A46 - Britain's Forgotten Light Tank - Tank Historia

A46 – Britain’s Forgotten Light Tank

The A46 was a British vehicle developed in the 1940s as a means to both ween off of American dependence and introduce a new light tank that would perform on the battlefield. This was certainly a possibility too, as this little machine was armed with the same 77 mm gun as the Comet.

It was designed to use the same running gear as the older Tetrarch light tank, but carry a much, much bigger gun, with more armor and more power.

Sadly though the A46 never left the drawing board, missing the end of WWII and then being subjected to the changing requirements of the early Cold War years. As a result the A46 would be overshadowed by the larger, more extreme vehicles of the era, and fade into obscurity.

Contents

Background

The A46 began its development in 1943.

At the time Britain was maxing out its tank-production capabilities, and was essentially forced to arrange a deal with the US to alleviate the strain. In this deal, the US would provide Britain with enough tanks and materials to enable them to begin new production in other areas.

This was certainly helpful for Britain in the short term, but it would send them further into debt and hand over even more control to the colossal superpower. US equipment was good, but Britain shared a similar sentiment to many Allied, and later NATO countries; relying on US vehicles, materials and weapons in the future would be financially damaging, and affect the nation’s pride and reputation.

A Lend-Lease Sherman in British Service.
A British Sherman in Sicily, 1943.

7 WW2 tanks starting up before they...
7 WW2 tanks starting up before they move out
As a result, Britain was keen to continue development of its own vehicles in the background. One such path was to precure a new light tank that would both replace the US Stuart family of light tanks and ensure a domestic vehicle was available for post-war use.

The basis of this new tank would be the pre-war Light Tank Mk VII, A17 Tetrarch, and its successor, the A25 Harry Hopkins.

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The ‘Tetrarch Mk 1’ or Light Tank Mk VII A17/Vickers No1 P.R.51 had been produced by Vickers-Armstrong in the late 1930s and saw limited action in WW2. Armed with a 2-pounder (40 mm) gun and only lightly armored, it had an excellent top speed of 40 mph on the road. However only a small number were built, and its overall career was unremarkable.

Tiger 1 & Normandy Bunkers
The Tetrarch light tank.
The Tetrarch light tank. Note its unusual running gear.

The second tank, Light, Mk VIII, A25 was a later design by Vickers-Armstrong in 1941, built by Metro-Cammell and served as a successor to the Tetrarch. Its design incorporated the lessons learned in developing the A17, such as a larger turret and thicker armor.

Both of these vehicles steered by literally bending the tracks, which was achieved by turning a steering wheel. For tighter turns the tracks could be slowed with Girling internal expanding brakes. This steering system required less power than contemporary types.

BANNER TIGER

The same suspension was also used on the Alecto, or 95 mm SP mounting M129, and would be eventually carried over onto the War Office’s new light tank. This new light tank would become the A46.

Alecto spg.
The Alecto, an air-transportable, light-weight self-propelled gun based on the A25 Harry Hopkins chassis.

Due to developmental issues and the light tank falling out of favour with some, the A25 was significantly delayed.

By 1943, only six of the thousand A25s ordered had been produced, so Britain was now equipped with the American Stuart light tanks. Once the order in 1943 came through for a late war/post-war light tank to be developed, Vickers quickly picked up the contract, as, although its previous light tanks had not been a success, they had experience with one of the main criteria listed; a steering system that required little power.

Specifically, the type used on the A17 and A25.

A25 Harry Hopkins, the basis of the A46.
The A25 brought improvements over the A17 Tetrarch, but its production was delayed so severely that it was barely involved in the war.

Development

The reason for wanting to reuse this steering system was that it required less power and a lighter transmission over conventional suspension systems. Therefore, a smaller engine could be used, and lighter frame could be built – extremely useful for a light tank.

A low weight was particularly important for the A46, as it was expected to be air-portable without disassembly. The tank did however have the ability to be easily dismantled prior to transport if required for long-distance or bulk flights.

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Lessons from the Tetrarch and, to a lesser extent, the Stuart, had also been taken into consideration. All of these vehicles were rather lacking in firepower, so for their new light tank Vickers wanted a gun capable of being effective against other tanks yet have a useful high explosive (HE) round.

A46 left side view.
A scale mock-up of the A46.

The weapon of choice was to be the 77 mm QF gun, which was derived from the 17 pdr and had been tested on the new A34 Comet. At the time this was incredible firepower for a light tank.

Initially the 77mm gun was prioritised for the A46, over that of even the Comet. However debates were held at the Tank Board about this as some saw the turretless Stuarts tanks fulfilling the role of the scout vehicle, using eyes and ears to relay positions and information instead of direct engagement. Meanwhile, others believed that the A46 should be able to engage targets of choice if needed.

Ultimately, it was decided that the 77mm should be prioritized for the Comet and cruiser tanks, as these would actually see combat while any new vehicle might be too late to enter the war, the end of which was now in sight.

A Meteor powered Comet.
The 77 mm would see service on the Comet, shown here.
Shermans starting up in Normandy

In 1944 the War Office placed an order for 80, even though Vickers had not yet presented any official plans.

On November 15th, 1944 the 44th meeting of the Tank Board took place at Chertsey. The minutes for this meeting show that it was held to inspect proposals for the requested light tank. Once the meeting had concluded the board reviewed the layouts, which were in the same building.

The Tank Board’s next meeting occurred in January 1945, during which it was noted that a mock up of the A46 would be ready by the end of the month. In addition, it was said that there had not been any major issues with the project.

A model of the proposed A46.
The A46 had a large turret ring that measured 72 inches in diameter.

At this point, the A46 was expected to enter production some time around mid-1946. Interestingly, this minutes noted that the concept “looked extremely good and should appeal psychologically to the troops”.

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The first full description of the A46 came in the following Tank Board meeting. There were to be two basic chassis types; the M132 with a front-mounted engine, and the M131 with a rear-mounted engine. The M131 was to be the basis of the tank, while the M132 was to be the basis of load carrying and support vehicles.

A46 light tank model.
The A46’s ballistic shape was much more advanced than its predecessors.

This meant the new hull could be easily adapted for other purposes if required. It was one of the Britain’s first modular designs that could allow the chassis to be reused for a variety of roles without being modified. Vickers happily agreed with the requirement, as it saw future growth in this system.

Towards the war’s end the War Office Britain had prepared itself for its next generation of vehicles in three new lines; the A45 series, which would become the FV200 Universal line (and eventually, Conqueror), the A41 line based around the Centurion, and a new Vickers light line.

Different variants, such as bridge layers and armored recovery vehicles, would be built on each of these new lines. However, the war’s end in 1945 meant none of these vehicles reached service in time, except the Centurion in small numbers.

M132 mock-up.
A mock-up of the front-engine M132.

While the A45 and A41 lines would eventually produce tanks, Vickers’ light tank line would not be so lucky. Only a single full-scale mock-up and a some wooden models were built before the war ended.

The A46’s Design

However, had the A46 been built it would have had some impressive features. As mentioned the tank would have been armed with the 77 mm QF gun, a weapon capable of dealing with the Germany’s heavier tanks.

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This is extremely impressive considering the A46 would have weighed just 16 tons (20 less than the Comet) and measured just 4.9 meters (16 ft) long, not including the gun. Its armor would have also been excellent for a light tank, with a maximum of 76 mm on the front and up to 50 mm on the sides.

Fate

Immediately after Germany was defeated, the Soviet Union became the new enemy for Britain and its Allies. The nation emerged from the war battered and wounded, but it still fired up a rearmament program to replace the older wartime vehicles with more modern, standardized types, now designated with a Fighting Vehicle (FV) number.

Work still continued on the A46, with it now having a front-engine layout by 1947. The drive sprockets remained at the rear, so the engine and transmission sent power to them via a centerline shaft. In addition, stowage bins were added to the rear of the vehicle to increase space for ammunition.

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However with a crew of four, a 77 mm gun and its small size, the A46 was looking like it was going to be too cramped for the crew to operate in for long periods of time. The 77 mm gun was a intrinsic part of the design, so Vickers was unable to create space by using a different weapon.

They handed the issue over to the Elswick department, who would then begin work on an autoloading system for the gun.

Sadly though the A46’s light tank’s story comes to an end here, at least for the most part. The project would transform into a fully-enclosed armored personnel carrier (APC), something of a novelty at the time. Despite having a number of features that would become standard on later APCs, Britain did not use this vehicle either, for unknown reasons.

CT26 armored personnel carrier.
The CT26 armored personnel carrier, the A46’s final form.

The FV300 series would take over the light tank requirement.

The A46 never left a legacy nor did it introduce any features that would revolutionize tank design. Much of its history will remain a mystery and its novel features such as the Elswick 77mm gun will remain so. If a footnote could be added to the pages of tank lore its that A46 was the last of the ‘A numbers’ and for the last well armed and armored light tank design, with all subsequent vehicles mounting either low velocity 76mm HESH guns or 30mm RARDEN cannons.

She is, if anything, the missing link between doctrines.