onto the field. As the Dorniers passed over the target No. 111 Squadron RAF engaged Roth's formation. Roth's aircraft was caught and shot down over Kent, while Günther Junger's machine was shot down by 19 year old Pilot Officer Hary Newton, but he was hit by return fire and forced to bale out. The raid was a disaster for 9 Staffel. Out of the nine bombers deployed two were lost over Britain, two were forced into the sea of the French coast, and a further two had to make forced landings in France.^[31][c]

Since the Fafnir was a low-altitude engine, the Luftwaffe responded by employing the Do 17 units in a number of terrain-following mass raids in an attempt to evade fighter opposition. The Dornier was maneuverable in comparison to the Heinkel and the more robust nature of radial engines made it ideal for low level attacks, with a number of units being fitted with 20 mm cannon (see image). The Junkers Ju 88 was now entering service in larger numbers, replacing the Do 17 at higher altitudes.

This advantage became moot on 7 September 1940, when the Luftwaffe switched to the bombing of London (known as the Blitz), requiring all-out attacks at medium altitude. Losses mounted and on 15 September 1940, the three Dornier-equipped Kampfgruppen suffered heavily, losing twenty shot down and thirteen damaged.^[32] Among these was the famous casualty of Dornier Do 17Z-2 F1 + FH Wk Nr.2361, piloted by Oberleutnant Robert Zehbe. The Dornier was shot down by the Hawker Hurricane of Alfred Keith Ogilvie of No. 609 Squadron RAF. Parts of the Dornier crashed into Victoria Station. Zehbe and two of his other four crew members were killed.^[33]

A significant event took place on 15 September 1940, known as the "Battle of Britain Day". Among the German bombers shot down that day was Dornier Do 17 F1+FS (Wrk Nr. unknown), found in a field near Shoreham. The Dornier was found to be fitted with a Flamethrower, installed in the tail. Oil, nitrogen and hydrogen cylinders were found in the fuselage, while the external pipe was fitted with a jet. Initially it was concluded that it was a smoke producing device to feign damage. But it was discovered that it was a device that was triggered by one of the rear gunners to destroy a fighter pursuing the bomber from line astern. However, the lack of oxygen meant that the device failed to function, and a continual spray of oil was emitted. This forced the first British fighter to break off, but others attacked. The pilot Feldwebel Rolf Heitsch survived the crashlanding, as did Feldwebels Hans Pfeiffer and Martin Sauter however the fourth, Stephan Schmid, died of his wounds.^[34] The battle continued into October as the Luftwaffe concentrated on night attacks which were carried out by units mainly equipped with the Heinkel He 111 and Junkers Ju 88, as they had bigger bomb loads, and the Ju 88 had a greater speed.^[15]

With the introduction of the Junkers Ju 88 and the new Dornier Do 217 entering production, the Do 17's days were numbered, and production ceased in mid 1940. Even with the end of production, the Dornier saw action in notable numbers after the Battle of Britain in the Balkan Campaign, Operation Barbarossa (the invasion of the Soviet Union), and with the other Axis air forces.

The Dornier Do 17s losses in the Battle of Britain amounted to 132 machines destroyed, the lowest losses of the three German bomber types.^[35]

Balkans Campaign

Initially, Yugoslavia had been pro-German, and looked set to join the Axis Powers, but a military coup had toppled the government and declared itself neutral. Infuriated, Adolf Hitler ordered the conquest of Yugoslavia. The Yugoslavs had ordered twenty Do 17 Ka-2 at the end of 1940. These machines differed from the German Dorniers in that they were powered by French Gnome-Rhône Mistral Major engines.^[36] In 1940, the Yugoslavs license built 50 of these variants. They vere involved in defence of the Yugoslavia and manage to act. They atacked German and Bulgarian forces and among this actions they were heavily damaged. Tragical story is happened in airfield Skopski Petrovac. During the 20 min. crescendo Germans destroyed 28 bombers.Do-17 participated in evacuation of King Peter Karadjordjevic from airfield Niksic. They were carrying golden bullion and escaped in to Grecce. Among this Do-17 evacuated Yugoslav personell from advancing German forces in to English hands. The Luftwaffe had committed Luftflotte 4 to the invasion. Included in its strength were KG 2 and KG 3, the only Kampfgruppes in a force of seven equipped with the Do 17.^[37]

Eastern Front

After the successful conclusion of the Balkans campaign, the Luftwaffe prepared for Operation Barbarossa, the invasion of the Soviet Union. By this time, the Kampfgruppes had effectively converted to the Ju 88 and the Do 17 played a minimal part. Only two reconnaissance Staffel, and three Kampfgruppen employed the Dornier.^[38] Kampfgeschwader 2 was the only sole fully equipped Luftwaffe wing that operated the Dornier. The Dornier's most notable action on the Eastern front occurred on 23-24 June at Grodno. The commander of the Soviet Western Front, General Armii Dmitriy Pavlov attempted a counterattack against Hermann Hoths Panzergruppe 3. With air superiority and no air opposition, Dornier Do 17s of III./KG 2 destroyed columns of Soviet infantry. With help from other units, the Luftwaffe destroyed 105 Soviet tanks. The Soviet 6th and 11th Mechanised Corps and 6th Cavalry Corps were routed. For his unit's particular effectiveness, the commander of 9./KG 2, Hauptmann Walter Bradel, received the Knight's Cross of the Iron Cross.^[39] Dornier crews also witnessed at first hand the deficiencies of Soviet fighter pilot training. On 30 June 1941 KG 2 were attacked by a formation of I-16s and MiG-3s led by Mladshiy Leytenant Dmitriy Kokorev. from 124 IAP/9 SAD. The poor tactics caused the Soviet fighters to get caught in the defensive fire. Soviet records show three of their fighters were lost in this attack, without scoring kills. Kokorev crashed his fighter onto one of the Dorniers which crashed. Kokorev survived and was credited with 5 kills before being shot down and killed in October.^[40]

As 1941 wore on, the Dornier was phased out. Surviving aircraft were used as test beds for new technologies, while many others were handed off to allied nations over the next two years. It was also the template for the much larger and totally new, yet similar-looking, Dornier Do 217. During October 1943 the Do 17s of Luftlandegeschwader 1 helped resupply, and partially evacuate the German 17th Army from the Kuban. Some Do 17s were still being used by Schleppgruppen 1 and 2 ("Glider towing unit 1 and 2") in early 1945.^[41]

The last of the "Flying Pencils" served with the Luftwaffe until late 1944. However, the Do 17 continued to see action in other air forces. Seven Do 17s serving with Finnish Air Force survived the end of hostilities and continued to serve until they were scrapped in 1947.^[2]

Total losses for Kampfgeschwader 2 on the Eastern Front in 1941 indicate three Do 17s lost in June, a further nine lost in July, nine in August, a single Dornier destroyed on the ground in September, three Do 17s in October, for a total of 24 lost in aerial combat and one on the ground. The unit was withdrawn at the end of October to convert to the Junkers Ju 88.^[42]

The Dornier was, and continues to be, overshadowed by the Luftwaffe's other bomber types, namely the He 111 and the Ju 88.

Night fighter

There were only two versions of the Do 17 night fighter, the Z-6 Kauz (Screech Owl), and Z-10 Kauz II. The glazed nose was removed and replaced with three 7.92 mm MG 17 machine guns and one MG FF cannon. This proved ineffective. The armament was upgraded, and the crew could reload the 20 mm cannon internally. The Z-10 contained an IR searchlight (Spanner-Anlage)for the Spanner infrared detection system.^[41][43] A single Kauz II was equipped with and tested the Lichtenstein C-1 navagation system.^[44] The Z-10 served for less than two years in the night fighter role, where it was used in Josef Kammhuber's defensive system, known as the Kammhuber Line. Each fighter was assigned a single "cell", with three strips of such cells running from Denmark to the middle of France. Within each cell, a direction center on the ground tracked both the Kauz and a single target, guiding them until the target was visible in night glasses or the Spanner detector.

All surviving Z-10s were removed from front line duty in summer 1942. They were either used as airframes to provide spare parts or transferred to night fighter schools.

Operational history in other Air Forces

Royal Yugoslav Air Force

Do 17K from the 3rd Bomber Regiment of Royal Yugoslav Air Force, April 1941

At the beginning of the April war, the Royal Yugoslav Air Force (RYAF) possessed some 60 Dornier Do 17Ks. The only air force unit that was armed with this type was 3 vazduhoplovni puk (3rd Bomber Regiment), composed of two bomber groups; 63rd Bomber Group stationed at the airport Petrovac near Skopje and 64th Bomber Group stationed at the airport Milesevo near Pristina. During hostilities, the aircraft factory in Kraljevo managed to produce three more aircraft of this type. Two were delivered to the RYAF on 10 April and one on 12 April 1941. The Luftwaffe destroyed 26 of these Yugoslav Dorniers in the initial assault. Total Yugoslav losses stood at four destroyed in aerial combat and 45 destroyed on the ground.^[45] Between 14 and 15 April, seven remaining Do 17Ks flew to Niksic airport and took part in the evacuation of King Petar II and members of the Yugoslav government to Greece. During this operation, Yugoslav gold reserves were also airlifted to Greece by seven Do 17s.^[45] After completing their task, five Do 17K were destroyed when Italian aircraft attacked the Greek Paramithia airport. Only two Do 17Kb-1s escaped destruction and later joined the RAF in Egypt, where they were allocated the serial numbers AX707, and AX706. However, both machines were destroyed in an air attack on 27 August 1941.^[46] During this time, it is also recorded that two Dorniers escaped to the Soviet Union.^[45]

Finnish Air Force

In November 1941, Reichsmarschall Hermann Göring decided to give 15 Dornier Do 17Z aircraft to the Finnish Air Force. No. 46 Squadron operated the Dorniers. The Finns used their Do 17 aircraft mainly for night bombing and against "soft" targets at the front, since the aircraft were considered obsolete – the speed and climbing abilities of the Do 17 were deemed inadequate by 1942 standards.

Only four aircraft remained in airworthy condition after the war. The Finns were obliged to scrap them in accordance with the peace treaty ending the conflict. The last one was scrapped in 1947.

Variants

Do 17E and F

The prototypes were powered by Daimler-Benz DB 600 engines, but these were constantly in short supply. Production started instead with the BMW VI inline engine, creating the Do 17 E-1 bomber and Do 17 F-1 reconnaissance versions. The bombload of the E-1 was 500 kg, and it was armed with two defensive MG 15 machine guns, one in a position on the cabin roof and one a small hatch in the floor with a restricted field of fire.

Do 17K

After seeing the Do 17 M V1 at the Zürich air races in 1937, the Yugoslavian Air Force bought licence rights for production at Drzavna Fabrika Aviona. They equipped it with the considerably better Gnome-Rhône 14N radial engines and added a Hispano 20 mm cannon and three 7.92 mm Browning machine guns. Three variants were built in Yugoslavia. The first being the Do 17Kb-1 bomber aircraft and the second was the Do 17Ka-2 reconnaissance aircraft. The final variant was the Do 17Ka-3 reconnaissance aircraft.

Do 17L and M

The Do 17 L-0 and Do 17 M-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 1,000 hp (750 kW). Two L and one M versions were built as prototypes, both with another MG 15 in the nose.

The feasibility of the Schnellbomber was demonstrated at the International Military Aircraft Competition at Zürich in 1937, where the Do 17M prototype finished ahead of all the fighters in the competition.

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. Production versions of the basic Do 17M model airframe were thus fitted with the new Bramo 323A-1 Fafnir of 900 hp (670 kW), which gave reasonable performance and raised the bombload to 1,000 kg. The resulting Do 17 M-1 was produced in small numbers and operated until the first year of the war, when they were withdrawn and sent to training units.

Do 17P

The L version would not be able to enter production with the DB 600, and the Bramo engine was rather thirsty and left the M models with too short a range for use in the reconnaissance role. BMW 132N radials of 865 hp (645 kW) were selected instead, which had lower fuel consumption for better range. This Do 17 P-1 was produced in some numbers, but why this version was not called the L-1 is a mystery. Another two prototypes with DB 600 engines were produced as the Do 17 R-0, but did not enter production.

Do 17S and U

When fast monoplane fighters began catching up with the speed of the Do 17, a completely new pod-like cockpit was designed for the aircraft 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 and the ventral gun moved to the back of the pod, allowing it to fire directly to the rear. The changes in the roof and floor made the whole front of the aircraft much larger.

Three prototypes with the DB 600 inverted V12 engines were constructed as the Do 17 S-0 reconnaissance version, but it did not go into production. An additional fifteen 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 in 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.

Dornier Do 17Z of the Finnish Air Force

Do 17Z

Wide-scale production finally settled on the definitive Do 17Z models. At first a batch of Z-0s were built with the Fafnir for testing, the DB 600 again proving to be too hard to come by. 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 bombload was reduced to 500 kg.

This was addressed in the major production model, the Do 17 Z-2. The Z-2 mounted the new 323P version of the Fafnir with 1,000 hp (750 kW), 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 bombload to be increased back to 1,000 kg. On the downside the new engines were also quite "thirsty" at low altitudes, and the combat range with a 1,000 kg bombload was a very short 205 miles (330 km). 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.

Modifications of the basic Z-2 model included the 'Z-3 and Z-6, the reconnaissance version, the Z-4 dual-control trainer, and the Z-5 which included floatation cells in the fuselage and engine nacelles in case it was forced down on water. Some 537 Z-2s were produced before the lines shut down in July 1940.

Do 17 Z-7/Z-10 Kauz I/II

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 MG 17s, 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. Later the design was further modified to the Do 17 Z-10 Kauz II, the solid nose now containing an IR searchlight for the Spanner infrared detection system. The Z-10 was armed with four 7.92 mm MG 17 machine guns grouped above the IR light and two 20 mm MG FF in the lower nose. Only ten 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 detection system. At least one Z-10, coded CD+PV, was used as a flying testbed to help developing the Lichtenstein radar system in late 1941/1942.^[47]

Do 215

Main article: Dornier Do 215

The Do 215 was developed as an export version of the Do 17Z series, was used as bomber, reconnaissance and night fighter aircraft.

Operators

 Bulgaria

• Bulgarian Air Force received eleven ex-Yugoslav aircraft in 1941. They remained in service until at least 1945.^[48]

Independent State of Croatia

• Zrakoplovstvo Nezavisne Države Hrvatske^[49]

 Finland

• Finnish Air Force
  • 46 Squadron received 15 aircraft in January 1942.^[50][51]

 Germany

• Luftwaffe

 Romania

• Royal Romanian Air Force received 10 worn Do 17Ms in November 1942.^[2]

 Hungary

• Royal Hungarian Air Force received one ex-Yugoslavian Do 17Ka-3.^[52]

Spanish State

• Spanish Air Force received ex-Legion Condor Do 17E, F, and Ps and 13 remained in service after the end of the Spanish Civil War.^[53][54]

 Switzerland

• Swiss Air Force operated a single Do 17Z-2, interned after landing at Basel Airport in April 1940.^[55]

Kingdom of Yugoslavia

• Royal Yugoslav Air Force
  • 209 Eskadrila JKRV

 United Kingdom

• Royal Air Force pressed to service^[56][45] two Yugoslav built Do 17K's which escaped Yugoslavia with King Peter and gold,^[57]

Survivors

Up until recently none of the Dornier twin-engined bomber variants were thought to have survived. In September 2007 a Do 215 B-5 (variant of Do 17Z) was found largely intact in the shallow waters off Waddenzee, The Netherlands.^[58] Various large relics of the Do 17 are held by public and private collectors.^[59]d 

One of the Dorniers suriving relics. A rudder of a Dornier Do 17 shot down on 28 August 1940. The hole at the top, is a 0.303 inch (7.7 mm) bullet hole

Specifications (Do 17 Z-2)

Data from ^[60]

General characteristics

• Crew: 4 (pilot, bomb aimer/gunner, two gunners)
• Length: 15.80 m (51 ft 9⅝ in.)
• Wingspan: 18 m (59 ft 0⅝ in.)
• Height: 4.56 m (14 ft 11½ in.)
• Wing area: 55 m² (590 ft²)
• Empty weight: 5,209 kg (11,480 lb)
• Loaded weight: 8,578 kg (18,872 lb)
• Max takeoff weight: 8,850 kg (19,500 lb)
• Powerplant: 2× BMW Bramo 323P Fafnir 9-cylinder radial engines, 750 kW (1,000 hp) each

Performance

• Maximum speed: 427 km/h (265 mph, 231 knots)
• Range: 1,160 km (721 mi, 626 nm,) at half combat load
• Service ceiling: 7,000 m (22,965 ft)
• Wing loading: 156 kg/m² (32.0 lb/ft²)
• Power/mass: 170 W/kg (0.11 hp/lb)

Armament

• Guns: 6× 7.92 mm (0.312 in) MG 15; lower nose gun occasionally replaced with 20 mm (0.787 in) MG FF or MG 151 cannon
• Bombs: Max load 2,205 lb (1,000 kg)
  
  • Twenty 50kg (110 lb) bombs internally
  • Four 250kg (551 lb) bombs internally^[61] However, fully loaded, the Do 17 Z-2 had a range of only 200 miles (320 km).^[62]

See also

Related development

• Dornier Do 215
• Dornier Do 217
• Dornier Do 317
  

Comparable aircraft

• De Havilland Mosquito
• PZL.37 Łoś
• Tupolev SB
  

Related lists

• List of bomber aircraft
• List of military aircraft of Germany
  

References

Footnotes

• ^a  The unit in question was 2nd Squadron of the 123rd Long Range Reconnaissance Group, or 2(Fernaufklaerungsgruppe)123.

• ^b  Goss quotes "IV. and V./KG 2" as carrying out the attack,^[63] however neither unit existed. It was actually II.KG 2.^[64] IV(Erg)./KG 2 and V.(Z)/.KG 2 were the only two similar named units, and they were not created until 16 August 1940 and 20 June 1943 respectively.^[65]

• ^[c] Goss again quotes "9/KG 76".^[31] This implies 9 Gruppe of KG 76. No such unit existed. Goss is referring to 9 Staffel of III Gruppe, Kampfgeschwader 76, or 9.III./KG 76

• ^d Photographs of the relics are provided under the "Relics" link at the bottom of the website.

Citations

Bibliography

External links

• Dornier 17 Research site
• Dornier Do 17 page -Aircraft of the Luftwaffe
• RAF officer's photos showing King Peter and 2 Do-17K's
• Website devoted to the Do-17K