In 1952 the American Army was about to put into service it’s brand-new light tank – the M41 Walker Bulldog.
The M41 was replacing the WW2 era M24 Chaffee in army service, and it was indeed a huge upgrade in speed, armour, and firepower.
However concerns were being raised that the M41 was simply too big for its role as a reconnaissance vehicle
while, at the same time, being too small and cramped to operate effectively as a frontline tank
The M41 was intended to be deployed alongside airborne units
but, weighing in at nearly 26 tons it was far too heavy for airdrops to be practical.
So, as early as May 1952 the US was in the market for a replacement vehicle
. Three companies were competing for a production contract – Cadillac Motor Car Division, Detroit Arsenal, and Aircraft Armaments Incorporated
Each had submitted their own proposal for the army’s new light tank
The Cadillac and Detroit designs were quite traditional vehicles, and the proposals were remarkably similar, so both would fall under the designation T71
The A.A.I proposal, however, was an innovative design, and was completely unique, resulting in the vehicle getting its own designation – T92
The T92 was radically different from the American light tanks that came before it, which was hugely attractive to the army
The proposal offered massively improved performance over previous designs, and provided the army with an opportunity to test some of the vehicle’s more novel features
Following a review of a full-scale wooden model of the vehicle, AAI were given a contract to produce a T92 prototype.
Shortly after, in July 1953, the army and the pentagon authorized continued development of the vehicle
Development would continue for the next few years, and would progress at such an impressive pace that its competitor, the troubled T71 project, would be cancelled in January of 1956.
The T92 was the last tank standing – but was it good enough?
The US army intended to find out, and the first T92 Pilot Model arrived at Aberdeen Proving Grounds for testing in November 1956.
There was a lot to test, as the design was almost completely novel
Most noticeably it was considerably smaller than the M41, with a short, flat hull and a very low profile
The hull consisted of numerous welded steel plates that sloped at the front to form its distinctive wedge-shaped silhouette
This had the added bonus, in theory, of helping to deflect the shockwave from a potential nuclear blast
The armour protection of the T92 wasn’t exactly nuke-proof, but offered a very respectable 31.7mm of plate at its thickest point on the front of the turret,
which was almost identical to the maximum protection of the M41.
Since the design kept the same armour thickness as the M41, it needed to shed some weight
This was accomplished using advanced materials – many components on the T92 were manufactured using a lightweight aluminium alloy
with the fenders being a blend of aluminium and fibreglass-reinforced plastics
These changes meant that the T92 weighed in at 18 tons – 8 tons lighter than its predecessor and light enough to be air transported or even deployed via parachute.
To further increase mobility, the vehicle used a unique “Torsilastic” suspension system.
Inside these 4 cylinders on the side of the vehicle there is a metal shaft firmly attached to a tight rubber sleeve.
Each roadwheel is connected to one of these metal shafts, and the rubber sleeve functions as a spring, absorbing shocks and softening the ride
while being a lot quieter than a metal spring system
Since the entire system is externally mounted, it meant that the T92 had a lot more space inside than similar sized vehicles.
The interior layout wasn’t typical either – the Continental AOI engine was located in the front right of the hull.
This was paired with an Allison XT-300 7 speed transmission, and both could be removed as one pack.
The driver sat to the left of the engine and could take advantage the vehicles 357 horsepower to reach a top speed of over 56 km/hr.
With the engine at the front of the tank, the crew compartment was shifted back,
and a large two-part armoured door was added to the rear of the vehicle.
This allowed for easy exit in case of an emergency, and provided more convenient access into the hull.
The vehicles distinctive turret sat on an 89-inch turret ring.
On either side of the turret were cupolas armed with machine guns – one for the gunner on the right and one for the commander on the left.
These could be armed with either a .50 calibre or .30 calibre machine gun, and could be independently rotated through 194 degrees.
Between these cupolas there was a large gap in the turret where the main armament was mounted.
Despite being so much smaller and lighter than the M41, the T92 mounted an almost identical 76mm gun in a cradle in the middle of the turret.
The difference being that the gun on the T92 was mounted upside-down.
This was to allow the addition of a semi-automatic loading mechanism,
meaning the loader, situated in the back left of the vehicle, could load shells onto a tray behind the breach,
which would then be rammed mechanically into the gun for firing, allowing the tank to fire up to 12 rounds a minute.
Both the gunner and the commander could aim and fire the main gun,
meaning the vehicle had some built-in redundancy and could keep fighting effectively with only 3 crew members if the worst should happen.
Testing in 1956 and 1957 was promising, but revealed a number of areas where the tank needed improvement.
Most of these issues revolved around the vehicle’s unique suspension and tracks.
The T92 used a rubberised band-type track that didn’t require pins, but instead were reinforced with steel cables.
These proved to be prone to breaking or slipping off, and were replaced with more typical tracks from an M24 Chaffee after just 202 hours of testing.
In an attempt to stop the vehicle from throwing its tracks, an additional compensating idler wheel was added at the back,
which kept keep tension on the tracks while traversing difficult terrain.
The 2nd Pilot vehicle arrived at Aberdeen in July 1957.
By this time the T71 had been cancelled, and the T92 project was well underway
with funding being made available to produce two more pilot vehicles that would incorporate the improvements suggested so far.
At this point, the vehicle was expected to enter full scale production by the middle of 1962.
Developments in the Soviet Union would ruin these plans.
In 1957 the US Army discovered that the Soviets new light tank, the PT-76, could swim.
It was at this point deemed critical that the US Army’s own light tanks be amphibious as well,
and the T92 was assessed to determine if it could be adapted into an amphibious vehicle
- the army concluded pretty quickly that it could not.
At this point questions were also asked about the effectiveness of the T92s 76mm gun
at a time when even 90mm guns would struggle to cause damage to soviet armour of the period.
In late 1958 the T92 project was cancelled,
and the Army began development of its own amphibious light tank,
which would eventually culminate in the iconic but problematic M551 Sheridan.
Of the two T92 vehicles that were built, only one is known to have survived.
The surviving pilot sat outside the Aberdeen Proving Grounds for years until it was moved into storage in 2010.
The T92 may not have ever seen combat
but by all accounts, it was an incredibly capable vehicle and would’ve made an excellent addition to the US arsenal.
Sunk because it couldn’t swim, the T92 will remain an iconic part of American armoured history,
and let’s hope the surviving example gets the restoration it deserves.