page_title: Schräge Musik
section_title: Interwar years
hierarchical_section_title: Schräge Musik / Background / Interwar years
caption_attribution_description: English: Bouton Paul Mk1 Defiant turret.
context_page_description: Schräge Musik, which may also be spelled Schraege Musik, was a common name for the fitting of a upward-firing autocannon or machine gun, to an interceptor aircraft, such as a night fighter. The term was introduced by the German Luftwaffe during World War II. "Schräge Musik" was previously a German colloquialism, meaning music that featured an unusual tuning and/or time signature. By itself, the word Schräge has often been translated as "slanting" or "oblique", although it may instead be rendered into English as "weird" or "strange".
  The first such systems were been devised World War I. They
  were also developed and used by the Japanese military during World War II. Like the Luftwaffe, the Imperial Japanese Navy Air Service and Imperial Japanese Army Air Service fitted such weapons to twin-engined night fighters. Both the Luftwaffe and IJNAS had their first victories with upward-firing autocannons in May 1943. Night fighters used them to approach and attack Allied bombers from below, outside the bomber crew's field of view and/or defensive fire.
context_section_description: The Boulton Paul Bittern was a twin-engined night fighter (designed to Specification 27/24) with an armament of barbette mounted guns, that could be angled upwards for attack against bombers, without having to enter a climb. The first of two Bittern prototypes flew in 1927, though performance was poor and the development stopped.
  The Westland C.O.W. Gun Fighter (1930) and Vickers Type 161 (1931) were designed in response to Air Ministry specification F.29/27. This called for an interceptor fighter operating as a stable gun platform for the Coventry Ordnance Works 37 mm autocannon produced by the Coventry Ordnance Works (COW).
  The COW gun had been developed in 1918 for use in aircraft and had been tested on the Airco DH.4. The cannon fired 23-ounce (0.65 kg) shells and was to be mounted at 45 deg or more above the horizontal. The tactic was to fly below the target bomber or airship and fire upwards into it. Gun firing trials with both types went well, with no detriment to airframe or performance, although the Westland prototype displayed "alarming" handling characteristics. Neither the Type 161 nor its competitor, the Westland C.O.W. Gun Fighter were ordered, and no more was heard of this use of the aerial COW gun.
  Similar logic lay behind the later Vickers Type 414 twin-engined fighter. This aircraft, which can be seen a natural successor to the Vickers COW gun fighter,  combined a streamlined monoplane two-seater fighter airframe with a remotely controlled nose-mounted 40mm cannon that could be elevated for no-allowance shooting.
  While turret fighters like the Boulton Paul Defiant and the naval Blackburn Roc addressed the same threat – enemy bombers attacking the UK – the approach was very different: upward-firing guns and no-allowance shooting are separate and distinct, the equipment that can do the one can, generally speaking, be arranged so as to do the other (unless the fixed armament is automatically triggered, as in the photo-cell firing arrangements detailed below). On paper at least, the advantages of flexible aim and weight of fire from a two-seater were clear: the pilot is not overburdened, several fighters could be brought to bear on a target together and there are two pairs of eyes per aircraft. However, the weight of a powered turret and air gunner imposed their own severe and often fatal penalties.
  The RAF put the Defiant into service in 1939, intending to use it against bombers, despite the bombers' numerous gun positions; however, it quickly became apparent that bombers escorted by nimble single-engined fighters bought within range by the speed and unprecedented territorial gains of blitzkrieg could not be engaged effectively. Despite being utterly outclassed as a day fighter, when moved to the night-fighter role it had some success, typically attacking from below and slightly ahead of the bomber, well outside its field of defensive fire.
  Meanwhile, in the United States, the twin-engine Bell YFM-1 Airacuda was designed as a "bomber-destroyer", touted as  "... a mobile anti-aircraft platform." Its armament included mainly forward-firing M4 37mm cannon, with an accompanying gunner mounted in a forward compartment of each of the two engine nacelles. Theoretically, the cannon could be slewed, aimed and fired at an oblique angle but flight tests and operational evaluation, disproved the theory: the type proved troublesome and except for initial flight testing in 1937, where full armament was carried, the nacelle cannon armament and the accompanying gunner–loaders were eliminated in the final development aircraft.
caption: Boulton Paul turret mounted on both the Boulton Paul Defiant and Blackburn Roc
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