The SU. . Army
The T69 as it sits today at the Armor & Cavalry Collection.
THE U.S. 90 MM GUN TANK T69
Robert L. Cogan, Curator
While autoloading tanks have become more common place in armies around the world, they’ve had a long and tumul- tuous history of development. Reliability, rate of fire, complexity of maintenance, and space for crew and ammunition are all challenges that have plagued devel- opment. For the U.S., the first foray into autoloading systems occurred during World War II with the T22E1, a variant of the program that would lead to the M26 Pershing. Reliability issues would cause the T22E1 to be scrapped in 1944, and no autoloading tanks would see service during the war. The idea, how- ever, persisted with American tank designers.
In December 1948, military characteris- tics for a new medium tank design, the T42, were published by the Ordnance Technical Committee. One of the speci- fications for the T42 was to include an automatic loading system if practical. The T42’s turret design (which would be later used for the M47 Patton II medium tank) proved too cramp to fit any autoloader designs. Another issue
Spring 2026 CAVALRY & ARMOR JOURNAL
that had to be solved was how to mini- mize the amount of move parts in the loader to prevent the 90 mm gun rounds from jamming. The answer, developed by the Rheem Manufacturing Company, was to use an oscillating turret.
In an oscillating design, the tank’s turret traverses left and right like a standard turret. However, elevation is obtained by rotating the entire top half of the turret up and down. This means the only move- ment of the gun on the loading line (the
The left side of the turret, showing the two separately cast pieces of the oscillating design.
path the round travels when loaded) is through its recoil and limits the possibility of jamming between the gun and load- ing system.
Rheem began working on its turret design in 1951, but construction would not be completed until January of 1955. That same month, the third T42 pilot vehicle, with registration number 30163671, was modified to receive the oscillating turret in Detroit and was designated as the 90 mm Gun Tank T69. The turret was armed
The T69 as it appeared during testing at the Aberdeen Proving Ground in 1955. 31
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