Do 17Z-2 Specifications

Crew: Pilot and four gunners/navigators/bomb-aimers

Powerplant: Two 1,000 hp Bramo 323P nine-cylinder air-cooled engines

Span: 59 ft ¾ in (18.00 m)

Length: 52 ft 0 in (15.85 m)

Max Speed: 265 mph (427 km/h) at 16,400 ft (4,998 m)

Armament: Between four and eight 7.92 mm machine guns in front, rear and beam cockpit mountings and ventral position

Bomb Load: Normal load of 2,200 lb (1,000 kg)

Photo Description: A Dornier Do 17Z bomber of KG 76 in flight, 1940. Bundesarchiv, Bild 101I-341-0489-10A / Spieth / CC-BY-SA 3.0

The Dornier Do 17 was a German light bomber used by the Luftwaffe during the early campaigns of the Second World War. It was designed by Dornier Flugzeugwerke in the early 1930s as a high-speed passenger and mail plane for Deutsche Lufthansa. Three prototypes were built but the aircraft was ultimately rejected by the airline due to the slim fuselage, which made it commercially impractical. One of the prototypes was later test-flown by a former Dornier employee and test pilot, Flugkapitan Robert Untucht, who was working as a liaison between Lufthansa and the German Ministry of Aviation (Reichsluftfahrtministerium, or RLM). He believed that a modified version of the aircraft could meet the RLM requirements for a Schnellbomber (fast bomber), a bomber fast enough to outrun defending fighter aircraft. As a result, Dornier was asked to produce a series of prototypes for military trials. The Do 17 was modified to include twin rudder fins, a glazed nose section, an internal bomb bay, and provision for defensive armament. Its long, slim fuselage earned it the nickname the Fliegender Bleistift (“flying pencil”). The bomber prototypes first flew in 1935 and proved faster than most fighter aircraft then in service. Two versions were subsequently ordered into production, the Do 17E-1 bomber and the Do 17F-1 long-range reconnaissance aircraft, both powered by two 750hp BMW VI 7.3 engines. The Do 17E-1 had a top speed of 380 km/h (263 mph) and could carry a bomb load of 750 kg (1,654 lb) with a three-man crew. It was lightly armed with a single rear-firing 7.92 mm MG 15 machine gun in a dorsal position and a second MG 15 machine gun fitted to fire downwards through a rear ventral hatch. Both aircraft entered Luftwaffe service in early 1937 and first saw action during the Spanish Civil War with the German Condor Legion.

With the Do 17 in full production, Dornier continued to develop and produce new variants. In July 1937, the Do 17M V-1 prototype was sent to Zürich to compete in the International Military Aircraft Competition. This was powered by two 1,000hp Daimler-Benz DB 600A engines and was able to reach a top speed of 457 km/h (284 mph), finishing ahead of all the fighters in the competition. Despite its success, the limited supply of DB 600 series engines meant that the production model, the Do 17M-1, was fitted with air-cooled Bramo Fafnir 323 A radial engines. This had a top speed of 420 km/h (250 mph) and was capable of carrying a 1,000 kg (2,200 lb) bomb load with a four-man crew. An additional fixed forward-firing MG 15 machine gun was added in the right windscreen. The reconnaissance version, the Do 17P-1, was powered by improved BMW 132N radial engines to give better range.

Combat experience gained in Spain revealed that the Do 17 was not as fast as initially thought and modern Soviet-built Republican fighters were capable of intercepting the aircraft. As a result, the forward fuselage was completely redesigned to allow greater defensive armament, more room for the crew, and better visibility. The Do 17S was the first variant to feature the new design followed by the Do 17U pathfinder version. Both aircraft were powered by DB 600 engines but only a small number were produced. The modified airframe was then fitted with Bramo Fafnir 323 A radial engines resulting in the Do 17Z, the main production variant. The Do 17Z-1 entered service in late 1938 but proved underpowered and could only carry a 500kg (1,102lb) bomb load. This was addressed in the Do 17Z-2, which was introduced in 1939. This version was powered by two Bramo Fafnir 323 P engines with two-speed superchargers and could carry a bomb load of up to 1,000 kg (2,200 lb). Defensive armament comprised six MG 15 machine guns in the front, rear upper, rear lower and cockpit side positions. The main drawback of the aircraft was its limited 330 km (200 mi) combat range when fully loaded. Production of the Do 17 ended in mid-1940, in favour of the more capable Junkers Ju 88 bomber.

At the start of the Battle of Britain, the Do 17 was still operated by three Kampfgruppen. The bomber was ideally suited for low-level attacks due to its maneuverable handling at low altitude and the robustness of the air-cooled radial engines. On 18 August 1940, nine Do 17s of 9.Staffel/KG 76 attacked RAF Kenley at low altitude destroying buildings, hangars, telephone lines, and several aircraft on the ground including eight Hawker Hurricanes. However, four Do 17s were destroyed, two seriously damaged, and the rest suffered minor damage. Even with greater defensive firepower, the Do 17 proved vulnerable to RAF fighters and units continued to suffer losses throughout the Battle. On 15 September, twenty Do 17s were destroyed and thirteen damaged. Among the casualties was Dornier Do 17Z-2 ‘F1+FH’ (Wk-Nr 2361) of 1.Staffel/KG 76, brought down by Sergeant Ray Holmes of No. 504 Hurricane Squadron. Holmes decided to ram the bomber after his machine guns failed, cutting the tail off with his port wing and causing the Do 17 to crash close to the forecourt of Victoria Station in central London. Holmes was forced to bail out of his badly damaged Hurricane, which crashed near the grounds of Buckingham Palace.

The Dornier Do 215 entered service in 1940 and was, in all main respects, similar to the Do 17 except for its two Daimler-Benz DB 601 engines. The Do 215 was originally an export model for Yugoslavia and Sweden, taken over by the Luftwaffe, and was only seen in small numbers during the Battle, mainly in the reconnaissance role.