Comet (tank)

The Comet tank or Tank, Cruiser, Comet I (A34) was a British cruiser tank that first saw use near the end of the Second World War, during the Western Allied invasion of Germany. The Comet was developed from the earlier Cromwell tank with a lower profile, partly-cast turret which mounted the new 77 mm HV gun. This was a smaller version of the 17 pdr anti-tank gun firing the same 76.2 mm (3") projectiles, albeit with a lighter charge, and was effective against late-war German tanks, including the Panther and Tiger.

The Comet rendered the Cruiser Mk VIII Challenger obsolete and was an interim solution until the completely new design Centurion tank was available. When firing APDS rounds, the 77 mm HV was superior in armour penetration capability to the 75 mm KwK 42 gun of the equivalent Axis tank, the Panther.

The Comet entered active service in January 1945 and remained in British service until 1958. In some cases, Comets sold to other countries continued to operate into the 1980s.

Combat experience against the Germans in the Western Desert Campaign demonstrated to the British many shortcomings with their cruiser tanks. Hence a request was made in 1941 for a new heavy cruiser tank that could achieve battle superiority over German models. For reasons of economy and efficiency, it had to use as many components as possible from the current A15 Mk VI Crusader tank.

The initial designs for the new Cromwell tank evolved into the A24 Mk VII Cavalier tank and the A27L Mk VIII Centaur tank, both powered by the Nuffield Liberty. Design progressed through the Mk VII (A27M) Cromwell, a third parallel development to the Cavalier and Centaur, sharing many of the same characteristics.

Under the newer A27M specification, Cromwell integrated a number of advanced features. The Meteor engine proved to be very reliable and gave the tank good mobility but some problems appeared based on the vehicle's shared heritage and significant jump in engine power. The tank was prone to throwing its tracks if track tension was not maintained properly or if it turned at too high a speed or too sharply. There were also some problems with suspension breakage, partly due to the Cromwell's high speed and it ran through a number of design changes as a result.

The biggest complaint was related to firepower; the Cromwell had originally been designed to carry the 57 mm Ordnance QF 6-pounder, also retrofitted to the Crusader tanks. In combat, these were found to be useful against other tanks but lacking any reasonable high explosive load they were ineffective against anti-tank guns or static emplacements. Prior to the Cromwell entering combat service, the Ordnance QF 75 mm was introduced which equipped the majority of Cromwells, an adapted version of the 6-pounder firing shells from the US 75 mm gun from the Sherman. This offered somewhat lower anti-tank performance than the 6-pounder but its much larger shell provided an effective high explosive load.

Several attempts had been made to further improve firepower by fitting a more powerful gun. In parallel with development of the Cromwell and QF 75 mm gun, a new Vickers High Velocity 75 mm tank gun had been designed but this proved too large for the Cromwell turret ring and left a shortage in offensive anti-tank capability. A prior requirement for a 17-pounder armed tank led to development of the A30 Mk VIII Challenger. Based on the Cromwell, the hull had to be lengthened and a much larger turret set on top to allow a second loader for the 17-pounder, a requirement of the older specification believed necessary for the larger ammunition. The very high turret of the Challenger was considered a liability and this led to experiments with the similar A30 Avenger version, an anti-tank version with an open-top turret.