T92 LIGHT TANK

Received in 1966 the US Army light tank М551 Sheridan made a splash among specialists. The case of aluminum alloys, 152-mm gun — launcher ATGM “Shillelagh”, the ability of the transport aircraft and parachute landing — it was all tanks for US, and for most light tanks the rest of the world a new word in the design and tactics of application. However, the value of these innovations were controversial, but it is not even that… All of the above is well known to many history buffs tanks. Much less known is that if the “cards lay” differently, the American army would get a completely different, though no less interesting light tank T92.

Since the story about this machine, I can not comment on the history of the American light tanks.

Enlisting in the Second world war with a 12-ton MZ “Stuart”, armed with 37-mm gun, American tank crews consistently move on the M5, and then the M24 “Chaffee”. This tank already weighed 16.5 tons and had a much more powerful 76-mm gun. The next step is the “weighting light tank” was the appearance in 1951, almost no different in the scheme of the M41 “Walker Bulldog”. 24-ton machine, superior firepower and weight of a medium tanks of world war II, became a “crowning development” of “classical” ways of improvement of a light tank. Trying to go this way was the creation in early 1953 t49 tank, armed with 90-mm cannon, and weighed over 25 tons. Despite the good results shown in the tests, the us military decided to go this way is meaningless, as it turns out the tank is too heavy and expensive to easy and too weakly armed (as conceded by the ammunition and sighting devices) and armored for a medium.

In may 1952, the Committee on arms announced the requirements for a new light tank that was to replace the M41. Initially it was assumed that the weight of the new machine is 20 tons, later this figure was reduced to 18. Tank wanted to arm the 90-mm gun, which gave him the opportunity to effectively deal with almost all armored vehicles a potential enemy, but the results of the preliminary study, made by experts of the Detroit Arsenal, it became clear that have limited the 76-mm gun, but it must be equipped with automatic loading. The competition received more than a dozen of various projects. In June 1953 at a meeting at Fort Knox has identified three contenders to win the competition.

The first of these was developed at the Detroit Arsenal and was a 18-ton tank armed with 76-mm cannon in the low desert tower. Ammunition of the guns was 60 shots, 18 of which were placed in the automatic loader. The presence of the latter allowed to reduce the crew to three people. Two of them, the tank commander and gunner were placed in the tower. The place of the third crew member — the driver is positioned in the center front of the hull. The armor corresponded to that of the precursor, the tank “Walker Bulldog”. In the aft were transverse-mounted 340-horsepower carburetor – tion engine AOI-628 and transmission of HT-270, transferring driving torque on the driving sprocket at the rear. Four carrier roller had torsion-bar suspension. Complementary suspension front idler wheels and three track-return rollers on Board.

T92:

1 — drive sprocket;

2 — support roller;

3 — supporting the roll;

4 — Dragoon;

5 — spare tracks;

6 — 76-mm gun Т185Е1;

7 — the hatch of the battery compartment;

8 — driver’s hatch;

9 — 7.62-mm machine gun;

10 — turret gunner;

11 hood left gas tank;

12 — hatch starboard of the tank;

13 — turret commander;

14 — 12.7-mm machine gun;

15 — lights;

16 — surveillance device commander of the tank;

17 — the commander’s periscope;

18 — periscope gunner;

19 — surveillance device of the gunner;

20 — entrenching tool in a special basket;

21 — aft double doors;

22 — box exhaust system;

23 — louver cooling the engine compartment.

The second project was proposed by the firm “Cadillac Motor car Division”. Tank T71 was a relatively lightweight (17 ton) machine with 76-mm cannon Т185 located in the regular (manned) tower. The weapon was the same gun M32, which was mounted on “Walker Bulldog”, but equipped with a device for quick loading. The crew consisted of four people, three of them — the commander, gunner and loader were situated in the turret, and the driver sat on the left in the front of the case. Booking is not different from the M41. Power unit was an engine AOI-628-1, leading leading asterisks located, unlike the previous draft, in front of the body. The scheme of the chassis, which had four track roller of large diameter with the torsion bar suspension on Board, was allowed to do without support rollers. The fuel was 570 liters, which provided a T71 cruising range 265 miles.

The third project of a light tank was developed by Constructora firm Aircraft Armaments Incorporated (AAI). Having a mass slightly less than 17 tons, it was very different from its competitors. 76-mm gun and coaxial 7.62-m machine gun was installed in a conventional tower and on the aft mast extension, which greatly reduced the height of the tank. The commander and gunner, which were located, respectively, left and right from the gun, got their own turret with a heavy machine gun. The loader located behind the tank commander. The fourth crew member, the driver sat in the front of the machine to the left of the engine. The power unit is represented perpendicular to the keel engine AOI-628-1 in the block with transmission HT-300. Suspension T92 for one Board included the leading wheel at the front and 4 paired carrier roller, the last of which played the role of a guide wheel. Carrier rollers not initially scheduled. Pendant — beam, torsion.

After considering all the projects it was decided to build models of new tanks. In the end, 18 June 1954, AA1 received an order to build two prototypes of the tank received index T92. At meetings on 5 November 1954 and January 27, 1955, in the original draft, there have been many changes, most of which was realized in metal in the construction of prototypes. For example, the suspension received carrier rollers (2 per side), the turret commander is a 12.7 mm machine gun mounted 7.62-mm (leaving, however, the possibility of the reverse replacement).

T-71:

1 — support roller;

2 — drive sprocket;

3 — 76-mm gun Т185;

4 — commander’s cupola with 12.7-mm machine gun;

5 — Luke’s gunner;

6 — the driver’s hatch.

The first T92 (No. 9В1281) arrived at Aberdeen proving ground 2 November 1956. However, due to the fact that the machine-gun turret did not arrive on time, the first tests of the tank was conducted without them. The second prototype (No. 9В1282), who arrived in Aberdeen on July 22, 1957, had a full set of weapons. The tests are quite satisfied with the military, and it was decided to launch a new machine in the series.

The body of the tank T92 was welded from cast and rolled parts. Protection was equivalent to that of its predecessor, the M41 tank, but weighed less due to the greater angle of bronzeitalia and use for some light alloys. Thus, the armor of aluminum alloys used for hatch covers, compartments of the power plant, batteries and auxiliary generator, and shutters of the cooling system was made of light alloy and reinforced plastic. The engine room was located right in front of and separate from the rest of the steel fireproof bulkhead. To his left there was a compartment of the auxiliary power unit and batteries. Behind them lies the place of the driver. For observation of the battlefield, he used 4 of the periscope M17 located around his manhole in addition, the manhole cover had a place for installing the infrared periscope M19. To evacuate from the tank the driver in addition to his hatch could use the emergency, who was under his seat. Interlocked with the engine, transmission Alison HT-300 had six gears forward and two back. The air intake for engine operation was carried out through the fungus on the top left of the tower, the exhaust is provided through louvres in the rear right over-crawler shelf. Two soft 75-gallon fuel tank was located in a compartment at the rear of the housing in front of the ammo rack. The chassis consisted of (for each side) drive wheel front location, four track roller with individual torsion bar suspensions, the first and the fourth (playing the role of sloth), which was equipped with an additional hydraulic shock-absorbers and two track-return rollers. Steel tracks with rubber pads on the tracks had a width of 406 mm and a length of 9.91 m. Two spare sections of tracks (7 tracks) was attached to the rear of the turret. In addition to the hatches in the top of the tank’s sheet, the tank had a double door in the rear of the chassis, each of the valves which were located on the device. Feature T92 was a tower epaulet unusually large for a small diameter machine — 2260 mm, 76-mm gun Т185Е1 was housed in a special external carriage, mounted on the center tower between two armored machine-gun turrets. Gun Т185Е1 was developed on the basis of gun M32, standing on the tank “Walker Bulldog”, which had the same ballistics and differed mainly in that it is adapted to operate the autoloader. With gun was paired 7.62-mm machine gun mounted on the gun. The right turret, armed with a heavy machine gun, took the tank commander, left — gunner, who, unlike the original draft, “got” is only 7.62-mm machine gun. Each turret was equipped with two periscopes, the height of which allowed to conduct surveillance over guns, and four observation devices, 6 were located on the “main” tower. Also, the turrets had periscopic sights for turret guns. The commander and gunner could carry out aiming and firing of guns, which they had on the M16 periscope, which was mounted on the main tower before the turrets. With the periscope of the gunner was paired telescopic sight.

Performance characteristics of light tanks of the US army 50-ies of XX century

* For trucks Т85Е1 and T110 respectively.

Both turrets had a rotation angle of 194°. Turning control of all three towers and vertical guidance guns could be carried out both electrically and manually with the possibility of an elevation range 10 to+60°. The fourth crew member — the loader was located behind the gunner. Loading can be carried out both manually and by means of the loading mechanism, store, which (7 shells) was between the commander and gunner. In addition, the shells stored in the ammo rack in the rear of the housing (28 shells) and the tower (24 shells). With a shell in the loading mechanism that gave ammunition to 60 rounds. Low capacity of the loading mechanism is required from the loader to either load it during the battle (which was quite possible, although uncomfortable), or you can go on loading the guns (or rather of the loading mechanism, as the shells in this case were charged not actually in the gun and feeder) manually. Bullet shells cannon and machine guns were thrown out of the tank through special hatches.

Tests conducted at Aberdeen-ish range, have revealed a number of shortcomings. So, caterpillar is constantly breaking down, and after 202 hours of testing it was replaced with a caterpillar with 356-mm trucks Т85Е1, standard for tank “Chaffee”. Due to the revealed tendency to falling of the tracks, it was decided to add in suspension idler at the rear. Other changes on the results of the tests, we can note the strengthening of the transmission, the transfer of the heater in the left rear of engine compartment, extra seal tower overhead, etc. (about 50 improvements).

View of engine compartment with open hatches:

1 — the support that holds the hatch of the engine compartment in the open position;

2 — rear exhaust manifold;

3 — louvers of the engine compartment;

4 — seal, installed on the hatch around the perimeter of the hole of the fan;

5 — inlet manifold;

6 — emergency valve overlap fuel line;

7 — seal the hatch of the engine compartment;

8 — power beam;

9 — pull the throttle (“gas”);

10 — control unit side brakes;

11 — the left bearing;

12 — pull adjustment range of the throttle control;

13 — right bearing;

14 — neck to fill the oil to the transmission;

15 — hatch oil filter transmission;

16 — protective frame rocker throttle;

17 is a front exhaust manifold;

18 — seal fan;

19 — neck for pouring oil into the engine;

20 — the crankcase breather tube of the engine.

Funds appropriated in 1957 for the production of two T92, which had become the standard for the series, went on upgrading the first two cars following the results of tests. The production of the 3rd and 4th samples of the tank was postponed until next year, deciding together to make their design all the changes. Looking ahead, I will say that they never was built.

Turret gunner:

1 — hatch cover;

2 — the bottom cover of the periscope;

3 — cover;

4 — armor cover for the machine gun;

5 — hole for ejection of spent cartridges;

6 — axis machine gun;

7 — eye for lifting turret;

8 — the case of the turret;

9 seal around the perimeter of the ring;

10 — viewing device;

11 — balancing mechanism of the hatch.

The driver’s hatch:

1 — head infrared periscope M19;

2 — the rotating base of the periscope;

3 — periscope M17;

4 — cover;

5 — frame observation devices of the driver;

6 — periscope M17.

It seemed that not a year passes as the first T92 will appear on the US army, but over his fate began to thicken the clouds. In early 1957, a special Committee of Congress have received intelligence reports that the Soviet troops began to receive light amphibious tanks PT-76. This information resulted in a revision of the whole concept of designing light tanks of the United States. So, it was decided necessary to make them floating. Unfortunately, to provide buoyancy T92 was not possible, because at the design stage the amount booked tried to reduce. To make the tank floating, it was required to increase its size to ensure acceptable displacement, which nullified virtually all of his dignity. And in June 1958 it was decided to stop work on the program of the new light tanks, including the construction of the third and fourth T92. Thus ended the fate of this interesting machine. Both made the tank a few years was used for various tests. One of these machines can now be seen in the tank Museum in Aberdeen.