- Yes
- No
The Australian Cruiser tanks were the first and only domestically produced tanks of the Commonwealth. Despite the war-induced material shortages and lack of prior experience, Australian engineers managed to create a design on par with those of other major nations. War Thunder already has the A.C.I and A.C.IV tanks, so here I shall introduce the Australian Cruiser Tank Mark III Thunderbolt, or A.C.III for short.
History
Despite the generally good performance of the A.C.I, its 2-pounder gun was recognised to be obsolete by the time it entered production in 1942. Therefore, up-gunning the A.C tank was made a priority. However, the rationale for choosing the 25-pounder appears unclear. Three leading theories I’ve picked up on are:
- The 17-pounder would take some time to arrive from Britain, while the 25-pounder was already produced locally. Therefore, the 25-pounder would be used as a stopgap until the 17-pounder was ready.
- The 25-pounder had a great HE shell that could be used in close support, similar to the other howitzer-armed close support tanks fielded by other nations.
- The AP shot of the 25-pounder was found desirable for anti-tank operations. This is plausible given that Australia was mainly expecting to fight lightly armoured Japanese tanks, against which the penetration of the 25-pounder would be adequate and the damage of the shell would be great.
The truth is likely a synthesis of these three theories: while the 17-pounder would be necessary to fight heavily armoured German tanks, the 25-pounder would work well in the interim (especially since many thought that a Japanese invasion of Australia was imminent) and would still be useful as a support tank later on.
Regardless of the actual reason, the 25-pounder armed version was sorely needed. A 25-pounder was experimentally mounted on an A.C.I and was eventually trialled on 29 June 1942, but the Army was in such a hurry to get the A.C.III that even before the trials were performed, they ordered 400 A.C.IIIs from the Ministry of Munitions on 27 May.
The first prototype A.C.III was produced in January 1943 and had several changes from the A.C.I apart from the new 25-pounder. The size of the turret was increased (the turret ring diameter increased from 54in to 64in) to house the bigger gun. The hull machine gunner was removed and the gun port was covered by sloped armour to increase ammo storage and hull protection. A new engine was installed, bringing power up to 397hp.
Testing of the A.C.III went well, with only minor faults being quickly corrected, and the first batch production of up to 150 tanks was authorised. But even as production went on smoothly (by May, 146 hulls and 106 turrets had been cast), support for the whole tank program began to wane. On 15 July 1943, the War Cabinet officially cancelled the Australian Cruiser tank program, replacing it with M4A1s received from the United States. The sole prototype A.C.III is now housed at the Australian War Memorial.
Debate about the gun
Update: As several commenters below have noted, the standard QF 25-pounder most likely was the gun fitted to the production A.C.III, while the L/34 25-pounder was a singular test vehicle (the use of the short 25-pounder, also stated below, is improbable). Since this suggestion is for the production A.C.III, the standard 25-pounder will be assumed, while the long barrel 25-pounder could be added as a separate vehicle.
There are three possibilities for the model of the gun.
The first is the standard Ordinance QF 25-pounder Mark II. The gun was produced in Australia from 1940 to 1943, so it’s usage is plausible. Anderson stated that the regular 25-pounder was used on the initial prototype (presumably the one converted from an A.C.I), while the production prototype used a lengthened gun (detailed below). On the other hand, the Ministry of Munitions document regarding the regular and shortened 25-pounder says (on page 25, page 20 in text): “It was fortunate the 25-Pdr. recoil system had already been redesigned in order that a standard 25-Pdr. Gun could be mounted in the Australian Cruiser tank…” This implies that the standard 25-pounder was modified to be used on the A.C.III, although it’s unclear whether this was just a test or was meant to be standardised for production.
The second is a lengthened 25-pounder. Cecil states that the gun was tested on an A.C.I (probably the initial A.C.III prototype described earlier), while Anderson says the gun was also used on the production prototype. Unfortunately, the two of them don’t exactly agree on specific design figures: Cecil claims it was an L/34 gun and increased muzzle velocity by 138m/s (although some say he was comparing the AP round to the regular HE round, so the actual increase is just 77m/s), while Anderson claims it was an L/32 gun and increased muzzle velocity by 46m/s. It’s even possible that they are talking about two different guns, both of which were tested on the A.C.III platform.
The third is the Ordnance QF 25-pounder Short (Aust) Mark I, an Australian variant of the 25-pounder with a shortened barrel. Anderson vigorously argued against this possibility, and I personally find it unlikely too. The Ministry of Munitions document quoted above suggests that the 25-pounder version for the A.C.III was already produced when development of the short version started, which was why the short version could readily reuse the recoil system. Additionally, the development timeline of the short 25-pounder had always lagged behind that of the A.C.III. While the initial prototype of the A.C.III entered testing in June 1942, design of the short gun only began in September. As proving ground and combat trials of the short gun were conducted in December 1942 and early 1943, respectively, the production prototype of the A.C.III had also been completed. Therefore, it is impossible for the short gun to have been mounted on the initial prototype, and improbable to have been used on the production prototype (the designers wouldn’t have used a gun still in testing, possibly subject to various faults and design changes, especially since they already had a reliable gun from the initial prototype available).
Specifications
Apart from the gun, the A.C.III’s specifications should be very similar to that of the A.C.IV in-game, which was developed from it.
Crew: 4 (driver, commander, gunner, loader)
Length: 6.32m
Width: 2.77m
Height: 2.56m
Empty weight: 26 tons
Max speed: 48km/h
Engine: Perrier-Cadillac triple engine (common crankcase), 397hp
Power to weight: 15hp/t
Armament: 25-pounder (see Debate about the gun section for debate over model) probably with AP, HE, HEAT; Vickers .303 coaxial MG
Gun elevation: unknown (both the A.C.I and A.C.IV have -10˚/+20˚ elevation, and blueprints suggest that there should be enough room inside the A.C.III turret for the same. However, the blueprints are quite blurred and I’m not a mechanical engineer, so I was unable to confirm these figures)
More pictures
Side on view
A.C.III at the Australian War Memorial
While the gun appears to be a 25-pounder, the hull suggests that this was probably the A.C.I fitted with the 25-pounder for gunnery testing
Image from “Fire! The 25-Pounder in Australian Service” alleging that a L/34 25-pounder was tested on an A.C tank
Closeup of turret
A few images of the blueprints; the full document is linked in the Sources section
In game
The arrival of the A.C.III will finally finish the Australian Cruiser tank series in War Thunder. The 25-pounder isn’t the best anti-tank weapon, but its AP penetration should be enough for side shots and the HEAT can crack harder targets (if it gets them, that is; there appears to be quite some debate on the forum over what rounds the 25-pounder had in service). The armour and mobility are both quite decent, always giving it an option to either tank shots or outmanoeuvre the enemy.
Sources
- “British and American Tanks of World War II” by Peter Chamberlain
- “Fallen Sentinel: Australian Tanks in World War II” by Peter Beale
- https://tanks-encyclopedia.com/ww2/Australia/AC3_Thunderbolt.php
- Full blueprints of the A.C.III at the National Archives of Australia
Sources for 25-pounder: - Ministry of Munitions document on the regular and short-barrelled 25-pounders
- https://nigelef.tripod.com/25pdrsheet.htm
- “Fire! The 25-Pounder in Australian Service” by Michael K. Cecil
