The Bordkanone 3,7 (BK 3,7) ("on-board cannon 3.7") was a German

anti-tank Anti-tank warfare originated from the need to develop technology and tactics to destroy tanks during World War I. Since the Triple Entente deployed the first tanks in 1916, the German Empire developed the first anti-tank weapons. The first deve ...

/bomber

autocannon An autocannon, automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large-caliber ( or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bull ...

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

and based on the earlier 3.7 cm Flak 18 made by

Rheinmetall Rheinmetall AG is a German automotive and arms manufacturer, headquartered in Düsseldorf, Germany. Its shares are traded on the Frankfurt stock exchange. History Rheinmetall was founded in 1889. Banker and investor Lorenz Zuckermandel L ...

. It was mounted on

Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...

aircraft such as the

Junkers Ju 87 The Junkers Ju 87 or Stuka (from ''Sturzkampfflugzeug'', "dive bomber") 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 Con ...

G-1 and G-2;

Henschel Hs 129 The Henschel Hs 129 was a World War II ground-attack aircraft fielded by the German ''Luftwaffe''. The aircraft saw combat in Tunisia and on the Eastern Front. A key requirement of the original specification was that the aircraft be powered by ...

B-2/R3;

Messerschmitt Bf 110 The Messerschmitt Bf 110, often known unofficially as the Me 110,Because it was built before ''Bayerische Flugzeugwerke'' became Messerschmitt AG in July 1938, the Bf 110 was never officially given the designation Me 110. is a twin-engine (Des ...

G-2/R1-3; Junkers Ju 88P-2 or P-3 and others. The cannon could be attached under the wings or the fuselage of the aircraft as self-contained

gun pod A gun pod is a detachable pod or pack containing machine guns, autocannons, revolver cannons, or rotary cannons and ancillaries, mounted externally on a vehicle such as a military aircraft which may or may not also have its own guns. Description ...

s with 12-round

magazines A magazine is a periodical publication, generally published on a regular schedule (often weekly or monthly), containing a variety of content. They are generally financed by advertising, purchase price, prepaid subscriptions, or by a combination ...

. It fired Armour Piercing Composite Rigid (APCR,

Tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolat ...

-cored) ammunition or high-explosive shells at 160 rounds per minute.

Service history

BK 3,7 equipped

ground attack In military tactics, close air support (CAS) is defined as air action such as air strikes by fixed or rotary-winged aircraft against hostile targets near friendly forces and require detailed integration of each air mission with fire and movement ...

aircraft were developed for tank hunting on the Eastern Front in an effort to blunt the massive numerical superiority of the Soviet

T-34 The T-34 is a Soviet medium tank introduced in 1940. When introduced its 76.2 mm (3 in) tank gun was less powerful than its contemporaries while its 60-degree sloped armour provided good protection against Anti-tank warfare, anti-tan ...

tank as the war turned against Germany. The concept was rather rudimentary, suffered from poor accuracy, severe weight penalty making the craft vulnerable to fighters, and low ammunition capacity; but could be extremely effective when operated by a sufficiently skilled and practised ground-attack pilot, such as

Hans-Ulrich Rudel Hans-Ulrich Rudel (2 July 1916 – 18 December 1982) was a German ground-attack pilot during World War II and a post-war neo-Nazi activist. The most decorated German pilot of the war and the only recipient of the Knight's Cross with G ...

in his BK 3,7 armed

Junkers Ju 87G The Junkers Ju 87 or Stuka (from ''Sturzkampfflugzeug'', "dive bomber") 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 Con ...

. The heavy-calibre autocannon-armed series of

Junkers Ju 88P The Junkers Ju 88 is a German World War II ''Luftwaffe'' twin-engined multirole combat aircraft. Junkers Aircraft and Motor Works (JFM) designed the plane in the mid-1930s as a so-called ''Schnellbomber'' ("fast bomber") that would be too fast f ...

twin-engined attack–

bomber destroyer Bomber destroyers were World War II interceptor aircraft intended to destroy enemy bomber aircraft. Bomber destroyers were typically larger and heavier than general interceptors, designed to mount more powerful armament, and often having twin en ...

aircraft series used twin BK 3,7 cannon, mounted side-by-side in a conformal ventral fuselage gun pod, in its Ju 88P-2 and P-3 versions. The P-3 version only differed through the addition of extra defensive armour. As with other examples of the P-series, the Ju 88P-2 and P-3 were perceived as failures as anti-tank and

aircraft. In contrast to the bombs delivered by

dive bombing A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target simplifies the bomb's trajectory and allows the pilot to keep visual contact throughou ...

, when the BK 3,7 was used to attack the relatively thin armour of the top of the turret and the engine compartment armour of a tank, kills could be achieved with a relatively light and cheap

armour-piercing Armour-piercing ammunition (AP) is a type of projectile designed to penetrate either body armour or vehicle armour. From the 1860s to 1950s, a major application of armour-piercing projectiles was to defeat the thick armour carried on many warsh ...

projectile that could be carried in much greater quantities than bombs. One of the two surviving

s is a G-2 model displayed at the

Royal Air Force Museum Cosford The Royal Air Force Museum Cosford, located in Cosford in Shropshire, is a free (currently, 2022) museum dedicated to the history of aviation and the Royal Air Force in particular. The museum is part of the Royal Air Force Museum, a non-departme ...

; the wings have attachment points for BK 3,7 gun pods but it is not displayed with them fitted.

References

Bibliography

* Rapid Fire, Anthony G. Williams, Shrewsbury: Airlife Publishing Ltd., 2000. .

External links

{{WWIIGermanAerialWeapons 37 mm artillery Aircraft guns Autocannon Weapons and ammunition introduced in 1942

Service history

See also

Weapons of comparable role, performance and era

References

Bibliography

External links