Science Fair Project Encyclopedia
A27M Cruiser Tank VIII Cromwell was one of the most successful series of cruiser tanks fielded by Britain in World War II. It was the first tank in the British arsenal to combine a dual-purpose gun, high speed, and reasonable armor.
The Cromwell was a the product of further development of British cruiser tanks, and was designed as the replacement for the Crusader tank, which was fast becoming obsolete. In late 1940, the General Staff set out the specifications for the new tank, and designs were submitted in early 1941.
Due to the typical rushed production and lack of components, the first make of these tanks, the Cavalier , had far too many problems to see active combat service. One of the key problems was that its Liberty engine was simply not up to the task.
A new engine, based on the powerful Merlin engine used in aircraft such as the Spitfire, was designed and called the Meteor. Rolls Royce, the makers of the Merlin, were already fully committed to its manufacture and could not spare the facilities for the Meteor, and manfucture was sent to the Rover Car Company . A modified tank design, the A27 Mk VIII, was then drawn up to take advantage of the new power available, approximately 600 hp, double that of the Liberty.
It would take considerable time for Rover to make ready production lines for the Meteor, so initial A27s were equipped with the antiquated Liberty engine. These became known as A27L Centaurs. It was not until a few months later, in January 1943, that sufficient quantity of the Meteor was available and the A27M Cromwell began production.
The Cromwell still had revisions to make before service, most notably upgunning from the 6 pounder to the 75mm gun, and it was not until June 1944 that it first saw action during Operation Overlord, the allied invasion of Normandy. It had a mixed reception by crews. It was faster and had a lower profile than the Sherman tank. However, while its armour was of equivalent thickness, it was less sloped and therefore less effective than that of the Sherman. Furthermore Sherman units included Firefly variants armed with 17pdr guns which were effective against Axis tanks at long range.
Many of the components of the Cromwell were used in its successor, the Comet.
First draft. Armed with the RO QF 6-pounder gun. It was used only for training.
Mark I with wider tracks and no hull machine gun. Experimental only.
Centaur armed with the 75mm ROQF Mk V gun. In 1943, most Centaur I's were converted to III's, but a few remained as such.
Centaur armed with a 95mm howitzer. This is the only version of the Centaur known to have seen combat, in service with the Royal Marines Armoured Support Group.
Centaur AA I
Used a Crusader AA II turret with twin Oerlikon AA guns. Were originally deployed in Normandy, but withdrawn as unecessary due to Allied air superiority.
Centaur AA II
Same as the AA I, but used twin Polsten AA guns.
Cromwell I (600)
Exactly the same as the Centaur I, but using the Meteor engine. Only a few built due to the switch from the 6 pounder to the 75mm gun.
Increased track width and removal of the hull MG to increase stowage. None produced.
Cromwell III (~200)
Centaur I upgraded with Meteor engine. Few produced due to scarcity of Centaur I's.
Cromwell IV (1935+)
Centaur III upgraded with Meteor engine. The most numerous variant.
Cromwell built from the start with the 75mm gun. Used a welded instead of riveted hull.
Cromwell armed with 95mm howitzer.
Cromwell VII (~1500)
Cromwell IV and V upgraded with additional armour, wider tracks, and additional gearbox. These were introduced very late in the war and did not see much in the way of combat.
Cromwell VI with same upgrades as VII.
Vehicles based on chassis
- Cruiser Tank Challenger
- Charioteer - 20 pounder gun as used in Centurion in a new turret on reused Cromwell hull. Used in British Territorial units and exported to Finland, Austria, Jordan.
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