Category: WW2 British Prototypes

United Kingdom (1937)
Light Tank – 1 Tested

There was a remote possibility that the 1939 British Expeditionary Force (BEF), sent to defend Belgium and France, could have been issued with the same Czechoslovakian-designed tank the Germans equipped their panzer divisions with and used during their May 1940 Blitzkrieg attack. The German’s designation for this tank was the Panzer 38(t).

TNH Tank

On 13th June 1939, the British War Office Mechanisation Experimental Establishment received a new Czechoslovakian tank by rail for examination and testing. It was manufactured by Českomoravská Kolben-Daněk (ČKD), which was based near the capital Prague, and called the Praga TNH-P 8-ton tank, or TNH. It was unpacked by ČKD company’s fitters who had accompanied the tank. The tank was completely equipped apart from the ammunition. ČKD were keen to sell its new tank to the British Army and other foreign powers.

This tank was designed to replace the Czechoslovakian Army’s LT vz. 35 tank and also be an export success. By the time rgw TNH was tested in the UK it had already been sold to Iran, Peru, and Switzerland. Lithuania had also put an order in by this point. It had a roomier interior than the earlier tank and a different suspension system. It was armed with a Škoda 37 mm gun in the turret and had two 7.92 mm Zbrojovka Brno vz.37 machine guns, one in a hull mount and the other coaxial, mounted in the turret. The armor on the front was 25 mm thick and 15 mm thick on the sides. The armor on the test vehicle sent to the United Kingdom was made of mild steel, with the exception of the turret front, which was armored.

Observations

The Driver’s Position

The British inspection team first examined the driver’s position, noting that it was on the “off-side of the vehicle.” This was unexpected for a European tank, as most had the driver position on the left side of the tank and not on the right. That was the first ‘plus’ mark noted on the report card. Czechoslovakian drivers drove on the left side of the road, just like in Britain, until March 1939, when the commander of the German occupation forces ordered a change over to the right side of the road to conform with German traffic legislation.

The inspectors recorded that the driver’s seat was adjustable for length but not for height and that the angle of the backrest could be adjusted. When the front vision hatch was locked in the open position, the driver looked through an opening that was 8 inches (20.3 cm) wide by 4 inches (10.16 cm) tall. This gave an adequate vision arc of 120º. In wet or dusty weather, a temporary glass windscreen could be locked into position. In combat situations, when the driver’s vision hatch was locked in the closed position for protection, an episcope was swung into position. Another means of vision to the front when the hatch was closed was for the driver to peer through the vision slit in the armored hatch. It was 5 inches (12.7) wide by 3/16 of an inch (4.76 mm) tall. Bulletproof glass, which was normally stored underneath the driver’s legs, could be quickly placed behind the vision slit. A small periscope gave limited vision to the right side of the tank, but the driver could not see to the left. He had to rely on the tank commander and the hull machine gunner sitting on his left to see that everything was clear.

The two steering tillers, when drawn back, engaged an epicyclic gear by clutch withdrawal and brake application to the plant ring. By pressing a knob on the end of the handle, an alternative brake could be applied which operated on the spider, thereby locking the track. Thus, the driver could steer by either epicyclic or clutch and brake methods. Communication between the driver and the commander was by a system of colored lights.

The Hull Gunner’s Position

The hull gunner was seated in a similar seat to the driver on the left side of the tank. He was also the radio operator and had to act as the co-driver. His position was rather cramped due to the wireless sets being placed on a level with his left shoulder. The machine gun on his right was fitted in a ball mounting. It had a limited traverse to the left and right due to the height of the sprocket wheels and mudguards. The gunner’s telescope was rather dark and had neither brow pad or eye padding. This would cause injury if used on the move. The ammunition belt of a hundred rounds was fed into the feed block and the remainder of the belt was suspended on guides from the roof, the whole belt being fed out of the ammunition box. The machine gun could be clamped in a central position and fired by the driver, who had a remote control trigger on his nearside steering tiller. The hull gunner sighted the gun through an open site visible through his periscope. The sight was a metal rod about 12 inches tall with a ring on the end. The base of the rod was attached to the glacis plate in front of the driver’s position.

The radio had two alternative aerials, one being a 10-foot vertical rod giving a range of 5 km, and the other being a ‘battle’ aerial carried on the running board and giving a range of 1 km.

Turret Gunner

The turret gunner, who was also the tank commander, had a canvas sling seat. He was provided with a nonrotating cupola which had three small periscopes and an episcope mounted on its four sides. He was assisted by a loader who operated the coaxial machine gun. The examination team commented on the report, “The optical apparatus, though ingenious, does not give as good vision as the War Department equivalent.” The 37 mm main gun and coaxial machine gun could be fired singularly or both together. The main gun mounting could be either elevated by shoulder control or by a gear control, the firing trigger being on the handle of the latter. When the gun was being fired, the mounting was locked in the position adopted and could not be elevated or depressed so long as the gun was firing. The turret could either be rotated by a hand traversing gear or by free traversing. Locks were provided for both the turret and the gun mountings for traveling. There was no internal turret basket. Ninety rounds of 37 mm shells were carried in boxes of 6 rounds. Usually, 30 of these rounds would have been armor-piercing, and the remaining 60 would have been high explosive shells. Each armor-piercing shell weighed approximately 2 lbs. The high explosive shell weighed 1.8 lbs. There was stowage for 2,700 machine gun rounds carried in 100 bullet belts, 3 belts fit in each ammunition box. Nine hundred of the rounds were armor-piercing.

The Hull

The British examiners looked at the tank’s fire precautions and the means of exit available to the crew in an emergency. The tank had two main crew hatches, one through the cupola lid in the turret and another above the hull gunner’s head. “Both are adequate,” was their conclusion. It was noted that the driver did not have his own exit hatch but had to either get out through the turret hatch or, if that was blocked, clambered over to the hull gunner’s position and got out through his hatch. It was also recorded that it was possible to get into the engine compartment through a small door in the offside internal bulkhead and to open the louvers from inside and get out that way. A large fire extinguisher was conveniently mounted on the wall of the fighting compartment.

The Engine

The tank was powered by a Praga TNHPS/II 4-stroke, 6-cylinder in-line 125 hp engine. A hand crank could be used to start the engine from inside the tank as well as from outside the vehicle. A mechanical governor limited the engine speed to 2,000 rpm. The maximum speed of 42 km/h (26 mph) was based on an engine speed of 2,200 rpm. Therefore, the top speed at the governed 2,000 rpm was only 38 km/h (23.6 mph). The engine was cooled by water circulated by a pump driven off the timing gear.

The radiator was mounted at the rear of the engine. Air was drawn in through the louvers under the engine covers, one on each side. It could also be drawn from the fighting compartment by opening slots in the bulkhead. The air inlet to the fighting compartment was controlled by opening an adjustable flap over the brakes and two small louvers. “It was not considered adequate. Steering gear pollutes the air with hot Ferodo and oil fumes,” the inspectors remarked. Air was drawn through the radiator by a ‘Keith’ type exhauster and out through a bullet-proof louver facing upwards on the rear of the tank. This exhauster was coupled to the crankshaft through a universal joint. There was a slipping clutch incorporated in the fan hub. The system did not contain any pressure valves. The vehicle exhaust was very quiet and, on cross-country work, the whole vehicle was quite unlike some other tanks, but it was very noisy on roads due to track noise.

No engine oil cooler was fitted, but the large cylindrical body of the oil cooler was finned and afforded some cooling properties. A large oil bath filter was used for filtering the engine air. A large “Autoclean” filter was fitted in the lubricating system of the engine. This also incorporated the relief valve for oil pressure. All petrol and oil pipes were of a flexible rubber and canvas hose type, secured by clips. The petrol tanks were in the engine compartment, one on each side. They held 24 gallons each. Petrol was drawn from the tanks by an A.C. engine operated pump. An electric “Autopulse” pump was also fitted for emergency use.

Transmission

The transmission was through a single plate clutch in the flywheel. This could not be withdrawn, however, as its only purpose was to give a ‘slip’ if the Wilson gearbox engaged too fiercely. The power was then transmitted by a propeller shaft through the fighting compartment to a Wilson five-speed and reverse box situated between the hull gunner and driver. This box was kept cool by taking the oil to a cooler incorporated in the radiator. There was also an ‘Autoclean’ filter situated in the radiator. Bolted onto the gearbox was the bevel box, which transmitted power to two epicyclic steering assemblies. These consisted of the normal clutch, epicyclic gear with brakes on the planet ring and spider. In addition to the two bands required for steering, each assembly had a third band that operated on the spider drum and was used for breaking. The power then passes through a final reduction to the sprocket, which was mounted on the front of the vehicle. The transmission was accessible for maintenance. The brakes could be adjusted either from inside the hull or through the flap, which admitted cooling air to the steering assemblies. This flap had four positions controllable by the driver. Only one was bullet-proof. This allowed the flap to be opened a quarter of an inch (6.35 mm), in which position a flange on the outside prevented the entry of bullets.

Suspension

The suspension consisted of two assemblies on each side that carried the hull on knife edges. Each assembly had two wheels. The wheels were 31 inches (78.74 cm) in diameter and were rubber-tyred. The assembly consisted of a leaf spring mounted on the center member and joined to the top of each wheel axle casting. From the center member, there were also two radius arms that ran to the bottoms of the wheel axle casting. The front and rear arms on each side were dampened by a spring-loaded, unadjustable friction shock absorber mounted on the pin joining the arm to the center member. Lubrication was by ‘nipples’ situated in the hubcap of the sprocket, idler and each wheel. The oil was carried by drillings to all necessary parts. The knife edges are not lubricated. The track lay on the two rear wheels but was carried on two small guide rollers above the front wheels.

Tracks

The tracks consisted of manganese nickel steel castings. The track pins were headless and made from nickel chromium or manganese nickel steels. They were secured by circlips. The pin was beveled at each end and had a groove turned in it at the appropriate place. The bevel expanded the circlet, which sprung into place when the groove of the pin reached it. Track adjustment was by adjusting the idler wheel mounted at the rear of the tank. The idler wheel bracket was rotated by means of a worm and ratchet operated from outside the vehicle. It was remarked in the report that the tracks were not new when received but did not appear to have worn much. Their rate of wear appeared low. They were strong and stayed on well.

Accessories

A headlamp, two side lamps, and a tail lamp were fitted. The side lamps had a red glass pointing upwards which could be easily seen from the air. Interior lamps were provided where necessary. A signaling lamp employing three colored lights was issued with the vehicle. There was a small flap provided in the turret top to push it through. A horn was fitted that could only be used when opened up as the wiring was carried through the open sight aperture of the hull gun and had to be disconnected when in action. A mirror in a tin case to protect it from stones was fitted. The electrical system was fully suppressed to prevent wireless interference. The vehicle was fitted with four Ramshorn towing hooks in addition to the drawbar at the rear.

Trials

This tank underwent tests from 17th – 29th March 1939. The weight of the vehicle fully loaded was 9.4 tons (8.52 tonnes). It completed 188 miles (302.5 km) by road and 103 miles (165.7 km) cross-country. The examiners made the following comments:

The commander’s field of view was not ideal. The vision from the episcope and the three periscopes was not continuous. It was also extremely hard to judge distance through these instruments. The commander was also hampered when looking through his scopes owing to there being no brow pad.

The hull gunner’s field of view was adequate to cover the ground over which he could fire. The driver’s vision was adequate except for road driving in traffic, as the driver needed one member of the crew to be observing on the outside of the vehicle. The driver’s position was comfortable except that there was not enough headroom. The hull gunner’s position was rendered uncomfortable by the wireless set, causing him to lean continuously to one side. He also suffered from a lack of headroom. The commander’s position was satisfactory, with the exception that the sling seat provided did not allow him to adopt a comfortable position behind the gun. The vehicle, when closed down, did not appear to be adequately ventilated, and fumes given off by the steering gear were very unpleasant after a time.

The power of manoeuvre was adequate and did not vary whether opened up or closed down. The vehicle was also easy to handle on side slopes. The steering required a little skill, as the action of the epicyclic break bands was rapid. Unless the brake was applied skilfully, the tank would turn more than was required when driving on roads. The controls were well-placed. The vehicle did not skid under normal conditions and was safe at any speed it could attain. It did not suffer from reverse steering, but when descending hills, the steering became very insensitive and heavy. The vehicle was not very large and was as conspicuous as a light tank. The balance of the turret was difficult to estimate, as it was extremely awkward to traverse under any circumstances. The traversing handle was very badly placed by British standards. It was to be operated while looking out of the cupola and not while looking through the telescope.

The suspension of the vehicle rendered it unsuitable as a gunnery platform. It had a short sharp juddering motion of about two inches pitch which rendered it impossible to keep the eye to the telescope. Apart from this, it was quite well sprung and rode across country about similar to the Tank, Cruiser, A9, Mk.1. On roads, the suspension was at times affected by a juddering motion, but otherwise, it was satisfactory. The capacity of negotiating natural obstacles was not adequate for a cruiser tank. It could cross a 5-foot stream but failed to cross a 6-foot stream due to the back falling in as the bank gave way. It would not climb a 4-foot sandbank; the sprocket failed to pull the nose up. It could be fitted with seven spuds on each side of the vehicle’s tracks. These spuds were quickly attached to the track, but the short length of the vehicle did not enable it safely to climb more than 3-foot vertical obstacles. It was estimated that the vehicle could cross a 7 foot hard sided trench. The vehicle climbed a 2 foot 10 inches wooden vertical obstacle. This was the safe maximum owing to the angle to which the vehicle tipped itself.

The tank was driven continuously for 94 miles on roads. It took 4 hours 35 minutes and the average speed was 20.5 mph. The average fuel consumption was 3.13 mpg. Fuel consumption over cross-country courses was 2.1 mpg. After a total of 291 miles, the oil levels did not need topping up. Life of the brakes appeared satisfactory. On a 188 mile journey to Lulworth Ranges, they did not require adjustment. They were only adjusted once after about 260 miles. Two engine stoppages occurred after the vehicle was being tested due to the changing from one fuel tank to the other. No special filters seemed to have been fitted. The tank underwent a number of tilting tests and performed satisfactorily.

Final Observations of the Mechanisation Board dated 22.5.1939

“The attempt to produce an inconspicuous machine with observation arrangements immune from bullet attack has resulted in a cramped fighting machine with control inferior to our standards. The “dance” of the vehicle … is particularly marked on roads and is due to the combination of long pitch narrow bar tread tracks and un-dampened suspension.”

Conclusion

The British rejected purchasing the Praga TNH-P 8-ton tank because it was deemed inferior to the current British Cruiser tanks, such as…, in its ability to cross obstacles, lack of smooth ride, and cramped fighting compartment. It was too thinly armored to be considered an infantry tank. Its Skoda 37 mm gun was not as powerful as the British 2 pdr gun. The tank was returned to the factory. In May 1940, the British fought in France with their Cruiser tanks against Panzer 38(t)s employed by the Germans. The Panzer 38(t) and its derivatives would stay in service far longer and in far higher numbers than any of the initial British Cruiser tanks.

Specifications
Dimensions (L/W/H)	4.6m x 2.12m x 2.4 m (15ft 1in x 6ft 11in x 7ft 10in)
Total weight	9.4 tonnes
Crew	4 (Commander/Loader, Gunner, Radio Operator/hull machine gunner and Driver)
Propulsion	Praga TNHPS/II 4-stroke, 6-cylinder in-line 125 hp petrol/gasoline engine.
Top Road Speed	42 km/h (26 mph)
Range (road)	250 km (155 miles)
Armament	Skoda 3.7 cm L/48.7 gun
Secondary Armament	2x 7.92 mm Zbrojovka Brno vz.37 machine guns
Turret Armor	front 25 mm, sides and rear 15 mm and top 10 mm
Hull Armor	front 25 mm, sides 15 mm, rear 15 mm and the top and bottom 8 mm

Source

Experimental Report on 8-ton Tank (Praga – TNH-P) MEE Report No.A99
National Archives at Kew WO 194/22.
S. J. Zaloga, Panzer 38(t), Osprey Publishing.
T.L. Jentz and H.L. Doyle (2007) Panzer Tracts No.18 Panzerkampfwagen 38 (t) Ausf. A to G und S.

United Kingdom (1940)
Land Battleship and Leaping Tank – None Built

The United Kingdom declared war on Germany following its invasion of Poland in September 1939. When it did so, there was a sudden realization among many that the country was in yet another major war in Europe against the same enemy they had fought just a generation beforehand. That previous war had been seared into the collective psyche of the nation as one characterized by almost unimaginable and unrelenting slaughter in the mud and trenches of the Western Front – a situation summed up too simply (but commonly) as one ended by the appearance of a new weapon known as the tank.

Faced with a new war, many in Britain foresaw a war fought along similar lines and one which would need new heavy tanks to smash through the German defensive lines, like the Siegfried Line. An official program had started in late 1939 under the auspices of the Special Vehicle Development Committee (S.V.D.C.), but this was by no means the end of ideas. Many inventive and scientific minds would also consider this and other problems associated with the war to come in this uneasy period from September 1939 and the start of the German campaign in the West in May 1940. Known as the ‘Phoney War’, it provided a brief window into the thinking behind some of these ideas for a war which had yet to start in earnest for Britain.

“Too much thought is being given to armies and man-power. This war will be won by the engineer and the scientist”

Arthur Janser

The man behind this 500-ton tank idea was Arthur Magnus John Janser. Janser is somewhat enigmatic and, although he is known to have come from Austria (with a date of birth recorded many years later in England as 17th June 1903), the chain of events which led to him being in Britain in 1940 are less than clear. An expert chemist, Janser, or ‘Dr. Janser’, as he is often referred to, thankfully submitted several patents in his lifetime, which provide some insight into his life pre-1940. Janser submitted his first patent in 1925 in Vienna (Austria) followed by another at the same time in Berlin-Charlottenburg, Germany. By 1934, he was in Paris, and by 1936, he was in London.

“Mr. Janser is a monarchist…being Viennese, [he] gave us some great inside dope on how the Nazis were confining his friend Sigmund Freud, the great psychologist”

He is described at times as an Austrian refugee and this is likely correct given the Anschluss ended Austria as an independent state in March 1938. By 1936, however, living in London, he managed to become engaged with a group of amateur (but by no means amateurish) scientists known as the British Interplanetary Society (B.I.S.). Formed in Liverpool in 1933, the B.I.S. expanded to London in 1936.

The British Interplanetary Society

Janser’s knowledge and skills as a chemist were much needed by the B.I.S., where he would propose solid rocket fuel motors for their various space rocket ideas. Other members of the B.I.S. included:

• Arthur C. Clarke (astronomer and noted science fiction author post-war),
• D. W. F. Mayer, H. Bramhill (draughtsman),
• Jack Happian Edwards (Head of the Technical Committee and Director of an Electronics firm),
• Ralph A. Smith (artist and engineer – his son later worked on the Apollo programme),
• Maurice K. Hanson (mathematician and payload specialist),
• William F. Temple,
• S. Klementaski (biologist),
• H. E. Ross (electrical engineer and man behind Project Megaroc in 1946 to adapt a German V-2 into a pilot carrying rocket),
• J. H. Edwards (research director),
• Eric Burgess (a writer, founder of the B.I.S., and a NASA consultant after the war),
• H. E. Turner (editor of the Manchester Interplanetary Society magazine), and
• A. Val Cleaver (aircraft engineer and Chief Engineer for Rolls-Royce rocket division).

Some of the meetings of this group were even held in Janser’s flat.

“A middle aged foreigner, Mr. Janser, a research chemist (who said he’d made a lifetime study of atoms) was smiling to himself most of the time, occasionally making dry comments, superiorly on his pinnacle of knowledge of the slow, lengthy, laborious & patient research necessary even to project a rocket into the stratosphere”

Janser, along with several other members of the BIS, were also a keen followers of Science Fiction literature (including Arthur C. Clarke), attending a convention held in London April 1938 on the subject of space travel. Janser did not attend the 1939 convention, although Clarke did, perhaps indicating that Janser was less interested in science-fiction stories than he was in the science-realities behind them.

“Mr. Janser is a many-sided genius. He has a bookcase which covers an entire wall, and it is full of books on every aperture of science, from chemistry to psychology, from astronomy to Biology”</blockquote>

Janser’s primary contribution to the B.I.S. was his proposal for solid propellant arranged in a cellular manner to produce enough thrust to propel a rocket to the moon. To this end, according to H. E. Ross, Janser produced between 80 and 120 possible propellant combinations for rocket fuels.

Although the B.I.S. members, consisting of about a dozen scientific experts, were not the first to consider rockets or space travel, they were the first to do so in such a systematic and thoughtful way. The Technical Committee of the B.I.S. considered each and every aspect of what it might take to put a man into space one step at a time, 30 years before the Apollo missions.

“Item Two of the agenda: the composition of a very light but efficient battery to heat the space-ship. Here Messrs. Edward and Janser started an argument on such a highly technical plane that I just sat there between them, agape, and the stream of words passing over my head like a beautiful rainbow. I gathered it was something about conductivity values. Arthur Clarke made occasional interjections which might or might not have been to the point, but at any rate showed us that Arthur grasped what was going on… It all ended with Mr. Janser promising to hunt through his books (all 2,000 of them) to find certain tables, and perhaps consult the National Physical Laboratory on this important subject…”

Between them, they were a group of men covering a wide range of scientific abilities, and Janser, amongst them, was clearly considered to be one of the luminaries of the group’s most technical elements – rocket propulsion. Just before the war, this team had finished their design for a solid-fuel type rocket capable of reaching and landing on the moon.

With the declaration of war in September 1939, the society was disbanded shortly afterwards, for the duration of the conflict. Many of those in the BIS ended up in uniform during the war. Janser, as an Austrian citizen, did not. Born in 1903 (his marriage certificate says 1904), he would have been in his late 30s at the outbreak of war and, at this time, many foreign nationals were detained for national security reasons. Many were shipped off to the Isle of Man, and, later, after security vetting, returned to their lives in Britain.

Barricading the Sky

It was whilst working with the B.I.S. that Janser would also meet with famous inventor Grindell Matthews (another member) to provide advice on rocket fuel. Matthews was working on his anti-aircraft rockets which carried a small explosive charge and which pulled a wire behind them to ensnare and destroy enemy aircraft.

Matthews appears to have been inspired by a speech by Sir Kingsley Wood (the Secretary of State for the Air) who had called for an inventor who could devise a way of “mining the skies” as protection against enemy aircraft. Janser wrote about these ideas in November 1939 with the title of “Barricading the Skies”. In the article, Janser discussed several ideas which had been put forth, including a barrage balloon filled with explosive gasses and tethered with electrified cables, electrified clouds, special clouds made from artificial poison gasses to choke the engines of aircraft, and even an all-metal airship replete with artillery.

“Mr. Janser comes around… [for a ‘jabber’]… He indicates that he is working on a new sort of ‘death ray’ & Grindell Matthews is also aiding and abetting him”

It would be Matthews’ rockets which, along with the standard barrage balloons, provided the answer to Wood’s question of protection of the sky. Matthew’s rockets, assisted by Janser’s rocket knowledge, would go on to see service during the war as ‘Parachute and Cable’ devices, bringing Janser’s ‘Barricade in the Sky’ article to reality.

“Janser told me [Bill Temple] it’s possible we may get a grant of £200 to help Grindell Matthews with his ‘Defence’ research work. Janser said the German military men already had an explsoive rocket which could be fired about 5 or 6 kilometres with more accuracy than a shell & were developing it rapidly. I said we may expect them one day to be coming over the channel”

Other Activities

In April 1939, Janser was elected as a fellow of the Royal Society of Arts in London, which allowed him to put ‘F.R.A.S.’ (Fellow of the Royal Society of Arts) after his name. His biography in the Journal of the British Interplanetary Society also shows him with F.C.S., and F.C.I.S. after his name, although it is unclear exactly to what these refer. However, F.C.S. is likely for a Fellow of the Chemical Society (the forerunner to the Royal Society of Chemistry) and F.C.I.S. may be in relation to being a Fellow of the Chartered Institute of Secretaries.

By November 1939, Janser is known to have been living at 28 Great Ormond Street, London from his patent, but he is also recorded with an address in Holburn as well (today, this address is opposite the world famous Great Ormond Street Children’s Hospital).

Other Arms

It is in consideration of Janser’s background, his genius, and his abilities, as well as his writings, such as those in newspapers in this period, that his tank concept makes sense. Janser would write a series of guides for the common person to help them to understand the inventions and ideas being bandied around in relation to the war, such as Matthews’ Death Ray. These appeared in ‘Guide and Ideas’ published weekly as a light hearted edition, with such articles as the secret life of showgirls and then, with Janser, some serious articles as well.

In this light and with war having broken out, he would find himself as an Austrian, an alien from a hostile country clearly trying to not only solve a technical problem, but also show his loyalty to the UK. Many such aliens were taken away, interned for reasons of national security and then progressively released. Janser appears to have been caught up in this and was interned on 25th April 1940. Interestingly, his internment ceased on 16th October 1940, and he was exempt from further internment. This was presumably because he was working for H.M. Arsenal in Woolwich at the time and they needed his expertise, but also marks the softening of the hard-line approach by Winston Churchill, which had previously ordered all foreign nationals detained as a possible security risk.

His tank concept was not lengthy or perhaps not particularly well considered. It did, however, reflect much of the concerns of the time about a war stuck between the French Maginot Line and the German Siegfried Line.

The Enormous Tank

In spring 1940, Janser was to write and espouse the need to rethink the trend of small and lightly armored tanks. Something much bigger, much stronger, more powerful, and much better protected than ever before was going to be needed. He declared that “recent advances in metallurgical research” allowed for the construction of tanks not just bigger than those in service, but bigger than those which had ever been in service before or since.

To make use of this knowledge, Janser suggested a tank of up to 500 tons could be built, protected by armor as thick as that on a battleship (30 cm or more) “mounting siege guns which fire special concrete breaking shells”. Assuming for a moment that advances in metallurgy were really such that new armor could be more powerful, then this would be a level of protection technically beyond that of a battleship. What he called “double-strength” steel was to be used and made with minerals unavailable in Germany. This new armor would effectively render it indestructible to enemy fire and unmatched on the battlefield.

What it really represented, was a totally unnecessary level of protection to guard against any possible threat from enemy guns. It was also a preposterous statement indicative either of someone trying to make a point merely about the level of protection (that of an indestructible vehicle), or simply that he did not have a clue what he was talking about in terms of armored vehicles, or maybe a bit of both.

He was, in spring 1940, simply repeating the same sort of thoughts and concerns of some in the upper echelons of the British military, in terms of thinking of bigger tanks to smash the Siegfried Line and specifically the concrete bunkers along it. What he did, however, was to go beyond ever their wildest fever-induced dreams of giant tanks. Janser produced a vision of a vehicle gliding over enemy tank traps and defensive works with impunity:

“A tank of five hundred tons built of this double-strength steel would sail serenely over tank traps and be impervious to land-mines. Ferro-concrete booby traps would crumple under its advancing caterpillars”

He may well have been correct in assessing that a tank of such weight might, simply by virtue of its great weight, crush beneath its tracks the sort of reinforced concrete structures arrayed before it in defensive lines. What he missed, however, is that the same weight of machine would undoubtedly perform the same task on the way to the front itself, destroying its own sides’ bridges, roads, and railways as it went.

Nonetheless, this 500-ton tank idea was certainly the right ‘scale’ of number to garner press coverage as far afield as Australia.

“Dr. Arthur Janser, famous Austrian research chemist now a refugee in England, believed that the Siegfried Line can be smashed. But new weapons and new types of ammunition are wanted..”

When Janser, in spring 1940, mentioned the need for new weapons and ammunition to fight the war, he was, of course, correct. The ‘500-ton’ tank may simply have served as a literary device to get attention to his call and he continued the description of his idea to reinforce the point.

Not only was this monstrous machine to be ludicrously heavy (more than two and a half times the weight of the heaviest tank ever made – the German Maus), but also armed with a siege gun. The standard British siege guns of the era were the BL 60-pounder (5 inch) and BL 9.2” howitzer. Both of these guns dated to WW1 or before and could fire large high-explosive shells weighing 27 and 130 kg out to a range of more than 9 km. Certainly, both guns would provide a phenomenal amount of firepower for such a tank and, given an overall weight of 500-tons, the size and weight of the guns became a moot point. Janser, to enhance the power of the siege guns, also proposed new and special anti-concrete shells which could thus shatter the German ferro-concrete bunkers, dragon’s teeth, and barriers of the Siegfried Line.

Janser did not elaborate further on his 500-ton tank idea but, assuming that 500-tons was a real prospective weight and not just something to engage the reader in consideration of new larger tanks, then it would need an engine. The largest tank built in Britain during the war was in the region of 80 tons and powered by a 600 hp engine, delivering around 7.5 hp/ton. Assuming an equivalent power to weight ratio was needed for this machine, Janser would have required engine/s capable of delivering 3,750 hp. This would have been well beyond any road-vehicle of the era and putting it squarely in the territory of power plants from either a ship or a locomotive.

Robot Soldiers

If the 500-ton tank idea was just a bit too much of a step into left field, and a ‘miss’ for the futuristic leanings of Janser, then his second point was spot on, albeit several decades too early.

Following on from this call for a new better armed and armored species of giant tank, Janser also proposed that to beat the Germans, more ‘robot-soldiers’ would be needed. By this, he was referring to his knowledge (from where he did not state) that the Germans and Czechoslovaks had, before the war, “exploited the possibilities of automatic machine-guns and the remote control of guns”.

The modern reader may be a little perplexed as to how a remotely operated gun is conflated with the word ‘robot’. In the 1940s, a ‘robot’ was simply a term being applied to not only a sort of shiny metallic humanoid, but also what today is considered more of a drone or remotely separately weapon of some description. A notable example of this term was the famous V-1 flying bomb being referred to in WW2 as ‘Robot Bombs’.

Any disappointment at the lack of a 1940s-era Cyberman concept, however, is quickly dispelled as Janser describes “robot soldiers armed with machine-guns or grenade-throwing apparatus and controlled by beam radio”, so whether he really thought of mechanical men or just drone vehicles is unclear. The use of drone vehicles is, of course, not a modern phenomenon, but the mass use of drones and unmanned ground combat vehicles is on the rise, albeit 80 years after he mentioned it. Just like then too, the issues of radio control being jammed or intercepted was a concern, and Janser stated:

“Even enemy jamming of the wireless waves could not put the robots out of action”

This rather vague additional line implied at least some level of direct control, so it possible that it was yet another simple rhetorical device to make his readers ponder the problems. Perhaps too, it was an acceptance of the limitations on a fully remote system and a tacit acknowledgement that the robot vehicle would still need a human crew member, with its weapons operating remotely instead. Either way, unfortunately, he chose not to expand on the idea.

The Grasshopper

The final of Janser’s three tank–related concepts was for a grasshopper tank. This was not a tank built to look like a grasshopper, but one which could, conceivably, be used as an alternative to driving-over and crushing obstacles, by simply leaping over them. In this part, Janser chose once more to bemoan the small light tanks in service and felt that some special war machine of this type, might, instead, be able to move quickly from place to place by jumping.

Oddly, for rather ill-considered or technically improbable idea, the Grasshopper idea was a real plan in Australia in 1944, although one unlikely to have been directly inspired by Janser’s call. Not only that, but back in the UK, there were also experiments with the use of rockets to ‘leap’ a vehicle over an obstacle or from the mud in which it had become stuck. No doubt Janser, being a rocket fuel enthusiast, would have approved in general terms of the idea of combining rockets and tanks, although the outcome was less than successful.

Conclusion

What can be made from Janser’s work on tanks? Was he really serious about a 500-ton or even a Grasshopper tank? The answer is ‘probably not’. Both such ideas were well within the common frame of science fiction, and, whilst he was not a writer himself, he did attend at least one convention and spent a lot of time with men very much in the sci-fi field and who wrote stories on it. Perhaps their influence rubbed off a little and, combined with the literary technique of what might be closely related to modern ‘clickbait’, Janser grabbed his readers’ attention with a ‘500-ton tank’. For the same reason that a 400-ton tank would be not less equally ridiculous but not hit the same attention-grabbing mark, Janser’s point was nonetheless clear.

Britain had, in general terms in 1939 and 1940, tanks which were in his opinion on the whole too small, too lightly armed, and too lightly armored. In specific terms, even the best of these tanks, the A.12 Matilda, which had a good level of protection, was still utterly unsuitable to lead a charge breaching the Siegfried Line to carry the war into the heart of Germany. Janser was not alone in that view, and various other projects and ideas were espoused at the end of 1939 through into 1940 for similarly large and heavy assault vehicles.

Unlike some of the wacky ideas of random members of the public and the occasional tweed-jacketed home inventor, Janser had a significant level of skill and knowledge in rockets and chemistry. This did not translate directly to tanks, but he continued his work and writing through the end of the war.

On a personal note, despite having applied for naturalization in July/August 1939, Janser was not naturalized until May 1947, at which time he was already married to Thora Ruby Christian Janser. He also became a fellow of the Physical Society in 1947 and had also been elected as a member of the Royal Society of Mechanical Engineers.

He would remain in London and continue his work as a “Research and Consulting Chemist” with an address of 3 Edgeware House, Chapel Street in May 1947, and in 1958, he provided the introduction to a book on past-life regression through hypnosis. Janser died in London in 1964, aged 58. His wife, Thora ‘Ruby’ Christian Raymonde (or Fairbairn), whom he married in Westminster in 1942, survived him and died in 1990.

The B.I.S. would continue its work too and is still going to this day, working on the problems of space travel and life on other planets. The author wishes to express his gratitude to the B.I.S. for their assistance in preparing this article.

Specifications Janser’s 500-ton tank
Crew	u/k
Dimensions	u/k
Weight	500-tons
Armor	‘battleship’ levels of improved steel
Armament	‘Siege’ guns
Engine	u/k
Speed	u/k
Propulsion	tracks

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United Kingdom (1934)
Infantry Tank – 1 Prototype Built

Of all the tanks in WW2 which may be derided or even mocked for being ‘ugly’ or useless, one which invariably makes the list is the British A.11 Matilda. This is partially the result of the overall poor showing of the British Expeditionary Force (B.E.F.) in France in 1940 and partially because of the strictures placed upon the design of the vehicle in the first place. It is also because the vehicle is generally not well understood and its combat record unappreciated.

The only people who really appreciated that latter element were the Germans in 1940, for whom the A.11 and its big brother, the A.12, came as a well-armored and unpleasant shock.

Whilst the A.11 was only in service with the British Army for a few years, it left a mark in the form of one of the most successful tanks of the whole war – the A.12 Matilda.

Misunderstood and underappreciated, the A.11 started as a scribble and resulted in a small, heavily armored tank which proved to be a shock to the Germans at the Battle of Arras in France in 1940. There, in conjunction with infantry and its replacement – the A.12 Matilda, the British succeeded in blunting the nose of the German advance. The A.11 Matilda seen in that battle, however, started with a special and slightly different prototype – the A.11E1 (A.11, Experimental model 1), with a history all of its own.

Origins

The A.11 ‘Matilda’ has its origins in the late interwar period, as the British Army was undergoing some head-scratching over not only the shape and dynamics of a future war but also how it would organize itself and what it needed to fight it. The British were generally cautious with new developments in tanks, due in no small part to the trauma of WW1, with the huge losses of men and equipment, and also to the significant limitations on expenditures as the British Empire sought to reconcile the cost of defending Europe from Germany.

Any new development, therefore, had to meet both a developmental limit, the new needs of the Army, and the strict budgetary constraints in force. Luckily for the British, these highly conservative restrictions matched with the equally austere Sir Hugh Ellis, Master General of Ordnance (M.G.O.) and Major-General A. E. Davidson as Director or Mechanisation (D.o.M.). Both men were skilled and competent in their field, with Davidson also a respected engineer, but both still saw future war along the lines of the last one.

In debating the primary role of a new tank for 1934, it was thought that it had to support infantry (an ‘I’ or ‘Infantry’ tank) in the attack against enemy infantry and positions. Enemy tanks could be dealt with by artillery, so a new tank really just needed heavy protection from enemy infantry and anti-tank guns as well as the means to deliver machine-gun fire. As it had to support infantry at their pace, the speed was almost irrelevant. As these two men debated their plans for what a new tank needed to be and how it should work tactically, they consulted with Major-General Percy Hobart, who was Inspector of the Royal Tank Corps (R.T.C.) at the time and proposed two solutions:

1. A small tank with a crew of two men armed with machine guns built in large numbers to swarm the enemy.
2. A heavy tank with a cannon.

The solution selected was the first one and, in October 1935, the legend of vehicle design, Sir John Carden, was approached to develop this idea. A skilled engineer and talented vehicle designer, he was also the head of tank design at Messrs. Vickers Armstrong Ltd., meaning whatever he designed, he could get into production quickly.

His rather crude initial sketch, finished on 3rd October 1935, was for this two-man small tank with a single turret and a single machine gun. A week later, this sketch was taken by Sir John Carden to Colonel M. A. Strudd, the Assistant Director of Mechanisation (A.D.o.M.). Being a technically simple vehicle and with no concerns over getting it into production in the time scale the Army was planning, just 6 months, it was approved as a project under A-vehicle number A.11. One thing not mentioned in most histories of the A.11 is revealed in that original sketch – the crossing of trenches by the vehicle was an important point, which perhaps hints at the sort of warfare terms about which the Army was still thinking. This new tank would manage to cross an impressive 8’ (2.4 m), more than adequate to cross any standard infantry trench.

It is commonly repeated online and even in some books that the ‘Matilda’ name was selected after the prototype was seen ‘waddling’ like a duck. The connection between Matilda and Duck is unclear in itself in this false history especially, as that particular Disney character with that name only appeared after the war. The name could, of course, not have been penned after seeing it move, as it is first written down on 10th October 1935, when the tank was not much more than a doodle. In fact, ‘Matilda’ was just a company name for the project – a code word to disguise what the vehicle was, although officially it remained just ‘A.11’.

The price of the project, at a time of small defence budgets, however, was somewhat extraordinary, some £15,000 for all of the development and draughting costs. In 2020 values, this is over £1m and each tank was projected to run at £5,000 (£364,000 in 2020 values). For a tank armed only with a small machine gun, this was still very expensive. This is a vehicle often referred to as cheap being built to a budget. For sure, it had a budget to be built to, but it was by no means a miserly one. For reference, a small light, machine gun (or even cannon-armed) tank from the same firm, like the Vickers Light Patrol tank, was on sale in 1933 for just £700 (around £51,000 in 2020 values). It is hard, therefore, to square quite why this Infantry tank might justify costing more than 7 times what that tank would.

Armor

Armor for this new type of tank was going to need to be heavy – very heavy for the era which given that even 20 – 30 mm or so was considered good protection for many tanks is saying quite a bit. A standard thickness of 60 mm was proposed for the tank, with the plate made from Vibrac 45 armor steel produced by the (Vickers) English Steel Corporation. The roof and floor plates were eventually to be just 10 mm thick and made from Homogenous Hard tank armor and proof against .303 rifle fire. Originally, however, for the prototype, the hull was not going to be made from armor plating, but mild steel ‘soft plate’ instead. On A.11E1, the rear and hull roof were made using thinner plates than that used on the eventual production models, just 7 mm thick for the floor and roof and 8 mm thick at the rear – albeit heavily sloped.

This is common enough in a prototype tank, as it makes manufacturing easier and cheaper and permits modifications to be done quickly prior to production. Of note too is that this prototype was only made in plate 60 mm thick, as this thickness was considered sufficient protection against the primary prospective enemy anti-tank weapon of the time – the excellent German 37 mm gun (3.7 cm Pak 36).

Despite having the appearance of a tank riveted to a frame, like many other tanks constructed in this period, the structure was physically strong and stiff enough that it was, in fact, simply riveted together without a frame.

Prototype – A.11E1

Despite being a technically simple vehicle, this first vehicle, A.11E1, now with an official War Department index number of T.1724, was not finished until September 1936, when it was handed over to the Mechanisation Experimental Establishment (M.E.E.).

Firstly, on 9th December 1936, splash tests were conducted at Farnborough and the turret, in particular, was found to be a problem. Here, under concentrated machine-gun fire using standard ball ammunition, it was found that the mantlet could actually break up under the stress of multiple impact and allow splash to enter the vehicle, to the detriment of the crew. As a result of this, Messrs Vickers-Armstrong replaced the mantlet with a cast steel mantlet which would chip away under the repeated stresses of concentrated fire, but would neither jam nor break up.

Some three months later, on 16th March 1937, armor plating 60 mm thick of the type intended for the primary armor was tested at Shoeburyness. Here, it was found that, whilst 60 mm rolled plate and 60 mm castings were sufficient to stop armor-piercing shots from the British two-pounder, there was not sufficient additional protection to allow for a sufficient margin of safety. As a result, the armor was recommended to be upgraded to a new requirement 65 mm thick with a tensile strength of 75 tons (76.2 tonnes) for production vehicles.

Further splash trials were carried out in November 1938 and, once more, there were problems. Specifically, splash could enter through the large driver’s hatch as well as through the engine louvers. On top of this problem, the bullet-proof glass selected by Vickers had the unpleasant characteristic of splintering when shot and had to be replaced. Quite why this testing process had to be dragged out over a nearly two-year period when the whole tank was needed ‘within 6 months’ is somewhat unfathomable. Nonetheless, the lessons from the trials meant that modifications to both thickness and splash protection were made between A.11E1 and production A.11 models.

Most noticeable are the changes around the driver’s area. On the prototype vehicle, the sidewalls of the hull are straight and cut flush with the surface. This created a sharp edge and provided no angling to reduce splash from small arms, which could go towards the driver’s hatch. These top edges of the side were therefore chamfered at roughly a 45-degree angle. Likewise, the tendency for splash to penetrate the leading lip of the large hatch was rectified with a protective strip riveted to the top edge of the driver’s panel. An additional change was the addition of a pair of horizontal raised strips across the full width of the glacis. These ribs would stop rounds that struck the glacis from ricochetting up into the direction of the driver’s visor or hatch edge. One splash guard which was later to be modified from the A.11E1 design, however, was the one that ran across the width of the hull roof in front of the turret. By the time the vehicle entered production, this was not as high and just covered the bottom edge of the turret.

Layout

The vehicle itself was very simple in arrangement. With just two crew, the driver sat centrally in the front, operating the steering and propulsion via levers and pedals. Behind him, and manning the gun as well as commanding the tank, was the second crew member, the commander. Both these men occupied the small yet adequate fighting compartment and were separated from the engine by an internal bulkhead. The driver sat forward in the hull and was provided with a single, full hull width rectangular hatch above him. This large hatch was supported by two hydraulic cylinders due to its weight. No episcope was originally fitted to A.11E1., but this was added during testing. Without it, the driver was limited to just a narrow view directly ahead when the hatch was closed – with it, he could provide additional situational awareness to the sides.

The rear of the vehicle sloped sharply downwards over the engine bay. Perhaps the most distinctive feature of the A.11 was the lack of mudguards over the top of the track run. This is surprising given how simple such a guard would be, whether in metal or even canvas (like the Medium Mark A ‘Whippet’ from WW1). The lack of a mudguard meant dirt and branches could be caught up in the tracks and dragged along the side of the tank or thrown up onto the engine deck, none of which would improve either the mechanical or combat efficiency of the tank. The only effort to prevent such a situation were rather small and sturdy guards fitted only over the rear-drive sprocket, which was a feature of the production vehicle – another lesson from A.11E1.

Size

Overall dimensions for A.11E1 were very much those of a small tank. Just 15’ 11” (4.85 m) long and 7’ 6” (2.29 m) wide from the outer track edges, with the track centres 6’ (1.83 m) apart. Overall, the top of the turret was barely 6’ (1.83 m) from the ground – an ideal size to cover a man advancing behind the tank. By the time the trials had ended, this increased to 6’ 1.5” (1.87 m) to the top of the episcope on the turret roof. Ground clearance was also very reasonable, measuring some 9.5” (240 mm) from the ground. For the sake of reference, this meant that the A.11 was shorter in length and height, and only slightly wider than the already small Renault FT of WW1.

Oddly, the trench crossing idea of managing to bridge an 8’ (2.4 m) wide trench from the original plan had been abandoned. The final design would manage just 6’ 6” (1.98 m), still enough to cross a normal infantry trench or a small ditch, whilst also keeping the overall length (and thereby, weight) of the machine down. Climbing performance was also acceptable, as those exposed tracks projecting from the front of the tank could easily grip onto a surface to help it climb a parapet or low wall, as long as it was no higher than 2’ 6” (0.76 m) high.

One other consideration in obstacle crossing for the design was the main armament, which, because it did not project, added zero risk of it becoming lodged in the bank of a ditch the tank was entering, as would be an issue with a long-barrelled weapon. That is not to say that the weapon in its armored cowl did not cause obstructions, because it did. It fouled on the driver’s hatch to the extent that, with the gun forward, the driver was not able to have his hatch fully open. No official fording capacity was noted in official data for the A.11.

Fittings

Every tank has to provide some external fittings and items for practical purposes, like lamps, so the vehicle could operate at night, or stowage for crew items externally, in order to free up internal space. The A.11E1 was absolutely no different but was supplied bare. No lamps, no boxes, almost no tools and this would indicate that the intention was to find a location during the trials.

Soon after trials started, these fittings started to appear, with a pair of odd-looking boxed-in headlamps fitted on stubby arms which projected from the sides of the hull, just level with the front of the turret.

With the first essential fittings added – those necessary to drive the vehicle safely, then followed the turret roof, with a boxy style of episcope and a rotatable episcope fitted into a hole cut in the front angle of the driver’s hatch. These two additions provided much-needed situational awareness for the crew. As the first suspension changes took place, so too did the stowage on the tank, going from none to two large boxes placed low (so as to not block the driver’s view slit) on either side of the driver’s compartment. The final change or addition during testing was the result of the lack of mudguards. For whatever reason these were left as just small and somewhat flimsy sheet metal covers which only went over the sprockets and no further. By the time the tank would enter production, some additional modifications took place with those lessons learned from A.11E1, like changes to the stowage and headlamps, plus additional features, like smoke grenade launchers on the turret, fire extinguisher mountings, and tow cables, but the essentials of the tank were sound.

The boxed-in headlamps in their protective casing would be changed too – standard car-type headlamps could be used instead. They would be easily damaged by enemy fire or even passage through heavy scrub but they were also cheap, simple, plentiful, and easy to fix.

One non-essential item which was added as almost an afterthought was a mine plough designed by the firm of Fowler. The Fowler coulter plough (coulter is not a company, but a vertical blade in front of the ploughshare itself), as it was called, was a somewhat ungainly device consisting of a pair of long arms formed from steel girders, with one on each side of the tank. Operated up and down from travel position to a deployed position via a drum-driven chain from a power take-off on the back of the transmission, the plough could be lowered so that the wheels on the ends of the arms ran along the ground surface.

A tubular framework projected ahead of the main frame, which ensured the plough followed the terrain ahead and kept scrub from clogging the front of the device. Behind this was a set of coulters on each side, which would cut the ground and ploughshare the dirt and any mines concealed within it to the left and right of the tank’s route. This was first tried on A.11E1 in 1937 and was found to be highly successful, to the extent that the necessary fittings for such a plough were then added to the first production A.11 tank, although, by then, the need to get tanks off the production line was more important than a rather complex device which had never been part of its original purpose.

Suspension and Tracks

The original sketch from Sir John Carden showed suspension substantially different from the ones which the vehicle was subsequently built with as a prototype. In the provisional sketch, there are clearly 4 distinct and separate bogies, each with a pair of road wheels and with a spring connected to the hull and the rear of each pair. Above each bogie was a track return roller. The system drawn closely matched that of the Dragon Mark IV Artillery Tractor produced by Vickers-Armstrong. It was almost certainly meant to be based upon that system. Just like that system, the tracks used were a medium pitch design made from cast manganese steel and connected together via a single steel pin. Each link also featured no rubber pads for use on roads, but a pronounced spud to gain better traction on soft ground.

However, when the vehicle was produced, it would not use this Dragon or Dragon-like Horstman suspension, but a different Vickers product derived from the suspension of their 6-ton tank.

As a matter of some confusion in the tale of the suspension for these vehicles, there are multiple marks of vehicles and there are several distinct suspension variations worked through on Vickers products at the time.

In essence, however, this proposed suspension consisted of a pair of bogies with a flat arrangement of 4 pairs of road wheels, each mounted in pairs. Each of those pairs was connected to one end of the spring leaves, providing a degree of movement, as the entire bogie could also rotate around a central pivot point. The design was complex. Using small wheels, whilst allowing them to be placed closer together, also resulted in a small external unit that was easily clogged with mud. This style of suspension had already been rejected by the M.E.E. as a problem, so it can only be surmised that it was added as a cost-saving measure, as it was already in production.

If there is criticism of the A.11, it has to focus mostly on this decision of choosing a system based on an idea from 1929 which the Army already disliked and had proven to be disappointing during testing. This was not a decision likely to find supporters, yet the solution was available and in production and it did work to the extent required. Pragmatism meant the suspension, as fitted, would be kept and that tweaks would have to be made just to make it work.

As it underwent testing at M.E.E., various problems were quickly identified and one of the first was that the toothed front idler was unnecessary. Further, the track was found to be collecting stones and these could become jammed in the rear sprocket. The solution to the former problem was simple – just replace the toothed idler sprocket with a non-toothed one. The latter was resolved in April 1937 and consisted of raising the rear sprocket by 5 inches (127 mm). This would not be the final change to the suspension of the A.11 during its service, but the A.11E1 had set the shape and suspension type which remained with the A.11 throughout its military career.

The hull production had changed too. The original sides of the A.11, as seen on A.11E1, were a simple two-piece fabrication with an offset vertical line of rivets about halfway down the length. On the production vehicles, this seam was retained, but the rearmost panel was now two panels which also had to be riveted together. This added a little weight to the vehicle, but also simplified production by reducing the amount of cutting of the thick armor plating which was required. Rivet-counters will also note that the front of the tank shows a different layout of rivets as well. On A.11E1, the nose of the tank was a separate panel and bolted onto the tank with a column of four bolts on each side. The glacis plate was likewise bolted onto the tank and the nose plate was changed for production. In production, the flat edges of the glacis plate were chamfered and riveted to the structure of the tank. The nose plate was now integral with the extensions either side of the front idlers and all riveted in one piece to the front of the tank.

Radio

No radio was fitted to A.11E1, presumably as a cost and complexity saving measure. Right from the outset, in 1935, no wireless set had been planned for A.11. This would be rectified by the time the tank entered production, as the Wireless Set No.11 was available by 1938 and would eventually be fitted as standard on all production tanks, although this would obviously add weight and take up valuable space inside.

Trials

Other than the already known problems with the suspension system chosen, the A.11 had a remarkably easy birth when it came to testing. The exhaust pipe being moved was just one of those small changes identified during testing to avoid problems in production vehicles. Indeed, that was the entire purpose of testing and the A.11 can be considered to have tested out very well.

Stowage

The two large stowage bins fitted to A.11E1 were varied for production models but remained essentially the same – two large boxes, either side of the hull. On the A.12 vehicle, which followed the A.11, these stowage bins were moved forwards and downwards to flank the nose of the tank. Behind the curved front armor of the A.12, those front bins actually provide a misleading shape on the front of the A.12, giving it a full-width flush appearance when it is, in fact, a narrow nose-shape just like the A.11. Moving those boxes forwards in that manner and making them integral with the vehicle also provided the advantage of some additional protection for the A.12.

Engine

Power for the A.11E1 was provided by a 3.62 litre Ford V8 petrol engine delivering 70 hp connected to a Fordson four-speed crash (manual clutch) gearbox. Drive for the 11.5” (292.1 mm) wide manganese steel tracks was delivered from this gearbox via final drives at the rear, connected to the sprockets. Steering was provided through a system of clutch and brake steering (i.e. brake the right track to turn right and vice versa), which was taken directly from the Vickers light tank and controlled by the driver in the same manner – a pair of steering levers. One problem identified during testing was that the exhaust pipe from the engine was prone to cause the engine oil to heat up, so it had to be rerouted, but this was a simple affair and certainly not a failure – just a tweak to avoid a problem. It meant a very minor external change of the exhaust from the rear deck at the bottom in the middle to the right-hand side of the back instead.

The engine was small and the result was a relatively slow vehicle. However, this did not matter. Indeed the A.11E1 proved to be faster than expected and perfectly satisfactory for speed. From the notes of Col. Strudd at that 10th October 1935 meeting with Sir John Carden when the tank concept was presented, it is clear that the Army was perfectly satisfied with a top speed of just 5 mph (8.0 km/h) although 8 mph (12.9 km/h) would be better. The A.11E1., could, in fact, achieve a top speed of 10.9 mph (17.5 km/h) on a road and 5.8 mph (9.3 km/h) off-road, but this was not a problem at all for the design, as it only had to keep pace with infantry on foot. The average speed the tank could sustain on a road was 8.17 mph (13.1 km/h) and 5.6 mph (9.0 km/h) off-road.

The internal fuel tanks held 43 Imperial gallons (195.5 liters) of petrol for an official maximum operational range of 80 miles (129 km). With 43 litres of petrol and a known fuel consumption rate during the trials of 2 gallons (9.1 litres) per hour on-road and 1.8 gallons (8.2 litres) per hour off-road, that also meant up to 21.5 hours of road use and 23.8 hours off-road.

Turret

Made in a single piece, the turret was a substantial casting with armor 60 mm thick all round. Provision was made for a single armament – either a Vickers .303 caliber machine gun or the somewhat beefier .50 Vickers instead.

Almost cylindrical in shape, the basic elements of the A.11 turret were the same as drawn originally by Sir John Carden. The cylinder was angled at the back, providing a little more space, and the front carried forwards the trunnions for the main gun, all within this one-piece casting.

Atop the turret was a simple circular hatch which opened in 2 pieces – two quarter circles at the rear half, forming a semicircle, opened out and the whole front half of the turret roof formed the other semi-circle. On the left side of this front half-circular hatch was the single episcope for the commander.

The original turret casting for A.11E1 was a little more complex than on the production model. The outer edge on the front half of the turret at the top is the reference point for spotting the difference. On the prototype, there is a pronounced half-rim running around the front of the turret and projecting from the sides. This is not easily visible on the production turret, which replaced this hard rim with a more rounded and less pronounced outswell, although the purpose was the same – to reduce the chances of ricochets up the sides of the turret hitting an exposed commander. The turret was also asymmetrical, with that rear swell offset to the right at the back and the front casting for the armament offset to the right as well at the front. This meant that the trunnion mount can be seen on the right-hand side of the turret but not on the left and the reason for this offset is obvious – it allows the commander to share space with the gun. With the primary (and only) weapon on the A.11 being the single machine gun, it was belt-fed from the left, so setting the gun off slightly to the right allowed the commander to operate the gun and reload it much more easily.

The rear of the turret would noticeably change from A.11E1 too, from a rounded back on the prototype to the production turret which angled-off the swell at the back of the turret and created a short ‘step’ underneath – a very modest change to create a little extra space inside.

Two more small features of note on the turret which would change from A.11E1 would be the addition of a small triangular bracket for mounting a radio antenna base on the rear right-hand side for the No. 11 Wireless Set inside, and the addition of a pair of mounts for the smoke grenade launchers, one on each side of the turret and operated by cable from inside. Both the addition of a radio and smoke grenades would be substantial improvements from the very basic tank which was A.11E1.

Armament

A.11E1 was intended to support infantry by providing not just a mobile protective shield in front of them, but also to suppress enemy positions with machine-gun fire. The machine gun, not the cannon, was the primary choice for killing enemy troops and destroying machine-gun positions, which were a major threat to the infantry. For A.11E1, the original weapon chosen was simply the standard water-cooled .303 calibre Vickers machine gun albeit, with a short note which followed saying “we can try our idea of M/C gun but this is not so urgent”.

‘M/C’ in this context may be taken to mean ‘Machine Cannon’ i.e. a heavy machine gun with added anti-armor capability over the standard .303 machine gun or another compact gun capable of firing a small high explosive charges as well. The details were clearly not finished, as the priority was to get the tank into development as soon as possible. The small turret would make the fitting of a larger gun harder but not impossible. For the development of the A.11, just two guns were selected, either a .303 calibre Vickers machine gun or its heavier brother, the 0.5 calibre Vickers machine gun. Whatever ‘machine cannon’ Sir John Carden and Colonel Strudd were discussing in October 1935 is not known.

Armament Options for A.11
Gun	Vickers Mark IVA	Vickers Mark V
Caliber	.303	0.50*
Muzzle Velocity	744 m/s	760 m/s
Weight (vehicle mounted)	65 ½ lbs. (29.7 kg)	71 ¾ lbs. (32.5 kg)
Rate of fire	500	650-700
Belt size	250 rounds	100 rounds
Note	* 12.7 x 81 mm (.5 Vickers also known as the ‘.5V/580’) rather than the 12.7 x 120mm (0.5 Vickers High Velocity also known as the ‘.5 V/690’). The number after the ‘V’ in both cases referred to the weight of the bullet in grains rather than a velocity

Both types of machine gun were available with a variety of ammunition, from a lead core ‘normal’ bullet suitable for general use to an armor-piercing round. When it comes to the common complaint about the A.11, that it was under-armed, the existence of armor-piercing ammunition for both guns has to be taken into consideration.

For the .303 caliber gun, armor-piercing rounds had been available since WW1, as had incendiary rounds. The Mark.VII.W.z Armour Piercing round of 1917 (known later as the W Mk.Iz from 1927) was a 174 grain (11.28 gram) cupro-nickel jacketed bullet with a 93 grain (6.02 gram) steel tip. Traveling at 762 m/s, the bullet was designed to meet a requirement that 70% of rounds could penetrate a 10 mm thick armor plate at 100 yards (91.4 m). An effective anti-armor range of 100 m does not sound like much, but was perfectly adequate to deal with close-by enemy positions and also for suppressing protected targets further away.

For the 0.5 calibre gun, the armor-piercing round was known as the ‘Armour Piercing W. Mark 1z’ and also featured a hardened steel core. The penetrative requirements for this round were that 7 times out of 10, it would be able to penetrate 18 mm of armor plate at 0 degrees and 15 mm at 20 degrees vertical, all at 100 yards (91.4 m). A tracer version of this round, known as the SAP Tracer FG, came in various marks and there was even an incendiary version of it, known as the ‘Incendiary B Mark I.z’.

Whilst the .303 was an ideal weapon for suppressing enemy positions, mowing down enemy troops and dealing with soft-skinned vehicles, it was not suitable for picking off enemy forces behind a shield, like a gun crew. It was also not suitable for dealing with light enemy armor. The option of mounting the .50 calibre version removed that problem at short ranges. Both guns were perfectly adequate for general work, with acceptable accuracy on target out to at least 1,500 m. Both versions were virtually indistinguishable from each other when fitted into the turret and concealed within the large cast armor housing over the water-cooling jacket, although only troop leader’s tanks were fitted with the 0.50 calibre.

Some 3,000 rounds (12 belts) of .303 caliber ammunition were eventually to be carried as standard, which would be sufficient for just 6 minutes of continuous automatic fire. In the trial photos, there is one which appears to show half a dozen ammunition cans on a shelf on the right hand side. Assuming this was an attempt to carry more ammunition, then that would be several more belts for perhaps as much as 5,000 rounds carried. Boxes for the .50 Vickers ammunition held just a single 100 round belt, such was the greater size of the round. Assuming the ammunition stowage for both guns was to be proportional, this would mean 1,200 .50 Vickers rounds, enough for just 2 minutes of continuous fire.

Production

A contract for the production of 60 tanks was signed at the end of April 1938 and, ten days later, another order for the same amount came, meaning a total of 120 tanks. This would be enough to provide tanks for 2 whole battalions.

Conclusion

The A.11E1 was a successful prototype. It arrived late and perhaps this was partially the result of the untimely death of its creator, Sir John Carden, in December 1935 in an air crash. Certainly, there was nothing particularly novel about the tank or some new technology that had to be invented for it to exist.

The A.11E1 occupies an unusual space within British tank design too, as it languished in that period in the 1930’s where a new weapon was needed, but not one was entirely sure on what they were really going to need. Nonetheless, the design was still capable of being modified from its original form into something a little more than that and of being a capable platform for a device like the Fowler mine plough. The reality for it was that, by the time it was in production and being delivered, there was already a replacement in the pipeline in the form of the A.12 Matilda. That particular vehicle had a much more difficult birth and yet it could not have existed in its final form without the A.11 beforehand. The heavily armored infantry tank which started with A.11 and its prototype A.11E1, became the foundation of the heavily armored A.12 and its most dominant feature. The A.11E1 should, therefore, not be seen as some retrograde step for the Army to some attempt to rerun the First World War, but an attempt to learn from that war and produce a tank sufficiently protected for the next one.

 

Specifications A.11E1
Dimensions (L-H-W)	15’11” (4.85 m) Long, 7’ 6” (2.29 m) wide, 6’ 1.5” (1.87 m) high
Engine	3.63 litre Ford V8 petrol producing 70 hp
Speed	top speed 10.9 mph (17.5 km/h) on road and 5.8 mph (9.3 km/h) off road, cruising speed 8.17 mph (13.1 km/h) and 5.6 mph (9.0 km/h) off road.
Armament	.303 or 0.5 Vickers machine gun
Crew	2 (Driver, Commander/Gunner)

Sources

Fletcher, D. (1991). Mechanised Force. HMSO, UK
Fletcher, D. (2017). British Battle Tanks. Osprey Publishing, UK
Foss, C., & McKenzie, P. (1988). The Vickers Tanks. Haynes Publishing, UK
Forty, G., & Forty, A. (1988). Bovington Tanks. DPC, UK
Brown, P. (2014). 1 ATB in France 1939-40. Military Modelling Vol.44 No.4. 2014
Brown, P. (2014). 1 ATB in France 1939-40. Military Modelling Vol.44 No.5. 2014
Solarz, J. (2008). Matilda 1939-1945. Tank Power vol. LXI. Warsaw, Poland
Obituary, Sir John Carden. Flight Magazine, 19th December 1935
Tank Training Vol. II Part III Pamphlet No.2 .303-IN., Vickers Machine Guns Marks VI, IVA, IBV and I. (1936). HMSO, UK
Tank Training Vol. II Part III Pamphlet No.5 .5-IN., Vickers Machine Guns Mark V. (1937). HMSO, UK
War Office File 194/44 Matilda Infantry Tank, September 1936
War Office File 291-1439 British Tank Data
Williams, A. (2012). The .5” Vickers Guns and Ammunition. https://quarryhs.co.uk/Vickers.html

United Kingdom (1939)
Heavy Tank – Concept Only

Background

The battlefields of the Western Front during WW1 were characterized by thick belts of barbed wire covered by machine-gun fire often from concrete bunkers, creating an area which was all but impassable to infantry. The ground, shattered by years of war and millions of rounds of artillery fire, was often a quagmire of mud into which men, beasts, and machines would drown. Even if they managed to cross all of that, they would be faced with having to cross enemy trenches, anti-tank ditches, minefields, and other obstacles.

The British tanks of WW1 were specifically designed to overcome much of these problems, adopting a characteristic quasi-rhomboidal shape in which the tracks would run over the top of the hull, producing a high leading point for the track and carefully shaped to maximize the ability to both climb a step and cross ditches.

The early designs were relatively crude affairs, with inadequate armor, quickly falling prey to German anti-tank rifles and slow enough to be hit by enemy artillery. As the war progressed, the British progressively improved the armor and layout to the pinnacle of the whole design evolution, in the form of the Anglo-American Mk.VIII heavy tank. It had improved armor, improved mobility, in a larger tank with more firepower, and still retained the ability to extract itself from the terrible ground conditions. However, that tank did not get the opportunity to show its true power during the war and the mass production of it, which was being put in place, was canceled with the end of the war. Nonetheless, the principles had been established and if only thinking in WW1 terms, then this layout of the tank was clearly going to be ideal.

In 1939, many people could see the clouds of war gathering over Europe as an expansionist Nazi Germany under Adolf Hitler became more and more assertive, dominant, and militaristic. With the 1938 invasion of Czechoslovakia by Germany, any doubts about the future aspirations of Hitler to become the preeminent military power in Europe were over. Despite the appeasement of men such as the British Prime Minister, Neville Chamberlain, Germany was not going to cease in its growth and there was little time to prepare for a new major land war.

Thus, on the eve of war, and apparently with little comprehension that the nature of this forthcoming conflict was going to be different from those conditions experienced 20 years prior, the Army was in a rush to find a heavy tank. They simply resorted to exactly what they knew had worked before, a Mk.VIII shaped vehicle, albeit with more armor and firepower than before and the additional task of smashing reinforced bunkers.

It is not without a substantial degree of irony that the man substantially responsible for the Mk.VIII design, Sir Albert Stern, had, unlike the Army, moved on in thought. Along with his colleagues on the not yet named design committee, he was proposing a much more modern design in the form of the 300G. That tank featured a high leading track to help climb, a longer hull to help cross obstacles, and firepower concentrated in the turret to better deliver its firepower.

Origins

Lt. Col. Sir Albert Stern, a man who was very much ‘made’ by his experiences in helping to shape armored warfare in WW1, was in a powerful position, with a title, wealth, experience, and contacts in government. He also foresaw what he thought was to come and, in June 1939, was asked to visit the Minister of Supply, Mr. Leslie Burgin, to discuss the issue of heavy tanks.

The outlook was dire. British tank development had, since the end of WW1, stood almost stationary. There were few tanks, and what there was a mixed bag of various types and quality, with the best armored of the bunch being the A.11 and A.12 Matildas. Both carried substantial armor for the time, 60 mm or more, enough to protect from most infantry weapons available short of artillery, yet both were under-armed and not long enough to perform the sort of assault role envisaged by some British military planners.

Despite the protestations of men such as General Sir Maurice Taylor, Senior Military Advisor to the Ministry of Supply, who was dead-set against heavy tanks, Stern had gathered supporters in the form of men such as Sir Maurice Grove Taylor and Major General Alexander Elliot Davidson, Director of Mechanisation at the Ministry of Supply, to his side.

If there was to be a new and heavy tank, these men decided it should be along the lines of what was already proven and with which they were familiar. Given the parlous state of interwar British tank design and the utter lack of a viable alternative, the outcome was as obvious as it was inevitable, the new heavy tank should be along the lines of the Mk.VIII tank of WW1. Whilst Stern and his team gathered together their expertise and came up with their idea in the form of 300G, the Army would busy itself with its own ideas and generate a list of specifications identified as RBM-17. Then, they made their own outline of a tank to meet their own specifications – the Citadel.

RBM-17

With the 300G in hand, Sir Albert Stern had an outline for what he and the members of his as yet unofficial committee felt would meet the sort of need they saw coming. This was not a full-scale reversion to the conditions of WW1, but an improved vehicle with more trench and obstacle crossing ability than existed before.

The philosophy of a new special tank was therefore already tacitly in place and set roughly even before war was declared on 3rd September. At that point, Britain was suddenly at war with a major and aggressive European power and had no heavy tanks at all. Although this initial idea that a new tank was needed was already in place, it is inextricable that it still took until 29th September for the results to travel all the way from the General Staff to the Adelphi Hotel, where rooms had been prepared for Stern and his team to work.

On 28th September 1939, however, when the Army brought with them their list of requirements for a new tank, it immediately meant that the 300G design, on which the team had been working, was redundant. The Army was absolutely insistent that the vehicle had to have certain features, including the firepower concentrated in sponsons and a large gun in the front to smash bunkers, two features impossible to accommodate into 300G. Further, they wanted a fundamental shift in design from a turreted machine back to an ‘all-round’ track machine, as this would facilitate heavy unditching equipment.

The specifications themselves clearly show exactly what the Army felt it needed in terms of a short-range special-purpose tank, but they also show the naivety on engineering matters and of tank design in general, especially as at one point, some felt this could be achieved for a vehicle under 40 tonnes in weight.

Criteria Set

Design

The tank to meet the requirements of RBM-17 was going to have to meet a set of criteria like no other tank had ever been asked to fulfill. This set, in September 1939, may well have seemed impossible to achieve to the General Staff. If one were to assume that they had deliberately set Sir Albert an impossible task to keep him busy and quiet, they were to find that even these extreme criteria were met and exceeded.

Requirement one, and the most important, was that it had to be able to cross a 16’ (4.9 m) wide trench and climb a parapet or other obstacle 7’ (2.1 m high). This was basically the widest anti-tank ditch and a high wall. Both of these obstacles were uncrossable by any British tank then in existence and the RBM-17 was to cross these without the aid of a fascine (a large bundle of sticks to fill in a ditch) or bridge.

Length Requirements

This first criterion, right from the start, guaranteed more than any other that the final size of the machine would have to be at least twice the length of the trench simply to avoid falling into it. A 16’ (4.9 m) wide trench, therefore, meant a tank 32’ (9.8 m) or so long. To climb a 7’ (2.1 m) step meant a very high track at the front in order to get purchase (grip) high on the wall or parapet. It is no surprise that these match the general ‘all-over’ track shape of the Mk.VIII tank.

Shape Requirements

The other reasons the RBM-17 was to follow the Mk.VIII’s shape were equally practical. The tank needed the maximum bearing surface on the ground, meaning the widest track possible, so it would not get stuck in soft ground. It also had to carry heavy unditching gear. In other words, it had to be able to get itself out of a hole or soft ground using a method like that used in WW1, a large spar of timber carried over the top of the tank, on which the tracks could get purchase to pull itself out. This ‘log extraction’ is still in use today and the carriage of an unditching beam or log is now most famously associated with Russian/Soviet tanks, which are often still seen with a log on the back. The method of use is identical in principle except that, in the RBM-17’s case, no crew would need to get out. In order for that spar to be carried over the tank by the tracks and underneath, it also determined that an ‘all-round’ track machine and one without a turret, which would get in the way of the spar, was needed.

Armor Requirements

The tank would have to be immune to both 37 mm and 47 mm anti-tank fire at 100 yards (91 m) and against the impact of a German 105 mm howitzer shell at normal impact. Given that the ‘rival’ A.20 was being considered around a 60 mm basis at this time due to a similar need to be immune to the 37 mm gun and yet could not meet the demand, the RBM-17 would have had to have not less than this thickness of armor at any point. More armor, of course, meant more weight.

The preeminent 37 mm anti-tank gun of the era was the German Pak 36, which could achieve around 64 mm of anti-armor performance at 100 m. For a 47 mm gun, weapons such as the French 47 mm SA 37 could deliver an anti-armor performance up to around 90 mm at just over 500 m and around 100 mm at 100 m.

A 105 mm shell, such as that from the German 10.5 cm leFH 18, was nearly 15 kg in weight with nearly 2 kg of explosives inside. Bearing in mind the often wafer-thin armor on the roof of tanks, being hit directly by such a shell would be devastating. Even a close ‘hit’ landing and bursting nearby was perfectly capable of crippling a vehicle, stripping off wheels or tracks or topping it over.

The Army was demanding immunity at 100 yards (just under 100 m), so clearly anything less than 80 mm of armor was going to be unacceptable, although the attention to protection from artillery would wane a little in emphasis as time went on.

Firepower Requirements

The gun was still not yet decided but had to be in the front and capable of defeating the heavy German bunkers (7’/2.1 m thick concrete) which were so worrisome to the General Staff. As such a gun would, by its very nature, be restricted to only a limited range of fire to the front, the tank would also need side armament to rake German positions as it passed them. Here, the General Staff wanted something simple, just a 2 pdr. and Besa machine gun combination in a sponson on each side. On top of this was to be a separate Besa pointing forwards and another to the rear. Eight smoke dischargers completed the required armament, as these would provide cover for the tank and infantry to follow.

All of this equipment and armament meant a crew complement of 7 to 8 men. The tank was to be powered by a diesel engine to reduce fire risk, fitted with a No.9 radio to speak with other tanks and troops, had to be able to go 50 miles (161 km) on its own and, on top of this, be able to be transportable by rail with little or no disassembly.

It must also be considered that Sir Albert and the soon-to-be-named ‘Old Gang’ clearly thought little of the ‘no turret’ and all-over track idea. Their first design was, in fact, far more similar in shape to the A.12 and A.20 than the Mk.VIII. When the requirements for the length of trench to be crossed were decided, the design grew longer, and when the turret was abandoned and all-round track selected by the General Staff, the Mk.VIII shape was inevitable. Those other TOG designs are known only by drawing number 300G in both a long and ‘compact’ form. Both were shelved in favor of the Mk.VIII approach, although the longer version would later be resurrected when a modicum of sanity returned to the General Staff.

In these early days, the selection of armament was a key consideration and a variety of armament and mounting options were considered across Sir Albert’s work and the A.20, including a 2 pdr./Besa 7.92 mm machine gun combination, as found in the turret of the A.12 Matilda, a 3” howitzer, a 3.7” howitzer, naval 6 pounder, and the French 75 mm gun, as used on the Char B1.

The 2 pdr./Besa option would only work if a turret was going to be selected for the tank, which meant a hull-mounted gun. With the 3” and 3.7” guns being low-velocity weapons, they were abandoned. This was because the work of Sir Albert had been given a very strict and very specific set of requirements, one of which would require a particularly powerful gun firing a high-velocity shell capable of breaching 7’ (2.1 m) of reinforced (ferro) concrete.

The requirements were specifically listed under the heading “Super-Heavy Tank (Land Battleship)” under the code ‘RBM-17’. The exact meaning of those code letters has never been adequately explained but, given that Sir Albert’s committee was already being labeled in a sort of British public-school humor kind of way as ‘The Old Gang’, it could be speculated that such a boyish kind of name was being thought of here for this ‘Really Big Machine’. The committee designing this vehicle would later (October 1939) receive a formal acknowledgment as the Special Vehicle Development Committee (S.V.D.C.), but they were equally happy using the ‘TOG’ term themselves as a badge of honor rather than as a mark of scorn, as has been happily assumed by some authors in the decades since the war.

The Citadel Design

Brigadier Kenchington from the War Office and Colonel Watson were the men who brought the RBM-17 specification ‘wish-list’ to the meeting with Sir Albert Stern. With them too was an interpretation of what this would look like for the committee to work on. It is not clear if the vehicle outline that they brought with them as a ‘Citadel’ tank was directly from these individual officers themselves or from the War Office or General Staff or a mix of the bunch, but the design was clear in realizing the needs of RBM-17.

Layout

The presented vehicle was a long, low, lozenge-shaped tank, roughly along the lines of the Mk.VIII, but with a large field gun mounted in the front of the hull with heavy unditching gear. It was drawn showing large round, presumably cast sponsons for the 2 pdr. / coaxial machine gun combination. One important note on this design is the issue of crew access. No doors are shown and, in correspondence over the next month or so, the only comment on this topic was on the removal of side doors behind the sponsons. This too was presumably similar in intent to the Mk.VIII, although the shape or style of such a door is unlikely to have been the same given the heavy armor requirement.

On top of the tank and projecting above the level of the tracks was a raised superstructure with a small cupola. This lookout allowed the commander to see where he was going and communicate to the driver in the front left. Whilst it may or may not have been rotatable, it was not an armed turret. The more notable issue on this raised section in the fighting chamber was that, just like the Mk.VIII, it would prevent the whole unditching beam over the top of the tank idea as well. Here, then, there seems to have been a disconnect in the minds of the military planners for the General Staff, who seemed to be confusing the earlier marks of British tanks, which used rails over a small raised structure for an unditching beam to travel over, with the rear-mounted beam on the Mk.VIII. Photographs of the Mk.VIII clearly show that the rails on its roof only extended over the rear section of the tail and thus that the beam would then not be able to be carried forward to help unditch the vehicle. The Mk.VIII therefore would only be able to deploy this beam backward to reverse out of a particularly boggy hole, whereas the early tanks, such as the Mk.IV, could deploy the beam forwards to get out of a hole forwards or in reverse.

Armor

No details on the armor for the Citadel idea were noted, other than the immunity requirement. Given that 37 mm and 47 mm anti-tank guns could respectively perforate between around 60 and 80 mm of armor at 100 yards (91 m), the requirements guaranteed armor not less than that already in use of the A.12 Matilda, with 3” (76 mm) of armor. Importantly, the immunity requirement did not specify that the armor had to be that thick per se, just that it needed to provide that level of protection. Whilst the vertical sides would need to be at least that thick, the front may not have needed to be, given the slope, but even so it would seem unlikely that the front, even sloped, would be thinner. The same is true of the sponsons, with their distinctive curved shape, projecting from the sides. Given the size of them, each would likely weigh roughly the same as the turret of the A.12 as well. It is not hard, therefore, to see why the desire to replace two of them with just one turret would finally win out later.

Armament

RBM-17 made it clear that the Army wanted a field gun in the front which could breach enemy heavy bunkers up to 7’ (2.1 m) thick and various options would be discussed with the S.V.D.C. as they tried to meet this demand. Of the options considered, there was little to choose from.

The biggest gun which could potentially be made to fit in the front was the venerable 60 pounder. The B.L. 60 pounder was over 30 years old and had seen extensive service in WW1, firing a 60 lb. (27 kg) shell containing 8 lbs. (3.6 kg) of high explosive at 650 m/s out to a range of 9 km. The gun itself was massive, employing a wheeled carriage and usually serviced by a crew of 10 men when used as a field gun. Even so, it produced a rate of fire of just 2 rounds per minute. The gun was also very long, with the barrel alone measuring nearly 5 m from breech to muzzle. This produced a problem for the front of the vehicle, as the barrel would potentially impale itself into an obstacle, such as the opposite face of a ditch when the vehicle was crossing it. Thus, the option of shortening the barrel was considered, even though this would reduce the muzzle velocity of the gun. However, as the long version firing HE could not defeat the 7’ (2.1 m) of concrete, the Army demanded that the gun would not be shortened.

Little discussion seems to have focussed on the two other huge problems of using such a gun in the front. Firstly, the fact that just one man was supposed to operate it and, no matter how much bully beef he might get, this would be an enormous task for one man who was also at some point supposed to use the front machine gun too. The second issue was how to mount such a heavy gun in the hull. Perhaps thankfully, this gun was discounted as a realistic option before any precious design resources were expended on trying to create a mounting that could take both the weight and the recoil.

The reality was that, in September 1939, there was no gun that could be mounted in the front which could achieve that 7’ (2.1 m) requirement. Whilst the demand for concrete destruction would be kept, it would end up as an ‘as much as possible’ requirement going forward through the end of 1939, rather than an absolute figure to be achieved.

Speed

The tank did not need to be fast in any way. There was simply no need. This vehicle would primarily be used for smashing enemy positions. Further, a slower vehicle emphasizing protection would resist the deleterious effect of enemy fire which it would attract, provide a more stable firing platform for firing back, and also clear a path for further tanks and troops to follow.

The low speed was also a reflection of reality. Whilst 5 mph (8 km/h) is certainly not by any means fast, it is surprisingly quick across the sort of terrible terrain which might be encountered in a Flanders-type shattered battlefield, with heavy mud and waterlogged ground. In fact, this speed would not only be faster than its forebears a generation earlier over such ground but also faster than any other tank in such conditions as well.

Crew

RBM-17 called for a commander, a driver, and a separate radio operator. Separating the radio operator from the commander, which was usually his dual job in a British tank, would at least take away one burden from him, but the job of commanding the vehicle was not going to be simplified much, as he would have to now control the crew operating the gun in the front hull and both sponsons. Two men, one for the 2 pdr. and one for the machine gun, would crew the sponsons on each side and just one man was supposed to operate the front hull gun on his own.

This herculean task for the front hull gunner/loader would certainly have been more than a little burdensome if a gun like the 60-pounder was adopted, having to haul the shells on his own, load them, aim the gun and fire, and then repeat. This would have been exhausting and slow work in the confines of the tank with all of the other activities going on, especially if it was moving at the time.

Power

The powerplant for this machine was not mentioned, described, or suggested. The fuel type was clearly spelled out as ‘diesel’. Although high speeds were not called for in the design brief, there was still going to be an issue over the availability of high-power diesel engines and how to transmit that power from the engine/s to the tracks. An eventual solution would be found to meet the need for power from a diesel thanks to Harry Ricardo, the engine designer on the S.V.D.C.

However, in September 1939, it was not that clear cut and engine options were severely limited by not only the power output needed, but also by the fuel type, as few diesel engines were available which could deliver the power of more than 500 hp which would be required and options to be considered included more than one engine, various domestic and foreign engines, and different types of transmissions to maintain efficiency.

Conclusion

The Army’s design for the Citadel was odd, harkening back to the worst days of the slaughter of WW1 and no doubt that conflict served up generous helpings of concerns of a repeat of it. Seemingly in haste, the Army had leapt on Stern’s idea that, quite rightly, the Army needed a new special tank to prevent that type of warfare from taking place. Equally, the high command appeared to be panicking. This rush to get ‘something’ is seemingly made clear by the disconnect over the general outline of a tank. The Army were insistent on a turretless tank, so as not to interfere with heavy unditching gear, yet this very requirement was gone even by the end of WW1 with the change from all-over rails to just rails at the back for the unditching beam. Indeed, it is unclear how the High Command seemingly lacked knowledge on the topic, as even in WW1, vehicles had gone away from this type of complete top rail, as seen on the Mk.VIII, Medium Mk.B Whippet, and Medium Mk.C Hornet. Why the Army seemed so insistent on no turret because it would interfere with this equipment makes no sense when a turret would make no more interference than the raised casemate. This, perhaps more than anything else, shows that the Army was rushing to get ‘something’ to fill a need rather than relying on experts like Stern’s committee to develop a new vehicle.

The proposed design had too many crewmen and was too hard to control. Reducing the crew meant fewer men would be needed, more space in the fighting chamber for air to circulate, more space to move around, and more space for storage of ammunition, etcetera. Fewer men could be achieved by the adoption of a turret which would concentrate the firepower equivalent to both sponsons in one place as, afterall, both sponsons could not fire on the same target at the same time in anything other than the very limited circumstances of the target being directly ahead of the tank a distance away.

Removing sponsons would not only eliminate the need for so many crew and improve the interior volume, but would also remove two other significant burdens. One was the problem of transshipment, as no sponsons, or just small machine gun sponsons were far easier to move, fold in, or remove than these huge sponsons demanded. Secondly, their removal would save a lot of unnecessary weight from men, armor, and guns.

Adopting a turret would become the logical conclusion as the S.V.D.C. got to work on the Army’s idea, as saving crew and weight, and improving the distribution of firepower issues altered the general shape of the eventual vehicle into the ‘TOG-1’. Even with a turret, it was not the vehicle that the S.V.D.C. would design to meet the needs of RMB-17. That vehicle would have to wait, as the committee formed under Stern got to work in October 1939.

The size of the machine was inevitably going to be big given the size of the trench that needed to be crossed and the same is true of the front contact, with a 7’ step requiring a high front end. The Army’s demand for an all-road track likewise demanded a machine shaped like the Mk.VIII.

What the struggle to find a suitable powerplant would show was just how unrealistic RBM-17 was as a demand. At one point, the Army’s goal was to make this monster of a tank under 40 tonnes, a completely ludicrous idea that any engineer or designer would have laughed at when the Army was literally demanding a gallon in a pint pot.

In the end, the Army would not be able to get what they wanted. The requirements, although they could be met, could also be improved upon. The S.V.D.C. under Sir Albert Stern would develop a vehicle along the lines wanted by the Army and eventually persuade them of the value of a turret over large sponsons, and that vehicle would be TOG-1. The performance of TOG-1 would also exceed the Army’s requirements for mobility and obstacle crossing and, in fact, exceed their extreme requirements for a vehicle for all but the ability to smash a 7’ thick reinforced concrete structure. That requirement would be practically impossible at the time anyway, regardless of what design they might have come up with, and would remain out of reach for a couple of years until the advent of the 17 pdr.

The Citadel, however, was a starting point for the SVDC, as limited and relatively crude as it was. With a team of experts and mandate for work, the restrictions of RBM-17 would fade a little as the war developed, but the special tank concept would continue and the Citadel became just a footnote in the history of the committee.

Specifications TOG Citadel
Dimensions	>32’ (9.75 m) long
Weight	>40 tons
Crew	7 – 8 (commander, driver, wireless operator, 4 – 5 gunners)
Speed (road)	5 mph required (min. off road of very bad ground)
Range	50 miles (80 km)
Fuel	Diesel
Primary Armament	heavy field gun such as 60 pdr. or shortened 60 pdr.
Sponson Armament	2 pounder gun and 7.92 mm BESA MG on each side
Other Armament	front and rear 7.92 mm BESA MGs
Armor	Sufficient to protect against 37 and 47 mm anti-tank guns and 105 mm howitzer
For information about abbreviations check the Lexical Index

Sources

Hills, A. (2017). The Tanks of TOG. FWD Publishing, USA.

United Kingdom (1925)
Tankettes – 10 Built

Sir Giffard Le Quesne Martel was arguably one of the most important men in early British tank development. During the First World War and in the immediate aftermath, he served in the Royal Engineers. During this period, he became heavily involved in the development of tanks and bridging. As a gifted engineer, during his life, he would construct no less than three armored vehicles at home. His first design was a one-man tank.

Major Martel began work on his one-man machine in January 1925. He looked at recent developments in warfare exposed by the Great War. The basic problem was to protect the infantryman and enable him to advance while giving enough firepower that he might outfight the enemy. This had, eventually and after much technical and doctrinal evolution, led to the tank.

However, a tank grouped several soldiers into one large target. In order to counter enemy anti-tank weapons, there seemed to be two possible alternatives. The first consisted of having the speed and mobility to avoid getting hit. The other option was to dramatically increase the armor protection of the tank. Major Martel saw this latter option as feasible from an engineering point of view. However, in a cash strapped post-war British Army, Major Martel knew that financial constraints would prevent such a solution. Building a large heavily armored tank would require stronger engines, thus increasing the cost above what the Treasury was willing to fund.

Major Martel saw a third way. What if the tank concept was boiled down to its smallest, most minimalistic design possible? By making a one-man tank which is immune to enemy small arms and armed with only a light machine gun, armoured units could vastly outnumber any potential anti-tank weapons and overwhelm them. Equally, the small size would make it significantly easier and cheaper to create such a vehicle with good mobility characteristics and would also make it harder to detect and easier to conceal.

The Martel One-Man Tankette

With this in mind, Major Martel started drawing up plans for a new class of vehicle, one he named “the Tankette”. These plans were completed by February 1925, and he started construction of the tank on a rotating table in his garage.

The prototype one-man tankette was powered by a Maxwell 20 hp petrol engine, mounted on the front of the vehicle, connected to an axle taken from a Ford car. The tracks and suspension were purchased from Roadless Traction Ltd, while the large spoked wheels at the back came off an old Federal lorry. The body was made of wood, but Major Martel was careful to add extra ballast to represent the weight of armor. Work was completed in August, and the first trials showed some minor problems, such as the tail stabilizer being too lightly sprung.

At the time, Major Martel lived at the Brown Cottage in Camberley. This town was home to the British Army’s Staff College. One afternoon, Captain B.H. Liddell-Hart, who worked at the college, was taking a walk through the countryside when he came across Major Martel, who was calmly taking his home-built tank for a drive. He stood there dumbfounded and watched as Major Martel took his creation through its paces over the surrounding countryside. He went away and wrote an article for the Daily Telegraph, drawing upon Arthur Conan Doyle’s Ivanhoe for mental imagery. This piece published on 28th August 1925 brought the idea to the attention of the larger world.

‘Surprise changed to awe when this twentieth century man-at-arms, mounted on his mechanical charger, climbed out of the road up an almost perpendicular bank at least four feet high, raced across a stretch of rough gorse country at a speed no runner could have approached and no horseman would have cared to attempt across such ground, turning abruptly in such a narrow circle that would have been the envy of a London taxi-driver. Next it headed for a small but steep hill, climbed it unfalteringly at a speed of 6-7mph, then threaded its way through a tree plantation which a horse or pack-mule could barely have traversed.’
Captain B.H. Liddell-Hart, Daily Telegraph, 28th August 1925

Nearly all British service tanks prior to this time had been large and relatively slow machines. Here, in front of Captain Liddell-Hart, was a tank that he described as about the size of a horse, with mobility that exceeded the cavalryman’s. There was a loophole that a small arm, likely a light machine gun, could be fired from. Captain Liddell-Hart saw this machine as a cavalryman who was immune to small arms. A series of demonstrations of the machine followed, many of which were held at the Staff College.

One becomes Two

The result of these demonstrations was that the War Office commissioned two vehicles to be built. Major Martel suggested Morris Commercial Motors Ltd. as the manufacturer. This involved changing the engine to a Morris 16 hp petrol one. Of the two tankettes to be manufactured, one would have a one-man body, while the other would have a two-man body. The bodies of each vehicle could be changed at will. The armored hulls for these were mostly identical, apart from the fighting compartment, which was wider on the two-man version. Morris designed the chassis to be identical in both cases. For example, the steering wheel, and gear levers, were in the center of the compartment, while the pedals were set to the left-hand side. This meant that, while the driver of the two-man machine would have access to all the controls, the gunner would be limited to the steering wheel only.

This interchangeability was because Morris’ designers were thinking ahead. They thought that, if the War Office was to pay for the tankettes to be produced, then the chassis without an armored body could be sold separately as a tractor. Thus, the company could use the government to pay for all the expensive items such as developing, fault correcting, and setting up the production facilities. Then, when the chassis rolled off the production line, either a one-man or two-man armored body could be bolted onto it, or a soft skin tractor body could be installed. Such a scheme could, theoretically, create significant profits.

As it would turn out, the chassis was wholly unsuited for use as a tractor, so this plan came to naught. Although unrecorded as to why the venture failed, it is likely down to the differing needs of tractors and tanks. A tractor would need the ability to pull objects such as plows and trailers, while the tankette would need speed and mobility. Thus, a tractor’s gearbox has to operate under a different load profile than a tankette’s.

In late 1925, Major Martel completed his detailed drawings liaising with Morris Ltd., and construction began. The first vehicle, a one-man machine, was completed in February 1926, its body was made from 8 mm mild steel. When weighed, it came in at 1 tonne over its projected weight of 2 tonnes. To reduce this 3-tonne weight, a redesigned chassis was developed with all spare weight savings that could be engineered incorporated, along with a reduction of the armor to 6 mm, which would not have been bulletproof. Trials at an abandoned mine showed that the 3-tonne weight was not that great a problem, so the armor was increased back to 8 mm, which was the same armor value as the standard British tank of the time, the Vickers Medium.

After testing during 1926, the War Office finally settled on the two-man design. This selection was down to the number of crew. The two-man design was seen as a better choice due to the extra crewman. In December, eight two-man machines were ordered. These, along with eight competing Carden-Loyd Mk.IV machines were used by the Experimental Mechanised Force in August and September 1927. Despite the small numbers involved, the Experimental Mechanised Force which ran the testing immediately demanded more machines for use during the 1928 maneuvers.

Due to the failure of the Morris plan to modify the chassis into tractors for the civilian market, Morris did not want to spend any more effort on developing the Morris-Martel. This quickly led to the death of the series and of the type.

In comparison, Carden-Loyd was happy to undertake the development of their machine in-house, freeing the War Office of the financial burden. This in-house development led very shortly to the successful Carden-Loyd Mk.VI, and in turn through to the Universal Carrier. From there, it is possible to trace a line of development that ran all the way up to the FV432 in the mid-1960s.

Description of the two-man version

The Morris Martel Two-Man tankette had its engine at the front of the vehicle, with the fighting compartment behind the engine. A radiator was at the front, under the bonnet. The bonnet nose was angled, with louvers in it. The transmission was behind the engine, running under the fighting compartment, being connected to the two drive sprockets. The exhaust ran on the left side of the fighting compartment, outside the armor. On either side of the engine were the tracks of the vehicle. The drive sprocket at the rear and the idler wheel at the front were both large and made contact with the ground. Two small double rubber-rimmed road-wheels completed the running gear. It is unclear how or even if any of the wheels had a suspension attached to them. A mud chute was present above the two road-wheels, meant to prevent mud from falling from the track onto the road-wheels.

The fighting compartment had the gunner on the right, manning a .303 Lewis gun with limited traverse and elevation. It is unknown how much ammunition could be stored onboard. The driver was on the left. The seats for both men could be raised and lowered to allow them to drive head-out or behind the armor. The driver had a vision slit to see when he was driving behind armor. It is unclear if this was in any way protected by a blind or by a bulletproof vision block.

At the rear of the tank were the stabilizer wheels. These had multiple purposes. They were meant to prevent the tank from tipping backward when running up slopes or hard terrain. These wheels also acted as a complementary means of steering the vehicle. Steering in other tanks at the time was done by braking one of the tracks and keeping power to the other, somewhat similar to how a small boat is steered using paddles. However, this means that the vehicle slows down because one of the tracks is stopped, that half of the power of the engine was wasted (differentials and Cletrac systems were not yet invented or in common use), and that significant wear and tear was applied to the brakes, clutches, and tracks.

On the Moris-Martel, the rear wheels worked as a very useful alternative when going on roads or hard terrain and doing relatively shallow turns. The vehicle could then turn using the wheels only, functioning like when a car is driven in reverse (wheels turn to the left when the vehicle turns to the right). This could be done without applying the brakes, without wasting engine power, and reducing wear on components.

When harder turns were required or when running on soft ground or gravel, the tracks could steer as usual. While this dual system did have its advantages, it was largely abandoned due to the added complexity and weight implied in having a secondary steering system.

Two headlights were placed in front of the fighting compartment, on either side. Two mudguards were placed at the rear of the vehicle, running from the fighting compartment to the rear wheels.

Conclusion

While the Morris-Martel would never go beyond the handful of chassis used for experimentation, it would give birth to the idea of the tankette, a class of vehicle that would become one of the oddities of the interwar period found in many countries’ arsenals. These descendants would take part in the wars leading up to, and the first stages of the Second World War.

In the United Kingdom, the concept of the tankette would go through several permutations such as the Crossley-Martel and Carden-Loyd One-man machines. Martel would return to the concept that gave birth to the Moris-Martel one-man tank in the mid-1930s with the Mechanical Coffin. In the end, all these ideas would die out. However, the two-man machine would lead into the most produced armored vehicle in history, and one of its most successful, the Universal Carrier.

Illustrations by Mr. C. Ryan, funded through our Patreon campaign.

Morris-Martel Tankettes specifications
Total Weight, Battle Ready	3 tons
Crew	One or two depending on the body.
Propulsion	Morris 16 hp petrol
Armament	1x .303 Light machine gun, or personal weapons
Armor	8 mm
Total Production	10

Sources

Martel Papers, IWM.
Private correspondence with Oliver Boyle

Additional images:
These images all come from the IWM, Martel papers.
Commercial Motor Magazine article on the Morris-Martel tractor