29+5 or 30+4
In June of 1944, the Allies landed in Europe. Many reports from the front lines of German heavy tanks became a weighty argument for accelerating the heavy tank program. A document describing two new heavy tanks was signed on September 14th, 1944. Engineers were to create the T29, with a 105 mm gun, and the T30, with a 155 mm gun.
In April of 1945, the military ordered that one of the T29 prototypes should be equipped with a 120 mm T53 gun. This vehicle was initially indexed T34. However, due to the end of WWII, work on the T29 slowed down, and this T34 prototype was never built.
The issue of increasing the firepower of tanks was still unsolved. The T53 gun, based on the 120 mm AA gun, could fire a shell at 1100 m/s, which was a very good result in those days. A HVAP shell with a tungsten core could reach speeds of 1300 m/s. In the middle of May of 1945, it was decided that this gun would be put into two prototype T30 tanks. The T34 index migrated to these vehicles.
Aside from the gun, the T34 had a different turret than the T30. In order to balance the long gun, a counterweight was installed on the rear. Otherwise, the vehicles were identical. In 1946, an experimental T34 was ready.
During trials at Aberdeen and Fort Knox, the military was faced with two serious issues. One was that the ventilation could not handle the amount of gases that formed during firing. After several shots, the concentration of gases inside the turret reached dangerous levels.
The second problem was that several tankers ended up in the hospital with burns. After firing, the barrel still held some amount of hot gases. As soon as the breech opened to extract the casing, they were sucked back into the turret, mixed with air, and ignited.
The problem was resolved with a fume extractor, a special device to extract excess gases from the barrel. It was installed on the cannon, near the muzzle. This device was already successfully used on several other tanks.
The T34 was not mass produced. Only two experimental vehicles were built. In the 1940s, the Ordnance Department re-evaluated its heavy tank plans, in part due to the appearance of the IS-3, which was lighter than its American equivalents, but had superior protection and comparable firepower.
As a part of an overall downsizing of the military budget, the T29, T30, and T34 programs were first reduced in scope, then cancelled completely. Most finished prototypes were scrapped. One T34 escaped this fate, and is currently present in the Patton museum at Fort Knox.
Article author: Vladimir Pinayev
- P. Chamberlain, K. Ellis, British and American Tanks of WWII, Moscow, Astrel, 2003
- R. Hunnicut, Firepower: A History of the American Heavy Tank, Presidio, 1987
Original article available here.