Categories
WW2 British Light Tanks WW2 Danish Armor

Vickers-Carden-Loyd Light Patrol Car

United Kingdom/Kingdom of Denmark (1932-1937)
Light Tank – 3 Built

The Carden-Loyd Mk.VI tankette was a huge commercial success. Many countries were eager to buy a small armored vehicle that was tracked, armored, and armed, providing the perfect cheap alternative to the expensive tank. In reality, the Mk.VI was far from perfect. Its mobility was inadequate, its armament had limited effectiveness, and its protection was far from adequate. In essence, the Light Patrol Car was to solve all these problems by providing a slightly improved suspension, armament in a fully traversable turret, and a fully armored roof. However, this made it more expensive, which was one of the main reasons just two of them were ever sold.

The first prototype of the Light Patrol Car. Several points of note are the armor, which is bolted except for the riveted turret, the suspension bogies with leaf springs, and the transmission housing positioned on the right side. Source: Beamish Museum

The Carden-Loyd Mk.VI

The fashion of cheap armored fighting vehicles was initiated by Lieutenant-Colonel and engineer Giffard Le Quesne Martel when he built a one-man tank that was accepted for official trials in December 1925. The publicity that surrounded this vehicle sparked the interest of engineer John Valentine Carden, who had a joint business with Vivian Loyd. In March 1926, they delivered a tankette prototype for official tests, which began the development process that brought forth a large number of prototypes, culminating in the Mark VI in 1928. As Carden-Loyd anticipated large orders, for which the company was too small to fulfill, it was taken over by Vickers-Armstrongs, under which the Carden-Loyd Tractors Ltd. trade brand was retained.

A picture of a British Mk.VI machine gun carrier from 1928, from which the Patrol Car was derived. While similarities between the two vehicles are easy to spot, there were quite some differences too. Source: tankdevelopment.blogspot.com

The Patrol Car prototype in comparison, seen here in Denmark in 1932. Source: ghrvpk.dk

The Mark VI was exported to at least seventeen countries and copies were made in six countries. In 1929, Lieutenant-Colonel Andersen-Høyer of the Danish Army Technical Corps (Danish: Hærens tekniske Korps, shortened to HtK) made a trip to the United Kingdom to study these new military developments. After having observed the Carden-Loyd tankette from Vickers, he was promised the loan of a light tank by the company. The costs for this, £200, were to be refunded if tanks were bought after the loan.

It is unclear if the idea of a tankette with a turret was already discussed in 1929 with the Danish delegation. According to David Fletcher, the idea of a turret came later from the desire to have overhead protection, which was not a standard feature on the regular Mk.VI, although various export versions had overhead covers. It is known that the first prototype was not finished earlier than 1932. It is safe to assume that the decision to design the Patrol Car was Vickers’ own initiative and did not come from a special Danish request.

Two views of the initial prototype. It stands out through the simplicity of the design, with the basic turret, straight fender, and small leaf spring-suspended bogies. Sources: The Vickers Tanks / Foss & Mckenzie (left) and Armour in Profile no.16 / R.J. Icks (right)

The single surviving Danish Patrol Car is on display at the Military Museum in Copenhagen. It is placed on its original purpose-built trailer. Note the mechanism on the front that secures the Patrol Car to the trailer. Source: Wikimedia

Design of the Light Patrol Car

The Patrol Car immediately shows its Carden-Loyd lineage, with the characteristic design of the suspension and chassis. Each track system consisted of 129 links, a front-mounted sprocket with 32 teeth, a rear-mounted idler with a tensioner, a return roller which was identical to a regular road wheel, and two pairs of bogies with two road wheels each. The pairs were suspended with flat leaf springs. The bogies were mounted to the suspension beam, which itself was attached to the lower hull with two heavy duty brackets. The leaf spring bogies were soon replaced by new bogies, featuring a new coil spring suspension. This type of suspension was further developed into the Horstmann suspension by John Carden and Sidney Horstmann in 1934.

The independent movement of the coil spring-suspended bogies can well be observed on this photograph of a Danish Patrol Car, taken around 1935 in Copenhagen. Source: Museum of Copenhagen

The widely available Ford Model A engine was chosen for the propulsion. This was a 3.3 l straight-four engine which had a maximum output of 40 hp at 2,200 rpm. The same engine was also used by the Ford AA, hence the engine is sometimes referred to as Model AA as well. It was mounted on the right side of the rear compartment and coupled to the transmission in front of it. As seen on other Carden-Loyd designs, the differential bulged out of the frontal armor and was protected by a removable armored cover. The transmission could be accessed through a hatch. The exhaust protruded out of the transmission compartment just behind this hatch, and ran further down alongside the right side of the rear compartment.

Although data on the dimensions and weight of the vehicle is conflicting between sources, the Danish version seems to have weighed 2.1 tonnes. A figure of 1.93 tonnes is also given, but this may concern a later variant which was changed to make it cheaper. As indicated by the weight, the vehicle was very small for an armored tracked vehicle, with a length of just 2.9 m [figures of 2.59 and 2.75 m are also given], a width of 1.75 m, and a height of 1.65 m.

According to factory specifications, it was able to reach a speed of 45 km/h, but due to bad performance, it is unlikely it ever reached this speed in practical use. With a 45.5 l fuel tank, an operational range of 150 km was achieved. As evidenced by various photographs, it could climb slopes up to 25° [47%].

The prototype on the move, now outfitted with the new coil spring bogies. Source: Mechanised Force / David Fletcher

A less dramatic scene, showing the Patrol Car in all its might. Source: Beamish Museum

Crew Layout

The left side of the rear compartment was reserved for the crew. The driver sat at the front and was provided with a single vision slit in the frontal plate, which provided just a limited view. The size of the slit could be changed by sliding an external armored cover up or down. If the driver needed a better view, his only way was to slide the top hatch open and stick his head out, blocking the firing arc of the turret and making himself vulnerable to enemy fire.

The commander, who also acted as the loader and gunner of the machine gun, was seated in the turret behind the driver. The turret itself was the most basic version of a design also seen on the commercial light and amphibious tanks. It was round with a square and offset extrusion to the front that housed the gun mount. It was turned by the commander with a manual traverse. An entry hatch was mounted on the turret’s roof and folded forwards.

This photograph finely illustrates the small size of the vehicles in comparison to the crew. Of note is also the special tracked carrier, which could transport additional equipment for the crew. Plenty of grass and mud is stuck to the suspension beam and the differential armor cover. Source: ghrvpk.dk

Armament and Protection

In terms of armament, the Patrol Car was standard issued with a Vickers-Berthier light machine gun, but the eventual fitted gun was up to the choice of the customer. The Danish Army for example, as the sole customer, decided upon the locally manufactured and used Madsen 8 mm. This came at the cost that the regular gun mount was replaced by just two simple vertical slits. One was used to put the gun through and the other to aim through.

Most of the vehicle was protected by 6 mm thick armor plates, with the exceptions of the floor and roof plates, which were just 4 mm thick. The layout of the offset transmission and engine, in combination with the specific suspension, was also utilized by the Carden-Loyd B11E10 three-man carrier, which was delivered to the British testing agency in 1933. Apart from this layout, both vehicles were quite different from each other.

The vehicle seen from the rear right. Note the little chains on the fender supports that were used to mount unditching/trench crossing planks. Source: Wikimedia

Danish Interest in the Light Patrol Car

In 1928, Denmark bought its first tank, an Italian Fiat 3000, for testing purposes. It went through a large testing program, but unsure what to further do with it, it was removed from service in 1929. Around the same time, several business trips were made abroad to study new military and armored developments and, in 1930, the War Ministry gave the greenlight to begin new armored car trials in 1931. The vehicles tested in this program were known as a Forsøgspanservogn [English: Experimental Armored Vehicles]. The first two armored cars were built locally to keep costs down. A special testing unit was established and existed between July and October 1931.

In May 1932, the unit was reinstated and re-equipped with the two armored cars, which by this time had been modified. Additionally, other cheap armored vehicle solutions were sought and found in the L-210 armored motorcycle from Swedish Landsverk, designated FP3, and the earlier offer from Vickers to test one of their vehicles. In the first half of 1932, Vickers was working on the first Light Patrol Car prototype which was to be sent to Denmark. After some delays, it was finally ready in the summer and arrived in Denmark in August. It came accompanied with a special tracked trailer.

The prototype in Denmark, together with its trailer. At low speeds, such trailers could be useful, but were often a hindrance in active combat. Source: ghrvpk.dk

Trials in Denmark

After being temporarily designated FP4 [Forsøgspanservogn 4], it was put to the test over the course of six weeks, but the results were disappointing, to put it mildly. Off-road performance was very poor, the tracks tended to throw themselves off, while steering on roads was practically impossible. However, these technical deficiencies were put aside, motivated by the optimistic idea that the vehicle had not yet been able to show its full capabilities in just six weeks of testing. Furthermore, the Landsverk armored motorcycle had yielded very little results too, so the Patrol Car was still favored over it.

Most importantly, though, was the financial side. Due to political decisions, the Danish Army had little money to spend. The cost for one vehicle was estimated somewhere around 20,000 kroner [circa £1,080] and operating costs were estimated at just 1 krone per kilometer driven, which were both very low for a tracked armored vehicle with a turret-mounted armament. In relative value, this would be roughly US$444,000 in today’s value, and US$22 per kilometer.

The prototype is seen here in a proposed transport configuration and placed on a Danish built Triangel 2T truck, fitted with a French P6 Kegresse half track system. Source: ghrvpk.dk

An Order for Two

Without another cheap alternative, and hoping new vehicles were better than its first appearance had shown, an order for two was placed at Vickers. These differed in several ways to the tested prototype. The entire layout was changed, with the turret now offset to the right and the transmission and engine moved to the left. This was the most important change, but other differences included new fenders with less steep supports and a curvature to each end, a different gunmount in the turret and additional vision slits for the commander, an added handle on the right side of the hull, and two towing hooks mounted on the rear plate.

Shown here is Patrol Car FP5. Visible changes to the prototype are the swapped layout, the different transmission hatch, a curved fender with less sloped supports, and a handle on the side armor below the turret. Source: ghrvpk.dk

These two vehicles arrived in August 1933 and were assigned the registrations FP4 and FP5 and equipped with a single 8 mm Madsen M1924 light machine gun, chambered to fire the Danish standard issue 8×58 mmR cartridges. Another addition were two ramps, carried on either side of the vehicle, which could be manually deployed to overcome trenches or similar obstacles.

It was quickly found that they were in very poor mechanical condition, even up to the point that the Danes began to consider this as a breach of contract. Engineers from Vickers had to travel to Copenhagen several times to fix errors and various teething problems. The main problems occurred with the suspension, the cooling system of the engine, and the exhaust. The training department found the vehicle’s performance hugely disappointing and doubted their usability. The HTK agreed with this, but pointed out that the army was in need of a cheap armored vehicle and for the price, the Patrol Car did its job well as a training vehicle until better alternatives would become available.

A relatively rare photo of both vehicles seen together. Note the ramps carried on the sides. Source: Om dansk rytteri 1932-1940, Del 3 / Per Finsted

Trailer Problems

During exercises, it was also found that the four-wheeled transport trailers which were delivered together with the vehicles had a problematic performance. An additional problem, although not directly related to the vehicle itself, were the Ford trucks assigned to pull the vehicles, which turned out not to be powerful enough. Trials with International and Fordson trucks resulted in the latter being chosen as a replacement for the Ford.

The Light Patrol Car in Army Service

From the delivery in August 1933, the Patrol Cars remained in service as training vehicles until 1937, when they were stored and designated as beredskabskøretøjer [English: Emergency Vehicles], only to be reactivated in case of special need. This never occurred and FP4 eventually disappeared, presumably to be scrapped. Remarkably, FP5 survived and is on display in the Danish National Military Museum in Copenhagen.

There is a rather amusing anecdote in which the Patrol Car was involved. During training, a conscripted hornblower from the reserves was assigned to the tank unit for communications, as these were not fitted with radios. He sat on top of one of the vehicles and was ordered to blow a signal if a bridge was found intact. Suddenly and out of nowhere, a bag filled with a chalk-water mixture landed next to the tank, giving the hornblower a proper whitewash. Bewildered, he looked up, only to spot a two-decker flying by with the sound of the loud laughter of the flight crew protruding from it, as the engine had been turned off to secretly approach the tank. The poor hornblower reportedly spent the rest of the exercise cleaning his uniform while the vehicle was ‘put out of action’ by the bomb.

FP4 during exercises in the countryside. Although barely visible, Giv Agt for Opbremsning! is written on the rear plate, which translates to ‘Be aware of braking!’ Source: dws-xip.com

Commercial Failure

Besides Denmark, the Light Patrol Car attracted no further commercial interest, especially since its cost exceeded a £1,000, which was still relatively cheap, but more expensive than the regular Mk.VI tankettes. Therefore, the decision was made in 1933 to offer a cheaper version with thinner armor and the older and cheaper leaf-spring suspension. By this, cost was brought down to £700, while an optional cupola with bullet-proof glass visors was offered for £50 extra. Despite an advertisement campaign, showing a drawing with a dramatic deployment of a patrol car during a protest, none were ever sold.

The dramatic drawing of the Light Patrol Car during use against riots. A point of interest is the cupola on the turret with bulletproof vision blocks. This option would cost £50. Source: tankdevelopment.blogspot.com

It is sometimes suggested that Finland, Sweden, and Portugal also bought a prototype each, bringing the built number up from three to six vehicles, but this appears to be false information. Indeed, Finland bought three Vickers-Carden-Loyd tanks in 1933, but these concerned the Commercial Light Tank M1933, the Light Amphibious Tank M1931, and the Mk. VIB tankette. Similarly, Portugal acquired six Mk.VI tankettes in 1931 and Sweden two Mk.VIs in the early 1930s, including a unique variant, but neither bought the Patrol Car.

Poland is sometimes suggested as being yet another evaluator of the Patrol Car. Notably, the comparable TKW was developed there, but it appears that its development coincided, or even predated the Patrol Car and there is no supporting evidence that the Patrol Car was ever tested by Polish authorities.

A Political Scandal

In 1932, a small-scale scandal erupted when Vickers-Armstrongs placed a page-sized advertisement for the Patrol Car in the German military magazine Militär-Wochenblatt. This was considered as a direct advertisement for Germany which was prohibited to own any tanks under the Versailles Treaty. After questioning in the House of Commons, the government had to clarify that no British arms were exported to Germany, while the Militär-Wochenblatt stated that the advertisement was aimed at foreign readers of their magazine.

This controversial advertisement was placed in the German military magazine Militär-Wochenblatt in 1932. Source: Militär-Wochenblatt

Conclusion

In the end, the Light Patrol Car was just one of many options developed by Vickers-Carden-Loyd and put up for sale in their ever growing commercial catalog of armored vehicles. While it seemed to deliver a promising upgrade over the original Mk.VI tankettes on paper, it turned out to be a technical failure in reality. For a turret-equipped tracked vehicle, it was cheap, but the more expensive light tank series was favored over it by many customers, which was certainly a better option. This was experienced by Denmark, whose two vehicles performed subpar and were considered useless in any tactical deployment. Nevertheless, their importance in the Danish Army should not be understated, as they provided good training experience. Unfortunately, they would never use this experience, as the Danish government capitulated almost immediately when they were invaded by Germany in April 1940.

The FP5 has survived and is displayed in the National Military Museum in Copenhagen on its transport trailer. This dark gray, almost black color, was the original livery, evidenced by various photographs. Source: Wikimedia

Seen on the front-left side. Source: Wikimedia

The Light Patrol Car in its Danish configuration. An illustration by Godzilla, funded by our Patreon Campaign.

Light Patrol Car specifications

Dimensions (L-W-H) 2.9 (or 2.59) x 1.75 (1.96 with boards) x 1.65 m
Total Weight, Battle Ready 1930 kg or 2100 kg
Crew 2 (commander/gunner, driver)
Propulsion Ford Model A engine, water-cooled, 40 hp
Speed (factory) 45 km/h [30 mph]
Range 150 km
Fuel tank 45.5 l [10 gal]
Armament 1x Vickers-Berthier MG or 8 mm Madsen M1924
Armor front, side, and rear 6 mm; roof and floor 4 mm
Climb 25°
Turning Circle 4 m
Total Production 3

Sources

Drostrup, Ole. Panser i Danmark. Træk af vort panservåbens historie 1918-1978, Lindhart og Ringhof, 1980 (2021 eBook version), ISBN: 978-8726582529.
Finsted, Per. Carden-Loyd kampvognen i Danmark, chakoten.dk.
Finsted, Per. “Om dansk rytteri 1932-1940, Del 1-4.”
Fletcher, David. Mechanised Force: British Tanks Between the Wars, The Stationary Office, 1991.
Foss, Christopher & Peter McKenzie. The Vickers Tanks: From Landships to Challenger, Haynes Publishing Group, 1988, ISBN: 978-1852601416.
Greve Sponneck, W. “Rytteriets Panservognskompanier.” In Danmarks Hær”, edited by Hektor Boeck, S.E. Johnstad-Møller, and C.V. Hjalf, 228-230. Copenhagen: Selskabet til Udgivelse af Kulturskrifter, 1934.
Seldes, George. Iron, Blood and Profits: an Exposure of the World-Wide Munitions Racket, Harper & Brothers, 1934.
http://armyvehicles.dk/cardenloyd.htm
http://historicalstatistics.org/ used to convert currency.

Categories
WW2 British Light Tanks

A.17, Light Tank Mk.VII, Tetrarch

United Kingdom (1938)
Airborne Light Tank – 100 Built

At the start of the 20th century, nations at war experienced rapid technological advancement, and with this development came a time of adaptation and experimentation. The end of the Great War saw many countries taking stock of what had been introduced and experienced, and the interwar period proved to be a time of rapid development, testing, and theorizing, of which armored vehicles were no exception. The British Army saw fit to change the makeup of their forces to accommodate new tanks and therefore broke the vehicle design into three groups; light tanks, cruiser tanks, and infantry tanks.
Infantry tanks were designed to provide armored support for infantry units, so speed was not a focus. The Royal Tank Corps, and the Cavalry Corps however, both requested faster Armored Fighting Vehicles (AFV) to fill the roles of rapid breakthrough, exploitation and reconnaissance. These ‘cruiser tanks’ were used as mechanized cavalry, utilizing lighter arms, and lighter armor than infantry tanks. The final category, light tanks, were designed to scout enemy positions, and act as policing vehicles for occupational forces, and as such, they consisted of minimal armor, and usually were only armed with machine guns. The Vickers-Armstrongs’ series of light tanks proved popular for the British Army.
As a result, British and Commonwealth nations used the Vickers-Armstrongs Light Tank Mk.VI extensively from the mid to late 1930’s. Due to its popularity, the Mk.VI was still in operational use at the start of World War II, however, chief tank designer Leslie Little was working on a private project to replace the Mk.VI, which would form the basis for the new Mark. VII Tetrarch. The name ‘Tetrarch’ is the Roman title given to the governor of one of four provinces of territory, or the Greek word for ‘ruler’.)

Tetrarch light tank at the Armoured Fighting Vehicle School, Gunnery Wing at Lulworth in Dorset, 25th of March 1943. Source: Imperial War Museum Collection

Development

When the British Expeditionary Force was deployed in Europe from 1939 to 1940, a majority of the armor available consisted of the Mk.VI. However, the Vickers-Armstrong company was developing the Light Tank Mk.VII. Starting the design in 1937, and proposed to the War Office in 1938, the “Purdah” (meaning a state of seclusion or secrecy) tank as it was nicknamed, was sent to trials by 1938. Originally, the Mk.VII was put through trials designed to test its viability as a ‘light cruiser’ tank, since the British Army was still satisfied with the Mk.VI at the time, and felt that it did not need to be replaced. Eventually, though the Mk.VII was rejected for the light cruiser role, in favor of the A.9, Cruiser Tank Mk.I.

Prototype Tetrarch from the factory. Note the odd muzzle break on the main weapon, and the Vickers machine gun cowling.
Trials for the Mk.VII lasted from May until June 1938, and at their completion, the War Office assigned the Mk.VII a new ordnance designation: ‘A.17.’ An order was put in for a limited run of 70 Mk.VIIs to be built in July but the number was raised to 120 in November with two required design changes. First, the armament would be changed from a 15mm Besa main gun, and a 7.92mm Besa machine gun to an Ordnance Quick-Firing 2-pounder (40mm) gun with a coaxial 7.92mm Besa. A second requirement specified the mounting of an external fuel tank on the rear of the vehicle to increase the operational range. In July of 1940, production started on the Mk.VII, but the War Office soon reduced the requested number of Mk.VIIs to the July 1938 number of 70, before raising it again to 100 and finally to 220.

Production

After the Mk.VII was approved for production by the War Office, the use of light tanks encountered several obstacles. In 1940, the Battle of France was ongoing, and the Vickers Mk.VI, which was better suited for light security duties, fared poorly in combat against German armor and many of the Mk.VIs were abandoned after the Battle of Dunkirk. British tank production began to focus on infantry and cruiser tanks, phasing out light tanks. Vickers production slowed due to a transfer of the Mk.VII from the plant at Elswick, Newcastle-Upon-Tyne, to the Metro-Cammell factory in Birmingham mid-1940. This was further exacerbated by Luftwaffe raids, which resulted in damaged supply lines, and also by the vehicle’s design flaws, such as a faulty cooling system. These factors pushed back the first production example to November 1940, with around 100 Mk.VIIs being produced through 1942, according to War Office documentation. These 100 tanks were given registration numbers, T.9266 to T.9365. Other sources place the number as high as 177, but this number has not been proven in official documents. In September 1941, the Mk.VII was then given the name “Tetrarch”.

General Sir Alan Brooke inspects a Tetrarch at the Army Staff College at Camberley, 6th of January 1941. Source: Imperial War Museum Collection

Design

When the Mk.VII Tetrarch was initially designed, it was meant as an upgrade to the existing Vickers Mk.VI. The armor thickness was increased to a maximum of 16mm using riveted plating, and the Henry Meadows Ltd. Type 30 twelve-cylinder engine produced up to 165 hp. The Mk.VII rode on a system similar to the Christie suspension system, by using long coil springs, and the tracks utilized four road wheels, which due to their size, also acted as supports for the track return. In addition, the Mk.VII also adopted the steering mechanism used by the Universal Carriers. Turning the tank was accomplished by warping or bending the tracks from side to side, in the direction desired, providing a turning radius of around 90 feet (27.4 meters), so for tighter turns track braking was still necessary. At 7.6 tons, the Mk.VII was capable of reaching travel speeds around 40 mph (64 km/h).
As with most scout tanks, the crew of three worked in tight quarters, with the commander and the gunner in the turret, flanking the driver. Due to the small number crew members, it fell to the commander to fill the role of loader. By 1944 the tanks were also upgraded with a 40mm Quick Firing 2 pounder, and some received Littlejohn adaptors, increasing the velocity and trajectory of the armor piercing composite non-rigid (APCNR) rounds fired. By using the APCNR, which had a softer metal on the outside, the slightly smaller Littlejohn adaptor would compress the round, provide some resistance, and increase the pressure behind the shot. The resulting velocity would increase from 853 m/s to 1,143 m/s, giving the 2pdr the ability to penetrate about 80mm of armor from about 150m.

Pictured here is the Tetrarch with a Littlejohn adapter fitted to the end of its barrel. The vehicle also has some small rubber flaps hanging from the front. Source: Imperial War Museum Collection

Variants

Despite the troubled production sequence of the Mk.VII, and the initial lack of support from the British Army in regards to its use, two variants of the Mk.VII were produced. The first was designated the Tetrarch I CS. With this variant, the 2-pounder was replaced with a 3-inch howitzer but otherwise was mostly unchanged. The second variant was the Tetrarch DD. This version mounted a Duplex Drive and canvas screens to enable flotation and water crossings. Trials were carried out in June of 1941 with the Tetrarch in the Brent Reservoir, as it was the lightest tank available to the British Army. Due to its success, the Duplex Drive was modified for mounting on Valentine tanks, and eventually M4 Medium tanks used during Normandy.

Fitted with the experimental flotation screen, Tetrarchs were the first British tanks tested for amphibious landings. Source: British National Archives

Mk.VII Tetrarch
Standard issue Tetrarch Light Tank.

Tetrarch CS (Close Fire)
Tetrarch with Littlejohn adapter fitted to the muzzle of the 2-Pounder main armament.

Mark VII Tetrarch fitted with the Littlejohn adapter
Tetrarch CS (Close Support), infantry fire-support variant fitted with a 3-Inch (76mm) Howitzer.All three illustrations are by Tank Encyclopedia’s own David Bocquelet.

Operational History

The first groups to receive Tetrarch Mk.VIIs were the 1st Armoured Division and the 6th Armoured Division, but when these units were sent to the North African Campaign, the Tetrarchs were deemed unfit for service, due to faulty cooling systems, and never shipped with them. The next British use came in 1941, in which twelve Tetrarchs were withdrawn from the 1st Armoured Division, and assigned to ‘C’ Squadron of the Special Service Squadrons. Six of these Tetrarchs were deployed to Freetown, West Africa. On the 5th of May 1942, with the start of Operation Ironclad in Madagascar, six ‘B’ Squadron Valentine tanks and six ‘C’ Squadron Tetrarchs were deployed as part of the amphibious assault at the port of Antsirane. Due to 75mm artillery emplacements and entrenched Vichy forces, the attacking British forces suffered the loss of four Valentines and three Tetrarchs, but eventually the objective was taken. By the end of the operation, only three of the twelve Tetrarchs were in running condition, and they remained stationed in Madagascar until 1943.

Tetrarch exiting a Hamilcar glider. Source: British National Archives
In 1940, the War Office and the British Army expressed a desire for airborne units to have access to heavier weaponry through the use of gliders. In January of 1941, the Tetrarch tank was paired with the General Aircraft Hamilcar, and three years later, training exercises began. Due to its success, the Tetrarch was re-designated as an airborne tank. On the 5th of June 1944, advance elements of the 5th Parachute Brigade landed and cleared the landing zone of anti-glider obstacles, so that the squadrons of the 6th Airborne Armoured Reconnaissance Regiment (AARR) could land on D-Day. Of the twenty tanks that took off for Normandy, one slipped free of its restraints and caused the glider to crash, two tanks collided upon landing, and another was hit by a landing Hamilcar glider. Eleven of the Tetrarchs also became entangled in the discarded parachutes, which took considerable time for them to be freed.
These delays in freeing the equipment, and the reorganization of airborne forces, saved the Tetrarchs from having to engage the counter-attacking Kampfgruppe, ‘Von Luck,’ which contained Panzer IV’s. The next day, the Tetrarchs were ordered to move to Bois de Bavent, and reconnoiter Troarn-Caen. After linking up with the 8th Parachute Battalion in Bois de Bavent, they proceeded to assist with the British advance on Normandy, providing reconnaissance for the troops. The first area they scouted was Escoville, where they engaged enemy infantry and gun emplacements, but they were forced to rely on infantry support to engage German armor. For the remainder of the operation, the AARR was used to assist in infantry reconnaissance or to relieve troops under fire so that they could be effectively replaced by fresh soldiers. On the 31st of July, the 6th AARR was placed under the control of the 5th Parachute Brigade, and used as a rapid reaction force, and were instructed to assist with minor pushes before the breakout in August. Eventually, the Tetrarchs were relegated to HQ roles, while ‘A’ Squadron of the 6th AARR began using Cromwells. The 6th AARR was withdrawn from mainland Europe in early September, with casualties totaling 10 KIA, 32 wounded, and 10 MIA, out of the 118 deployed. This would be the final time the Tetrarchs saw combat.

Soviet Service

In June 1941, due to the start of Operation Barbarossa, the USSR was added to Britain’s Lend-Lease program. While the Lend-Lease was originally started as a method for the United States to provide aid, the British government also participated in giving aid and planned to send a fraction of the produced Tetrarchs to the USSR. Twenty tanks were delivered on the 27th of December 1941 in Zanjan, Iran, but no further deliveries were made. After crews were trained in their use, the tanks were transferred to the 151st Tank Brigade, and were used alongside the Soviet T-26. They fit into Soviet tank doctrine, who still used light tanks for scouting and combat roles, and eventually, they saw combat when the 151st Tank Brigade was under the command of the 47th Army on the Transcaucasian Front. During fighting near the Abin River on the 27th of January 1943, the 151st experienced fifteen bailouts (the crew abandoning the tank after it was hit) in their attempt to take a hill. By the 31st of January, only fourteen tanks were still operational, and on the next day of fighting, another six were lost. Even after recovery efforts, on the 1st of February 1943, the 47th Army had only nine working Tetrarchs, and by May, only seven remained running. Due to a lack of spare materials for repairs, the number continued to dwindle as the remaining tanks were transferred to the 132nd Tank Regiment and the 5th Guards Tank Brigade. By September, only two Tetrarchs remained, and they were retired in the autumn of 1943.

Tetrarchs in use by the 21st Training Tank Regiment in Shahumyan, Armenia. March 1942. Source: warspot.ru

Tetrarchs donated to the USSR pose for the camera alongside T-34 tanks in the Caucus mountains, 1942. Notice the infantrymen riding on the Tetrarchs. Source: As taken from WorldWarPhotos.info

Legacy

The invasion of Normandy was the last time the Tetrarchs were used in combat, however, they were not disbanded until around 1950. Declared obsolete in January 1946, their role as an airborne tank was gradually replaced by the M22 Locust, which was adopted by the British armed forces in 1943, relegating the Tetrarch to training roles for their remaining four years with the 3rd Hussars. Despite the short service life of the Tetrarch and the problems which occurred during development, it still secured a unique place in history for itself. The use of light tanks in airborne operations proved the versatility of armored vehicles and paved the path for future air transportable tanks. To this day, tanks are still airlifted and dropped off in hard to access locations on the battlefield and enable rapid deployment of armor to many different environments, an idea pioneered by the Light Tank Mk.VII.

Tetrarch specifications

Dimensions (L-W-H) 13′ 6” x 7′ 7” x 6′ 11” (4.11 m x 2.31 m x2.12 m)
Total weight 16,800 pounds (7,600 kg)
Crew 3 (Commander, gunner, driver)
Propulsion Henry Meadows Ltd. Type 30 twelve cylinder engine, producing 165 hp
Speed (road) 40 mph (64 km/h)
Armament Ordnance QF 2-pounder (40mm) gun (or 3 in (76.2 mm) howitzer)
1 x 7.92mm BESA machine gun
Armor 4 to 16 mm
Total production around 100 (6 Prototypes)
For information about abbreviations check the Lexical Index

Links, Resources & Further Reading

Chamberlain, Peter; Ellis, Chris (2001). British and American Tanks of World War Two: The Complete Illustrated History of British, American, and Commonwealth Tanks 1933–1945. Cassell & Company. ISBN 0-7110-2898-2.
Fletcher, David (1989). Universal Tank: British Armour in the Second World War – Part 2. HMSO. ISBN 0-11-290534-X.
Flint, Keith (2006). Airborne Armour: Tetrarch, Locust, Hamilcar and the 6th Airborne Armoured Reconnaissance Regiment 1938–1950. Helion & Company. ISBN 1-874622-37-X.
Pasholok, Yuri. The Hard Fate of a Light Tank. READ HERE
Ware, Pat. (2011).British Tanks: The Second World War: Rare Photographs from Wartime Archives. Barnsley, South Yorkshire: Pen & Sword Military, ISBN 2:00281436.
Williams, Anthony G. (1999). The Vickers 40mm Class S Gun with Littlejohn Adaptor. The Cartridge Researcher: European Cartridge Research Association, https://www.quarryhs.co.uk/sgun.htm

Categories
WW2 British Light Tanks WW2 US Light Tanks

Light Tank (Airborne) M22 Locust

 United States of America/United Kingdom (1941)
Airborne Light Tank – 830 Built

The M22 Locust came about in 1941 as a request from the British War Office for a bespoke air-deployable tank. Until this point, the British had been using the Light Tank Mk.VII Tetrarch for the role. The Tetrarch did not start out as an airborne tank however, so it was believed to be inferior to a vehicle dedicatedly designed for this role.

The United States Ordnance Department received the request and began work on finding a suitable designer and builder. The famous J. Walter Christie was first on their list, who in turn produced a prototype in 1941. This prototype did not meet the size requirements, however, so the Ordnance Department looked elsewhere. The Marmon-Herrington Company then came forward with their own design. The design was approved and the Company produced a wooden prototype in August of 1941 which was designated ‘Light Tank T9’.
Christie's unused design for the project - Photo: warspot.ru
Christie’s unused design for the project – Photo: warspot.ru

Development of the T9

Marmon-Herrington was already a trusted producer of light tanks for the United States Marine Corp (USMC), so were seen as the perfect candidate to produce the United States’ first air-mobile tank. The specifications were set for a tank light in weight and able to be transported either by the US’s Douglas C-54 Skymaster transport, the specially designed Fairchild C-82 Packet or the British General Aircraft Hamilcar glider. At the time, there was no thought given to parachuting the tank in, as large and strong enough parachutes did not exist at the time. The idea was to land the tank on the ground once the first wave of paratroopers or glider infantry had secured a suitable landing area.
In April 1942, a trial vehicle was produced and sent to Fort Benning, Georgia for testing. Between the conceptualization and pilot phases, however, the tank slipped over its 7.9-ton weight limit. This led to the deletion of some of the tank’s extra features such as the power-traverse for the turret, gun stabilizer, and fixed bow machine-guns bringing the weight back down to 7.4 tons. Two prototypes of this revised designed were produced in November 1942 and designated T9E1. One of the vehicles was dispatched to Great Britain for testing along with an accompanying team of engineers. The team reported that the tank was well received and that the British were more than happy to purchase the tank.
One of the test models of the T9
One of the test models of the T9.
The British placed an order for the tanks, with production set to begin in late 1942. However, technical issues kept dogging the production of the tank, delaying it until the April of 1943. The tank didn’t officially receive it’s M22 designation until late 1944, with the British eventually nicknaming it ‘Locust.’

The Locust’s Anatomy

The M22 was one of the smallest tanks the United States had ever built, yet it still carried a crew of 3. These consisted of the commander, who also served as the loader, who, along with the gunner, was positioned in the turret, with the driver positioned on the right side of the hull. The driver had a small armored hood over his head with vision ports embedded.
Like it’s invertebrate namesake, the M22 was fast. Propelled by the 165 hp Lycoming O-435T horizontally opposed 6-cylinder gasoline engine, the tank could reach, in theory, 40 mph (64 km/h). More than fast enough for it to save itself from a sticky situation. The running gear was based on the type found on the M3/M5 Stuart Light Tanks, being slightly lower than the original. It retained the forward drive sprocket and Vertical Volute Spring Suspension (VVSS) with large trailer idler wheel at the rear.
Early model of the T9E1 during trials
Early model of the T9E1 during trials.
The M22’s speed would also serve as it’s protection. The tank was not designed to fight it out against heavy enemy armor, merely supply its accompanying airborne infantry with light armored support. As such, armor on the vehicle was only 12.5 mm (0.49 in) at its thickest.
The main armament consisted of the 37 mm (1.46 in) Tank Gun M6. This was the same gun found on the M3/M5 Stuart Light Tanks, the M3 Lee/Grant, and the M8 armored car. It could fire a range of ammunition types, including APCBC (Armor-Piercing Capped Ballistic-Capped) and HE (High Explosive). The AP ammunition could penetrate roughly 25 mm (1 in) of armor at 1,000 yards (910 m). The secondary armament consisted of a single coaxial Browning M1919 .30 cal. (7.62 mm) machine gun mounted on the right of the 37 mm gun.

Faults, Faults, and more Faults…

Until this point, the Ordnance Department had been more than happy with the developments of the T9E1 vehicle. However, Fort Knox, who had run their own tests with the tank offered a drastically different opinion in a report to Ordnance:

“Light Tank T9 is not a satisfactory combat vehicle in its present state of development due to the lack of adequate reliability and durability…and cannot be used for landing operations with any degree of success.”

Following more scathing reports such as this, the initial order of approximately 1,900 T9s was terminated with 830 tanks produced. Not exactly the swarm the tank’s name would suggest.
A British service M22 Locust emerging from a Hamilcar glider during tests
A British service M22 Locust emerging from a Hamilcar glider during tests.
Further tests by both nation’s armored boards only highlighted more the faults appearing with the M22’s design. The first issues came with the very core of the tank’s reason for being, the airmobile capability. It was found that loading the M22 onto a Douglas C-54 took a crew roughly 24 minutes, with unloading taking around 10 minutes. This was because the vehicle had to be ‘decapitated’. The turret was hoisted off and placed inside the aircraft, while the hull was driven under the belly of the C-54. It would then be suspended from the aircraft via the lifting eyes on the right and left flanks, above the suspension bogies. This method was not ideal in combat conditions. It was also apparent that deployment from a fully laden C-54 would require the capture of a suitable airfield.
In 1944, it was eventually concluded that the design of the tank was actually quite obsolete, with its armor (discussed in the above anatomy section) able to be penetrated by .50 caliber rounds.
Along the same lines, a number of complaints flowed in about the M22’s 37 mm main armament, ranging from its lack of anti-armor capabilities to the weakness of its High-Explosive rounds. The subsequent burst from the shells was too weak, making them inadequate for observation uses. Also, with the removal of the power traverse unit, the turret had to be hand cranked, meaning rotation was extremely slow.
An unreliable transmission also resulted in numerous breakdowns, meaning the tank would take up a lot of “shop time”.
Production model M22 with protective cover over the barrel - Photo: Osprey Publishing
Production model M22 with protective cover over the barrel – Photo: Osprey Publishing

Standard issue American M22, with side skirts
Standard issue American M22, with side skirts.

American M22 named Bonnie from the 28th Airborne Tank Battalion, one of the only American units to be equipped with the tank.
American M22 named “Bonnie” from the 28th Airborne Tank Battalion, one of the only American units to be equipped with the tank.

An example of the M22 Locust in British service.
An example of the M22 Locust in British service. Note the Littlejohn adaptor at the end of the Barrel and 2in Smoke-Bomb launchers on the turret.

Illustrations are by Tank Encyclopedia’s own David Bocquelet

Service

USA
Two specially organized combat units were formed to undergo training for deployment with the M22. These were the 151st Airborne Tank Battalion activated on August 15, 1943, and the 28th Airborne Tank Battalion activated on December 6, 1943. The formation of the 151st came too late for them to see action as part of the Airborne forces involved with the commencement of D-Day in June of 1944. In the July of that year, they were relocated from their original base at Fort Knox to Camp Mackall in North Carolina. The 28th were redesignated as a standard Tank Battalion following a loss of interest by Airborne Command in October 1944.
Crew of an M22 sat aboard their tank named
Crew of an M22 sat aboard their tank named “Bonnie” from the 28th Airborne Tank Battalion – Photo: Osprey Publishing
A mere total of 25 M22s were deployed to the European theater by US forces. These were sent to the Sixth Army Group in Alsace for potential use by the venerable 1st Airborne Divison. What happened after this, however, is somewhat of a mystery as records are not currently known to exist.
Great Britain
Despite the Locust’s highlighted faults, the British War Office still wanted the tanks, believing they were more than adequate for their intended role. As such, 230 M22s were shipped to the United Kingdom under the Lend-Lease Act. The first 17 to arrive were handed to the 6th Airborne Armoured Reconnaissance Regiment (AARR) to supplement their existing arsenal of Tetrarchs.
A British Locust with the Little John adapter - Photo: Wikimedia Commons
A British Locust with the Little John adapter – Photo: Wikimedia Commons
The British made a few minor modifications to the tanks, including the addition of smoke-bomb launchers on the side of the turret, and the incorporation of the Little John adapter at the end of the muzzle. This adapter, in conjunction with special ammunition, operates under the squeeze-bore principal. The adapter is has a partially narrower aperture than the rest of the barrel, meaning the shell is under higher pressure causing it to fly faster and punch harder.
Operation Varsity
The tanks saw action with the British during Operation: Varsity, the March 1945 landings around the Rhine. Two Locust equipped units of the 6th AARR were assigned to the Operation. This operational deployment would be the Locust’s only chance to ravage the hypothetical crops of the Reich, and it bore mixed results. As designed, the tanks were brought in by Hamilcar gliders. 8 of the gliders took part in the assault. One glider was lost when the M22 it was carrying broke loose of its bindings and crashed through the tail section of the aircraft, sending both vehicles plummeting to the Rhineland. The remaining gliders touched down as planned, apart from one which hit a ditch at high speed spitting the tank causing it to tumble a number of meters with it eventually coming to rest upside down.

After this debacle of a landing, only 6 tanks remained operational. One went to support paratroopers of the US 17th Airborne Division but was knocked out by an unknown German tank destroyer. The Locust’s incessant mechanical problems once more reared their ugly heads when one tried towing a Jeep out of a downed glider. It remained in action, though, and supported elements of the 12th Parachute Battalion. Remaining Locust would continue to provide support in various infantry actions during the operation with mixed success due to the weakness of its 37 mm HE ammunition.

T18, the only Variant

The only variant built on the chassis of the Locust was the T18 Cargo Carrier (Airborne). This was a turretless M22 hull designed to operate in the same way as the M22 base vehicle. It was intended to tow supplies or air-mobile guns, such as the M2 or M3 105 mm (4.13 in) howitzer, from gliders and supply aircraft. The vehicle was not accepted for production.
The T18 tractor in testing - Photo: Osprey Publishing
The T18 tractor in testing – Photo: Osprey Publishing

Fate

The M22 was ultimately a failure and was very much a victim of its time. The technology needed to fully exploit the capabilities of an air-mobile tank was not available in time for the war. Though designed during the war especially for the M22, the Fairchild C-82 Packet was not ready until the conflict had ended. Surprisingly, long after its dismissal by both US and British Forces, the M22 saw combat again in service with the Egyptian army in the 1948 Arab-Isreali War.
Despite its many failures, however, the M22 succeeded in paving the way for future American air-mobile tank projects. These included the M56 Scorpion and M551 Sheridan.

The M22 Locust on display at The Tank Museum, Bovington – Photo: Author’s Photo
Quite a few M22 Locusts do survive to this day, in locations such as the Tank Museum in Bovington, the Rock Island Arsenal Museum in Ilinois of USA, and the Royal Dutch Army Museum at Delft in Netherlands. Others can be found the hands of private collectors world wide.

An article by Mark Nash

M22 Locust Specifications

Dimensions (L-W-H) 12’11” x 7’1” x 6’1”
(3.96 x 2.24 x 1.84 m)
Total weight 7.4 tons (74.3 tonnes)
Crew 3 (driver, gunner, commander/loader)
Propulsion Lycoming O-435T horizontally opposed 6-cylinder 4 cycle petrol/gasoline engine, 192 hp
Speed (road) 35 mph (56.3 km/h)
Operational range 110 miles (177 km)
Armament 37 mm (1.46 in) Gun M6 in mount M53 in turret
30 cal. (7.62 mm) MG M1919A4 machine gun
Armor 9.5 mm (0.37 in) to 25.4 mm (1 in)
For information about abbreviations check the Lexical Index

Links, Resources & Further Reading

Presidio Press, Stuart, A History of the American Light Tank, Volume 1, R.P. Hunicutt
Osprey Publishing, New Vanguard #153: M551 Sheridan, US Airmobile Tanks 1941-2001
M22 on The Tank Museum’s website.
www.tank-hunter.com
The M22 on Warspot.ru. (Russian)
English translation of the above article on Tank Archives