Vickers Vigilant

Vigilant
Vickers Vigilant
Type	Wire-guided Anti-tank missile
Place of origin	UK
Service history
In service	1960s
Used by	United Kingdom, Finland, Kuwait, Dubai, Switzerland, United States of America
Wars	none
Production history
Designed	1956
Manufacturer	Vickers-Armstrong (Aircraft) Ltd
Specifications
Weight	31 lb (14 kg)
Length	3.5 ft (1.07 m)
Diameter	0.12 m
Warhead	HEAT, 6 kg
Detonation mechanism	impact
Engine	I.C.I. dual-thrust solid fuel rocket
Wingspan	0.27 m
Operational range	200 m to 1375 m
Flight ceiling	n/a
Speed	348 mph (155.6 m/s)
Guidance system	MCLOS wire-guided
Steering system	control surfaces
Launch platform	infantry or vehicle

The Vickers Vigilant was a British 1960s era MCLOS wire guided anti-tank missile used by the British Army that was also licence-built in the USA for the US Marine Corps as Clevite.

Vigilant was a private development begun in 1956 by the Vickers-Armstrongs Guided Weapons Department at Brooklands, Surrey for the anti-tank role in the British Army, the name being formed from VIsually Guided Infantry Light ANti-Tank missile. Vigilant was wire-guided and optically tracked, like its successor Swingfire. As well as infantry use, it could be mounted on vehicles such as the Ferret armoured car and Land Rovers. Vigilant had a short service life: Swingfire started to replace Vigilant from 1966 onwards.

The missile system could be deployed in a number of configurations. The man-portable configuration consists of a launcher which doubles up as a transport container, a combined sight and controller, a battery and a 63 meter long cable. An optional Missile Selector Box allowed up to 6 missiles to be controlled by, and widely separated from, a single sight controller. The launcher box is placed on the ground facing the direction of expected targets, and then connected by the cable to the sight controller, which can be deployed some distance away. The sight controller is a pistol grip design, with two grips. The front grip has the launch trigger, and the rear grip has a thumb joystick for steering the missile. A low-magnification (3.2x) monocular forms the sight itself. Engraved stadia lines allow simple ranging, based on a typical tank target bridging the lines once in range.

The operator tracks the target using the sight mechanism, then launches the missile using the front trigger. Once the missile is in flight, he steers the missile into his line of sight using the thumb joystick. The missile's auto pilot uses a gyroscope to maintain a straight flightpath directly away from the launch point, compensating for any wind buffeting. When the operator moves the joystick, the missile applies a steering correction in the appropriate direction, once the joystick is released the opposite correction is applied automatically, keeping the missile travelling directly away from the launch point. Vigilant has a reputation for ease of control and high success with minimal operator training. This was largely due to the 'velocity control' method of Vigilant, relying on gyroscopes, rather than the simpler 'acceleration control' of competing missiles such as Entac or SS.11.