“Cruiser Mk VIII Challenger”的意思、由来-开放百科全书

The Tank, Cruiser, Challenger (A30) was a British tank of World War II. It mounted the QF 17-pounder anti-tank gun on a chassis derived from the Cromwell tank to add anti-tank firepower to the cruiser tank units. The design compromises made in fitting the large gun onto the Cromwell chassis resulted in a tank with a powerful weapon and reduced armour. The extemporised 17-pounder Sherman Firefly conversion of the US-supplied Sherman was easier to produce and, with delays in production, only 200 Challengers were built. The Challenger was able to keep up with the fast Cromwell tank and was used with them.

History

The driving force in the development of Challenger was W. A. Robotham. Roy Robotham had been a Rolls-Royce executive in the car division who, with no work to do, had led a team to develop a tank powerplant from the Rolls-Royce Merlin aircraft engine. The Rolls-Royce Meteor gave the British a powerful, reliable engine, which was used in the A27M Cruiser Mk VIII Cromwell tank. Robotham's contributions gained him a place in the Ministry of Supply and on the Tank Board, despite his lack of experience in tank design.{{sfnp|Fletcher|1993}}

The General Staff brought forward specification A29 for a 45 ton, 17 pounder armed cruiser tank based on needs identified in the African desert campaign. The design weight of this vehicle was too heavy and the specification was passed over in favour of the alternate specification, A30, which was {{convert|10|LT|t|abbr=on}} lighter.^[2] In 1942, an order for an A30 based tank was placed with Birmingham Railway Carriage and Wagon Company (BRC&W) expecting it to be based on the Cromwell components also being manufactured by BRC&W. The turret and gun mounting were in the hands of Stothert & Pitt. Birmingham Carriage had to modify the Cromwell hull to take a bigger turret.

The design received additional emphasis when, in May 1943, it was found in that the Cromwell could not carry its intended armament. Vickers had been developing a {{convert|75|mm|in|abbr=on}} L 50 calibre high velocity tank gun. It was realised late in the design process that the Cromwell's turret ring was too small for the gun.{{sfnp|Fletcher|2006}}{{page needed|date=June 2015}} The Challenger would be the only British cruiser tank to mount a weapon that could tackle heavier German armour until the arrival of the A34 Comet.

British tank production was limited by resources and insufficient numbers could be made. In the lead up to D-Day, Sherman tanks were fitted with the 17 pounder, creating the interim 17 pounder Sherman (Sherman Firefly). Converting Sherman tanks was simpler than producing Challengers, so the A30 order was cancelled after about 200 had been built, allowing BRC&W to concentrate on the Cromwell.

The tank was rendered obsolete when the Vickers HV 75 mm gun was developed to become the {{nowrap|77 mm HV}} (actually 3 inch = 76.2 mm calibre) to arm the Comet tank. The {{nowrap|77 mm HV}} used the same projectiles as the 17 pounder with a reduced propellant charge. The 17 pounder gun was reintroduced briefly on earlier marks of the Comet's successor, the Centurion tank.

Design

The turret mounted the Ordnance QF 17-pounder gun required in the Tank Board specification and the hull machine gun was removed to provide stowage space for the long 17-pounder cartridges. The War Office expected that this larger ammunition, together with its stowage forward, would require two loaders, which raised the turret crew to four, the commander, gunner, loader 1 and loader 2. To fit the larger weapon and additional crewman in the turret, a much larger turret than that of the Cromwell was specified, developed separately, which had a significant effect on the design and was not resolved until later development of Avenger.

To carry the weight of the 17-pounder and ammunition, an extra wheel station and suspension arm was needed, lengthening the hull. This change in length, without a corresponding change in width across the tracks, reduced mobility compared to the Cromwell, although speed remained high at 25 mph. To limit the weight, the amount of armour was reduced but this could only be achieved on the turret, {{convert|63|mm|in|abbr=on}} on the front and {{convert|40|mm|in|abbr=on}} on the sides compared to {{convert|75|mm|in|abbr=on}} and {{convert|60|mm|in|abbr=on}} on the Cromwell. As the base of the turret was unprotected, a jacking feature was fitted to clear jams. The additional length allowed larger hatches to be fitted in the hull while still clearing the turret, providing easier access than Cromwell.

The first Challenger was completed in September 1942, only eight months after development had commenced. When the second was tested at Lulworth, it was found that although it would be effective at long range against the current best-gunned tank in German service (the Panzer IV "Special" with the long {{convert|75|mm|in|abbr=on}} gun), at shorter ranges it would be at a disadvantage due to its slow firing rate and thin armour. The Challenger had been developed in anticipation of more heavily armoured Axis tanks, following the trend in Nazi German tank design. At roughly the same time the Tiger 1 entered service with the German army, placing an immediate need for a 17-pounder armed tank in response.{{sfnp|Robotham|1970}}{{page needed|date=February 2017}}

Design approvals took five months; although changes to the design were minor, a committee met to determine whether a requirement for a 17-pounder tank existed. An order for a small production run of 200 was placed in February 1943 but production capacity was limited by the production of the Cromwell tank. In November, it was announced that no more would be ordered and production priority was moved to the Sherman Firefly, rapidly to produce 17-pounder armed equipments, while design priority was concentrated on the A34 Comet, which replaced the Cromwell, Firefly and Challenger.

Controversy

Upon Robotham's appointment as Chief Engineer to the Department of Tank Design, the lack of progress on an (A29) 17-pounder armed tank could not adequately be explained. Robotham's memoirs indicate a lack of awareness that any such requirement existed within the department and military users were still unsure whether the tank was required at the point when the rushed A30 design had been completed and prototype vehicles run.{{sfnp|Robotham|1970|p=165}} The Challenger was then rushed into production alongside existing production runs of Cromwell, limiting the number of tanks that could be produced.

The dubious reliability of earlier British tank designs, along with limited manufacturing capacity, led to a joint mission to the US to explore US tank options and share design experiences learned from action. The British and Commonwealth forces introduced a much larger contingent of US-made vehicles, each using dual purpose 75 mm guns with reduced anti-armour capability (US doctrine placed artillery as the primary anti-tank weapon, while tanks used the dual-purpose gun to fire high-explosive shells at un-armoured targets).

Cromwells carrying the 6-pounder had been delayed in design and the move to cancel Challenger while switching Cromwell to the dual purpose 75 mm gun (with a corresponding drop in anti-armour performance) left British and Commonwealth forces without a main-force tank weapon capable of taking on the equivalent generation of Axis tanks. The lack of firepower was keenly felt by tank crews fighting heavier armed and sometimes more heavily armoured, Axis tanks. The Firefly was used as a stop-gap, which was only resolved, much later, with the A34 Comet. While Comet improved significantly upon both Cromwell and Challenger designs, its design and production followed that of the Cromwell and was delayed much longer than an equivalent production (and evolution) of Challenger.

Performance

The 17-pounder gun mounted on the Challenger offered sufficient performance against the majority of German AFVs, including the Tiger I and Panther tank and had a higher top speed and cross country mobility than the Panzer IV or StuG III. The armour of the Challenger offered very little protection against contemporary German anti-tank guns and was lower than that of the Cromwell, which often operated with Challengers.

In combat, the Challenger fulfilled much the same role as the Sherman Firefly, providing overwatch for the other tanks in the troop, as its 17-pounder could penetrate almost all German AFVs frontally, unlike the 75 mm. It was deployed in a similar manner at a troop level, this was typically one 17-pounder armed tank (such as Challenger or Firefly) to three 75 mm armed tanks (Cromwells or Shermans); at times, the deployment of 17-pounder armed tanks was increased to two per troop.

The Challenger was based on the reliable Cromwell tank, which used the new Rolls-Royce Meteor engine, which was far more reliable and powerful than the ageing Liberty engine used in earlier British Cruiser designs like the Crusader tank. Its reliability was slightly below that of the Cromwell, as a problem was experienced with track throwing, caused by mud building up in the wheels but this was resolved in the field.^[3] Supply and maintenance were vastly simplified through the use of common parts with the Cromwell.

In comparison with the Firefly, the tank lacked the sloping forward armour but presented a lower profile and avoided the Firefly's constraint on gun depression. The Challenger provided 10{{formatnum:}}° of gun depression while Firefly was limited to 5{{formatnum:}}°, which was significant disadvantage in combat.{{sfnp|Robotham|1970}} It was preferred within Cromwell units as it shared similar mobility and manoeuvrability, whereas the Firefly was slower. Despite a lower design weight than the earlier A29 specification, the Challenger was heavy and required dockyard equipment to ship, making it impractical to use in amphibious assaults, such as the D-day landings.

Service

The vehicle entered front-line service during the Allied invasion of Normandy but no provision had been made for deep wading trunking and the A30 was unable to participate in the landings; Challenger crews had to wait until the Mulberry harbours were built and ports captured. The Challenger and Firefly, equipped with 17-pounder, were added to tank squadrons to deal with opposing heavy tanks and many Challengers were issued to units using Cromwells. The tank was unpopular at first, with crews complaining about the lack of armour, the high silhouette and the tracks being thrown.^[4] Troops used to the low profile of the Crusader and Cromwell found the height a serious problem, although it was still shorter than the comparable Sherman Firefly.

Confidence in the vehicle grew and it became preferred over Firefly, being lower, faster and more manoeuvrable but the early bad reputation persisted with others.^[5] Allied forces were issued with the Challenger, the 1st Polish Armoured Division receiving several in mid-1945 and the 1st Czechoslovak Armoured Brigade used it during the siege of Dunkirk in late 1944.^[6]{{sfnp|Fletcher|2006|p=47}} After the war, the Czechoslovak government purchased 22 Challengers from the brigade inventory, which served in the Czechoslovak army (first with the 11th, later 23rd, Tank Brigade and then with the 13th Independent Tank Battalion) until they were put in reserve in 1951 and scrapped in 1959.^[7]

Variants

A30 Avenger SP2 or SP 17pdr, A30 (Avenger) was a development of Challenger to be used as a self-propelled gun. It removed the second loader's position and featured a much lower profile turret and lower superstructure on the hull. An additional stowage bin was provided on the glacis plate for a large camo net and return rollers were added to the tracks.{{sfnp|Royall|2000}}

Avenger featured a permanent opening in the turret roof covered with an armoured cover supported a few inches above. This provided the commander and loader with full 360 degree visibility.{{sfnp|Royall|2000}}

As many as 500 vehicles appear to have been planned and 230 vehicles were ordered from BRC&W, but this dropped to 80 with the end of the war. It is not known how many were actually built; the SP2 nomenclature indicates its production with the Valentine Archer (SP1) and Alecto (SP3).{{sfnp|Royall|2000}}

Avenger suffered in trials as the engine had to remain running to run the turret traverse motor, because the noise and exhaust could give the vehicle away. Winter trials in a prolonged stationary position also failed in comparison with Archer, when Avenger's steering failed. Both vehicles had problems with camouflage. The vehicle was dropped from trials in 1950, along with removal of Achilles, its US derived equivalent.{{sfnp|Royall|2000}}

While the Avenger was only used for trials and was ultimately unsuccessful as a self-propelled artillery piece, in comparison with the purpose built vehicles, it provides an interesting example of what could have been possible for the Challenger tank had it not been forced to accommodate the second loader and larger turret during the tank design. This is highlighted in Robotham's memoirs, indicating that it may have been corrected had design effort not moved to the Comet.{{sfnp|Robotham|1970}}

Survivors

Two vehicles survive, one at the Overloon War Museum in the Netherlands; the other was awaiting restoration at the Isle of Wight Military Museum in the United Kingdom until its closure. Once restored, it will be displayed at the Bovington Tank Museum.^[8]

Notes

1. ^{{cite book | last = Bishop | first = Chris | title = The Encyclopedia of Weapons of World War II | publisher = Barnes & Noble | location = New York | year = 1998 | isbn = 978-0-7607-1022-7 |page=27}}
2. ^http://www.historyofwar.org/articles/weapons_cruiser_tank_A29.html ; retrieved 18 June 2016
3. ^Track Throwing, 15.11.44; Rm/GB.5/SW.15.11.44
4. ^Note from Service Engineer, 15.11.44; AA.2/JB.11.11.44
5. ^The Rolls Royce Meteor - Cromwell and other applications; Historical Series No. 35 published by the Rolls Royce Heritage Trust
6. ^Hayward The Other Challenger quoting Six Monthly RAC Progress Reports
7. ^{{cite book |last= Francev|first= Vladimír|title=Československé tankové síly 1945-1992 |year=2012 |publisher=Grada |location=Prague |isbn=9788024740294 |page=186}}
8. ^{{cite web |url=http://the.shadock.free.fr/Surviving_Cruiser_Tanks.pdf|title=Surviving Cruiser Tanks |author=Pierre-Olivier Buan|page=39|date=25 October 2011 |work= |publisher=Surviving Panzers website |accessdate=5 November 2011}}