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. It was designed as in improvement on the earlier Cromwell tank, mounting the 77mm HV gun in a new lower profile and part-cast turret. This gun was effective against late war German tanks including the Panther, and at most ranges the Tiger. The tank was widely respected as one of the best British tanks of the war, and continued in service afterwards.

Comet was a development of the Cromwell, rendered the Challenger obsolete, and led to the development of the Centurion tank. The 77mm HV was a superior weapon to the 75mm KwK 42 gun of the equivalent Axis tank, the Panther, when firing APDS rounds.

The Comet saw action in the closing stages of the second world war, saw post-war combat during the Korean war, and remained in British service until 1958. In some cases, Comets sold to other countries continued to operate into the 1980s.

Background
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 to the Nuffield Organisation and Leyland Motors Ltd 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 Cruiser tank Mk VI Crusader tank.

The initial designs submitted were the A24 Cruiser Tank Mk VII Cavalier tank from Nuffield powered by a Nuffield-Liberty L-12 engine and the A27L Cruiser tank Mk VII Centaur tank from Leyland, which was also powered by the Liberty L-12 but would be able to use the more powerful Rolls-Royce Meteor when it became available.

The Cruiser tank Mk VII (A27M) Cromwell was the third parallel development to the Cavalier and Centaur. The Cromwell's Meteor engine proved to be very reliable and gave the Cromwell good mobility, but some problems did appear. 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. Most notably the Cavalier/Centaur/Cromwell series could not mount the intended 75mm HV gun.

A 17 pounder armed tank based on the Cromwell, the A30 Cruiser Mk VIII Challenger tank, was under development. To handle the large gun, the Cromwell hull had to be lengthened and a large turret set on top. Due to the slow production of Challengers, the Sherman Firefly (a Sherman tank fitted with the 17 pounder gun) conversion received official support.

Until the Challenger was available, one Firefly would be issued to each troop of Cromwells (giving three Cromwells and one Sherman Firefly); but this was unsatisfactory, due to the different maintenance requirements and associated supply complication of two tank models, as well as the performance difference between Cromwell and Sherman.

Tank, Cruiser, Comet l (A34)


With the A34 (the General Staff specification), later named Comet, the tank designers opted to correct some of the Cromwell's flaws and enhance the Cromwell's main strengths, low height and high speed. Originally, it had been expected that Cromwell would use a new gun from Vickers: the "High Velocity 75mm". However, as designed, the gun would not fit into the turret size available.

Development of the gun continued, and as work commenced on the Comet, the gun design evolved into the 77mm HV. . The gun now used the same calibre (76.2 mm) projectile as the 17-pounder, but the cartridge case was from the older QF 3 inch 20 cwt anti-aircraft gun loaded to higher pressures. The resulting round was completely different from 17-pounder ammunition.

The 77mm HV had a lower muzzle velocity than the Ordnance QF 17-pounder on Challenger and Firefly, but the ammunition was much more compact and more easily stored and handled within the tank. This made it possible to mount the gun on a smaller turret ring - the Challenger turret had been so large to allow space for two loaders - without making the hull wider.

Several other improvements were made over the Cromwell's original design: armour protection was increased, the hull was fully welded as standard, ammunition was stored in armoured bins, the suspension was strengthened, and return rollers were added. A new lower profile welded turret was created using a cast gun mantlet. The turret was electrically traversed (a design feature taken from the Churchill tank), with a generator powered by the main engine rather than the hydraulic system of the Cromwell. Armour on the Comet ranged from 32 mm to 74 mm on the hull, while the turret was from 57 to 102 mm.

As with later Cromwell's, the Comet tank's top speed was limited from the Cromwell's 40+ mph to a slower, but respectable 32 mph. This change preserved the lifespan of suspension and engine components and reduced track wear.

Similar to later Churchill's, Comet benefitted from lesson's learned in the co-operation of tanks with infantry. It was fitted as standard with two radio sets: a Wireless Set No. 19, for communication with the regiment and the troop, and a No. 38 Wireless for communication with infantry units. Like many British tanks, it also had a telephone handset mounted on the rear so that accompanying infantry could talk to the crew.

Production
Comet tanks were built by a number of British firms led by Leyland, including English Electric, John Fowler & Co., and Metro-Cammell.

The mild steel prototype was ready in February 1944 and entered trials. Concerns about the hull gunner and belly armour were put to one side to avoid redesign, but there was still sufficient delay caused by minor modifications and changes.

Production models did not commence delivery until September 1944. Comet was intended to be in service by December 1944, but crew training was delayed by the German Ardennes Offensive.

By the end of the war, 1,200 had been produced.

Second World War
The British 11th Armoured Division was the first formation to receive the new tanks—deliveries commenced in December 1944—and the only division to be completely refitted by the end of the war. Due to its late arrival in the war in north west Europe, the Comet did not participate in big battles, although it was used in combat. The Comet was involved in the crossing of the Rhine and the later Berlin Victory Parade in July 1945. The Comet's maximum speed of 32 mph was greatly exploited on the German Autobahns.

Cold War
During the following Korean War, the Comet served alongside the heavier Centurion tank, a successor introduced in the closing days of the Second World War on an experimental basis but too late to see combat. The Centurion was formally adopted in 1949 and was partly based on the Comet design. The Comet remained in British service until 1958, when the remaining tanks were sold to foreign governments; up until the 1980s, it was used by the armies of various nations such as South Africa, which maintained several as modified recovery vehicles.

Forty-one Comet Mk I Model Bs were also used by Finnish Defence Forces armoured brigade until 1970. The tanks were stored until 2007, when four of them were auctioned. Four Comets were delivered to the Irish Army in 1959 and a further four in 1960. Severe budget cutbacks affected the service lives of the Comets, as not enough spares were purchased. The Comet appealed to the Irish Army as it was cheap to buy and run, had low ground pressure and good anti-tank capability. However, faulty fuzes meant the withdrawal of the HE ammunition, which limited the tank's role to an anti-tank vehicle. With stocks of 77 mm ammunition dwindling in 1969, the army began an experiment to prolong the life of the vehicle. It involved replacing the turret with an open mounting with the Bofors 90 mm Pv-1110 recoilless rifle. The project was cancelled due to lack of funds. The last 77 mm Comet shoot was in 1973 and the tanks were withdrawn soon afterwards. One is preserved in the Curragh Camp and two more survive in other barracks.

Operators

 * 🇨🇺 Cuba
 * 🇿🇦 South Africa
 * 🇲🇲 Myanmar
 * 🇿🇦 South Africa
 * 🇲🇲 Myanmar
 * 🇲🇲 Myanmar

Variants
Comet had two hull versions:
 * Model A
 * with exhaust exiting the top rear of the vehicle using a Normandy cowl similar to Cromwell.


 * Model B
 * a post-war update with twin fishtail exhausts exiting the rear armour.

Other vehicles were based upon the Comet:
 * Comet Crocodile
 * One surviving photo reveals the existence of the Comet Crocodile . This mounted a flamethrower and pressurized trailer similar to the Churchill Crocodile.  Little is known about it.


 * FV4401 Contentious
 * The Comet was used as the basis for the experimental FV4401 Contentious, a self-propelled air transportable anti-tank gun mounting a 105mm L7 gun in an open mounting on the shortened hull of a Comet, and using the vehicle's hydraulic suspension system to adjust elevation, similar to the method used on the Swedish S-Tank. One or two prototypes were built and tested before the project was cancelled.

Tanks of comparable role, performance, and era

 * German Panther - medium tank, entered service in 1943
 * Soviet T-34-85 - medium tank, entered service in 1944
 * United States M4A3E8 - medium tank, entered service in 1944