page_title: Junkers Ju 87
section_title: Evolution
hierarchical_section_title: Junkers Ju 87 / Development / Evolution
caption_attribution_description: English: w:Junkers Ju 87 with its inverted gull wings.
context_page_description: The Junkers Ju 87 or Stuka was a German dive bomber and ground-attack aircraft. Designed by Hermann Pohlmann, it first flew in 1935. The Ju 87 made its combat debut in 1937 with the Luftwaffe's Condor Legion during the Spanish Civil War and served the Axis forces in World War II.
  The aircraft is easily recognisable by its inverted gull wings and fixed spatted undercarriage. Upon the leading edges of its faired main gear legs were mounted the Jericho-Trompete wailing sirens, becoming the propaganda symbol of German air power and the so-called Blitzkrieg victories of 1939–1942. The Stuka's design included several innovations, including automatic pull-up dive brakes under both wings to ensure that the aircraft recovered from its attack dive even if the pilot blacked out from the high g-forces.
  The Ju 87 operated with considerable success in close air support and anti-shipping at the outbreak of World War II. It led air assaults in the invasion of Poland in September 1939. Stukas were critical to the rapid conquest of Norway, the Netherlands, Belgium and France in 1940.
context_section_description: The design of the Ju 87 had begun in 1933 as part of the Sturzbomber-Programm. The Ju 87 was to be powered by the British Rolls-Royce Kestrel engine. Ten engines were ordered by Junkers on 19 April 1934 for £20,514, two shillings and sixpence.
  The first Ju 87 prototype was built by AB Flygindustri in Sweden and secretly brought to Germany in late 1934. It was to have been completed in April 1935, but, due to the inadequate strength of the airframe, construction took until October 1935. The mostly complete Ju 87 V1 W.Nr.4921 (less non-essential parts) took off for its maiden flight on 17 September 1935. The aircraft was later given the registration D-UBYR. The flight report, by Hauptmann Willy Neuenhofen, stated the only problem was with the small radiator, which caused the engine to overheat.
  The Ju 87 V1, powered by a Rolls-Royce Kestrel V12 cylinder liquid-cooled engine, and with a twin tail, crashed on 24 January 1936 at Kleutsch near Dresden, killing Junkers' chief test pilot, Willy Neuenhofen, and his engineer, Heinrich Kreft. The square twin fins and rudders proved too weak; they collapsed and the aircraft crashed after it entered an inverted spin during the testing of the terminal dynamic pressure in a dive. The crash prompted a change to a single vertical stabiliser tail design. To withstand strong forces during a dive, heavy plating was fitted, along with brackets riveted to the frame and longeron, to the fuselage. Other early additions included the installation of hydraulic dive brakes that were fitted under the leading edge and could rotate 90°.
  The RLM was still not interested in the Ju 87 and was not impressed that it relied on a British engine. In late 1935, Junkers suggested fitting a DB 600 inverted V-12 engine, with the final variant to be equipped with the Jumo 210. This was accepted by the RLM as an interim solution. The reworking of the design began on 1 January 1936. The test flight could not be carried out for over two months due to a lack of adequate aircraft. The 24 January crash had already destroyed one machine.
  The second prototype was also beset by design problems. It had its twin stabilisers removed and a single tail fin installed due to fears over stability. Due to a shortage of engines, instead of a DB 600, a BMW "Hornet" engine was fitted. All these delays set back testing until 25 February 1936. By March 1936, the second prototype, the V2, was finally fitted with the Jumo 210Aa engine, which a year later was replaced by a Jumo 210 G (W.Nr. 19310). Although the testing went well, and the pilot, Flight Captain Hesselbach, praised its performance, Wolfram von Richthofen told the Junkers representative and Construction Office chief engineer Ernst Zindel that the Ju 87 stood little chance of becoming the Luftwaffe's main dive bomber, as it was underpowered in his opinion. On 9 June 1936, the RLM ordered cessation of development in favour of the Heinkel He 118, a rival design. Udet cancelled the order the next day, and development continued.
  On 27 July 1936, Udet crashed the He 118 prototype, He 118 V1 D-UKYM. That same day, Charles Lindbergh was visiting Ernst Heinkel, so Heinkel could only communicate with Udet by telephone. According to this version of the story, Heinkel warned Udet about the propeller's fragility. Udet failed to consider this, so in a dive, the engine oversped and the propeller broke away. Immediately after this incident, Udet announced the Stuka the winner of the development contest.
caption: The Stuka had inverted gull wings, as shown in this photograph. Also visible are the two separate sliding "hoods" of the canopy.
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