Schräge Musik

Schräge Musik (German pronunciation: [ˈʃʁɛːgə muˈziːk]) was a common name for the fitting of an upward-firing autocannon or machine gun, to an interceptor aircraft, such as a night fighter.

The first such systems were developed (though not widely employed) in World War I as anti-Zeppelin defenses by the French and British, in an era when fighters struggled to match the altitude capacity of the German airships and were forced to devise means to attack from below.

The later resurrection of the concept by the Germans was inspired by observed weaknesses in the standard British night bomber aircraft of the WW2 era (the Avro Lancaster and Handley Page Halifax), which lacked ventral ball turrets in order to save weight, making them vulnerable to covert approaches and attacks from below under the cover of darkness.

In keeping with the plans of the Allied Combined Bomber Offensive, the American B-17 Flying Fortress and B-24 Liberators operating in Europe (factory-equipped with ball turrets) typically bombed by day, thus experiencing far fewer encounters (and relative losses) from Schräge Musik.

In the initial stages of its operational use by German air crews, from mid-1943 to early 1944, many attacks using Schräge Musik achieved complete surprise while destroying many British bombers.

When firing upward at roughly a 45° elevation, when the attacking aircraft and its target are travelling at about the same speed and the range is fairly short, the trajectory will appear straight.

The pilots of Royal Aircraft Factory B.E.2 night fighters, after trying various schemes for attacking the Zeppelin raiders of 1915–1916, hit on the idea of firing a mixture of explosive and incendiary bullets into the body of the airship from below.

Several tractor-configured single-seat biplanes of the time featured machine guns mounted on the centre section of the top wing to fire over the radius of the propeller to bypass the need for synchronization gears).

That Dolphin entered service near the end of World War I, and was delivered with a pair of .303 in (7.7 mm) Lewis guns on a cross-tube connecting the upper wing spars.

British ace Albert Ball in particular was a great exponent of this technique,[2] The Germans copied the arrangement in 1917, when Gerhard Fieseler of Jasta 38 attached two machine guns to an Albatros D.V, pointing upwards and forwards.

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.

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.

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.

In July 1942, Schoenert discussed the results of his experiment with General Josef Kammhuber, who authorized the conversion of three Dornier Do 217J-1s, to add a vertical armament of four or six MG 151s.

[9] Schönert was made CO of II./NJG 5, and an armourer serving with the Gruppe, Oberfeldwebel Mahle, developed a working arrangement with the unit's Messerschmitt Bf 110s, mounting a pair of MG FF/M 20 mm (0.79 in) cannon in the rear compartment of the upper fuselage, firing through twin holes in the canopy's glazing.

While the small .303 in (7.7 mm) calibre made these tail turret guns less effective than hoped, rear-gunners also maintained a watch for fighters and the pilot would make evasive manoeuvres such as corkscrews.

The Jägerfaust system, firing 50 mm (2 in) projectiles vertically into the lower sides of bombers, was triggered by an optical device as the pilot passed beneath the target.

The Ju 88 G-6 was guided into position from sighting and final approach by commands from the radar operator, with the pilot only taking over when visual contact was made just prior to firing.

[18] By mid-1944, He 219 aircrew were critical of the MK 108 installation, because its low muzzle velocity and limited range, meant that the night fighter had to be close to the bomber to attack and be vulnerable to damage from debris.

"To overcome some of the problems, many NJG pilots closed the range at a lower level, below the Monica zone of coverage, until they could see the bomber above; then they pulled up into a climb with all front guns blazing.

He ordered that the mid-upper turrets be removed and the "displaced gunner would lie on a mattress on the floor as an observer, looking through a perspex blister for night fighters coming up from below".

[10] Some early Lancaster B. IIs had retained the FN.64 ventral turret but its sighting periscope provided an overly tight field of view that left the gunner blind, and the traverse speed was too slow, making it useless.

NJG 4 was operating from Gutersloh (later an RAF base) and in the space of 20 minutes, between 20.43 and 21.03, Schnaufer and his crew, using their upward firing cannons [from a Bf 110G night fighter], shot down seven Lancasters.

On 21 May 1943, at about the same time as the Luftwaffe's Oberleutnant Schoenert had his first victory with Schräge Musik in Europe, the field-modified J1N1-C KAI shot down two B-17s of the 43rd Bomb Group who were attacking air bases around Rabaul.

Air Ministry Specification F.9/37 led to the second, Rolls-Royce Peregrine powered, prototype of the Gloster G39 having its armament installed at an angle of +12° for 'no-allowance' firing – three dorsal 20mm cannon in the fuselage and two in the nose.

Similar logic lay behind Air Ministry specification F11/37, which specified a turret-mounted cannon armament: of three companies who tendered (Armstrong Whitworth and Bristol) had turrets that could only traverse through the forward hemisphere, as did Air Ministry specification F22/39, written around the Vickers Type 414 twin-engined fighter, which combined a streamlined monoplane two-seater fighter airframe with a remotely controlled 40mm cannon in the nose that could be elevated for no-allowance shooting.

[32] The American Northrop P-61 Black Widow night fighter could deliver a Schräge Musik-like surprise of its own, because of the design of its remote dorsal turret carrying a quartet of .50 caliber Browning M2 machine guns, that could elevate to a full 90° position.

[35][better source needed] In 1947, the United States Air Force tested a Schräge Musik gun installation on a Lockheed F-80A Shooting Star standard "day fighter" aircraft (s/n 44-85044) to study the ability to attack Soviet bombers from below.

[36] A final attempt to exploit a fully traversing turret was found in the original 1948 design of the Curtiss-Wright XF-87 Blackhawk all-weather jet fighter interceptor.

[38] Freeman Dyson, who was an analyst for Operations research of RAF Bomber Command in World War II, commented on the effectiveness of Schräge Musik: The cause of losses... killed novice and expert crews impartially.