A synchronization gear (also known as a gun synchronizer or interrupter gear ) was a device enabling a single-engine tractor configuration aircraft to fire its forward-firing armament through the arc of its spinning propeller without bullets striking the blades. This allowed the aircraft, rather than the gun, to be aimed at the target.
155-527: 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 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 (e.g., jazz ). The standard usage of
310-472: A "follower" on this cam wheel. At the same time the machine gun used was also changed – an lMG 08 machine gun, the so-called "Spandau", replacing the Parabellum used with the prototype gear. At this time the Parabellum was still in very short supply, and all available examples were required as observers' guns, the lighter and handier weapon being far superior in this role. The first victory using
465-415: A "safe" period, when the blades of the propeller were well out of the way, and this adjustment had to be checked at intervals, especially if the propeller was changed or refitted, as well as after a major engine overhaul. Faults in this adjustment (for example, a cam wheel slipping a millimetre or two, or a pushrod flexing) could well result in every bullet fired hitting the propeller, a worse result than if
620-482: A "safe" range before firing, otherwise risking speedy destruction of his propeller. The second requirement was for a gun that would reliably fire (or hold its fire) exactly when required. Not all automatic weapons were equally amenable to synchronization. When it was ready to fire, a synchronized machine-gun needed to have a round in the breech, the breech closed, and the action cocked (the so-called " closed bolt " position). Several widely used automatic weapons (notably
775-598: A consequence, fighters at the time had cannons added back in external "gun pods", and virtually all fighter aircraft retain autocannons in integral internal mounts to this day. After the Second World War, autocannons continued to serve as a versatile weapon in land, sea, and air applications. Examples of modern autocannons include the 25 mm Oerlikon KBA mounted on the IFV Freccia , the M242 Bushmaster mounted on
930-406: A contrast with SCHRÄGE MUSIK! Again the technique was to approach deliberately at a lower level, but this time all the night fighter pilot had to do was slow up a little, rise up below the bomber and hold formation. An NJG expert could follow his observer's directions, acquire the bomber visually, close and destroy it within 60 seconds. The firing position, with the bomber 65° to 70° above the fighter,
1085-588: A cyclic rate of 800 or 1,000 rounds a minute, it was necessary to supply at least one impulse (if not two) for every rotation of the propeller, making it more liable to failure. The intricate mechanism of a mechanical linkage system, especially of the "push rod" type, could easily shake itself to pieces when driven at this rate. The final version of the Fokker Eindecker, the Fokker E.IV , came with two lMG 08 "Spandau" machine guns ; this armament became standard for all
1240-518: A flexible drive, a column of hydraulic fluid, a cable, or an electrical connection. Generally, mechanical systems were inferior to hydraulic or electric ones, but none were ever entirely foolproof, and synchronization gears at best always remained liable to occasional failure. The Luftwaffe ace Adolf Galland in his memoir of the war period The First and the Last describes a serious faulty synchronization incident in 1941. A pilot would usually only have
1395-511: A forward 30° angle, also placed in the fuselage behind the cabin. The Type 99 20mm calibre autocannon ordnance used by Japanese aircraft was based on the drum-magazine fed Swiss Oerlikon FF ordnance which was itself the basis for the Germans' own MG FF weapon, used to pioneer Schräge Musik for the Luftwaffe. The Japanese Army Air Force Mitsubishi Ki-46 "Dinah" twin engined fighter was used to test
1550-468: 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. This demanded fine judgement, gave only a second or two of firing time and almost immediately brought the fighter up behind the bomber's tail turret. Schräge Musik produced devastating results, with its most successful deployment in the winter of 1943–1944. This
1705-415: A machine gun's rate of fire exactly proportional to the revolutions per minute of a spinning aircraft propeller, would require an impractical level of complexity. A machine gun normally fires a constant number of rounds a minute, and while this may be changed by modifying the gun, it cannot be varied at will while the gun is operating. The rate of rotation of an aircraft propeller, meanwhile, especially before
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#17328510931061860-627: A method of firing forward through a tractor propeller was the Swiss engineer Franz Schneider , formerly with Nieuport , but by then working for the LVG Company in Germany. The patent was published in the German aviation magazine Flugsport in 1914, meaning that the concept became public knowledge at an early stage. The linkage between the propeller and the gun is achieved with a spinning drive shaft, rather than
2015-408: A mirror above his head, parallel to a similar mirror placed behind the gunsight (where the eye would normally be), which was further to the rear, functioning together in the manner of a periscope . 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. What
2170-586: A modern autocannon ranges from 90 rounds per minute , in the case of the British RARDEN, to 2,500 rounds per minute with the GIAT 30 . Rotary systems with multiple barrels can achieve over 10,000 rounds per minute (the Russian GSh-6-23 , for example). Such extremely high rates of fire are effectively employed by aircraft in aerial dogfights and close air support on ground targets via strafing attacks, where
2325-419: A new tactic to avoid the turret guns: instead of approaching directly from the rear they would approach about 1,500 ft (460 m) below the bomber, pull up sharply and start firing when the nose of the bomber appeared in the gunsight. As the fighter slowed and the bomber passed over them, its wings were sprayed with cannon or machine gun rounds. While effective, this manoeuvre was difficult to perform, there
2480-465: A rate of over 200 rounds a minute: much faster than conventional artillery while possessing a much longer range and more firepower than the infantry rifle . In 1913, Reinhold Becker and his Stahlwerke Becker firm designed the 20mm Becker cannon , addressing the German Empire 's perceived need for heavy-calibre aircraft armament. The Imperial Government's Spandau Arsenal assisted them in perfecting
2635-425: A reciprocating rod. The impulses needed to operate the trigger, or in this case to prevent the trigger from operating, are produced by a cam wheel with two lobes at 180° apart situated at the gun itself since firing is to be interrupted by both blades of the propeller. No attempt was made (so far as is known) to build or test an actual operating gear based on this patent, which attracted little or no official interest at
2790-548: A remotely controlled nose-mounted 40mm cannon that could be elevated for no-allowance [1] 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, and the equipment that can do the one can, generally speaking, be arranged so as to do
2945-492: A role to which they were suited as tank armour is often lightest on top. The Polish 20 mm 38 Fk auto cannon was expensive to produce, but an exception. Unlike the Oerlikon, it was effective against all the tanks fielded in 1939, largely because it was built as an upgrade to the Oerlikon, Hispano-Suiza, and Madsen. It even proved capable of knocking out early Panzer IIIs and IVs, albeit with great difficulty. Only 55 were produced by
3100-453: A semi-automatic weapon rather than a completely automatic one. The third requirement is for a linkage between the "machines" (engine and gun) to be synchronized. Many early gears used an intricate and inherently fragile bell crank and push rod linkage that could easily jam or otherwise malfunction, especially when required to work at higher speeds than it had been designed for. There were several alternative methods, including an oscillating rod,
3255-524: A short period of time. The development of guided missiles was thought to render cannons unnecessary and a full generation of western fighter aircraft was built without them. In contrast, all Eastern Bloc aircraft kept their guns. During the Vietnam War , however, the United States Air Force realized that cannons were useful for firing warning shots and for attacking targets that did not warrant
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#17328510931063410-552: A similar manoeuvre to the later German Schräge Musik attacks, more often from slightly ahead or to one side, rather than from directly under the tail. During the Blitz on London of 1940–1941, the Defiant equipped four squadrons, shooting down more enemy aircraft than any other type. The Defiant Mk II was fitted with AI.IV radar and a Merlin XX engine. A total of 207 Defiant Mk IIs were built but
3565-407: A single cannon shell with a high-explosive payload could instantly sever essential structural elements, penetrate armour or open up a fuel tank beyond the capacity of self-sealing compounds to counter, even from fairly long range. (Instead of explosives, such shells could carry incendiaries, also highly effective at destroying planes, or a combination of explosives and incendiaries.) Thus by the end of
3720-403: A single gun, firing at a modest cyclic rate through a two-bladed propeller driven by a rotary engine, was becoming obsolete. Stangensteuerung gears for "stationary", i.e. , in-line engines, worked from a small cam immediately behind the propeller (see illustration). This produced a basic dilemma: A short, fairly robust push rod meant that the machine gun had to be mounted well forward, putting
3875-404: A single shot. The majority of these impulses would catch the gun in the process of ejecting a spent round or loading a fresh one, and would thus have no effect; but as soon as the firing cycle was completed, the gun would be ready to fire as soon as it received the next impulse from the synchronizing gear. The delay between the end of the firing cycle and the arrival of the next firing impulse slowed
4030-694: 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
4185-408: A synchronized "aircraft" gun such a delay can produce a rogue firing, sufficiently "out of time" for it to risk hitting the propeller. A very similar problem could arise where the mass of a special round (such as an incendiary or explosive one) was different enough to produce a substantial difference in muzzle velocity. This was compounded by the additional risk to the integrity of the propeller due to
4340-525: A synchronized gun-equipped fighter is now believed to have occurred on 1 July 1915 when Leutnant Kurt Wintgens of Feldflieger Abteilung 6b , flying the Parabellum-armed Fokker M.5K/MG aircraft "E.5/15", forced down a French Morane-Saulnier Type L east of Lunéville . Exclusive possession of a working gun synchronizer enabled a period of German air superiority on the Western Front known as
4495-477: A wide spread of fire that would have been impossible to match with the "safe zone" between the whirling propeller blades. Fokker's initial answer to this was the fitting of extra "followers" to the Stangensteuerung's large cam wheel, to (theoretically) produce the "ripple" salvo necessary to ensure that the guns were aimed at the same point on the propeller disc. This proved a disastrously unstable arrangement in
4650-422: Is likely that an aircraft which is capable of shooting at an enemy machine will have the advantage. The most suitable weapon is a light, air-cooled machine-gun What was not generally agreed on was the superiority, at least for an attacking aircraft, of fixed forward-firing guns, aimed by pointing the aircraft at its target, rather than flexible weapons, aimed by a gunner other than the pilot. The idea of coupling
4805-407: Is regarded as the archetypal modern revolver cannon . With multiple chambers and a single barrel, autocannons using the revolver principle can combine a very high rate of fire and high acceleration to its maximum firing rate with low weight, at cost of a reduced sustained rate of fire compared to rotary cannon. They are therefore used mainly in aircraft for AA purposes, in which a target is visible for
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4960-458: Is typically fed from a belt system to reduce reloading pauses or for a faster rate of fire , but magazines remain an option. Common types of ammunition, among a wide variety, include HEIAP , HEDP and more specialised armour-piercing (AP) munitions, mainly composite rigid ( APCR ) and discarding sabot ( APDS ) rounds. Capable of generating extremely rapid firepower , autocannons overheat quickly if used for sustained fire, and are limited by
5115-540: The Inspektion der Fliegertruppen ( Idflieg ) at Döberitz near Berlin . Inspection of the propeller from Garros' machine prompted Idflieg to attempt to copy it. Initial trials indicated that the deflector wedges would not be sufficiently strong to cope with the standard steel-jacketed German ammunition, and representatives from Fokker and Pfalz, two companies already building Morane copies (although, strangely, not Schneider's LVG concern) were invited to Döberitz to inspect
5270-582: The Fokker Scourge . The German high command was protective of the synchronizer system, instructing pilots not to venture over enemy territory in case they were forced down and the secret revealed, but the basic principles involved were already common knowledge, and by the middle of 1916 several Allied synchronizers were already available in quantity. By this time, the Fokker Stangensteuerung gear, which had worked reasonably well for synchronizing
5425-610: The German D-type scouts starting with the Albatros D.I . From the appearance of the Sopwith Camel and the SPAD S.XIII in mid-1917, right through to the end of gun synchronization in the 1950s, a twin gun installation was the international norm. Having the two guns firing simultaneously would obviously not have been a satisfactory arrangement. The guns needed to both fire at the same point on
5580-536: The Lewis gun and the Italian Revelli ) were triggered from an open bolt , with an unpredictable interval between triggering and firing, and were thus not suitable for synchronization without extensive modification. In practice it was found necessary for the gun to be fired in semi-automatic mode. As the propeller revolved, a series of firing impulses was transmitted to the gun, each of which could trigger it to fire
5735-610: The M2/M3 Bradley , updated versions of the Bofors 40 mm gun , and the Mauser BK-27 . The 20 mm M61A1 is an example of an electrically powered rotary autocannon. Another role that has come into association with autocannons are that of close-in weapon systems on naval vessels, which are used to destroy anti-ship missiles and low flying aircraft. Synchronization gear There were many practical problems, mostly arising from
5890-562: The Messerschmitt 410 Hornisse (Hornet) bomber destroyer. 300 examples of the BK 5 cannon were built, more than all other versions. The PaK 40 semi-automatic 7.5 cm calibre anti-tank gun was the basis for the BK 7,5 in the Junkers Ju 88 P-1 heavy fighter and Henschel Hs 129 B-3 twin engined ground attack aircraft. The German Mauser MK 213 was developed at the end of the Second World War and
6045-534: The Nachtjagdgeschwadern (NJG, night fighter wings) were equipped with heavy fighters fitted with radar in the nose and a combination of front-firing and defensive weapons. In the standard interception, the fighter approached the target from the rear to get into a firing position, presenting the night fighter crew with a much smaller target, a problem compounded by the Royal Air Force bombers (such as
6200-581: The Oerlikon 20 mm , the Bofors 40 mm and various German Rheinmetall autocannons would see widespread use by both sides during the Second World War; not only in an anti-aircraft role, but as a weapon for use against ground targets as well. Heavier anti-aircraft cannon had difficulty tracking fast-moving aircraft and were unable to accurately judge altitude or distance, while machine guns possessed insufficient range and firepower to bring down aircraft consistently. Continued ineffectiveness against aircraft despite
6355-606: The Schräge Musik armament format in its Ki-46 III KAI version in June 1943, using a 37 mm Ho-203 cannon with 200 rounds of ammunition, the largest calibre autocannon used for Schräge Musik-type operations. It was mounted in a similar position in the fuselage as the Luftwaffe's night fighters. Operational deployment began in October 1944. One of the main Japanese fighters using this device
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6510-464: The Whitley and Wellington medium bombers) first being fitted with twin-gun hydraulic tail turrets, later upgraded to four guns to fend off just such attacks. 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. Night-fighter pilots developed
6665-516: The 43rd Bomb Group who were attacking air bases around Rabaul. The Navy took immediate notice and placed orders with Nakajima, for the newly designated J1N1-S night fighter design. This model was christened the Model 11 Gekkō (月光, Moonlight). It required only two crew and like the KAI, had a 20-millimetre (0.79 in)-calibre twinned pair of Type 99 Model 1 cannon firing upward and a second pair firing downward at
6820-576: The 62 bombers lost out of the 800 despatched. In 1943, Commander Yasuna Kozono of the 251st Kōkūtai , Imperial Japanese Navy in Rabaul came up with the idea of converting the Nakajima J1N (J1N1-C) Irving into a night fighter. 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
6975-584: 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 . Later similar Japanese experiments with upward-firing cannons on their night fighters in 1944 (intended to target the American B-29 Superfortress fleet firebombing Japan by night ) were largely fruitless, owing to
7130-522: The B-29's notably superior speed and altitude. 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. The crews that survived such attacks, during this period, often believed that damage and casualties had been caused by ground-based anti-aircraft artillery (AA or AAA), rather than fighters, and much confusion resulted until
7285-503: The Baltic Sea coast through 1942. An angle between 60° and 75° was found to give best results, allowing a target turning at 8°/sec to be kept in the gunsight. 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
7440-501: The Defiant into service in 1939, intending to use it against bombers, despite the bombers' numerous gun positions. However, the unexpected German territorial gains in France meant that bombers were escorted by fighters. 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
7595-422: The Defiant was retired as radar-equipped Beaufighter and Mosquito night fighters entered service in 1941 and 1942. Turret fighters with four 20mm cannon were specified under F.11/37 but got no further than a scaled prototype . A Douglas Havoc , BD126 , was fitted with six upward-firing machine guns in the fuselage behind the cockpit. The guns could be controlled in elevation from 30–50 degrees and 15 degrees in
7750-523: The Eindecker led to numerous gun synchronization devices, culminating in the reasonably reliable hydraulic British Constantinesco gear of 1917. By the end of the First World War , German engineers were well on the way to perfecting a gear using an electrical rather than a mechanical or hydraulic link between the engine and the gun, with the gun triggered by an electro-mechanical solenoid . From 1918 to
7905-453: The F-89 design abandoned the swiveling nose turret in favor of a more standard front-firing cannon arrangement. A similar design – with .50 caliber machine guns – would also be tested on a United States Navy Grumman F9F Panther . 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
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#17328510931068060-632: 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. A small number of Halifax and Lancaster bombers were fitted with a machine-gun mounted to fire through the hole where the turret would have been, normally of .303 in (7.70 mm) although Canadian units tended to use the 0.50 in (12.7 mm) machine gun. Initially these were unofficial, but Mod 925 provided an official modification in aircraft not equipped with H2S bombing radar , which covered
8215-498: The MK 108s be removed and replaced by MG FF/Ms or the angle of the mounting be changed. Although He 219s continued to be delivered with the twin 30 mm mounted, these were removed by front line units. Using the Schräge Musik required precise timing and swift evasion; a fatally damaged bomber could fall on the night fighter if the fighter could not quickly turn away. The He 219 was particularly prone to this; its high wing loading left it at
8370-538: The Me 163 were promising, with six operational aircraft modified. On 10 April 1945, a Halifax bomber was shot down by Fritz Kelb flying a Jägerfaust -equipped Me 163B, most probably from I. Gruppe / JG 400 operating from Brandis, Germany . As experimental aircraft were developed as night fighters, such as the Horten Ho 229 , a Schräge Musik system was incorporated from the start. The experimental Horten Ho 229 flying wing series
8525-550: The Parabellum gun, synchronized with the first version of the Fokker gear. This prototype gear had such a short life that a redesign was necessary, producing the second, more familiar, production form of the gear. The gear used in the production Eindecker fighters replaced the oil pump's mechanical driveshaft-based system with a large cam wheel, almost a light flywheel, driven directly from the spinning rotary engine's crankcase . The push rod now took its reciprocating motion directly from
8680-506: The Saulnier patent, Fokker's gear was designed to actively fire the gun rather than interrupt it, and, like the later Vickers-Challenger gear developed for the RFC, it followed Saulnier in taking its primary mechanical drive from the oil pump of a rotary engine. The "transmission" between the motor and the gun was by a version of Saulnier's reciprocating push-rod. The main difference was that instead of
8835-491: 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
8990-498: 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. The Boulton Paul Defiant "turret fighter" was originally conceived under the F.9/35 specification for a "two-seat day and night fighter" to defend Great Britain against massed formations of unescorted enemy bombers. Regardless of
9145-593: 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
9300-553: 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 . For this purpose a .303 in (7.7 mm) air-cooled Lewis gun was mounted in front of the pilot, firing upward. Exploitation of this led to the destruction of six German airships between September and December 1916. Later British night fighters were similarly armed with upward-firing guns. Several tractor-configured single-seat biplanes of
9455-478: The ability to attack Soviet bombers from below. Twin 0.5 in (12.7 mm) machine guns were fixed in an oblique mount. 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. Armament was to be a nose-mounted, powered turret containing four 20 mm (.79 in) cannon, but this installation
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#17328510931069610-497: The action of a semi-automatic weapon. It has been pointed out that this was a practical design that should have worked, but it did not. Apart from possible inconsistencies in the ammunition supplied, the real problem was that the gun used to trial the gear, a gas-operated Hotchkiss 8 mm (.323 in) machine gun borrowed from the French army, was fundamentally unsuitable for "semi-automatic" firing. Following initial unsuccessful tests,
9765-502: The adjective schräg is often translated as " slanting " or " oblique ", but its slang usage is often translated as "weird" or "strange". 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
9920-408: The advantage that the bomber crew could not see them against the dark ground or sky, yet allowed the German crew to see the silhouette of the aircraft before they attacked. The optimum target for the night fighter was the wing fuel tanks, not the fuselage or bomb bay, because of the risk that exploding bombs would damage the attacker. "To overcome some of the problems, many NJG pilots closed the range at
10075-407: The advent of the constant-speed propeller , could vary widely, depending on the throttle setting and what maneuvers were being performed. Even if it had been feasible to pick a particular point on an aircraft engine's tachometer at which a machine gun's cyclic rate would permit it to fire through the propeller arc, this would be very limiting. It has been pointed out that any mechanism that achieved
10230-504: The airborne radar operators to whom fell the task of final location of individual targets. The path of the returning bomber stream was clearly marked by the pyres of numerous downed victims. 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. As it was, on that black night, four night fighter crews accounted for 28 of
10385-509: The amount of ammunition that can be carried by the weapons systems mounting them. Both the US 25 mm M242 Bushmaster and the British 30 mm RARDEN have relatively slow rates of fire so as not to deplete ammunition too quickly. The Oerlikon KBA 25 mm has a relatively mid-high rate of fire 650 rounds per minute but can be electronically programmed to 175-200 rounds per minute. The rate of fire of
10540-481: The arc of the propeller, and even efforts, doomed to failure, to synchronize the Lewis Gun which was at the time the "standard" British aircraft weapon – was the expedient of firing straight through the propeller arc and "hoping for the best". A high proportion of bullets would in the normal course pass the propeller without striking the blades, and each blade might typically take several hits before there
10695-538: The azimuth by the gunner in the nose. The aircraft was tested at the A&;AEE in 1941 and then by the GRU and Fighter Interception Unit. 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. The Northrop F-89 Scorpion
10850-454: The bomber stream, to pick up radar emissions from the German night fighters. Wing Commander J. D. Pattinson of 429 "Bison" Squadron, recognized an unseen danger but to him, it "was all presumption, not fact". 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". Some early Lancaster B. IIs had retained
11005-404: The breech of the gun out of the pilot's reach for clearing jams. If the gun was mounted in the ideal position, within easy reach of the pilot, a much longer push rod was required, which tended to bend and break. The other problem was that the Stangensteuerung never worked well with more than one gun. Two (or even three) guns , mounted side by side and firing simultaneously , would have produced
11160-523: The case of three guns, and was rather less than satisfactory, even for two. Most of the early Fokker and Halberstadt biplane fighters were limited to a single gun for this reason. In fact, the builders of the new Albatros twin-gunned stationary-engine fighters of late 1916 had to introduce their own synchronization gear, known as the Hedtke gear or Hedtkesteuerung , and it was evident that Fokker were going to have to come up with something radically new. This
11315-467: The cause was successfully pinpointed. During World War I , pusher-configured fighter aircraft with flexibly-mounted forward-firing machine guns (especially the Royal Aircraft Factory F.E.2s ), enabled gunners to discover the principle of zero-deflection shooting. When firing upward at roughly a 45° elevation, when the attacking aircraft and its target are travelling at about the same speed and
11470-579: 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 ,
11625-405: The current historical consensus points to a synchronization device having been in development by Fokker's team (including engineer Heinrich Lübbe ) prior to the capture of Garros's machine. Whatever its ultimate source, the initial version of the Fokker synchronization gear (see illustration) very closely followed, not Schneider's patent, as claimed by Schneider and others, but Saulnier's . Like
11780-415: The deflector blades must have put undesirable stress on the engine's crankshaft. On 1 April 1915 Garros shot down his first German aircraft, killing both the crew. On 18 April 1915, after two more victories, Garros was forced down (by ground fire) behind German lines. Although he was able to burn his aircraft, Garros was captured and his special propeller was sufficiently intact to be sent for evaluation by
11935-502: The earlier phases of the war, the Japanese aircraft they dealt with were not only unusually lightly built but went without either armour plate or self-sealing tanks in order to reduce their weight. Nevertheless, the U.S. also adopted planes fitted with autocannon, such as the Lockheed P-38 Lightning, despite experiencing technical difficulties with developing and manufacturing these large-calibre automatic guns. Weapons such as
12090-523: The edge of stalling speed when matching the Lancaster's cruising speed, and therefore quite unmaneuverable. The same was true to a lesser extent of other Luftwaffe types such as the Ju 88, which was considered quite a "hot ship" by its crews. This was also a problem during normal stern attacks at low closure rate, but it was even more exaggerated during Schräge Musik attacks, since the pilot could not even make use of
12245-412: The end of 1915 , almost entirely replaced wood and fabric biplanes . At the same time as they began to be made from stronger materials, the machines also increased in speed, streamlining, power and size, and it began to be apparent that correspondingly more powerful weapons would be needed to counter them. Conversely, they were becoming much better able to carry exactly such larger and more powerful guns;
12400-417: 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, 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
12555-464: The expenditure of a (much more expensive) missile, and, more importantly, as an additional weapon if the aircraft had expended all its missiles or enemy aircraft were inside of the missiles' minimum target acquisition range in a high-G close range engagement. This was particularly important with the lower reliability of early air-to-air missile technology, such as that employed during the Vietnam War. As
12710-470: The failings of the first form of the gear had become clear, Fokker's team had adapted the new system to the new Parabellum MG14 machine gun, and fitted it to a Fokker M.5K , a type which was at the time serving in small numbers with the Fliegertruppen as the A.III. This aircraft, bearing IdFlieg serial number A.16/15 became the direct forerunner to the five M.5K/MG pre-production prototypes built, and
12865-414: The feat of firing between the whirling blades of a propeller without striking them could be described as "interrupting" the fire of the gun (to the extent that it no longer actually works as an automatic weapon at all), and also as "synchronizing", or "timing" its fire to coincide with the revolutions of the propeller. A typical synchronizing gear had three basic components. First, a method of determining
13020-448: The firing impulses were sometimes timed to occur at every two or three revolutions of the propeller, or, especially in the case of hydraulic or electric gears, at the rate of two or more for each revolution. The diagrams in this section assume, for simplicity's sake, one impulse for one revolution, so that each synchronized round is "aimed" at a single spot on the propeller disc. The timing of each impulse had to be adjusted to coincide with
13175-450: The firing mechanism to the propeller's rotation is an affectation. The objection is the same as to any gun position which is fixed along the longitudinal axis of the aircraft: the pilot is forced to fly directly at the enemy in order to fire. Under certain circumstances this is highly undesirable. As late as 1916, pilots of the DH.2 pusher fighter had problems convincing their senior officers that
13330-415: The form of steel wedges which deflected the bullets which might otherwise have damaged the propeller, or ricocheted dangerously. Garros himself and his personal mechanic Jules Hue are sometimes credited with testing and perfecting the "deflectors". This crude system worked after a fashion, although the wedges diminished the propeller's efficiency, and the not inconsiderable force of the impact of bullets on
13485-426: The forward-firing armament of their aircraft was more effective if it was fixed to fire forward rather than being flexible. On the other hand, August Euler had patented the idea of a fixed gun as early as 1910 – long before tractor aircraft became the norm, illustrating his patent with a diagram of a machine gun-armed pusher . Whether directly inspired by Euler's original patent or not, the first inventor to patent
13640-521: The front of a single-engine aircraft's fuselage , guns began to be mounted in the wings instead, firing outside the arc of the propeller so not requiring synchronising. Synchronizing became unnecessary on all aircraft with the introduction of propellerless jet propulsion . A mechanism to enable an automatic weapon to fire between the blades of a whirling propeller is usually called an interrupter or synchronizer gear. Both these terms are more or less misleading, at least insofar as explaining what happens when
13795-576: The fuselage or wings. The 37 mm BK 3,7 cannon, based on the German Army's 3.7 cm FlaK 43 anti-aircraft autocannon was mounted in pairs in underwing gun pods on a small number of specialized Stuka Panzerknacker (tank buster) aircraft. The BK 5 cm cannon , based on the 5 cm KwK 39 cannon of the Panzer III , was installed in Ju 88P bomber destroyers , which also used other Bordkanone models, and in
13950-426: The gear functions. The term "interrupter" implies that the gear pauses, or "interrupts" the fire of the gun at the point where one of the blades of the propeller passes in front of its muzzle. Even the relatively slowly revolving propellers of First World War aircraft, however, typically turned twice or even three times for each shot a contemporary machine gun could fire. A two-bladed propeller would therefore obstruct
14105-501: The gun and firing it with the "normal" trigger rather than the remote Bowden cable used for forward firing. These could then be used to attack enemy aircraft from the blind spot below the tail. Most notable of the airplanes used were the Nieuport 11 , 16 and 17 and 23 fighters from 1915 onwards, and the tactic was continued in British service, with the Royal Aircraft Factory S.E.5s and Sopwith Dolphin . That Dolphin entered service near
14260-552: The gun had to be returned, and the experiments ceased. When the pilots of the British Royal Flying Corps and Royal Naval Air Service arrived in France in 1914, they were equipped with pusher aircraft too underpowered to carry machine guns and still have a chance of overtaking the enemy, and tractor aircraft which were difficult to arm effectively because the propeller was in the way. Among other attempts to get around this – such as firing obliquely past
14415-407: The gun is situated at the engine (driven in this case by the same spindle that operated the oil pump and the tachometer) and the impulses themselves are transmitted by a reciprocating rod rather than Schneider's rotating shaft. The idea of literally "interrupting" the firing of the gun gives way (probably as the result of experience) to the principle of pulling the trigger for each successive shot, like
14570-459: The gun six times every firing cycle of the gun, a four-bladed one twelve times. A gun set up this way would be interrupted more than forty times per second, while firing at only around seven rounds per second. Unsurprisingly, the designers of so-called interrupter gears found this too problematic to be seriously attempted, as the gaps between "interruptions" would have been too short to allow the gun to fire at all. True synchronization, though, with
14725-423: The gun was fired through the propeller with no control at all. The other main type of failure resulted in fewer or no firing impulses, usually due to the generator or linkages either jamming or breaking. This was a common cause of synchronized guns "jamming". The speed of the propeller, and thus the distance that it travelled between the firing of the gun and the arrival of the bullet at the propeller disc, varied as
14880-546: The gun. The firing button for the gun simply engaged a clutch at the engine which set the flexible drive (and thus the trigger motor) in motion. In some ways this brought the new gear closer to the original Schneider patent (q.v.) . A major advantage was that the adjustment (to set where on the propeller's disc each bullet was to impact) was now in the gun itself. This meant that each gun was adjusted separately, an important feature, since twin synchronized guns were not set to be fired in strict unison, but when they were pointing at
15035-483: The guns in aircraft failed, as the weight severely limited both speed and altitude, thus making successful interception impossible. The more effective QF 2 pounder naval gun would be developed during the war to serve as an anti-aircraft and close range defensive weapon for naval vessels. Autocannons would serve to a much greater extent and effect during the Second World War . The German Panzer II light tank, which
15190-520: The ideas of August Euler , who seems to have been the first to suggest mounting a fixed armament firing in the direction of flight (in 1910). However, the first practical – if far from reliable – gear to enter operational service was that fitted to the Fokker Eindecker fighters , which entered squadron service with the German Air Service in mid-1915. The success of
15345-516: The inherently imprecise nature of an automatic gun 's firing, the great (and varying) velocity of the blades of a spinning propeller, and the very high speed at which any gear synchronizing the two had to operate. In practice, all known gears worked on the principle of actively triggering each shot, in the manner of a semi-automatic weapon . Design and experimentation with gun synchronization had been underway in France and Germany in 1913–1914, following
15500-427: The introduction of self sealing fuel tanks provided reliable protection against these small projectiles. These new defenses, synergistically with the general robustness of new aircraft designs and of course their sheer speed, which made simply shooting them accurately in the first place far more difficult, entailed that it took a lot of such bullets and a fair amount of luck to cause them critical damage; but potentially
15655-466: The large numbers installed during the second World War led, in the West, to the removal of almost all shipboard anti-aircraft weapons in the early post-war period. This was only reversed with the introduction of computer-controlled systems. The German Luftwaffe deployed small numbers of the experimental Bordkanone series of heavy aircraft cannon in 37, 50 and 75 mm calibres, mounted in gun pods under
15810-419: The limited climb performance available at the edge of the flight envelope to avoid debris from the stricken target. Schräge Musik allowed German night fighters to attack undetected, using special ammunition with a faint glowing trail replacing the standard tracer, combined with a "lethal mixture of armour-piercing, explosive and incendiary ammunition". Approaching from below provided the night fighter crew with
15965-513: The lower sides of bombers, was triggered by an optical device as the pilot passed beneath the target. This was tested on the Fw 190, and was destined for installation in the Messerschmitt Me 163 B and the Me 262B. The definitive night fighter version of the Messerschmitt Me 262 , the Me 262B-2, was also designed to carry such an installation but it did not work and was not used operationally. Trials with
16120-473: The mechanism and suggest ways that its action might be duplicated. Anthony Fokker was able to persuade Idflieg to arrange the loan of a Parabellum machine gun and ammunition so that his device could be tested, and for these items to be transported forthwith to the Fokker Flugzeugwerke GmbH at Schwerin (although probably not in his railway compartment or "under his arm", as he claimed after
16275-419: The mid-1930s the standard armament for a fighter aircraft remained two synchronized rifle-calibre machine guns , firing forward through the arc of the propeller. In the late 1930s, however, the main role of the fighter was increasingly seen as the destruction of large, all-metal bombers , for which this armament was inadequate. Since it was impractical to fit more than two guns in the limited space available in
16430-477: The more powerful 30 mm (1.2 in) calibre, short-barrelled MK 108 cannon , such as those fitted to the Heinkel He 219 , fully contained within the fuselage. 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. They demanded that either
16585-409: The nature of the round. The "trigger motor" could theoretically take two forms. The earliest patent (Schneider 1913) assumed that the synchronization gear would periodically prevent the gun from firing , thus operating as a true, or literal "interrupter". In practice all "real-life" synchronization gears, for which we have reliable technical details, directly fired the gun : operating it as if it were
16740-458: The night of June 12/13, 1944 and were headed for base. In the tail gun turret I was searching in the dark for any enemy fighters who might be following us out of the target area. Suddenly I heard cannons barking loudly and saw lights flashing directly below. What the hell was that? I didn't see the fighter – just the flashing. We took evasive action and that was it. — Air Gunner Leonard J. Isaacson. Schräge Musik (or Schrägwaffen , as it
16895-561: The official dogma... I blame the ORS and I blame myself in particular, for not taking this result seriously enough... If we had taken the evidence more seriously, we might have discovered Schräge Musik in time to respond with effective countermeasures. Autocannon An autocannon , automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large- caliber (20 mm/0.79 in or more) armour-piercing , explosive or incendiary shells , as opposed to
17050-569: The ordnance. Although only about 500+ examples of the original Becker design were made during World War I, the design's patent was acquired by the Swiss Oerlikon Contraves firm in 1924, with the Third Reich's Ikaria-Werke firm of Berlin using Oerlikon design patents in creating the MG FF wingmount cannon ordnance. The Imperial Japanese Navy 's Type 99 cannon , adopted and produced in 1939,
17205-462: 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 performance penalties. The RAF put
17360-453: The pilot, firing upwards for night fighter combat. 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. While it was a promising aircraft in its own right, by the time that the second prototype
17515-404: The position of the propeller at a given instant was required. Typically, a cam , driven either directly from the propeller shaft itself, or from some part of the drive train revolving at the same speed as the propeller, generated a series of impulses at the same rate as the propeller's revolutions. There were exceptions to this. Some gears placed the cam within the gun trigger mechanism itself, and
17670-505: The propeller disc , which means that one had to fire a tiny fraction of a second later than the other. This is why early gears designed for a single machine gun needed to be modified in order to control two guns satisfactorily. In practice, at least part of the mechanism had to be duplicated, even if the two weapons were not synchronized separately. From the beginnings of practical flight, possible military uses for aircraft were considered, although not all writers came to positive conclusions on
17825-409: The push rod passing directly from the engine to the gun itself, which would have required a tunnel through the firewall and fuel tank (as shown in the Saulnier patent drawings), it was driven by a shaft joining the oil pump to a small cam at the top of the fuselage. This eventually proved unsatisfactory, as the oil pump's mechanical drive spindle was insufficiently robust to take the extra load. Before
17980-410: The question of synchronization. Early synchronized guns of the 1915–1917 period had a rate of fire in the region of 400 rounds per minute. At this comparatively leisurely rate of fire a synchronizer can be geared down to deliver a single firing impulse every two or three turns of the propeller, rendering it more reliable without unduly slowing the rate of fire. To control a faster gun, with, for example,
18135-487: The range is fairly short, the trajectory will appear straight. The bullets' true path is a parabola, but the movement forward of both aircraft, and the air passing the aircraft counter the tendency of the round to arc down after leaving the muzzle so it appears to follow a straight line, simplifying accurate sighting which then requires no deflection or leading of the target. The pilots of Royal Aircraft Factory B.E.2 night fighters, after trying various schemes for attacking
18290-491: The rate of engine revolutions changed. Where muzzle velocity was very high, and the guns were sited well forward so that the bullets had a very short distance to reach the disc of the propeller, this difference could be largely ignored. But in the case of relatively low muzzle velocity weapons, or any gun sited well back from the propeller, the question could become critical, and in some cases the pilot had to consult his tachometer, taking care that his engine revolutions were within
18445-565: The rate of fire in comparison with a free-firing machine gun, which fires the moment it is ready to do so; but provided the gear functioned correctly, the gun could fire fairly rapidly between the whirling propeller blades without striking them. Some other machine-guns, such as the Austrian Schwarzlose and the American Marlin , proved less than perfectly adapted to synchronization, although eventually predictable "single shot" firing
18600-478: The rear compartment of the upper fuselage, firing through twin holes in the canopy's glazing. Schönert used such a modified Bf 110 to shoot down a bomber in May 1943. From June 1943, an official conversion kit was produced for the Junkers Ju 88 and Dornier Do 217N fighters. Between August 1943 and the end of the year, Schönert achieved 18 kills with the new gun installation. Before the introduction of Schräge Musik in 1943,
18755-541: The requirement, the use of its dorsal turret was based on the "broadside" fighter interception and combined fighter attack tactic of bomber interception. Attempts to take on single-seat fighters with Defiants led to catastrophic results in 1940 over France and during the Battle of Britain . With such high losses in day operations, the Defiant was transferred to night fighting and there the type achieved some success. Defiant night fighters typically attacked enemy bombers from below, in
18910-432: The smaller-caliber kinetic projectiles ( bullets ) fired by a machine gun . Autocannons have a longer effective range and greater terminal performance than machine guns, due to the use of larger/heavier munitions (most often in the range of 20–60 mm (0.79–2.36 in), but bigger calibers also exist), but are usually smaller than tank guns , howitzers , field guns , or other artillery . When used on its own,
19065-486: The subject. By 1913, military exercises in Britain, Germany, and France had confirmed the likely usefulness of aircraft for reconnaissance and surveillance, and this was seen by a few forward looking officers as implying the need to deter or destroy the enemy's reconnaissance machines. Thus aerial combat was by no means entirely unanticipated, and the machine gun was from the first seen as the most likely weapon to be used. It
19220-554: The target dwell time is short and weapons are typically operated in brief bursts. The first modern autocannon was the British QF 1-pounder , also known as the "pom-pom". This was essentially an enlarged version of the Maxim gun , which was the first successful fully automatic machine gun, requiring no outside stimulus in its firing cycle other than holding the trigger. The pom-pom fired 1 pound (0.45 kg) gunpowder-filled explosive shells at
19375-462: The target in his sights for a fleeting moment, so a concentration of bullets was vital for achieving a "kill". Even flimsy First World War aircraft often took a surprisingly large number of hits to shoot down, and later, larger aircraft were even harder propositions. There were two obvious solutions – to fit a more efficient gun with a higher cyclic rate of fire , or increase the number of guns carried. Both of these measures impinged on
19530-451: The technology of which was in the meantime also developing, providing significantly improved rates of fire and reliability. When the Second World War did break out, it was swiftly realised that the power of contemporary aircraft allowed armour plate to be fitted to protect the pilot and other vulnerable areas. This innovation proved highly effective against rifle-calibre machine gun rounds, which tended to ricochet off harmlessly. Similarly
19685-467: 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. Oberleutnant Rudolf Schoenert of 4./ NJG 2 decided to experiment with upward-firing guns in 1941 and began trying out upward-firing installations, amid scepticism from his superiors and fellow pilots. The first installation
19840-504: The third wave lost 29 of their 166 bombers, well over the 10 per cent losses considered "unsustainable". In this raid 40 aircraft were lost: 23 Lancasters, 15 Halifaxes and two Short Stirlings . Adoption of Schräge Musik began in late 1943 and by 1944, a third of all German night fighters carried upward-firing guns. Schräge Musik proved most successful in the Jumo 213 powered Ju 88 G-6. An increasing number of these installations used
19995-473: 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 ). Both the French mountings and the British Foster mounting allowed a machine gun to be tipped back to reload and whether by accident or design, this allowed the gun to be held at an intermediate angle (ideally about 45°) and fired upward, steadying
20150-616: The time of the Polish Defensive War. However it was in the air war that these weapons played their most important part in the conflict. During the First World War, rifle-calibre machine guns became the standard weapons of military aircraft. In the Second, several factors brought about their replacement by autocannon. During the inter-war years, aircraft underwent extensive evolution and the all-metal monoplane , pioneered as far back as
20305-463: The time. The exact form of the synchronization gear fitted to Schneider's LVG E.I of 1915 and its relationship to this patent is unknown, since no plans survive. Unlike the Schneider patent design, Saulnier's device was actually built, and may be considered the first practical synchronization gear to be tested. For the first time, the cam producing the to-and-fro movement conveying firing impulses to
20460-518: The turret location. Even in the last year of the war, 18 months after the Peenemunde Raid, Schräge Musik night fighters were still taking a heavy toll, for example on the Mitteland – Ems Canal Raid, 21 February 1945, On this particular night the night fighters were to score heavily. The ground radar stations responsible for initial guidance to the vicinity of the bombers did their job well, as did
20615-487: The war). The story of his conception, development and installation of the Fokker synchronization device in a period of 48 hours (first found in an authorised biography of Fokker written in 1929) is not now believed to be factual. Another possible explanation is that Garros's Morane, partly destroyed by fire as it was, had sufficient traces of the original synchronization gear remaining for Fokker to have guessed how it worked. For various reasons this also seems unlikely, and
20770-599: The war, the fighter aircraft of almost all the belligerents mounted cannon of some sort, the only exception being the United States which in most cases favoured the Browning AN/M2 "light-barrel" .50 calibre heavy machine gun . A fighter equipped with these intermediate weapons in sufficient numbers was adequately armed to fulfill most of the Americans' combat needs aloft, as they tended to confront enemy fighters and other small planes far more often than large bombers; and as, in
20925-667: The word "autocannon" typically indicates a non-rotary weapon with a single barrel . When multiple rotating barrels are involved, such a weapon is referred to as a "rotary autocannon" or occasionally " rotary cannon ", for short (particularly on aircraft). Autocannons are heavy weapons that are unsuitable for use by infantry . Due to the heavy weight and recoil , they are typically installed on fixed mounts , wheeled carriages , ground combat vehicles , aircraft , or watercraft , and are almost always crew-served , or even remote-operated with automatic target recognition / acquisition (e.g. sentry guns and naval CIWS ). As such, ammunition
21080-624: Was a risk of collision and, if the bomb load exploded, it could destroy the night fighter. Systems similar to the original Schräge Musik , such as the Sondergerät 500 or Jägerfaust , were tested on day fighters and other airframes, with the largest-calibre upward-firing aerial ordnance in German service, based on the quintuple-launcher of the 21 cm Nebelwerfer infantry barrage rocket, the experimental heavy-bomber based Grosszerstörer (heavy destroyer) also under test. The Jägerfaust system, firing 50 mm (2 in) projectiles vertically into
21235-707: Was a time when Bomber Command losses became unsupportable: the RAF lost 78 of 823 bombers that attacked Leipzig on 19 February, and 96 of the 795 bombers that attacked Nuremberg on 30/31 March 1944. RAF Bomber Command was slow to react to the threat from Schräge Musik , with no reports from shot-down crews reporting the new tactic; the sudden increase in bomber losses had often been attributed to flak. Reports from air gunners of German night fighters stalking their prey from below had appeared as early as 1943 but had been discounted. A myth developed among RAF Bomber Command crews that "scarecrow shells" were encountered over Germany. The phenomenon
21390-497: 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
21545-531: Was achieved, typically by modifying the trigger mechanism to emulate "closed bolt" firing. Most weapons that were successfully synchronized (at least in the First World War period) were (like the German Parabellum and Spandau guns and the British Vickers ) based on the original Maxim gun of 1884, a closed bolt weapon operated by barrel recoil. Before these distinctions were fully understood, much time
21700-662: Was also based on the Becker/Oerlikon design's principles. During the First World War , autocannons were mostly used in the trenches as anti-aircraft guns . The British used pom-pom guns as part of their air defences to counter the German Zeppelin airships that made regular bombing raids on London . However, they were of little value, as their shells neither ignited the hydrogen of the Zeppelins nor caused sufficient loss of gas (and hence lift) to bring them down. Attempts to use
21855-511: Was also called) was first used operationally during Operation Hydra (the first instance of the Allied bombing of Peenemünde ) on the night of 17/18 August 1943. Three waves of aircraft bombed the area, and a diversion on Berlin by RAF Mosquitoes attracted the main Luftwaffe fighter effort, which meant that only the last of the three waves was met by many night fighters. Number 5 Group and 6 Group in
22010-408: Was an almost ideal one. The fighter could see the bomber clearly, as a darker silhouette either blotting out the stars or against paler sky or high cloud. It presented the biggest possible target and reflected any light from searchlights, ground fires or TIs [target indicators]. With the two aircraft in close formation, there was an ideal no-deflection shot. And the fighter was perfectly safe, because it
22165-509: Was completed the conventionally-armed Bristol Beaufighter was already in production, so neither the G39 nor the subsequent Gloster Reaper were pursued. 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
22320-407: Was designed in late 1916 and took the form of a new synchronization gear without any rods at all. The cam that generated the firing impulses was moved from the engine to the gun; the trigger motor in effect now generated its own firing impulses. The linkage between the propeller and the gun now consisted of a flexible drive shaft directly connecting the end of the engine camshaft to the trigger motor of
22475-563: Was effectively the prototype of the Fokker E.I – the first production single-seat fighter aircraft armed with a synchronized machine gun. This prototype was demonstrated to IdFlieg by Fokker in person on 19–20 May 1915 at the Döberitz proving ground near Berlin. Leutnant Otto Parschau was test flying this aircraft by 30 May 1915. The five production prototypes (factory designated M.5K/MG and serialed E.1/15 – E.5/15 ) were undergoing military trials shortly thereafter. These were all armed with
22630-563: Was made late in 1942, in a Dornier Do 17Z-10 that was also equipped with the early UHF-band version of the FuG 202 Lichtenstein B/C radar. 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 . Further experiments were carried out by the Luftwaffe flight testing centre Erprobungsstelle ) at Tarnewitz on
22785-499: Was much danger of its failing, especially if it were bound with tape to prevent splintering (see diagram below, and illustration to the left). After his early synchronization experiments failed, Saulnier pursued a method trusting rather less to statistics and luck by developing armoured propeller blades that would resist damage. By March 1915, when French pilot Roland Garros approached Saulnier to arrange for this device to be installed on his Morane-Saulnier Type L , these had taken
22940-482: Was one of the most numerous in German service during the invasion of Poland and the campaign in France , used a 20 mm autocannon as its main armament. Although ineffective against tank armour even during the early years of the war, the cannon was effective against light-skinned vehicles as well as infantry and was also used by armoured cars . Larger examples, such as the 40 mm Vickers S , were mounted in ground attack aircraft to serve as an anti-tank weapon,
23095-570: Was only fitted to the mock-up and never incorporated in the two prototypes. In the Soviet Union the concept lasted slightly longer, with elevatable guns being tested on a Mikoyan MiG-17 in the early 1950s. 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. This result contradicted
23250-496: Was originally designed to meet the 1945 United States Army Air Forces Army Air Technical Service Command specification ("Military Characteristics for All-Weather Fighting Aircraft") for a jet-powered night fighter to replace the P-61 Black Widow. The N-24 company proposal was armed with four 20 mm (.79 in) cannon in a unique trainable nose turret that could rotate 360˚ with the guns able to elevate to 105˚. Ultimately,
23405-545: Was proposed for consideration, with a form of unusual upward-firing armament for testing on the V4 night fighter prototype, photoelectric fired vertically mounted rockets or recoilless guns , instead of cannon armament inspired by the Jagdfaust . In the Ju 88 G-6 night fighter, which was fast and manoeuvrable, the Revi 16N gunsight was modified to allow the pilot to aim at the target by placing
23560-651: Was the Kawasaki Ki-45 "Nick". With the Schräge Musik installation on the Nakajima J1N1-S "Gekkō" (two or three 20mm cannons firing upwards, some had two firing downwards), the Nakajima C6N1-S "Myrt" single-engined, high-speed reconnaissance aircraft was used with a pair of 20 mm Type 99 cannons. One variant of the common A6M5 Zero single-seat fighter—the A6M5d-S—had a 20mm Type 99 cannon mounted just behind
23715-467: Was thought to be "AA shells simulating an exploding four-engined bomber and designed to damage morale. In many cases these were actual 'kills' by Luftwaffe night fighters... It was not for many months that evidence of these deadly attacks was accepted." A detailed analysis of the damage done to returning bombers clearly showed that the night fighters were firing from below. Defence against the attacks included mixing de Havilland Mosquito night fighters into
23870-404: Was wasted on attempts to synchronize unsuitable weapons. Even a closed bolt weapon needed reliable ammunition. If the primer in a cartridge is faulty to the extent of delaying the firing of the gun for a tiny fraction of a second (quite a common case in practice with mass-produced ammunition) this is of little consequence in the case of a gun in use by infantry on the ground, but in the case of
24025-490: Was well below the Monica beam and could not be seen by any member of the bomber's crew. The only snag was that the Luftwaffe's guns were so effective that the night fighter usually had to get out of the way very fast. It was rather like 1916, except that a Lancaster with one wing blown off tumbled downwards and backwards faster than an ignited airship. We had dropped our bombs on a synthetic-oil plant in Gelsenkirchen, Germany
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