Oerlikon 20 mm cannon
Oerlikon 20 mm cannon | |
---|---|
API blowback | |
Elevation | Manual, -15°/+90° |
Traverse | Manual, full 360° |
Rate of fire | L70: Cyclic: 450 rounds per minute Practical: 250-320 rounds per minute L85: Cyclic: 900 to 1,000 rounds per minute |
Muzzle velocity | L70: 820 m/s (2,700 ft/s) L85: 1,050 m/s (3,400 ft/s) |
Effective firing range | Against low-flying aircraft (HE round) L70: 914 m (1,000 yd) L85: 1,500 m (1,600 yd) |
Maximum firing range | HE round at 45° L70: 4,389 m (4,800 yd) L85: 6,800 m (7,400 yd) |
Feed system | Cylindrical magazine holding 60 rounds, Later adjusted to be a belt fed gun |
The Oerlikon 20 mm cannon is a series of
Blowback-operated models
History
Origins
During
Because the Treaty of Versailles banned further production of such weapons in Germany, the patents and design works were transferred in 1919 to the Swiss firm SEMAG (Seebach Maschinenbau Aktien Gesellschaft) based near Zürich. SEMAG continued development of the weapon, and in 1924 had produced the SEMAG L, a heavier weapon (43 kg) that fired more powerful 20×100mmRB ammunition at a slightly higher rate of fire, 350 rpm.
In 1924 SEMAG failed. The Oerlikon firm, named after the Zürich suburb of Oerlikon where it was based, then acquired all rights to the weapon, plus the manufacturing equipment and the employees of SEMAG.
Oerlikon
In 1927 the Oerlikon S was added to the existing product line. This fired a still larger cartridge (20x110RB) to achieve a muzzle velocity of 830 m/s (versus 490 m/s for the original Becker 20x70RB gun), at the cost of increased weight and a reduced rate of fire (280 rpm). The purpose of this development was to improve the performance of the gun as an anti-tank and anti-aircraft weapon, which required a higher muzzle velocity. An improved version known as the 1S followed in 1930.
Three sizes of gun with their different ammunition and barrel length, but very similar mechanisms, continued to be developed in parallel. In 1930 Oerlikon reconsidered the application of its gun in aircraft and introduced the AF and AL, designed to be used in
In 1935 it made an important step by introducing a series of guns designed to be mounted in or on the wings of fighter aircraft. Designated with FF for Flügelfest meaning 'wing-mounted', these weapons were again available in the three sizes, with designations FF, FFL and FFS. The FF fired a slightly larger cartridge than the AF, 20x72RB, but the major improvement in these weapons was a significant increase in rate of fire. The FF weighed 24 kg and achieved a muzzle velocity of 550 to 600 m/s with a rate of fire of 520 rpm. The FFL of 30 kg fired a projectile at a muzzle velocity of 675 m/s with a rate of fire of 500 rpm. And the FFS, which weighed 39 kg, delivered a high muzzle velocity of 830 m/s at a rate of 470 rpm.[4]
Apart from changes to the design of the guns for wing-mounting and remote control, larger drums were introduced as it would not be possible to exchange magazines in flight. For the FF series 45, 60, 75 and 100 (and a rarely used 150) drum magazines were available, but most users chose the 30 or 60-round drum.
The 1930s were a period of global re-armament, and a number of foreign firms took licenses for the Oerlikon family of aircraft cannon. In France, Hispano-Suiza manufactured development of the FFS as the Hispano-Suiza HS.7 and Hispano-Suiza HS.9, for installation between the cylinder banks of its
The incorporation of the improvements of the FFS in a new anti-aircraft gun produced, in 1938, the Oerlikon SS. Oerlikon realized further improvements in rate of fire on the 1SS of 1942, and the 2SS of 1945 which achieved 650 rpm. However, it was the original SS gun which was widely adopted as anti-aircraft gun, being especially widely used by Allied navies during World War II.
This gun used a 400-grain (26-gram) charge of
World War II
The Oerlikon FF was installed as armament on some fighters of the 1930s, such as the Polish
The French firm of Hispano-Suiza was a manufacturer of aircraft engines, and it marketed the moteur-canon combination of its
The Oerlikon became best known in its naval applications. Initially the Oerlikon was not looked upon favorably by the
Just a few weeks before the fall of France, the Oerlikon factory approved manufacture of their gun in the United Kingdom, under licence. The Royal Navy managed to smuggle out the necessary drawings and documents from
The Oerlikon gun was installed aboard
The
The Oerlikon was also used as the basis for the
Romania purchased 45 pieces from Germany during the first half of World War II.[6]
Post-war
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It is still in use today on some naval units, nominally as a last-recourse anti-air weapon, but mainly used for firing warning shots or incapacitating small vessels.[citation needed]
Description
Unlike most high-powered autocannons, the Oerlikon and its derivatives have a
This unique chamber and bolt design necessitates the use of a characteristically shaped cartridge: the case has straight sides, very little neck, and a
Ammunition feed is typically by a 60-round drum magazine on the top of the gun. During sustained firing, the magazine must be frequently changed, reducing the effective rate of fire. Belt-fed versions of the gun were developed to overcome this limitation. A trigger in the right-hand grip controls fire. Used cartridges are ejected from below the breech.
Different nations and services operated a number of mounting types for the same basic gun. In a typical single-barrel naval version, it is free-swinging on a fixed
During World War II, twin and quadruple Oerlikon mounts were developed, both for army and for navy use. The British Navy operated a hydraulically operated twin-gun mount. The US Navy operated a quad mount developed for PT boats by Elco Naval Division, Electric Boat Company, called the Elco "Thunderbolt" mount. Prototypes were built and tested in late 1942 and operationally deployed on several Elco PT Boats in the Mediterranean.[9][10] It was also placed experimentally on the battleships Arkansas, Colorado, Maryland, West Virginia, Washington, Massachusetts, and training ship Wyoming.
Variants
Type | F | L | S[11] | FFF | FFL | FFS |
---|---|---|---|---|---|---|
Caliber | 20 mm | |||||
Action | API blowback | |||||
Weight [kg] | 30 | 43 | 62 | 24 | 30 | 39 |
Length [mm] | 1,350 | 1,820 | 2,120 | 1,350 | 1,880 | 2,120 |
Barrel length [mm] | 800 | 1,200 | 1,400 | 760 | 1,200 | 1,400 |
Rate of Fire [rpm] | 450 | 350 | 280 | 520 | 500 | 470 |
Muzzle velocity [m/s] | 550- 575 | 670- 700 | 835- 870 | 550- 600 | 675- 750 | 830 |
Cartridge type | 20x 70RB | 20x 101RB | 20x 110RB | 20x 72RB | 20x 101RB | 20x 110RB |
Shell weight | 127g | |||||
Feed system | Box magazine 15 rounds | Drums of 30, 45, 60, 75, 100 rounds or box magazine of 15 rounds |
Gas-operated models
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Although guns with blowback action had played an important part in WW2, it was obvious that something better was needed, especially for the universal demand for a high rate of fire.[12]
As a response to this demand, Oerlikon developed "power reserve loading" action,[12] introducing a gas-operated mechanism to unlock the breech.[13] The gun produced to this design after the close of hostilities of WW2, and was called the 5TG,[12] presently KAB.[14] It was the first Oerlikon gun design that differed radically from the original Becker design.[13]
Shortly after the War, Oerlikon began development of another gas-operated autocannon, 204-Gk, presently KAA.[14] Both 5TG (KAB) and 204-Gk (KAA) uses 20mm×128 ammunition cartridge being developed by Oerlikon in 1943.[14]
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GAM-B01, shipboard mount with single KAA
-
M113
-
High-angle gun mount with single KAB
See also
- List of autocannon
- List of API blowback firearms
- 20mm caliber
- 2 cm Flak 30/38/Flakvierling
- 20 mm modèle F2 gun
- 25 mm Hotchkiss anti-aircraft gun
- Hispano-Suiza HS.404
- Type 96 25 mm AT/AA gun
- Type 99 cannon
References
- ^ Budge, Kent G. (2014). "20mm Oerlikon Light Antiaircraft Gun". The Pacific War Online Encyclopedia. Retrieved 30 May 2019.
- ^ "Switzerland Oerlikon 20 mm/70 (0.79") Mark 1"". NavWeaps.com. 14 January 2011. Retrieved 24 September 2011.
- ^ "Britain 20 mm/85 (0.79") GAM-BO1". NavWeaps.com. 21 June 2008. Retrieved 23 October 2011.
- ^ a b c Williams (2000).
- ^ Johnson (1944), Appendix.
- ISBN 978-1-85409-267-0.
- ^ "The Machine Gun", Volume4, George M.Chinn., pages 12 and 15
- ^ "The Machine Gun", Volume4, George M.Chinn., page 13
- ^ Elco Naval Division Memo. General Information on Elco Thunderbolt Mount, Mark II, Bayonne, NJ: 1 December 1942.
- ^ Motor Torpedo Boat Squadron Twenty-Nine Memo to CNO. The Electric Boat Company Thunderbolt Quadruple 20 MM Powered Mount installed on PTs, operational report on, New York, NY: 19 February 1945.
- ^ "Oerlikon F/L/S (FFF/FFL/FFS) 20-мм автоматическая пушка".
- ^ a b c Chinn 1951b, pp. 547–553.
- ^ a b Chinn 1951b, pp. 554–561.
- ^ a b c Chinn 1987, pp. 257–262.
Bibliography
- Campbell, N. J. M. (1985). Naval Weapons of World War Two. ISBN 978-0-87021-459-2.
- Chinn, George M. (1951), The Machine Gun: History Evolution and Development of Manual, Automatic, and Airborne Repeating Weapons, vol. I, Bureau of Ordnance
- Chinn, George M. (1951b), The Machine Gun: Development During World War II and Korean Conflict by the United States and their Allies, of Full Automatic Machine Gun Systems and High Rate of Fire Power Driven Cannon, vol. III, Bureau of Ordnance
- Chinn, George M. (1987), The Machine Gun: Development of Full Automatic Machine Gun Systems, High Rate of Fire Power Driven Cannon, and Automatic Grenade Launchers by the United States and her Allies, following World War II, Korean Police Action, and the Vietnam Conflict, vol. V, Bureau of Ordnance
- Friedman, Norman (2006). The Naval Institute Guide to World Naval Weapon Systems. Annapolis: Naval Institute Press. pp. 478–480. ISBN 978-1-55750-262-9.
- Heller, Daniel (2002). Zwischen Unternehmertum, Politik und Überleben. Emil G. Bührle und die Werkzeugmaschinenfabrik Oerlikon, Bührle & Co 1924–1945 [Between Entrepreneurship, Politics and Survival: Emil G. Bührle and the Oerlikon, Bührle & Co. Machine Tool Factory 1924-1945] (in German). ISBN 978-3-71931-277-0.
- Johnson, Melvin M. Jr. (1944). Rifles and Machine Guns : A Modern Handbook of Infantry and Aircraft Arms. New York: William Morrow and Co.
- Pawle, Gerald (1978). Secret Weapons of World War II. New York: ISBN 0-345-27895-X.
- Williams, Anthony G. (2000). Rapid Fire: The Development of Automatic Cannon, Heavy Machine-Guns and Their Ammunition for Armies, Navies and Air Forces. ISBN 978-1-84037-122-2.
- "Navy Day". The Harvester World. 35 (12). Chicago: Harvester Press: 12. December 1944.
External links
- Williams, Anthony G. (July 2013). "Of Oerlikons and Other Things……". Military Guns & Ammunition.
- "Naval Quad mount". Navsource.org.
- Zlámal, Stanislav (12 May 2009). "2cm VKPL vz. 36 Oerlikon". Fronta.cz (in Czech).
- World of Warships (24 August 2017). "Naval Legends: Oerlikon". YouTube. Archived from the original on 30 October 2021.