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Cromwell - A27 cruiser tank - case report

      Let's talk about one of the best cruiser tanks ever produced by the UK during WWII. Today's subject is about the Cromwell cruiser tank - A27.

Cromwell A-27 cruiser tank from Guards Armoured Division - B Squadron of Welsh Guards Regiment
      The Cromwell tank, officially Tank, Cruiser, Mk VIII, Cromwell (A27M), was one of the series of cruiser tanks fielded by Britain in the Second World War. Named after the English Civil War leader Oliver Cromwell...
Olivier Cromwell - 25 April 1599 / 3 September 1658
    ...the Cromwell was the first tank put into service by the British to combine high speed from a powerful and reliable engine (the Rolls-Royce Meteor), and reasonable armour. The intended dual-purpose high velocity gun could not be fitted in the turret and the medium velocity dual purpose gun fitted proved inadequate. An improved version with a high velocity gun became the Comet A34 cruiser tank.
A34 cruiser Tank Comet
      The name "Cromwell" was initially applied to three vehicles during development. Early Cromwell development led to the creation of the A24 Cavalier.
A24 cruiser tank Cavalier

      Later Cromwell development led to the creation of the competing Tank, Cruiser, Mk VIII, Centaur (A27L) design. The Centaur tank was closely related to the Cromwell, both vehicles being externally similar. The Cromwell and Centaur tanks differed in the engine used; the Centaur had the 340 hp Liberty engine, the Cromwell had the significantly more powerful 600 hp Meteor.
A27 cruiser tank Centaur
      The Cromwell first saw action in the Battle of Normandy in June 1944. The tank equipped the armoured reconnaissance regiments of the Royal Armoured Corps, in the 7th Armoured Division, 11th Armoured Division and the Guards Armoured Division. While the armoured regiments of the latter two divisions were equipped with M4 Shermans, the armoured regiments of the 7th Armoured Division were equipped with Cromwells. The Centaurs were not used in combat except for those fitted with a 95 mm howitzer, which were used in support of the Royal Marines during the amphibious invasion of Normandy.
Centaur Mk IV CS - HUNTER
Tilly-sur-Seulles, Normandy - France - June, 1944.
      Development of the Cromwell and Centaur dates to 1940, as the Crusader tank was being readied for service. The General Staff was aware that the Crusader would become obsolete, and in late 1940 they set out the specifications for a replacement tank, expected to enter service in 1942, fitted with the QF 6 pounder gun.
Crusader Mk III tank, 1 January 1943.North Africa
      Vauxhall responded with the A23, a scaled down version of their A22 Churchill infantry tank. This would have had 75 mm of frontal armour, used a 12-cylinder Bedford engine, carried a crew of five and would had the cast/welded turret like A22 Churchill design.
Vauxhall A23 tank prototype
Notice the cast/welded turret Churchill design.
      Nuffield submitted the A24, heavily based on its Crusader design and powered by its version of the Liberty engine, a V-12 design dating the late days of World War I and now thoroughly outdated. Nevertheless, as the design was based on the Crusader, it was expected it could be put into production rapidly.

      The final entry was from Leyland and Birmingham Railway Carriage & Wagon (BRC&W). Their design was similar to the Nuffield, but with different suspension and tracks.
      The designs were received and examined in January 1941, with Nuffield's A24 being declared the winner on 17 January. Six prototypes of the Cromwell were ordered for the spring of 1942. These arrived four months late, and by this time the design was already outdated. It was put into production anyway, but in service it proved underpowered. Only a small number were built.
      Delays in the A24 program led to demands to get the QF 6 pounder into service earlier. This led to a series of up-gunned Crusaders mounting the 6-pounder.
      The earlier introduction of US M3 Lee/ Grant and M4 Sherman tanks placed a dual purpose 75 mm gun into British and Commonwealth service.
      The 75 mm could fire a more effective HE shell than the 6-pounder at the cost of a reduction in armour-piercing performance. The 6-pounder firing solely AP shells was a retrograde step. Once the Vickers 75 mm HV gun was seen to be too big for the Cromwell turret, work was begun in December 1942 on the Ordnance QF 75 mm (a development of the 6-pounder that fired US ammunition) for fitting to British tanks. Mark IV Cromwells were delivered with 75 mm guns from November 1943.
American 75mm ammo - high explosive
      To maintain the capability to take on Axis tanks, production was to be split: 
      Noting the problems with the medium velocity 75 mm dual purpose weapon, Vickers had already commenced development of a high velocity 75 mm gun that would fire American 75 mm ammunition but at a much higher velocity.

      While Cromwell development had been underway, Soviet forces rejected the US Sherman tank that was to be provided through the third protocol of lend-lease. This led to a surplus in Sherman tank manufacturing capacity, and significant pressure was placed for the Cromwell programme to be cancelled in favour of US-produced Shermans. This would otherwise see a significant proportion of Sherman tank assembly lines closing. A complete move to Sherman tanks was not acceptable to British forces who would then be dependent on the US for tank production. At the same time, Cromwell with the Meteor engine and a HV weapon was shown to have superior power and armament, while US efforts to produce the Sherman replacement, the T20 Medium Tank, were not receiving sufficient attention. The impact of ceasing tank manufacture in Britain would keenly be felt by workers and the war economy at home.

      A compromise was achieved with a reduction in British tank production during 1943 and 1944, with an increase in consumption of Sherman tanks, the remainder being delivered in parts as spares. Centaur production bore the brunt of this reduction, having only been continued to maintain factories producing Cromwell hulls while the number of Meteor engines was inadequate. It had already been arranged that Centaur production would be phased out when Meteor engine production increased. The list of machine tools required for the increase in Meteor output was also agreed, allowing Cromwell manufacture to scale.
      At the same time as negotiations with the US, problems were being encountered with the use of the Vickers 75mm HV gun in the Cromwell, with a larger turret ring being required. This was now expected to be introduced in mid 1944, leaving the majority of Cromwells with the medium velocity gun similar to the Sherman. Design of the high velocity variant was split to a separate specification. Intended as just another version of Cromwell, the new A34 version eventually needed significant re-engineering leading to production of the A34 Comet, which used a high velocity gun firing 17-pounder ammunition from a gun by a smaller cartridge down a shorter barrel. In the interim, the A27M version started.
A34 Comets from 11th Armoured Division in the Weser bridgehead, Germany, 7 April 1945.
Early trials
      The first real field test of the design was carried out in August–September 1943, when examples of the Centaur, Cromwell, Sherman Mk.III M4A2 (diesel engine) and Sherman Mk.V M4A4 (multi-bank petrol engine) were tested in Exercise Dracula, a 3,200 km long trip around Britain. The Shermans proved to be the most reliable by far, requiring 420 hours of specialist fitter attention over a total distance travelled of 22,508 km. In comparison, the Cromwells drove 18,639 km and required 814 hours of maintenance. The Centaur managed only 13,667 km due to constant breakdown, and required 742 hours of repair work.
Sherman Mk.III (M4A2)
      The Cromwell and Centaur were given additional time to work out these problems. The Cromwell problems were mostly related to oil leaks and brake and clutch failures, an observer noting that these were well-known and should already have been corrected. The crews expressed their love for the design and especially its speed and handling. The Centaur was largely dismissed, with one observer expressing his hope that units were being equipped with it only for training purposes. The same reviewers unanimously supported the Sherman. A similar test in November demonstrated the Cromwell was improving, while the underpowered Centaur fared no better than in the first test.
Sherman Mk V (M4A4)
      Alongside Cromwell production, Centaur production design also allowed for the later conversion to the Meteor engine. A small number were retro-fitted for trials as Cromwell III and Cromwell X. As the Cromwell proved itself, larger numbers were fitted with the Meteor engine on the production line as Cromwell III and IV (not to be confused with the earlier Cromwell III design project).

Final specification:

      The production model design was finalised on 2 February 1944 when Leyland released specifications for what they called the "Battle Cromwell". This included a number of minor changes to the basic design, including 6 mm of extra armour below the crew compartment, the introduction of an all-round vision cupola for the commander, seam welding all joints to waterproof and strengthen the tank, and standardising on the A27M version with Meteor engine and Merritt-Brown transmission. The Cromwell Final Specification was applied part way through the production of Cromwell III and IV, changing the appearance and specification of both vehicles. The specification was later improved toward the end of the war with the Cromwell VII, resulting in an upgrade programme.
      Centaur and Cavalier never met the requirements to enter front-line service. Most were used for training, although a few notable exceptions were used in action.

      Total A27 production consisted of 4,016 tanks, 950 of which were Centaurs and 3,066 Cromwells. In addition, 375 Centaur hulls were built to be fitted with an anti-aircraft gun turret; only 95 of these were completed.
Centaur AA Mk I - notice the small 3 men turret from Crusader Mk.III AA tank

Centaur AA Mk.II with 4 men big turret
     Production was led by Leyland Motors on Centaur, and Birmingham Railway Carriage and Wagon Company on Cromwell. Several other British firms also built Centaur and Cromwell tanks, however, as the numbers required were greater than any one company could deliver. Companies contracted to build the tanks included English Electric, Harland and Wolff, John Fowler & Co., LMS Railway, Metro-Cammell, Morris Motors and Ruston-Bucyrus.
      Production of Cromwell and Centaur was split into two different groups. Cromwell was to be built by BRC&W and Metro-Cammell while Centaur was to be built by Leyland, English-Electric, Harland & Wolf, John Fowler & Co., LMS, Morris, Ruston-Bucyrus. Nuffield also switched production to Centaur when Cavalier completed. To increase Cromwell production capacity, English Electric switched from manufacturing Centaur to Cromwell, but remained tooled for Centaur. This resulted in a number of Cromwells being built with Centaur hulls. By January 1943, when production started, Leyland had become the production and design lead for A27 series including subcontractors producing components. Records show that John Fowler & Co. also produced both varieties.
      Vauxhall produced two Cromwell pilot models - with a turret similar to that of the Churchill - in the expectation that they would build Cromwells once production of Churchill was terminated in 1943, but Churchill production was extended and Vauxhall withdrew from the Cromwell programme.

Design described:

      The frame was of riveted construction, though welding was used later. The armour plate was then bolted to the frame; large bosses on the outside of the plate were used on the turret.
      The suspension was of the Christie type, with long helical springs (in tension) angled back to keep the hull sides low. Of the five road wheels each side, four had shock absorbers. The tracks were driven by sprocketed wheels at the rear and tension adjusted at the front idler, this being standard British practice. 
    Some variants were produced with 360 mm tracks; later, 394 mm tracks were used. As with previous Christie-suspension cruiser tanks, there were no track return rollers, the track being supported instead on the tops of the road wheels, known as the "slack-track" design. The side of the hull was made up of two spaced plates, the suspension units between them, and the outer plate having cutouts for the movement of the road-wheel axles.
      The gearbox had five forward and one reverse gears. The first gear was for "confined spaces, on steep inclines turns". The transmission was the new Merrit-Brown Z.5, which offered differential steering without clutching or braking, a major advance on previous designs. It gave the Cromwell superb maneuverability, with only the German Tiger I, using a similar design, able to match it.
      The Rolls Royce Meteor engine delivered 540 hp at 2,250 rpm giving the Cromwell speed as well as maneuverability. This was the maximum rpm, which was limited by governors built into the magnetos. Fuel consumption on "pool" petrol (67 octane) was between 0.5 and 1.5 miles per gallon depending on terrain.
Rolls Royce Meteor engine
      The driver sat on the right in the front of the hull, with the hull gunner on the left, separated by a bulkhead. The driver had two periscopes and a visor in the hull front. The visor could be opened fully or a small "gate" in it opened; in the latter case, a thick glass block protected the driver. A bulkhead with access holes separated the driver and hull gunner from the fighting compartment.
Cromwell with 6 pdr. turret
      A further bulkhead separated the fighting compartment from the engine and transmission bay. The engine compartment drew cooling air in through the top of each side and the roof and exhausted it to the rear. To allow fording through up to 1.2 m deep water, a flap could be moved to cover the lowermost air outlet. Air for the engine could be drawn from the fighting compartment or the exterior; it was then passed through oil bath cleaners. It was modified so that the exhaust fumes were redirected so that they were not drawn into the fighting compartment, a problem found when tanks were drawn up together, preparing to advance.

      In June 1944, the Cromwell saw action during Operation Overlord, the Allied invasion of Normandy. It had a mixed reception by crews, being faster, with a lower profile and thicker frontal armour plate than the Sherman tank, but also being smaller and more cramped. Cromwell had 76 mm (3 in) of frontal armour compared with 51 mm (2 in) on the glacis of the early Shermans, though it was unsloped and hence less effective in head-on combat. On later Cromwells this was further increased, first to 83 mm (3 1⁄4 in), then to 100 mm (4 in).
Cromwell tank crew of 4th County of London Yeomanry, 7th Armoured Division,
preparing a meal in front of their vehicle, Normandy, 17 June 1944.
Turret and armament:
      In common with British tank doctrine of the time, the vehicle was designed to fire on the move. The turret offered hydraulically powered turret traverse motors with proportional speed control. Later vehicles fitted an all-round view cupola for the commander to identify and track targets. Both gunner and commander had Vickers rotating and pivoting periscopes, while episcopes were fitted in the cupola. There was a 7.92 mm Besa machine gun mounted co-axially to the main armament, operated by the gunner. A second was gimbal mounted in the front of the hull, with 45 degrees horizontal and 25 degrees vertical movement. Sighting was by a No. 35 telescope, which was connected through a linkage to the mounting. In the top of the turret was a 2-inch "bombthrower" angled to fire forward. Thirty smoke grenades were carried for it.
Cromwell with ROQF 75 mm turret
      Early models of the Cromwell were equipped with the QF 6-pounder (57mm) gun. Using the new armour-piercing discarding sabot round, which became available in quantity in early 1944, this gun could penetrate over 100 mm of steel armour at ranges on the order of 910 m, making it effective against all but the most heavily armoured tanks.
      However, British tankers had long complained about this weapon's lack of a useful high explosive (HE) round for attacking soft targets like trucks, anti-tank guns and infantry defences. A HE shell had been introduced for the 6-pounder, but it was described as being largely useless—the calibre of the gun was simply too small to carry a useful load of explosive. This was not entirely accidental; British tank policy of the time suggested that different models of the same tank, carrying different specialised weapons, was a better solution to this problem than a single weapon that attempted to do all things.
     Experience with the US M3 75 mm gun suggested this thinking was wrong, that a single gun could be used in a "dual purpose" role against both tanks and softer targets.
 A M3 75mm gun being salvaged from a knocked-out Sherman tank at 26th Armoured Brigade
workshops in Perugia, Italy, 30 June 1944.
The entry point for an 88mm shell can be seen on the side of the tank's hull.
      This led Vickers to begin development of a 75 mm weapon of 50 calibres in length, which would fire the same HE shell as the US gun, but with a higher propellant load that would make its anti-tank rounds more effective. However, as examples of this weapon began to arrive in May 1943, it was clear it would not fit into any turret that could be mated to the Cromwell's turret ring.
     This problem was eventually solved by the realisation that the 6-pounder could be bored out to 75 mm and fire unmodified US ammunition. While this would lead to less anti-tank performance, this was considered a reasonable trade-off in exchange for the rapid introduction of the HE rounds. The resulting ROQF 75 mm could be easily swapped out with the 6-pounder, and newly built models mounting the gun were known as the Mark V. The ROQF 75 mm would be the primary weapon for the majority of Cromwells produced.

     A close support version of the Cromwell (CS) was fitted with the 95 mm howitzer in place of the 75 mm gun. This too fired HE, though its primary role was delivering smoke shells, covering the other tanks in the unit. This howitzer it was also installed on the Royal Marines' Centaurs turrets. A rapid differentiation between the two tanks is usually facilitated by the absence of the machine gun in the front hull front of Centaur CS.
Cromwells of A Squadron, 10th Mounted Rifle Regiment, 1st Polish Armoured Division
passing an imposing windmill in the village of Terheijden, 6km north of Breda, Holland in early November 1944.
The leader Cromwell is a CS 95mm howitzer. Notice the Besa 7.7 MG in the front hull.

    Some command or OP tanks had the armament removed, leaving space in the turret for further radios. These were fitted with a dummy wooden gun, so as not to appear different to the enemy and attract hostile fire.

Cromwell and Centaur differences:
      Aside from the engine and its ancillaries (fans, radiator, clutch, etc.), both vehicles are very similar designs. While similar however, there were a number of minor variations between Cromwell and Centaur caused by the divergence of design and production.
      Increases in Cromwell's design weight from 24 to 27 tons resulted in a reworking of the suspension during the design process, which was not reflected on Centaur. Cromwell had heavier grade suspension with longer suspension arms. Cromwell's shock absorbers and springs were improved against Cavalier, and increased to four (compared with Centaur's three).
      The method of track tensioning is a commonly noted difference. Initially, the design based on A24 Cavalier used a worm drive for tensioning. This was noted as being slow to operate, and trapped dirt. BRC&W developed an alternative ratchet mechanism based on the Valentine tank, and this was incorporated into the A27M Cromwell design, also enabling the tank to accept wider 15.5" tracks. Centaur under Leyland continued without this development. Some of these differences can be seen in Cromwells built with Centaur hulls, although many were removed with the introduction of the Cromwell final specification. This included the Cromwell method of track tensioning.
      By comparison, Cavalier can easily be identified by the vehicle's rear armour plate, which incorporates Crusader style horizontal angled exhaust louvres.
Cavalier, Cruiser Mk.VII, A24 under construction - rear view
    Cromwell and Centaur both have a flat rear armour plate, with exhaust venting to the top immediately behind the engine deck. For this reason, many Cromwell and Centaur vehicles had a cowl fitted to direct the exhaust gases back where they could not re-enter the tank fighting compartment.
Profile of Cromwell Mk IV tank
Notice the exhaust cowl in the deck of the tank
Further developments:
      An earlier requirement for a 17-pounder armed tank became more important when the Vickers HV 50 calibre 75mm gun failed to fit on Cromwell. A version of Cromwell mounting the more powerful Ordnance QF17-pounder (76.2 mm) had been commenced early in the development process. This required a much larger turret ring, which in turn required the hull to be lengthened and an additional road wheel to be added to each side for a total of six. The result was the Cruiser Mk VIII Challenger, but these were somewhat unwieldy and produced only in small numbers. While successful, production ceased with the much easier conversion of Sherman Firefly allowing greater numbers to be fielded.
A30 Cruiser Challenger
   However, development of the Vickers HV 50 calibre 75mm gun continued, with the bore increasing to fire modified versions of the 17-pounder ammunition. This gun and its ammunition were designed specifically to fit in a turret that a reworked Cromwell-sized design could carry. This gun became the 77 mm HV with only slightly lower performance than the base 17-pounder. By the time this weapon was ready, a number of other changes had been worked into the tank design, producing the A34 cruiser tank Comet which replaced both the Cromwell and Challenger.
A34 cruiser tank Comet
      The A24 design specification had originally been constrained by the available tank engines of the time, delivering only 300 hp and limiting the weight. The evolution to A27M increased the weight slightly, but fitting a 600 hp engine almost doubled the power-to-weight ratio and created a very fast tank. This was combined with the Merrit-Brown gearbox that allowed the tank to steer while still powering both tracks, allowing it to maintain speed while manoeuvring, while tanks like the Sherman or T-34 lost power while turning and necessarily slowed down.
Cromwell at full speed, in ramp test...
      Cromwell was the fastest British tank to serve in the Second World War, with a top speed of 64 km/h. This speed was extremely beneficial in both attack and defence, outmanoeuvring opponents. At least one case is known of vehicle commanders using the vehicle's fast speed to jump large gaps. In The Netherlands, a troop of three Cromwells was able to leap a 6 meters wide canal when surprised by enemy forces. This speed proved too much for even the Christie suspension and in later models the final drive ratio was changed to lower the top speed to 51 km/h, which was still fast for its time.
A Cromwell tank 'jumping' a distance of 9,5meters (31 feet) after taking off from a concrete ramp.
A demonstration at the Royal Armoured Corps - 13th June 1952.
Even at this age, the girl remains very agile !!
      The Cromwell's armament was changed from the 6-pounder to the dual purpose 75mm. This gave a significant reduction in armour penetration compared to newer 6-pounder ammunition, which was becoming available, but added the ability to fire HE (High Explosive) shells, which were more capable against other targets, such as anti-tank guns. The High Velocity 75mm gun was developed in an attempt to give both good anti-tank and HE performance, but in May 1943 proved too big to be fitted to the Cromwell. This issue led to the development of the A34 Comet, while the gun bore was increased to 76.2mm to gain compatibility with the 17-pounder (albeit with smaller shell casings).
A34 Cruiser Comet
      The dual purpose 75 mm main gun fired the same ammunition as the US 75 mm gun as used on the Sherman, and was also fitted to the Churchill, it had around the same HE and armour-piercing capabilities as the 75 mm equipped Sherman tank. The Cromwell's speed and low profile gave an advantage over the Sherman however, giving the tank the element of surprise and making return fire more difficult. Cromwell crews in North-West Europe succeeded in outflanking the heavier and more sluggish German tanks with superior speed, maneuverability and reliability.

      The armour on the Cromwell ranged from 8 mm up to 76 mm thick overall. On all-welded vehicles built by BRC&W, the weight saved by the welding allowed for the fitting of additional appliqué armour plates on the nose, vertical driver's plate and turret front, increasing the maximum thickness there to 102 mm. These vehicles are identified by their War Department numbers carrying the suffix W, e.g. T121710W. The armour compared well with that of the Sherman, although the Cromwell did not share the Sherman's sloped glacis plate.
Cromwell armor diagram
      While the Cromwell was a match for the majority of Axis tanks in use, it was not a match for the armour and armament of the latest German heavy vehicles developed at the same time. British tank design would go through another stage, the Comet tank, before developing the Centurion tank.
Centurion tank - prototype
Combat action


      The Cromwell tank entered front-line service with the Allied invasion of Normandy in June 1944. Cromwells landed with the following forces on D+1. They saw extensive action with the British Army, forming part of the 6th Airborne Division, 7th Armoured Division, 11th Armoured Division, Guards Armoured Division, and 1st (Polish) Armoured Division. The tank was also used by the 1st (Czechoslovakian) Independent Armoured Brigade Group as part of the First Canadian Army in Dunkirk.
Cromwells firing among hedgerows. Normandy, 1944.
Notice the War Department number with W:
Cromwell with apliquée armour described above...
      Cromwells were used as the main tank in the armoured brigades of the 7th Armoured Division, while being used in the armoured reconnaissance regiments of the other British armoured divisions (11th Armoured Division and Guards Armoured Division) in North-west Europe. It excelled at this task because of its speed and low profile. The tank was praised for its speed and reliability, while its low profile made it harder to spot.

      The Centaur was chiefly used for training; only those in specialist roles saw action. The Centaur IV Close Support version with a 95 mm howitzer saw service in small numbers as part of the Royal Marine Armoured Support Group on D-Day. Originally intended to serve as static pillboxes, these examples retained the engine allowing the Marines to advance the tank inland.
Centaur Mk IV CS - HUNTER
Tilly-sur-Seulles, Normandy - France - June, 1944.
      A number of Centaurs were also re-purposed as combat engineering vehicles, such as armoured bulldozer.
Centaur dozer tank - Tank Museum Bovington
      The Sherman remained the most common tank in British and other Commonwealth armoured units in Europe. The Cromwell, in turn, was succeeded by small numbers of the Comet tank. This was based on the Cromwell and shared many components but had been designed from the outset to mount a superior gun, the 77 mm tank gun (a version of the 17 pounder with different ammunition). Only the 11th Armoured Division was fully re-equipped with the Comet before the war ended.

Post war:
      After the war, the Cromwell remained in British service, and saw service in the Korean War with the 8th King's Royal Irish Hussars. Cromwell Tanks were used by Czechoslovakia and Israel.
     Fifty-two Centaur I tanks were donated in early 1946 to the Greek Army, during the opening stages of the Greek Civil War but they were kept in storage due to the lack of trained personnel.
      The British army, Austria and Jordan used the upgraded Charioteer version of the Cromwell post-war. Jordanian vehicles saw action in conflicts in the Middle-East.

Cromwell tank hierarchy.png

Obs.: The development of hull types and armaments occurred independently. Hull types applied to all variants. A single mark could cover up to four types, and a type up to six marks making classification complex. Combinations of mark and type were applied by different manufacturers.

Cromwells types:
  • Cromwell I: Early vehicles armed with the Royal Ordnance QF 6 pounder (57 mm) gun (with 64 rounds of ammunition). Only 357 produce due to the switch from the 6 pounder (57 mm) to the 75 mm gun.
Cromwell I with 6 pdr. gun
  • Cromwell II: Pilot vehicle built by Vauxhall with cast turret similar to Churchill mk.VII. This did not enter production.
Cromwell II with 6 pdr. gun. Notice the shape of turret
  • Cromwell III: Centaur hull fitted with Meteor V12 engine. Turret houses Royal Ordnance QF 6 pounder. Only ~ 200 produced due to scarcity of Centaur I's.
Cromwell III with 6 pdr. gun and side skirts type desert
  • Cromwell IV: Centaur hull fitted with Meteor engine. Turret houses 75 mm ROQF Mk V gun. Later Cromwell IV's saw the introduction of the Final Specification, changing some features (such as track-adjuster) to normal Cromwell standard. The most numerous variant with over 1,935 units produced.
Cromwell IV with 75mm gun
Welsh Guards regiment - Guards Armoured Division
  • Cromwell V: Cromwell built to Final Specification and armed with the 75 mm gun.
Cromwell V with 75mm gun
  • Cromwell VI: Cromwell built to Final Specification and armed with 95 mm howitzer. 341 produced.
Cromwell VI with 95mm howitzer
  • Cromwell VII: Upgrade to Cromwell IV, V, and VI armed with the 75 mm gun. Some hulls were upgraded with features from later hull types. Wider (15.5 inch) tracks, and upgraded suspension (where not fitted earlier in the production programe). These were introduced very late in the war and did not see much in the way of combat. ~ 1,500 produced, Some saw combat in the Korean War and many were later converted to FV4101 Tank, Medium Gun, Charioteer.
Cromwell VII with 75mm gun
  • Cromwell VIII: Cromwell VI reworked with same upgrades as VII but retaining the 95 mm howitzer.
Hull variants:

      Hull types ranged from Type A to Type F. Each type applied a different package of changes to the hull design to different marks of tank. Changing the vehicle type allowed the introduction of changes without changing the overall offensive capability.

Major features:
Applicable to:
ARivetedFirst version with:
  • Top opening driver & hull gunner hatch
  • 4 lockers
  • Layered 6 mm + 8 mm floor plate
  • Cromwell I
  • Cromwell III
  • Cromwell X
  • Cavalier I
BRivetedAs A, but:
  • Side opening hatch for hull gunner
  • 3 lockers
  • Hull gunner periscope deleted
  • Centaur I
  • Cavalier I
CRivetedAs B, but:
  • Engine compartment armour reduced to save weight
Later vehicles added:
  • Hull gunner periscope reinstated
  • Revised trackguards
  • Cromwell I
  • Cromwell III
  • Cromwell IV
  • Cromwell V
  • Centaur I
  • Centaur III
  • Centaur IV
DD: Riveted
Dw: Welded
As C, but:
  • Engine deck redesigned for ease of access to radiators
  • Hull gunner periscope
  • Revised trackguards
On welded vehicles:
  • Single-piece pivot-opening driver hatch
  • Applique armour
  • Cromwell IV
  • Cromwell Vw (welded)
  • Cromwell VI
  • Centaur III
  • Centaur IV
EE: Riveted
Ew: Welded
As D, but:
  • 14mm single skin floorplate to hull
On welded vehicles:
  • lower ratio final drives
  • Cromwell IV
  • Cromwell Vw (welded)
  • Cromwell VI
FRivetedAs E, but:
  • Driver and hull gunner side opening escape doors
  • 2 lockers
  • 2 turret bins replacing the removed lockers
  • towing rope on front glacis
Later vehicles added:
  • sprung towbar
  • Cromwell IV
  • Cromwell VI

Vehicles based on Cromwell/Centaur chassis:

      A number of further vehicles were based on the Cromwell tank hull, either re-working existing vehicles or built from scratch with the Cromwell as the basis:

  • Cromwell Command: The main gun was removed and it carried one each of the No. 19 (Low Power) and No. 19 (High Power) wireless sets. These were used by brigade and divisional headquarters.
Cromwell Command  from 1st Armored Division - exercises before the invasion of the continent
 Scarborough - England - 14 July 1944.
Notice the dummy gun 
  • Cromwell Observation Post: Cromwell IV, Cromwell VI, or Cromwell VIII fitted with extra radio equipment; 2 x No. 19 and 2 x No. 38 (portable) radios. The main gun was retained.
  • Cromwell Control: Two No. 19 Low Power radio. Main armament kept. Used by regimental headquarters.
  • Centaur, AA Mk I: Used a Crusader III, Anti-Aircraft Mk II turret fitted with twin 20 mm Polsten guns. Were originally deployed in Normandy, but withdrawn as unnecessary due to Allied air superiority. 95 were produced.

Centaur AA Mk.I

Centaur AA Mk.II
  • Centaur Dozer: A Centaur with the turret removed and given a simple dozer blade operated by a winch. Since the winch passed over the top of the hull it was not possible to retain the turret. One of "Hobart's Funnies". 250 produced.

Centaur dozer
  • Centaur Observation Post (OP): A Centaur with a dummy main gun, and extra radio communications. 
  • Centaur Kangaroo: A Centaur with turret removed to make space for passengers. (few produced).
Centaur ARV with crane stowed

Centaur ARV with crane in position

  • FV 4101 Charioteer: a post-war  Cromwell hull upgraded with a QF 20 pounder gun in a tall turret, designed in the 1950s to give more fire support. 200 produced.
FV 4101 Charioteer tank destroyer
Yad la-Shiryon Museum, Latrun - Israel. 2005
Other variations in Cromwell tanks:
  • Cromwell CIRD: Several "Cromwell IV" tanks were experimentally equipped with Canadian mine detonators CIRD (Canadian Indestructible Roller Device) in trials at SADE, where it was found that the center of gravity of the set was very shifted forward, generating great instability and preventing its effective use in an operational way. The Churchill infantry tank was more suitable, being chosen.   See more about this specialized aparatus in this Bunker's article about Churchill Mk.IV AVRE CIRD.
Cromwell Mk.IV with CIRD in trials at Specialized Armour Development Establishment (SADE)
  • Cromwell Prong: In 1944, many "Cromwell" tanks were equipped with the Cullin Hedgerow Cutting Device, which is a set of plowshares enabling overcoming live fences surrounding fields in Normandy (bocages). The device was designed by Sergeant Cullin from the US Army.  After the fighting in Europe, the devices were dismantled.
Centaur with Cullin Device in test installation in Great Britain.
Many Cromwells used this device in Europe.
Cromwell IV in trials with Tulip rockets.
Cromwell Tulip - artistic view
Designs based on the Cromwell:
      The Cromwell tank design was also used as the basis for the design of following vehicles:
  • A30 Challenger: The design combined a lengthened Cromwell chassis with widened superstructure to mount the 17-pounder gun in a new turret.
A30 Challenger
  • A30 Avenger SP 17pdr: A version of the Challenger using a lighter open-topped turret in a gun-carrier role.
A30 Avenger SPG
  • A33 Excelsior: An experimental design with elements of Infantry tank as a possible replacement for Churchill tank. When the Churchill continued to meet requirements, development was halted.
A33 Excelsior
  • A34 Comet: A tank based on lessons learned from the Cromwell development, incorporating a larger turret ring, now enabling this class of tank to utilise the latest gun available. This tank reflects much of what was intended for the Cromwell.
A34 Cruiser Comet

Tank, Cruiser, Mk VIII, Cromwell (A27M)
TypeCruiser tank
Place of origin                                                                                   United Kingdom
Service history
In service1944–1955
Used by
British Army, Israeli Army,
Greek Army,Portuguese Army
World War II, 1948 Arab-Israeli War, Korean War
Production history
Leyland, then Birmingham Railway Carriage and Wagon Company from 1942
ManufacturerNuffield Mechanisation and Aero
Unit cost£10,000
No. built4,016
Mass28.0 t
Length6.35 m
Width2.908 m
Height2.49 m
5 (Commander, gunner, loader/radio operator, driver, front gunner)

Armour76 mm on Mk.IV, 100 mm on Mk.V
Ordnance QF 75 mm
with 64 rounds
2 x 7.92 mm Besa machine gun with 4,950 rounds
EngineRolls-Royce Meteor V12 petrol
600 hp (450 kW)
Power/weight21.4 hp (16 kW) / tonne
Merritt-Brown Z.5 gearbox (five forward and one reverse gear) driving rear sprockets
SuspensionImproved Christie
Ground clearance410 mm
Fuel capacity500 l + optional 140 l auxiliary
270 km on roads
130 km cross country
Speed64 km/h with 3.7:1 final reduction drive

The kit:
      When I built this kit many years ago, I did not photograph the construction steps. The kit was built in a crude way and brush-painted, with wrong markings and no research. But since plastic is almost eternal and the Law of Conservation of Matter in Plastic Modeling states that "Nothing is lost, everything changes!", I decided to bring this old lady back to life. And in honor of its longevity, I did an "old-time" painting. Verlinden rules !!!!
The amazing Tamiya kit (#35221), from 1997.
      I stripped all the old paint and the wrong markings with a 24-hour caustic soda bath. After this pickling bath, I neutralized the alkalinity of the plastic surface with a quick bath (2 hours) in vinegar + water (50% + 50%). This pH neutralization is very important to prevent caustic soda residues from attacking future paint, especially in small recesses. After the acid bath, an abundant running water wash and the plastic is ready (after drying, of course) for a new painting without scares or accidents. 
      Sorry about don't have photos of these steps, but these steps are almost obscene and I want to keep the Bunker FREE FOR ALL AUDIENCES rating.
      But while all this chemistry developed, I went to research the markings I wanted for my Cromwell. My kit in question is a Prong version, with the Cullin hedgerow cutter. Cromwell Mk.IV Prong from 11th Armoured Division; 15th/19th The King Royal Hussars - Armoured Reconnaissance (Recce) Regiment, C Squadron in France, Normandy, September 1944.

      The decals are from my spare parts ark and the painting I used Vallejo and AK colors:

Like the vast majority of tanks in France in 1944, this Prong featured a large amount of stowage stuff on its rear deck. Tine to select some details from Value Gear:
Value gear details positioning test...

      And the old Tamiya girl after a light weathering and with the accessories installed: Meet the Cromwell Mk.IV Prong providing recce duties in the C Squadron of Armoured Reconnaissance Regiment from 15th/19th The King Royal Hussards. in the 11th Armoured Division at Normandy, France. September 1944.
Cromwell Mk.IV Prong - C Squadron of Armoured Reconnaissance Regiment from 15th/19th
The King Royal Hussards - 11th Armoured Division - Normandy, France. September 1944.

Cromwell Mk.IV Prong with Kojak and Rover, the dog.

Cromwell Mk.IV Prong - C Squadron of Armoured Reconnaissance Regiment from 15th/19th 
The King Royal Hussards - 11th Armoured Division - Normandy, France. September 1944.
See you soon, Lads!!