Experimental, USA, WWII

The Freakiest Anti-Aircraft Half-Tracks

If you thought tanks were the only things used to make extremely weird anti-aircraft guns, then you are mistaken! The trusty US half-track also saw many crazy ideas built upon it, including some very bizarre anti-aircraft gun mounts.

These ranged from the successful, like the M16, to the downright ridiculous, such the T68 we cover in this article.

So here’s a list of some of the weirdest self-propelled anti-aircraft versions of the US half-track.

Development of the Half-Track AA Gun

As we’ve covered in our articles on the Chaffee AA vehicle and the Sherman with a ball turret, the US got to work on modern self-propelled anti-aircraft guns quite early in the Second World War.

In fact, they were already hard at work before they had even entered the war. The were able to use the events occuring over the Atlantic Ocean in Europe to help with this.

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SPAAGs were not new; they had already participitated in the First World War. However the Second World War’s battlefields saw an unprecedented level of movement and mobility.

These changes in warfare would bring many weird vehicles.

But at the same time, aircraft had become much more dangerous to ground units, and were now a common and deadly component of battle.

Units on the battlefield needed a way to defend against them wherever they went, and as a result, the SPAAG concept received major attention.

However, making a SPAAG isn’t as simple as just bolting an AA gun to a truck (unless you’re a Toyota Hilux). They need to be stable, capable of handling the weight, have sufficient room for crew and ammunition, and be able to keep up with other mechanised forces.

Ideally they will include some armor protection too. And, of course, other factors such as parts supplies, ammunition types, ease of manufacture etc. all play a big part.

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The US already had a vehicle perfectly suited for this role: the M2 half-track. This legendary American half-track had been developed in the late 30s, and could be adapted for many different roles. The most produced version (50,000+ units) was the M3, which had a slightly longer body for the armored personnel carrier role.

The M2 was a reliable, adaptable design that served as the basis for many vehicles.

There was also the M5, which was mostly the same as the M3, but was built by a different manufacturer to meet production demands.

The half-track had armor, it could go places wheeled vehicles couldn’t, and it was a sturdy platform to fire guns from. The M3 was the most suitable for the AA role because of its larger body.

The US first began developing an AA half-track in 1941 with the T1. The T1 was fitted with a Bendix turret from a B-25 Mitchel medium bomber, armed with two .50 caliber machine guns. During the T1’s development, a new turret from Maxson was tried.

The M16 multiple gun motor carriage. These vehicles served throughout WWII, and even the Korean War.

This proved much better, and the type would eventually enter production in 1942 as the M13. Further development of this vehicle would result in the famous and highly successful M16, with the M45 “Meat Chopper” quad .50 caliber turret.

However throughout the war the US continued to develop AA versions of the half-track, producing some very interesting results.

T1E3

The T1E3 came from the initial attempts to make an AA half-track. These first efforts actually used aircraft gun turrets, as they were a quick way of providing anti-aircraft capabilities.

The T1E3 was fitted with a Martin turret that contained two .50 caliber machine guns. Eagle-eyed readers may recognise this as the dorsal turret used on B-17s. That’s right, the T1E3 had a B-17 turret on top.

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This turret was not as good as the Maxson design used on the M13 and M16, and the T1E3 was cancelled in May 1944.

The T1E3, with the twin .50 cal aircraft turret.

T37

This multiple gun motor carriage was armed with four .50 caliber machine guns in a large drum-like rotating mount. Development of the T37 began in late 1941, and it was based on the M3.

Two versions were made; the first, the T37, had its four .50 cals arranged with two above the other. The second, the T37E1, had its four .50 cals placed in a row, with the central guns staggered further back.

The T37. The framework in front of the guns prevented them from being depressed lower than the cab.

Both variants used air-cooled, aircraft-type .50 cals. The crew and guns were protected from the sides by a large 12.5 mm-thick circular shield.

Because there was no spare capacity for production, the T37 was cancelled in 1943.

T10

The T10 was an attempt to create a vehicle similar to the M13, but armed with 20 mm cannons rather than .50 cals. Work on this began in mid 1941, and saw the attachment of two Oerlikon Mark IV 20 mm cannons onto a modified Maxson M45 turret.

The Oerlikon had a fire rate slightly slower than the .50 cal, but it fired a much heavier round that could carry explosive filler. Naturally, this was lethal against aircraft.

The T10 with two Oerlikon 20 mm cannons. They were mounted on a modified M45, the mount used on the M16 half-track.

The T10 performed well and an improved version, the T10E1, nearly entered service. However it was cancelled due to a lack of self-destructing 20 mm rounds. Still, White (manufacturer of the half-track) had produced over 100 examples of the T10E1. These units were converted into M16s with .50 cals.

T68 Multiple Gun Motor Carriage

The T68 is one of the most absurd on the list. It mounted two, yes, two, 40 mm guns. However, rather than being positioned side-by-side as most twin-40 mm mounts do, the T68’s guns were stacked on top of each other, creating a very precarious-looking machine.

An equilibrator for the guns was positioned above them, increasing the height even further.

The T68 is just, well, crazy.

The chassis that it was attached too was a heavily modified M3, and appears to have been stripped of its armor plating, perhaps to keep the weight down. In practice the vehicle was far from satisfactory, and the project was cancelled in June 1943.

T54

The T54 was an attempt to fit an M1 40 mm cannon (US-built version of the Bofors 40 mm) on a half-track.

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While the gun technically fit, the half-track struggled under the weight and recoil of the gun. A second version, the T54E1, added a circular armored shield and outriggers.

The T54’s 40 mm gun at maximum elevation.

The outriggers would be extended before firing and stabilised the half-track. But these features only worsened the T54’s weight issues. Eventually the type was cancelled in late 1942 in favour of tank-based AA mounts.

Elco Quad 20 mm M2

This might be one of the craziest on the list: four 20 mm cannons and two .50 caliber machine guns mounted on an M2. The guns were contained within an Elco turret that had originally been made for PT boats, known as the Mark 15 Thunderbolt.

The 20 mms were located in the center of the turret, and were flanked by the two .50 cals on the outer edges.

A rear view of the turret, with four 20 mm and two .50 cals.

In the Pacific Theatre this turret was found to provide immense firepower, even against vessels, so it must have been terrifying on a half-track. This vehicle was one the most powerful SPAAGs of the war, even beating out the Canadian Skink AA tank.

However the M2 struggled to handle the weight of the turret and the project was eventually cancelled.

M15

The M15 is the only half-track on this list that actually entered service. The M15 began in 1941 as the T28 to fit a 37 mm autocannon on a half-track. The T28 was initially built on an M2, but the design later switched to the M3 as it was larger.

On the back of the M15 was an M1A2 37 mm automatic cannon and two .50 caliber machine guns. The .50 cals were useful in guiding the 37 mm with their tracers, and provided a greater volume of fire.

The M15 half-track. Image credit: afvdatabase.com.

The guns were semi-enclosed by a large armored shield that dominated the rear of the vehicle.

Over 2,000 M15s were built, with the type first seeing service in North Africa. They were a successful design, capable of firing upon both aircraft and ground targets, and even fought through Korea.