20 mm Polsten

Polsten
A Canadian towed anti-aircraft mounting featuring three Polsten cannons.
Type	Autocannon
Place of origin	Poland
Service history
In service	1944 - 1950s
Used by	UK, Commonwealth
Production history
Designed	1939-1941?
Manufacturer	John Inglis
Unit cost	£60 - £70
Specifications
Weight	57 kg (126 lb)
Length	2.1 m (6 ft 11 in)
Barrel length	1.45 m (4 ft 9 in) (barrel)

Calibre	20 mm (0.78 in)
Rate of fire	450 rpm
Muzzle velocity	830 m/s (2,700 ft/s)
Effective firing range	1,000 m (3,281 ft)
Maximum firing range	2,000 m (6,562 ft)
Feed system	60 round drum magazine or 30 round box magazine

The Polsten was a low cost Polish development of the 20 mm Oerlikon gun. The Polsten was designed to be simpler and much cheaper to build than the Oerlikon without reducing effectiveness.

Development

When Nazi Germany invaded Poland in 1939, the Polish design team escaped to England and resumed work together with Czech and British designers. The need for the Polsten was apparently mooted in June 1941. It went into service in March 1944 alongside the Oerlikon. Both the Oerlikon and the Polsten used similar 60 round drum magazines, however, the Polsten could use a simpler box magazine with 30 rounds. It remained in service into the 1950s.

When compared to the Oerlikon cannon which was made out of 250 parts, the Polsten was made out of 119 parts, without sacrificing the effectiveness or the reliability of the cannon. Simplification of the design of the Polsten cannon made its production much cheaper. The cost of one Oerlikon cannon was about £350, while the cost of the Polsten was between £60 and £70.

The Polsten was used as a substitute for the Oerlikon in the same roles, one of which was as an airborne unit anti-aircraft gun. It was used on a wheeled mounting that could be towed behind a jeep. Various double, triple and quadruple mounts were developed. John Inglis Limited of Toronto, Ontario in Canada produced many thousands of guns and some 500 quadruple mountings that saw limited service at the end of the war. These multiple mounts were both trailered and truck mounted.

The Polsten gun was used for armoured vehicles equipped with anti-aircraft guns based on the Cromwell/Centaur tank.

The Polsten was also mounted on early models of the Centurion tank not coaxially with the main gun but in an independent mount on the left hand side of the turret.

The origin of the name is not entirely clear. Some sources suggest Poland and the "Sten Company" to give Pol-sten, though the Sten gun was not made by a Sten Company. Official (United Kingdom) sources indicate the name to have been a compound based on Poland and the Royal Small Arms Factory Enfield in the same manner as the Bren gun (Brno + Enfield) or Sten (Shephard, Turpin + Enfield); also to reflect the gun design being mostly Polish (and the magazine mostly Czech) and the 8 Polish engineers in the design department. The "Sten" ending may also have linked in with the idea of the gun as a cheaper and quicker to produce weapon just like that gun was.

References

Postan, M. M., Hay, D. and Scott J.D. (1964). Design and Development of Weapons: Studies in Government and Industrial Organisation (History of the Second World War, United Kingdom Civil Series) London: HMSO & Longmans, Green & Co.
Anti-Aircraft: Polsten 20mm Quad

External links

Wikimedia Commons has media related to 20 mm Polsten.

Airborne Polsten gun

British Commonwealth artillery of World War II

Tank guns	QF 2 pounder QF 3 pounder QF 6 pounder QF 75 mm QF 3 inch Howitzer QF 17 pounder 77 mm HV QF 95 mm Howitzer

Anti-tank guns	QF 2 pounder QF 6 pounder QF 17 pounder

Field guns and howitzers	75 mm Gun M1917 QF 18 pounder 25 pounder Gun-Howitzer 25 pounder Short QF 4.5-inch howitzer

Medium and Heavy guns and howitzers	BL 4.5-inch Medium Field Gun BL 60-pounder gun BL 5.5-inch Medium Gun BL 6 inch Howitzer BL 6-inch Gun Mk XIX 155 mm Long Tom BL 7.2-inch howitzer BL 8 inch Howitzer BL 9.2-inch howitzer 240 mm howitzer M1

Mountain guns	75mm Pack Howitzer M1 3.7 inch Mountain Howitzer

Mortars	SBML 2inch Mortar ML 3-inch Mortar ML 4.2 inch Mortar

Anti-aircraft weapons	Z Battery 20 mm Oerlikon 20 mm Polsten QF 1½-pounder Mk III QF 2-pounder naval gun Bofors 40 mm QF 3 inch QF 3.7 inch QF 4.5 inch Mk II QF 5.25 inch Mk II

Coast defence	QF 6 pounder 10 cwt QF 12 pounder QF 4.7-inch Mk I–IV BL 6 inch Mk VII & Mk XXIV BL 7.5 inch Mk VI BL 8 inch Mk VIII BL 9.2 inch Mk X BL 14 inch Mk VII BL 15 inch Mk I

Railway artillery	BL 9.2 inch Mk XIII railway gun BL 12 inch Mk V railway howitzer BL 18 inch railway howitzer

This article is issued from Wikipedia - version of the Tuesday, November 04, 2014. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.

20 mm Polsten

Development

See also

References

External links