The Heavy Tank T29 was developed in response to the appearance of heavy German tanks in the European theatre, and carried a 105mm gun on a chassis similar to that used on the M26 Pershing.
As soon as US armoured forces clashed with German tanks in Tunisia in December 1942 it became clear that the newest German tanks were rather more formidable than expected, and that US tank design and doctrine wasn't as good as believed. Things only got worse when the Tiger began to appear in significant numbers, starting in Tunisia in 1943 and continuing during the fighting in Italy. In 1944 work was quite advanced on the Medium Tank T26E1, which emerged in 1945 as the M26 Pershing, armed with a 90mm gun. This could just about cope with the Tiger, but it was likely that the Germans would soon produce heavier tanks.
In March 1944 development began on a new heavy tank, to have superior firepower and armour to the T26. It was to use a Ford GAC V-12 liquid cooled engine, providing 750-770hp, and use a cross-drive transmission (a single unit that acted as the transmission, steering gear and brakes).
On 14 September 1944 the production of four pilots for a new heavy tank was approved, split into two Heavy Tank T29s, armed with a 105mm gun and two Heavy Tank T30s, armed with a 155mm gun. The two models would be very similar, other than the main gun and related equipment.
The new tank used a number of features from the Pershing. Its tracked were based on the Pershing's T80E1 tracks, with 5in end connectors added to give a width of 28in. The T29 had eight road wheels (up from six on the Pershing). The hull was constructed from a similar mix of cast armour and rolled plates. The hull was fairly simple in form - almost rectangular, with a sloping front. The top of the superstructure was only slightly above the top of the tracks.
The original version of the cross drive transmission had an electric control system, with a mechanical back up if the electrics failed. The electric system lacked any feedback, and was replaced with a mechanical system, using a single control lever. Both the driver and co-driver had controls, and the emergency backup system was also retained. The cross-drive system made the tank much easier to steer. It could also be used to turn the tank on the spot, very handy in difficult terrain.
The T29 had a massive turret, at least half the length of the tank itself. The 80in turret ring was carried just in front of the centre of the vehicle, but extended a long way back. The turret was so large that it could carry a crew of four. The tank commander sat in the centre of the large bustle, under his cupola. The gunner was on the front-right, and there were two loaders, one on each side of the rear part of the cannon. Two hatches were located on the turret roof just above their positions.
The T29 was armed with a 105mm gun T5E1 in a combination gun mount T123. It was a long barrelled gun, with a muzzle velocity of 3000ft/ sec with a 39lb armour piercing shot or 3,700ft with a lighter hypervelocity armour piercing shot. It could also fire a 33.5lb HE shell. There was space for 63 rounds of 105mm ammo in the tank.
In February 1945 the General Staff authorised production of the T29, as they wanted its 105mm gun for use against Japanese bunkers and caves. On 1 March 1945 production of 1,200 tanks was suggested. On 12 April production of 1,152 tanks was approved (as a 'limited procurement' type), and in the same month another four pilot models were ordered. One of these late became the prototype for the Heavy Tank T34, armed with a 120mm gun T53. Army Ground Forces objected to the T29 on the grounds that it was too big and they had no requirement for them, but they had an unfortunate track record of blocking heavier tanks, including the Pershing, leaving the American armoured forces in Europe struggling with equipment that wasn't capable of taking on the Panther or Tiger II tanks.
In mid 1945 one Heavy Tank M6A2E1 and one Heavy Tank M6A2 were used to test the gun, mount, fittings and internal installations for the T29.
As the war came to an end a number of changes were made to the T29 orders. The production contract was cancelled after one T29 had been completed. A second was partly completed. All of the existing parts were then moved to the Detroit Arsenal, to be used to produce ten pilots (reduced to eight on 10 July 1947).
The first T29 was delivered to the Aberdeen Proving Ground in October 1947. By this point there was no interest in the type in its own right, but it was used to test the power train, as many of its components were being considered for newer designs. The second T29 was delivered in April 1948 and the third in May 1948.
The T29s were used for a number of experiments. The first one was given an Allison liquid cooled V-12 aircraft engine, as the T29E1. In order to fit the new engine the hull had to be lengthened by almost two inches.
The second T29 was given the Heavy Tank Turret T5, which used a hydraulic power turret traversing and elevating mechanism and a computing gun site produced at MIT. In 1948 this version was designated as the T29E2.
The eighth T29 was given a modified 105mm gun that could operate with a range finder T31E1 and telescope T93E2 in a modified mount, and a number of panoramic telescopes. It was used to test out integrated fire control systems, as the T29E3. The range finder had a base length of nine feet, so the T29E3 can be identified by the boxes containing the range finder lenses, mounted on the sides of the turret. Similar range finders were common on warships.
Hull Length: 25ft
Hull Width: 12.5ft
Height: 10ft 7in
Combat Weight: 138,000lb
Engine: 750hp Ford GAC V-12 liquid cooled engine
Max Speed: 18.5mph, 22mph on roads
Armament: One T5 105mm gun, one coaxial .50 MG, one .50in AA gun on turret, one .30 MG in bow mount