German WW2 Bombers: Junkers Ju 87 Stuka

The Junkers Ju 87 or Stuka was the most famous Sturzkampfflugzeug (German dive bomber) in World War II, instantly recognisable by its inverted gull-wings and fixed undercarriage.

The Stuka's design included some innovative features, including an automatic pull-up system to ensure that the plane recovered from its attack dive even if the pilot blacked out from the high acceleration, and wind-powered sirens on the wheel covers that wailed during dives to scare its victims.

The Stuka was sturdy, accurate, and very effective, but also slow, unmaneuverable, underarmed, and vulnerable to enemy fighters. The Germans learned in the Battle of Britain that air superiority must be obtained before ground attack aircraft could be effectively used. After the Battle of Britain, the Stuka was little used in western Europe, but it remained effective further south where Allied fighters were in short supply (notably in the attacks on Crete and Malta, and was used in vast numbers on the Eastern Front, although the steady rise in Soviet airpower as the war progressed meant that Stuka squadrons suffered very heavy losses.

Over 5700 Ju87 Stukas were built.

Ju87 General Characteristics

(Models not listed include the Ju.87C, intended for use on the aircraft carrier Graf Zeppelin, the Ju.87R long-range version of the Ju.87B, the Ju.87C naval derivative of the Ju.87B, the Ju.87H disarmed versions of the equivalent D-models for use as trainers, and the Ju.87K export models.)

Ju87 D Variant

Despite the Stuka's vulnerability to enemy fighters having been exposed during the Battle of Britain, the Luftwaffe had no choice but to continue its development as there was no replacement aircraft in sight. The result was the D-series. In June 1941 the RLM ordered five prototypes, the Ju 87 V21–25. A Daimler-Benz DB 603 powerplant was to be installed in the Ju 87 D-1, but it did not have the power of the Jumo 211 and performed "poorly" during tests and was dropped.[56] The Ju 87 D-series had better streamlined oil- and water-coolers, and an aerodynamically refined cockpit with better visibility and space.[57] In addition, armor protection was increased and a new dual-barrel 7.92 mm (.312 in) MG 81Z machine gun with an extremely high rate of fire was installed in the rear defensive position. The engine power was increased again, the Jumo 211 J-1 or Jumo 211P now delivering 1,420 PS (1,044 kW, 1,401 hp).

The fuel capacity of the Ju 87 D was also increased to 1,370 L (360 US gal). Tests at Rechlin revealed it made possible a flight duration of 2 hours and 15 minutes. With an extra two 300 L (80 US gal) fuel tanks it could reach four hours flight time.[57] Production of the D-1 variant started in 1941 with 495 orders made. These aircraft were delivered between May 1941 and March 1942. The RLM wanted 832 machines produced from February 1941. The Weserflug company was tasked with their production. From June to September 1941, 40 Ju 87 Ds were expected to be built, increasing to 90 thereafter.[58] Various production problems were encountered. Just one of the planned 48 was produced in July. Of the 25 the RLM hoped for in August 1941, none were delivered.[58] Only in September 1941 did the first two of the planned 102 Ju 87s roll off the production lines.[59] The shortfalls continued to the end of 1941. During this time the WFG plant in Bremen moved production to Berlin. Over 165 Ju 87s had not been delivered and production was only 23 Ju 87 Ds per month out of the 40 expected. By the Spring of 1942 to the end of production in 1944, 3,300 Ju 87s, mostly D-1s, D-2s and D-5s had been manufactured.[59] The D-series saw extensive use in the Eastern Front and the Middle East. Bomb carrying ability was massively increased from 500 kg (1,100 lb) in the B-version to 1,800 kg (3,970 lb) in the D-version (max load for short ranges, overload condition), a typical bomb load ranged from 500-1,200 kg (1,100-2,650 lb).

The D-2 was a variant used as a glider tug by converting older D-series airframes. It was intended as the tropical version of the D-1. It was to have heavier armour to protect the crew from ground fire. The armour reduced its performance and caused the Oberkommando der Luftwaffe to "place no particular value on the production of the D-2".[57] The D-3 was an improved D-1 with more armour for its ground-attack role. The D-3 was converted from D-2 status and equipped with the Jumo 211 J. A number of Ju 87 Ds were designated D-3Ns or D-3/ trops and fitted with night and tropical equipment.[57] The D-4 designation applied to a prototype torpedo-bomber version which could carry a 750–905 kg (1,650-2,000 lb) aerial torpedo carried on a PVC 1006 B racks. The D-4 was to be converted from D-3 airframes and operated from the aircraft carrier Graf Zeppelin.[61] Other modifications included a flame eliminator and, unlike earlier D variants, fitted with two 20 mm MG 151/20 cannon while the radio operator/rear gunner's ammunition supply was increased by 1,000 to 2,000 rounds.

The Ju 87 D-5 was based on the D-3 design and was unique in the Ju 87 series as it had wings 0.6 metres longer than previous variants. The powerplant was upgraded to the Jumo 211 P in-line engine with supercharger intercoolers. In August 1943, this was replaced with the Jumo 211 J-1. This engine increased rate of climb by 15 m/s (2,953 ft/min). With introduction of the Jumo 213 and increased power and climb rate, the lengthened wings were no longer needed.[60] The window in the floor of the cockpit was reinforced and four, rather than the previous three, aileron hinges were installed. Higher diving speeds were obtained of 650 km/h (408 mph) up to 2,000 m (6,400 ft). Range was recorded as 715 km (443 mi) at ground level and 835 km (517 mi) at 5,000 m (16,400 ft).[60]

Fuel capacity was in the form of one main 480 L (127 US gal) fuselage tank and two wing tanks of 150 L (40 US gal) capacity. Two 300 L (80 US gal) drop tanks could also be installed under the wings. The D-5 was also fitted with a 20 mm MG 151/20 cannon in each wing. Both magazines had a capacity of 180 rounds. The radio operator/gunner operated 7.92 mm (.312 in) MG 81Z. Ammunition loads usually ranged from 1,400 to 2,000 rounds.[60] The D-6, according to "Operating instructions, works document 2097", was built in limited numbers to train pilots on "rationalised versions". However due to shortages in raw materials it did not go into mass production.[63] The D-7 was another ground attack aircraft based on D-1 airframes upgraded to D-5 standard (armor, wing cannons, extended wing panels), while the D-8 was similar to the D-7 but based on D-3 airframes.[63] The D-7 and D-8 were both were fitted with flame dampers, and could conduct night operations.

The Ju 87 E and F proposals were never built, and Junkers went straight onto the next variant. Another variant derived from the Ju 87 D airframe was called the Ju 87 H, and saw service as a dual-control trainer.

In January 1943 a variety of Ju 87 Ds became "test beds" for the Ju 87 G variants. At the start of 1943 the Luftwaffe test centre at Tarnewitz tested this combination from a static position. Oberst G. Wolfgang Vorwald noted the experiments were not successful, and suggested the cannon be installed on the Messerschmitt Me 410.[64] However, testing continued, and on 31 January 1943 Ju 87 D-1 W.Nr 2552 was tested by a Hauptmann Hans-Karl Stepp near the Briansk training area. Stepp noted the increase in drag, which reduced the aircraft's speed to 259 km/h (162 mph). Stepp also noted that the aircraft was also less agile than the existing D variants. D-1 and D-3 variants operated in combat with the 37 mm (1.46 in) BK 37 cannon in 1943.

Ju-87-D Known prototypes

* Ju 87D V 21. Registration D-INRF. W.Nr 0870536. Airframe conversion from B-1 to D-1. First flown on 1 March 1941.
* Ju 87D V 22 Registration SF+TY. W.Nr 0870540. Also airframe conversion from B-1 to D-1. First flown on 1 March 1941.
* Ju 87D V 23 Registration PB+UB. W.Nr 0870542. Also airframe conversion from B-1 to D-1. First flown on 1 March 1941.
* Ju 87D V 24 Registration BK+EE. W.Nr 0870544. Also airframe conversion from B-1 to D-1/D-4. First flown on 1 March 1941.
* Ju 87D V 25 Registration BK+EF. W.Nr 0870530. Also airframe conversion from B-1 to D-4 trop. First flown on 1 March 1941.
* Ju 87D V 30 is the only known prototype of the Ju 87 D-5. W.Nr 2296. First flown on 20 June 1943.
* Ju 87D V 26-28, Ju 87 V 31, and V 42-47 were experiments of unknown variants

Ju87- C

On 18 August 1937 the RLM decided to introduce the Ju 87C. The Ju 87 G was intended to be a dive and torpedo bomber for the Kriegsmarine. The type was ordered into prototype production and available for testing in January 1938. Testing was given just two months and was to begin in February and end in April 1938. The prototype V10 was to be a fixed wing test aircraft, while the following V11 would be modified with folding wings. The prototypes were Ju 87 B-0 airframes equipped with Jumo 211 A aero engines. Owing to delays the V10 was not completed until March 1938. It first flew on 17 March and was designated Ju 87 C-1. On 12 May the V11 also flew for the first time. By 15 December 1939 915 arrested landings on dry land had been made. It was found the arresting gear winch was too weak and had to be replaced. Tests showed the average braking distance was 20–35 metres. The Ju 87 V11 was designated C-0 on 8 October 1938. It was fitted out with standard Ju 87 C-0 equipment and better wing-folding mechanisms. The "carrier Stuka" was to be built at the Weserflug Company's Bremen plant between April and July 1940. Between July 1940 and August 1941 120 Ju 87 C-1s were built.

Among the "special" equipment of the Ju 87 C was a two seat rubber dinghy with signal ammunition and emergency ammunition. A quick fuel dump mechanism and two inflatable 750 L (200 US gal) bags in each wing and a further two 500 L (130 US gal) bags in the fuselage enabled the Ju87-C to remain floating for up to three days in calm seas.[53] On 6 October 1939, with the war already underway, 120 of the planned Ju 87 Tr(C)s on order at that point were cancelled. Despite the cancellation the tests continued using catapults. The Ju87 C had a takeoff weight of 5,300 kg (11,700 lb) and a speed of 133 km/h (82 mph) on departure. The Ju 87 could be launched with a SC 500 kg (1,100 lb) bomb and four SC 50 kg (110 lb) bombs under the fuselage. The C-1 was to have two MG 17s mounted in the wing with a MG 15 operated by the rear gunner for defensive purposes. On 18 May 1940, production of the C-1 was switched to the R-1. The fleet of Ju 87 Cs that existed were lost throughout the war.