Vickers S

The Vickers Class "S" was a 40 mm (1.57 in) cannon used to arm British aircraft for attacking ground targets in the Second World War.

Vickers S
A Hawker Hurricane fitted with two S-gun Shandur, Egypt (1942)
Service history
Used byRoyal Air Force
WarsSecond World War
Production history
Produced1942
VariantsMk 1, Mk 2
Specifications
Mass320 lb (134 kg)
Length9 ft 9 inches (2.97 m)
Barrel length5 ft 7 in (1.7 m)
Cartridge weight4 lb (1.8 kg) 40x158R
Calibre40 mm (1.6 in)
Rate of fire100 rounds/min
Muzzle velocity1,870 ft/s (569.98 m/s)
with 3lb shot
Feed system12-round drum
later 15 rounds

History

The Vickers Class "S" 40 mm (1.57 in) gun was developed in the late 1930s as an aircraft weapon. The ammunition was based on the 40x158R cartridge case of the naval 2 pdr Anti-aircraft gun (the "Pom-pom"). The weapon was a long-recoil design derived from the 37 mm 1½pdr "COW gun" from Coventry Ordnance Works.The gun was originally intended as a bomber defensive weapon and was tested as such in a turret fitted to a modified Vickers Wellington II. This was not adopted for service, but when the need to attack tanks from the air was identified, the "S" gun was chosen and special armour-piercing ammunition developed.[1]

Combat history

The only aircraft built to carry the Vickers S were ground attack variants of the Hawker Hurricane. Mark IID and Mark IV Hurricanes could mount one under each wing, in conformal gun pods.

No. 6 Squadron RAF operated the Hurricane IID in North Africa from mid-1942. Claims by pilots using the Vickers S included 47 tanks destroyed (of 148 tanks hit), as well as nearly 200 other vehicles. However, the Hurricane IID was poorly armoured for the ground attack role and ground fire caused heavy losses. In addition, 40 mm ammunition was seldom effective against vehicles as well-armoured as the Tiger I tank.

Mark IV Hurricanes (operational from 1943) had improved armour around their engine, cockpit and fuel tanks.

From 1944, Hurricanes armed with the Vickers S served in the South East Asian theatre. In most cases HE ammunition was used against road vehicles and river craft.

Assessments carried out in South East Asia showed a relatively high level of accuracy: an average of 25% of shots fired at tanks hit their target. (By comparison, RP-3 60 pound rocket projectiles only 5% against tank-sized targets.) However, 40 mm HE rounds were twice as accurate as AP rounds, possibly because the lighter weight and higher velocity of the HE round gave it ballistics similar to that of the .303 in (7.7 mm) Browning machine gun that were used for sighting.

See also

Weapons of comparable role, performance and era

References
  1. Wallace, G.F. (1972). "10, The 40mm Guns". The Guns of the Royal Air Force 1939-1945. London: William Kimber. ISBN 0-7183-0362-8.
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