Sir John Valentine Carden survives.

10 December 1935. 19:00hrs. Croydon Airport, England.
  • 10 December 1935. 19:00hrs. Croydon Airport, England.

    Sir John Carden stepped off the Savoia-Marchetti S.73 and felt like kissing the ground. The last few minutes of the flight had been as scary as anything he had ever experienced. The pilot had apologised to the people on board for the difficulties caused by icing on the wings. It had been a close-run thing, but the plane had landed safely. Someone remarked that any flight you walked away from was a good flight. Carden reminded himself of this. He was making his way to his club in London for a day or two, then he was facing a long train journey north to Vickers-Armstrong in Newcastle, his employers.
    10 January 1936. 09:00hrs. Vickers-Armstrong. Newcastle-upon-Tyne.
  • 10 January 1936. 09:00hrs. Vickers-Armstrong. Newcastle-upon-Tyne.

    Carden looked up from his notes, he’d come in early to finalise his drawings before the management meeting that was due to begin at 10am. The A9E1 had been plaguing his dreams, there were so many issues that needed resolving that he had been tempted to scrub the whole idea and start off with a fresh piece of paper. The problem was he was trying to design to a requirement that was at best wishful thinking, and at worst, contradictory.

    The General Staff requirement for the A9 was for a Medium tank (though they were starting to call it a Cruiser tank) which should be cheaper than the A7 or A8; but have the same firepower and protection of the Medium Mark III. It shouldn’t weigh more than 7 tons, with a top speed of 25mph, have the ability to cross trenches, only need 14mm armour, and a single engine. Therefore, to keep costs down, Carden had tried to use as much off the shelf material as possible on the A9E1. The prototype had utilized as much commercial and readily available parts where possible. The engine was a Rolls-Royce Phantom II six cylinder 7.7l, a reliable option that produced 120 bhp and, in theory, driving through a Meadows five speed gear box, could propel the vehicle at the required 25 mph. Carden had adapted a fully hydraulic turret traverse from bomber aircraft production, the first in a British tank. Carden’s particular ‘bright idea’ for this tank was for a new type of suspension, mounted on road wheels of different sizes. Each bogie, there were two per side, had a large return roller, along with two slightly smaller rollers with coil springs. Each bogie had one larger and two smaller wheels, and this should provide the tank's suspension with a remarkable degree of flexibility.

    The War Office specification had been changed in November 1934 to replace the traditional 3-pdr gun, with the new high velocity 2-pdr. To Carden’s mind the requirement retained, unfortunately, the front mounted machine guns that would provide 190° arc of fire. Carden wondered if the dustbins, as he called them, for two Vickers HMGs weren’t just a trap for the poor men stuck in them. It meant that the total crew was six men and despite the thinness of the armour, Carden knew that there was just no way all this could be brought in at the required weight, never mind the price that Vickers had promised. Looking at his watch he realised that the management meeting was about to begin and he grabbed his notes and drawings and rushed to the board-room.

    The A9E1 prototype was nearing completion on the factory floor and it was due to be transported to Farnborough to be tested by the Mechanisation Experimental Establishment (MEE) by July at the latest. The issue on the agenda therefore was just how far off the requirement was the tank going to be, and was there anything that could be done, in a timely fashion to make it more likely to pass the tests it would be put through. The question was posed to Carden, who had to be frank and say that it was probably over-weight, but there was little or nothing that could be taken off the tank that would save 3 tons, without drastically changing the General Staff requirement. It was his strong opinion that deleting the two front turrets would be a good start to saving weight, but he’d been informed that Percy Hobart himself had written them into the specification.

    The bombshell that the two turrets for the prototype hadn’t yet been produced was something of a dampener on the discussion. The manager of the project was quite acerbic in his opinion of the subcontractor whose excuses had been getting more and more outlandish for the problems with delivery. What was now clear was that they wouldn’t be ready in time for the trials, and delaying delivery to Farnborough would be counter-productive. Carden agreed, he had calculated the weight of the turrets with the heavy machine guns, and suggested putting in lead weights into the positions, which would at least keep the vehicle from being too heavy at the rear and light at the front.

    Beyond that, everything else seemed to fully functional, and sending it off to Farnborough would go ahead as planned. Carden wanted to make sure that the prototype had enough time on the test track to test out the suspension and the lubricated tracks. Farnborough would give it a much more thorough test, but Carden’s concern was to make sure there wasn’t any particular defect that would show them up. He was assured that this would be the case, especially now that they didn’t have to wait for the front turrets. He asked for this to begin as soon as possible so that any obvious deficiencies could be rectified before the MEE testing.

    Discussion turned to the progress on the
    A10 specification. This had arrived a few months after the A9. Obviously, someone in the War Office was thinking that the 14mm armour protection, at best protecting it from small arms fire and splinters, was problematic. Another tank, with greater protection would be needed to support the infantry, and so a prototype had been ordered from Vickers. Carden had used the same basis of the A9 for the A10. Without the need for front machine-gun turrets, Carden showed his drawings, which provided a sloped front which allowed the thicker armour to be even more effective. The problem that Carden had identified was that the Rolls-Royce car engine wouldn’t be powerful enough to move the heavier machine at the required speed. He noted that the A9 was at the upper limit of what the engine could effectively move. The need for a more powerful engine had to be sorted, and sooner rather than later. The A10E1 prototype would start to be built in the next few months, as Carden was still looking for a definitive answer on the engine.

    The other thing that had been on Carden’s mind was the
    A11, yet another requirement that had arrived on his desk the previous autumn. The codename was Matilda, a small, two-man, heavily armoured tank that simply carried a machine gun. This had been an extremely easy design, almost a textbook exercise. Like the A9, Carden had used off the shelf stock parts, a Ford V8 engine, a Fordson gearbox, a steering mechanism similar to the one used in Vickers light tanks and suspension adapted from the Vickers 6-Ton Tank Model E. The prototype was being put together, there was going to be a problem getting the armour plate, but it was due to be shown to the MEE just after the summer. Carden wasn’t terribly proud of it, but at £5000 per unit, it simply showed that you got what you paid for. The fact that it wouldn't have looked out of place in 1918 also said much more about those providing the specifications that the designers who had to bring it to completion.

    It occurred to Carden while he was working on the A10 and A11 that the two requirements were somewhat related. His initial design for the A11 had got him thinking about a even heavier A10. A tank with much better protection, but carrying a decent gun. It would need to be sufficiently mobile; it wouldn’t need to be too fast, but certainly faster than a pure Infantry tank. If he was right, the basics in his design for the A10 would be a good starting point.

    The War Office had also put out the requirement for the
    A12, an infantry support tank with a 2-pdr gun, but the work had gone to Vulcan Foundry. Carden wondered how they would get on, as they had no experience of building tanks. What he could see was that the A10 would be a reasonable basis for something like what they were asking for. It could well be worthwhile putting some ideas together in case Vulcan struggled to get it going. Talking over the idea with the management had raised some interesting ideas. The turret mounted 2-pdr was it was probably the best anti-tank gun in the world. But when he had been looking at the close support version of the A9 and A10, it was clear that the size of the turret limited any improvements. If a bigger gun was ever ordered, there would be problems trying to squeeze it into the current turret. The problem rose in part from the need to keep the tanks’ size within the limitations of the rail network, and the capacity of the army's bridging equipment. That would need some consideration.

    Vickers had always had an eye on the export market and so the idea of designing a tank from scratch that might find a market, especially as the situation with Herr Hitler taking over in Germany, made the possibility of re-armament much more likely. Having a design ready to go, well protected, reasonably mobile and with the capacity to increase the size of the gun, would be worth the investment once Carden had cleared his desk of the A9E1, A10E1 and A11E1. Though no doubt each of the tanks would need a second prototype, each designated E2.
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    10 July 1936. 16:00hrs. MEE, Farnborough. England.
  • 10 July 1936. 16:00hrs. MEE, Farnborough. England.

    The prototype A9E1 had been put through its paces. The whole affair had been a bit embarrassing. The Rolls-Royce engine had proven itself completely underpowered. Because of the look of the thing, quite modern compared to the tanks they were used to, and with the expectation of the 25mph speed, it had been decided to have a race between what started life as the Medium Mark 4, against what it was due to replace: the Medium Mark II and Medium Mark III. The Mark III won the quarter mile race, and the A9E1 struggled to beat the 11-year-old Mark II. It did not bode well, but worse was to come. When the tank was put through its paces on rough ground and in fast turns, the ‘lubricated tracks’, which should have been taut, had a terrible tendency to ‘slew’ and fall off the runners. The suspension was found to be poorly guided and supported by the chassis, giving a particularly bouncy ride. Altogether it was a very poor showing.

    The saving grace was that Sir John Carden had had a couple of months of tinkering with the prototype at the factory. There he had been able to see what the problems were, and much more importantly work out how he was going to resolve them. Regarding the suspension he identified the fundamental problem being the way the bogies were positioned. If he had had more time, he would have liked to reposition them before the trials here. As it was, he had been able to show his workings to the team assessing the tank. They agreed with his diagnosis and the plan to fix the problem. As well as repositioning the bogies, hydraulic shock absorbers would be fitted to correct the pitching. Altogether this would resolve the running problems. It was also patently obvious that a car engine, even for a Rolls-Royce, wasn’t capable of moving a tank, especially one 3 tons over the expected weight.

    If, after all was said and done, a second prototype was ordered, the A9E2, it would have a more powerful engine, a re-jigged suspension, and he was particularly happy that he had managed to sow the idea of deleting the dust-bin machine gun turrets. He’s been able to show a drawing of a simplified front, with the driver and one machine gunner, who could also act as radio-operator. If the tank was to act in a cavalry type role, for reconnaissance and exploitation, the commander would be better off with one less thing to think about. By freeing up the space lost to a turret, the radio could be repositioned. Carden had also noted that a more powerful engine would allow some kind of applique armour to be fitted, giving slightly more protection. He was also able to say, truthfully, that he could have the second prototype ready in about six months, allowing for an alternative engine to be sourced and tested.

    The letter authorising the A9E2 prototype, as discussed, arrived at Vickers-Armstrong two weeks later.

    You might find watching this instructive.
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    15 September 1936. 19:00hrs. Moscow. CCCP
  • 15 September 1936. 19:00hrs. Moscow. CCCP

    Sitting at his desk, Lt Col Giffard le Q. Martel, Assistant Director of Mechanization, tried to marshal his thoughts. Having spent the last week or so at Red Army manoeuvres he had been shocked, stunned and quite angry. The people in Britain, especially his fellow army officers, thought of the Red Army as if it were still the mob they’d pitched up to fight in 1919 with the Whites. The fact that mob had since undergone something of a renaissance had passed unnoticed in the West. While the loss to the Poles in the 1920’s had reinforced the Western notion of the Soviets as Communist losers, it had led to a transformation of the Red Army into something really quite frightening.

    Martel had seen plenty of exercises on Salisbury Plain in his time, and with a keen eye for the role of the tank in modern warfare, the Medium Mark IIs and IIIs along with the tankettes and light tanks the Royal Tank Corps fielded might have looked pretty impressive to some. Then he had watched the Red Army tanks going through their paces in the Byelorussian CCP. If it was sheer numbers, that would be one thing. In one exercise he had seen something like ten times the total amount of serviceable armoured vehicles the entire British Army fielded. Yes, there were plenty of light tanks and tankettes that wouldn’t have looked out of place on Salisbury Plain. In fact, he could see among the Soviet vehicles some that had clear Carden-Loyd antecedents; others such as the T-26 that had developed from the Vickers 6 tonner. But then there were two other types that had really caught his attention.

    Though the good graces of General Wavell, whom he was accompanying, he’d even managed to have a close up look at the T-28 and the BT-2. The T-28 was obviously something developed from the idea of the Vickers A1E1 Independent. It was obviously an infantry tank. It was heavy, over 25 tons; it had a 500hp engine, developed from a German BMW aero-engine, which pushed it along at a reasonable 20mph; it was well armoured, 20-30mm; and had a 76.2mm howitzer. Compared with the A7E3 that Woolwich was working on, this tank was night and day; worse still, the Soviet tank was in production and equipping an army. There were elements of the T-28 he hadn’t been impressed by: it had twin machine gun turrets in addition to the main gun turret, which made it look formidable but probably caused more problems than it solved. The Soviet tank wasn’t perfect, he picked up from some idle chat that it had a tendency to break down and an uncomfortable ride. But it outclassed everything the British Army had, and at a guess, the French and the Germans too.

    If the T-28 could trace its genesis back to good old British design, the BT-2 was as alien as anything he could imagine. He had watched it going along roads at something like 30mph, though it could have been faster, and over rough country just a few miles an hour less. On the testing ground there was a prepared bank with a five feet vertical drop on the far side. With his own eyes he had seen the tank leap through the air and clear a 30-foot gap, without apparent damage to the suspension or the crew!

    It was lightly armoured, only 6-10mm, and had a 37mm gun, with a co-axial machine gun, it was obvious from the exercises that it was designed to replace the horse cavalry role of reconnaissance and exploitation. Martel had discovered that, once again, it was using an aero-engine (again BMW originally), producing some 300hp, so it could drive the 10 ton tank at almost 40mph, probably more on the road off its tracks. There-in was the revelation. The BT-2 had four large road wheels which adjusted independently to the ground over which they travelled. What also had shocked Martel was the information that the wheels were rubber coated, so they could travel along roads without the tracks altogether. It seemed that since the Soviets could rely less on the rail network to carry tanks from one place to another, they had invested in a system where the tank could propel itself to the required destination, at a good speed and with a very good chance of actually arriving there without breaking down!

    On further investigation Martel had discovered that the suspension system was not of Russian origin, but American: it was the invention of J Walter Christie of New Jersey. The Soviets has somehow managed to acquire the right to produce, sell and use his M1928 design for a period of 10 years, despite the American government’s ban on exporting military equipment. In his report to General Elles, the Master General of the Ordnance, Martel almost begged that a working example of the Christie design be acquired and examined to see if the British could join what was obviously the future for fast tanks.
    1 October 1936. 11:00hrs. Newcastle-Upon-Tyne. England.
  • 1 October 1936. 11:00hrs. Newcastle-Upon-Tyne. England.

    The Vickers-Armstrong Design Department had plenty of experience in designing tanks, and their latest work, the Mark VIB Light Tank, had just entered into production. The order book was looking quite full, and with the A9, A10 and A11 being designed, the Design Department, headed by Sir John Carden, was extremely busy.

    Carden had just arrived back from Rolls-Royce. The fact that the Phantom engine had proven unsuitable for the A9 had led him back to the manufacturer in his search for a more powerful alternative. Rolls-Royce were clear that this particular engine was the most powerful engine they had, outside of their aero-engines. That had led to a discussion about the use of Rolls-Royce engines in land speed records. George Eyston’s Speed of the Wind and Malcolm Campbell’s Blue Bird had both used Rolls-Royce engines to break records. The Blue Bird’s R V12 engine, providing about 2300hp was something the Rolls-Royce was particularly proud of. What Speed of the Wind was using, an un-supercharged Kestrel, provided the car with just under 500hp, and had shown itself well suited for the endurance records. Harry Ricardo had also made a diesel version of the Kestrel, providing 340hp, allowing Eyston’s team to make create diesel land speed records just a few months earlier that year.

    Carden’s friend, Giffard Martel, had shared his experience of seeing Russian tanks being powered by aero-engines that had made a mighty difference in the light tank to its speed, and as able to drive a heavier tank at a good pace. His company, Vickers-Armstrong, wanted to replace the Phantom engine in the A9 with an AEC bus engine producing 110hp. Carden wasn’t convinced that the power needed to drive a double-decker bus around London’s road was the same that a tank needed. The size of the Soviet T-28, at 25 tons, was more likely to be future of tanks, rather than the 16 ton limitations that were currently placed on tanks. Having an engine providing more like 500hp really had to be the future, a tank would need something in the region of 20hp per ton to be truly mobile. He noted that the 70hp Ford V8 that was going into the A11 infantry tank was fundamentally the same engine that was in the Universal carrier, and the difference was between pushing 11 tons at 8mph or 3 tons at 30mph.

    The problem that the Rolls-Royce people identified was that the price per engine might be a problem for the treasury. After all, if they were only ordering a few hundred tanks for a tank brigade, then there wouldn’t be much profit in setting up a production line for an engine that would have such a limited run. Roy Robotham had suggested some of the older V12 engines might be worth looking at, there were some old Eagles lying around doing nothing, and the Rolls-Royce Condor had also been produced in a diesel form, if Carden was interested in using that rather than petrol. He knew there were some other manufacturers who had V12s that weren’t bad. Napier’s Lion had been used by John Cobb’s Napier-Railton which had done well the previous year in land speed records. If he remembered correctly that provided the kind of horsepower that Carden was talking about.

    Bringing all this together at the Design Team meeting, it was clear that the company weren’t keen on looking at aero-engines, which were just so much more expensive than bus engines. The War Office hadn’t designated the kind of horsepower that Carden was talking about. Management were persuaded to allow Carden to test putting the Meadows six cylinder engine used in the Mark VIB light tank into the A11E1 prototype. It was only an extra 18hp over the Ford, but it might give the tank a slightly better performance and shouldn’t change the price too much. As for the A9E2, the AEC Type A179 6-Cylinder Petrol, providing 150hp would be used instead of the Rolls-Royce Phantom, as planned. Carden insisted that the A10E1, which would be much heavier than the A9, would need something nearer 300hp if it was expected to carry the 30mm armour at a cruiser’s speed. Rolls-Royce had offered Carden a couple of second-hand Eagle IX engines for experimentation. They were long in the tooth, but he reckoned the time spent figuring out how to turn an aero-engine into a tank-engine would be time well spent. It would at least either prove or disprove his theory that future tanks would need more powerful engines.
    1 November 1936. 14:00hrs. The War Office. London, England.
  • 1 November 1936. 14:00hrs. The War Office. London, England.

    The report from the MEE in Farnborough had arrived on the desk of General Sir Hugh Elles, the Master General of the Ordnance. The A11E1 had been put through its paces and found satisfactory, but only just. Mechanically it was fine, there were a few small details that were easy fixes, such as the exhaust pipe heating up the oil engine oil and so it would need to be rerouted. The four sets of Vicker’s double sprung bogies on each side gave the impression of length, and some tinkering would need to be done to sort out the problem of stones getting stuck in the drive sockets. The original Ford engine’s replacement with the Meadows had provided a little extra power, as suspected, giving the tank a top speed of 10mph.

    The reasons it was found wanting by the MEE personnel was that the tank commander was overwhelmed with too many duties. Originally conceived, the idea of this infantry tank was to be a mobile pillbox. The idea was to have a swarm of these machine gun armed vehicles that would cover the infantry while they got their weapons onto the flanks and into the rear of an enemy. Because they would be working in large numbers over small distances, radios would be superfluous. There was no copula on the turret because there would be no need for a look-out, all that the machine-gunner would need to do was man his weapon. The two-man tank went against all that Vickers-Armstrong had been preaching about in developing the Light Tanks. The MEE agreed that the commander, having to also work the gun, would be overloaded with responsibility. Now that a radio was considered necessary, Carden had had to squeeze one in to the hull at the rear of the turret, which involved the commander having to do strange contortions to be able to work it properly, all the while taking his eyes off what was going on around him.

    The report of the MEE to the War Office suggested that the original concept, with the need to keep the price of the tank down, had resulted in a tank that, certainly was well enough armoured, but seemed to have made no progress from the 1918 Mark V tank. Therefore, the question was whether something was better than nothing, especially as it didn’t look as if the War Office was likely to build enough of these to perform the “swarm” attack previously envisaged.

    An addendum to the report from the tank’s designer, Sir John Carden, noted that he had provided a working model based on the price and requirements originally given him. Having worked on it, he noted that it would be possible, with the length of the machine, to increase the turret ring from the current 34.1 inches to something that would enable it to take a larger turret, at least providing something that two men, commander and gunner, could act in their separate roles. The nature of the armament as a single machine gun was simply a cheaper alternative. In the original specification that Colonel Studd (Martel’s predecessor as Assistant Director of Mechanisation) had signed off on in 1935 he had agreed to look at using Vicker’s semi-automatic 40mm gun, the basis of the Navy’s anti-aircraft pom-pom. It wasn’t as powerful as the 2-pdr anti-tank gun, but would provide the infantry with a more powerful, and quick firing High Explosive round, in addition to co-axial machine gun fire. In fact, he noted, that the Latvians has bought six Vickers light tanks armed with this weapon, so up-armouring a turret already designed to take it would be eminently feasible. The 40mm gun would also be able to fire an anti-tank round, giving the tank some degree of protection from enemy tanks, which it currently lacked.

    Carden noted that the problem with the changes he suggested would be that the price of the individual tank would increase, but so would the capability of the tank. The basics were all there, the suspension, gearing and engine were all tried and tested. If this was to be considered, putting some extra armour over the exposed tracks would allow increase the size of the turret ring, and also allow a larger engine to be fitted, providing greater power. This was necessary so that the extra weight would not unduly tax the machinery and therefore the mobility of the tank. All of this would mean that the army could have something that was more like a tank than a mobile pillbox.

    General Elles called in Colonel Martel, who had also read the report. The Soviet T-28, as reported by Martel, had set the cat among the pigeons of the Royal Tank Corps. When Hobart had originally described his swarm of infantry supporting tanks, he had also suggested that there would need to be a bigger version, with a gun, to see off enemy tanks. The thought of having two separate tanks, one smaller and one larger would inevitably mean that there would be situations where the wrong tanks were in the wrong places at the wrong times. Having one well-armoured tank, with a gun that would be able to support the infantry against fixed positions (this would need the capacity to fire HE shells), and also be able to take on enemy tanks, would be closer to ideal. The problem was that the ideologues like Hobart and Fuller, saw different tanks for different roles as being the way forward.

    Martel was working hard to get a copy of the Christie suspension for examination, his contacts with Lord Nuffield had paid off and a version of the tank (called a convertible tractor to enable it to be exported to the UK) was due later in the month. Having seen the Soviet system, and knowing that French had gone down the road of defining the roles of tanks as Cavalry and Infantry, Martel’s idea was forming into a similar focus. The Light and Mediums currently being used by the RTC would have to be replaced. Carden’s notions for an improved A11 certainly fitted with the idea of replacing the Mediums as infantry support tanks. If the Cavalry regiments when they were mechanised had something more like the BT-2 rather than the Vickers Mark VIB, it would give them a much better capability. The A9 was a step in that direction, but Martel firmly believed that a Christie suspension would be much better. The A10 came out of the same place as the Mediums, and unless Vickers could do something exceptional, it wasn’t clear to Martel where it would fit into the scheme of things. General Elles did note that with the arrival of new anti-tank guns, such as the Boys Rifle that had been demonstrated, the armour on all tanks would have to be increased.

    Elles was keen on trying to get more companies involved in tank design and manufacture. While the idea of an improved A11 was acceptable, the basic idea of a heavily armoured gun tank designed as such from the start was desirable. Perhaps Vulcan Foundry might be approached with a specification, which would be A12 in the normal scheme. Martel noted that they may need help from the Department of Tank Design at Woolwich Arsenal to get them started. Martel noted that Lord Nuffield was keen to get involved in tank production too, and the Christie system might be a route into that.

    The plan over the next few years was to mechanise a couple of cavalry regiments per year, equipping them with Vickers Mark VIBs and other reconnaissance vehicles. If that process took place over a slightly longer time period, then they might be able to be equipped with better tanks. In the meantime, three battalions of the Royal Tank Corps currently using Medium tanks could be equipped with the up-graded specification A11 infantry tanks. This might be able to get past the Treasury, even if the price per tank was a bit higher than originally specified. It would also please some of the Cavalry Colonels that they would have longer with their horses. The specification for an A11E2 was written and sent off to Vickers-Armstrong, while a new specification, A12E1, would be written and offered to Vulcan Foundry at Newton-Le-Willows.
    27 November 1936. 14:00hrs. Birmingham, England.
  • 27 November 1936. 14:00hrs. Birmingham, England.

    Nuffield Mechanisation and Aero was Lord Nuffield’s response to the Prime Minister Stanley Baldwin’s request to bring up to date the mechanisation of the British army and the ground echelon of the RAF. Having seen the Christie tank going through its paces at Farnborough, Lord Nuffield was enthusiastic about getting that kind of fast tank into the hands of the army. He had brought together all the people that would be needed to work out the process of getting the idea of a tank put into reality.

    Morris Motors had no experience of the kind of heavy engineering that building tanks demanded. The Tank Design Team from Woolwich had offered help and that was much appreciated. The discussion went through the various elements of a tank. The engineers had had a good look at the Christie suspension and were well on the way to sorting out how they would go about copying it. The gearbox and transmission were likewise straightforward enough to be copied. The tracks had come in for some criticism from the MEE, so a team was delegated to have a look at what could be done to make a system that would work properly. Getting armour plate and working out how to build it was another task that would have to be dealt with. There was a little discussion about the advantages of using welding over riveting the new tank. Welding was a growing capability, but within the group it was felt that adding yet another innovation to building tanks for the first time, was a step too far. It was bad enough that the riveters would have to learn how to deal with armour plate without having to sort out welders too.

    The main issue that Lord Nuffield would have to deal with personally was trying to sort out the engine. The Christie tank was powered by a Liberty V12 engine, so his Lordship would use his contacts to acquire more engines, and seek to gain a license to build it locally. Wolseley Motors, that Morris had bought over, would be in a good position to actually build them once the license was acquired. Colonel Martel had discovered that the RAF had stocks of an equivalent British engine, the Napier Lion. It had been tested and was powerful enough, though its use of higher-octane petrol would have to be dealt with. The War Office decided not to acquire them for tank production, so Nuffield would have to get the American engine.

    The team were upbeat about their task, but also conscious they were at the beginning of a great endeavour. They were aware of the complexity of doing something completely new, but as a company they were confident of their ability. Nuffield wanted the prototype of the A13E2 (the original Christie tank is designated A13E1) to be ready within a year. There were a few raised eyebrows among the team, but he was the boss, and if that was what he wanted, then the team would do what they could to deliver.
    12 December 1936. 15:00hrs. Newcastle-Upon-Tyne. England.
  • 12 December 1936. 15:00hrs. Newcastle-Upon-Tyne. England.

    Colonel Justice Tilly, as Chief Instructor of the Royal Tank Corps at Bovington Camp, had been invited to come and inspect the work that was being done on the tanks that his trainee tank men would be working on in the future.

    The Mark VI light tank, and its predecessors, were well known to the RTC, the latest model, the VIB had a few improvements over the Mark V and the Mark VIA, but still suffered, in Tilly’s mind with being top heavy and really only good for reconnaissance. The conversion of the cavalry regiments, for whom reconnaissance was one of their specialities, the tank was adequate. However, for screening and exploiting, the other two cavalry specialities, the two machine guns (.50 and .303 Vickers) were limited at best. The increase of armour to 14mm in the light tank suggested that the days of using a heavy machine gun against an equivalent vehicle was fading fast. What worried Tilly more was that it wasn’t only the mechanised cavalry regiments that were being equipped with the light tank. As these were the only tanks in full production all too many were ending up in the hands of people who needed a proper tank capable of taking on another tank.

    He had been pleasantly surprised that when the Mark VI had been sent to Bovington a couple of Vickers employees had been sent down with it to help sort out the driving and maintenance manuals. This had helped speed up the process of making some changes to the production models which had improved some of the simple things that would make life easier for the soldiers fighting and maintaining the vehicle.

    Next on the tour was the A9E2 which was at an advanced stage of its build. He’d seen the A9E1 at Farnborough, and was glad to see that the E2 had taken on board some of the criticisms of its predecessor. It looked like the new layout of the suspension would overcome the problems of it bouncing all over the place. Losing the two forward machine gun turrets gave the tank a better balance. The AEC engine that replaced the Rolls-Royce Phantom was also judged an improvement. Though to Tilly’s mind it only took the tank to its new limits of speed and armour, as the power didn’t have any spare capacity should the tank need to be upgraded again. He also took the chance to speak to the Vickers team about the tracks. The idea of ‘lubricated tracks’ was all very well in theory, but if there was one thing that tank crews hated above all was having to try to re-attached tracks that broke or threw themselves off the suspension. Being clever with tracks wasn’t about making them more complicated, it was much more about making them trustworthy and practical. He was happy to see some nods of agreement from his hosts.

    His basic problem with the A9 was where it fitted into the scheme of things. The idea that was being floated around of ‘cruisers’ had come from a lecture Fuller had given which used naval categories to describe tanks types. The origin of this thinking went all the way back to the ‘Land Ship’ committee that had given birth to the tank in the first place. Tilly wasn’t impressed with the notion. If the A9 was to take its place in the army if fell between the stool of being a light reconnaissance tank like the Mark VI and a medium tank. Tilly was of the opinion that what was needed was a new and improved medium to replace the old Mark IIs that were obsolete. The Medium Mark IIIs and the A6 and A7s seemed to be going nowhere as far as Tilly could see, and the Vickers men nodded in agreement again.

    In Tilly’s opinion creating a tank of around 7 to 10 tons wasn’t going to be big enough to do the job the RTC needed. Just about everybody was happy enough with the 2-pdr gun, as an anti-tank gun replacing the old 3-pdr, and the promised 25mph was impressive. It left the problem, like the Mark VI that it relied on speed rather than armour to keep it out of trouble. If the British army was introducing the 2-pdr as an anti-tank gun, then no doubt everyone else would have something in the 37-47mm range as their own AT gun. Having armour only of 14mm to protect it seemed ludicrous. While the E2, with the weight saving of losing the two turrets and one gunner meant that some more armour could be fitted around more vulnerable spots, Tilly still thought it was too little.

    Which brought them to the A10E1. This prototype was due to be displayed in the Spring and Tilly was the first man outside of Vickers to have a good look at it. The decision had been taken to make two models initially, the difference being in the engines. The first was as specified, a single AEC bus engine, the same as in the A9. Since the A10, would weigh something like 14 tons fully loaded, the design team were sure that, like the underpowered A9E1, this would be just as unsatisfactory. With 30mm of armour it was a bit more like what Tilly was arguing for, but it would lose the kind of speed that the A9 promised. That was why Vickers was making the second model. There had been a lot of debate amongst the design team about this. The company managers, aware of costs, wanted to look at simply creating a double AEC engine. By putting two engines in, it would theoretically double the power available. However, it posed a fairly serious engineering challenge. Working out how to keep the two engines working harmoniously would be difficult and probably would be a nightmare in the field. With this Tilly strongly agreed.

    The second prototype was going to be a bit longer than the first, 19 feet like the A9, needed because the engine was one of the Rolls-Royce Eagle IXs that had been acquired. No one was suggesting that this was what would actually be the engine of choice, it was out of production, but it would answer the question of whether an aero-engine could be used to power a tank, giving it the kind of power to weight ratio required. A third choice had also been suggested which was the original idea in the old A6 specification was to use a Thornycroft RY 12 marine engine developing about 500hp.

    The question that Tilly immediately asked was about the range these tanks would have. He could only imagine that either of these powerful beasts would be thirsty creatures. A tank that had to stop every hour to be refuelled wasn’t going to be much use to anybody. He was informed that the A9 was rated for about 120 miles radius of action on roads. The A10 with the same engine would be a bit less, with the bigger engine, and bigger size, allowing a larger fuel tank, it was hoped the radius would be nearer 140 miles. There were too many ‘maybes’ and ‘hoped for’ in that answer for Tilly’s ease of mind. At least they knew that the longer a tank could be in action with enough fuel and ammunition, and crew that weren’t terribly inconvenienced by cramped and difficult conditions within the tank, the better. It that lesson hadn’t been learned from the early days of tanks in 1916-18, then they should all give up and go home.

    Talking of tanks from the days of Cambrai and the 100 days, they came to the A11E1. Progress on the E2 was still in the early stages. Tilly had seen the A11’s demonstrations at Farnborough and wondered about what had happened to the last twenty years. If it sat beside a Whippet tank it wouldn’t look as if much progress had been made at all. At this point Sir John Carden joined the group and invited Tilly to join him when he’d finished the tour of the plant, there were a couple of questions that he’s like to ask him. Tilly was happy to oblige and it seemed a good time to have a look at the drawings for the A11E2 that Carden had in his office.

    The two men had met before on a couple of occasions and had many mutual friends and acquaintances. A couple of pink gins arrived and Carden showed him what he hoped was a slightly more acceptable infantry support tank. He wanted once more to replace the Meadows engine which the AEC bus engine, providing the A11 with a bit more power again. Putting in 135hp rather than 88hp would propel the tank at something more than a cross-country runner’s pace, even with the bigger turret’s weight. Tilly liked the idea of the 40mm semi-automatic gun. Supporting infantry was something that an HE shell would be better at than simply a machine gun. With the pink gin loosening the inhibitions, that gave Carden the chance to ask one of his outstanding questions.

    It seemed to him, looking at the direction the War Office were going that the A11 and A12 specifications for infantry support tanks, well protected themselves, but carrying only machine guns or the 2-pdr. The old Great War machines, at least the males, carried a six pounder to deal with well protected defences. Surely there was an argument for a gun that could provide a reasonable HE capability? To Justice Tilly’s mind, Carden was straying into what many regarded as heretical thinking. The fight to keep the Royal Tank Corps alive, when the Machine Gun Corps had been suppressed after the war, meant that doctrine about the right use of tanks had become not dissimilar to Christian doctrine. There was orthodoxy and heresy, and quite a few popes in the tanking fraternity who wouldn’t be slow to condemn the heretics.

    The example cited by Carden was that he was meant to design two different turrets for the A9 and A10, one carrying the 2-pdr and another for Close Support tanks that was to be fitted with the QF 3.7inch howitzer. This fired a half-decent 20lb shell, but with limited range, and as Carden understood it, was really only used to fire off smoke shells. Colonel Justice Tilly, as Chief Instructor at Bovington, felt he had to defend the orthodoxy. Tanks, with the exception of the light reconnaissance machines, were to fight tanks, whether in support of infantry being attacked by tanks or in manoeuvre warfare. What counted was the ability to defeat enemy armour. If fixed defences were a problem, then the artillery would be called on to suppress it, the infantry overcome it, and the tanks would then exploit the gap.

    Carden noted that this wasn’t quite the same as the 100 days offensive at the end of the Great War. There the combined efforts of all, infantry, artillery, tanks, and even aircraft, were utilised together to defeat the Germans. This seemed to have given way to Fuller’s navy battles on land, where light units, like destroyers sniffed out the enemy, then the cruisers were the fast and hard hitting force, backed up by battlecruisers or heavy battleships. The War Plan of 1919 had never been put to the test, and Carden wondered if the Russians, French or even Germans were playing from the same textbook.

    What amazed Tilly was that Carden then brought out a sketch book. He admitted looking at the A12 specification that Vulcan Foundry were working on and wondered what his own notion might be. He had drawn up some ideas. Fundamentally he had taken the A10 to its logical conclusion. He had one drawing with the current suspension, another using Horstmann’s system. Powered with an engine producing 500hp, it would have to grow beyond the current limitations of rail transport. A wider body would allow a larger turret ring, which would give the possibility of having a bigger gun than the currently sufficient 2-pdr.

    According to Martel’s report from Moscow, the Soviet T-28 was armed with a 76.2mm howitzer. There were two British 3-inch guns which provided the same calibre. There was howitzer and an anti-aircraft gun. The 3-inch anti-aircraft gun was being replaced by the newly designed 3.7-inch gun, meaning that the 3-inch 20 cwt AA gun was going to be surplus to requirement. Carden reckoned he could knock a fair few cwt off a tank mounting, but the turret would need to be pretty large. The muzzle velocity and the size of the shell would be a match even for the big new French tanks that were starting to appear. It might cause some problems for the gunner, but it could easily take an anti-tank round as well as the HE round it was designed for. The Ordnance QF 3-inch howitzer was developed from the QF 13-pdr of Great War vintage. Both these options would require a very big turret, and that was probably some way off the War Office’s list of requirements.

    Which brought Tilly and Carden to another set of drawings. In this case he was looking for an intermediate solution, and he had looked to the past for inspiration. The 6-pdr gun on the male Mark I tanks had started life as a naval gun, and Vickers and Woolwich still have the capability to manufacture guns in 57mm. The early tank 6-pdr gun was a cut down version, L23 barrels compared with the naval L40 barrels. A modern version would surely provide tanks with a gun to replace the 2-pdr. If the A11 and A12 were anything to go by, to say nothing of the French tanks, then more powerful guns were going to be needed, and if they were capable of firing both a good anti-tank and HE shell, then so much the better, surely? If that was the case, then it may well be necessary to design a follow on to the A10 which would have more than the 60-70mm armour of the A11 and A12, with a big enough turret ring to mount bigger guns as they came along. 500hp engines might need to grow too, and it certainly seemed the way things were going in the aero-engine sector, more and more powerful engines were being designed for aircraft to fly faster and carry more load.

    So, the drawing that he had spent the most time, going from the detailed drawings was the an A10, lengthened and widened, a raised engine compartment for the bigger engine, around a 60-inch turret ring, and a long barrelled 6-pdr gun. Tilly noted the figures of 80mm armour on the front and turret, 70mm on the sides, an overall weight of around 20 tons. The turret was wider, bulging outward to provide more elbow room presumably. He noted that the gun was on an external mantlet. Another heresy was hidden here. British tank gunners fired on the move. A large part of the training was RYPA, Roll, Yaw and Pitch Apparatus, not unlike their naval cousins dealing with all the movements of a ship at sea. The traverse mechanism of the turret was matched by an elevation controlled by the gunner’s shoulder, and therefore of the steadiness of the ride of the tank was important. The gun had to be finely balanced about the trunnions, meaning that a greater inboard length of the gun. An external mantlet meant that Cardin was designing a geared elevation system for his improved A10.

    When asked about it, Carding simply remarked that the Close Support 3.7-inch howitzer required the geared elevation. It simply meant that a larger gun wouldn’t be able to be manipulated by the gunner’s shoulder, therefore it made sense to put the balance further forward, allowing more space in the turret for gun recoil and ease of loading. Surely firing from a stationary position was more inherently accurate than firing on the move? Besides, if war came and a great many new trainees were to become tank gunners how much time and effort on RYPA would have to put into that training compared with learning a much simpler geared elevation coupled with the traverse system? Tilly found himself grinding his teeth, this man would need to be kept far away from Percy Hobart.

    Another pink gin later and Carden showed off some more of his flights of fancy as he called them. Using the same basic platform of the improved A10, Carden had tried to imagine how the new artillery piece, the 25-pdr might be conveyed like the old Birch gun system. It seemed odd, but he had reversed it, so that barrel was over the engine compartment at the rear. Instead of a turret, the gun and its crew would basically fill the fighting compartment, and the sides of the tank would be built up to give them some protection against counter-battery fire. He had a few ideas about improving the notion of the universal carrier, using the Dragon tractor as a basis for carrying a squad of infantrymen under the shelter of steel following their own artillery closer than possible if walking, and falling on the enemies’ positions before they could react. In another drawing he had an anti-aircraft gun mounted on a tracked base. These were all ideas that Tilly recognised from the various permutations of the Experimental Mechanical Force and wondered whether he’d see the possibilities that had engendered brought to birth. Carden’s drawings suggested that it might just come about, God and His Majesty’s Treasury allowing.
    12 January 1937. 09:00hrs. Mannheim, Germany.
  • 12 January 1937. 09:00hrs. Mannheim, Germany.

    The contract to build Sonderkraftfahrzeug (Sd.Kfz.) 141 had arrived and the Daimler Benz team were working out the practicalities for putting it into production. The basic requirement which the Daimler-Benz prototype had successfully embodied weighed 15 tonnes, with the armour on the front, sides and rear of the tank chassis and turret being 14.5 mm thick. Only the gun mantle and front of the turret were slightly thicker at 16 mm. Powered by a Maybach HL 108 TR 250 hp engine its five large road wheels, with coil spring suspension, had two track return rollers. The specification was for the 3.7cm KwK 36 L/46.5 gun, with three machine guns, two co-axial with the main gun, the other in the hull. It was expected to be able to travel up to 165km at a maximum speed of 35km/h. The problem for the production team was that they were successful car and truck makers, the experience of building panzers was new to them.

    The company had been involved in making parts of the superstructure and turret for the Sd.Kfz 101 and 121 (Pz.Kpf.W. "Panzerkampfwagen" I and II), but building a complete panzer would be a challenge. Knowing that the journey of a thousand miles starts with a single step, the production team began to write the detailed manufacturing specification. The design, specification and procurement of machine tools would be done and detailed manufacturing drawings would be acquired from the draughtsmen. The tooling and jigs would have to be prepared, with the company plant having to sort out the production facilities. The procurement of materials, components, and assemblies would have to be managed, as would the recruitment and training of the workforce, all before the first panzer could be built. There was a lot to do, and there was some pressure to getting it done in a timely fashion. The winning of the contract to build the Pz.Kpf.W. III was a great boon for the company, but it would involve a great deal of work to get it done.
    15 March 1937. 12:00hrs. London, England.
  • 15 March 1937. 12:00hrs. London, England.

    The Cabinet had approved the deficiency programme of the Army over the next five years and the figure was agreed at £214 million. The Air Defence of Great Britain (ADGB) was a new requirement for the army and the Cabinet had approved an immediate £37 million to this role. The Regular Field Force would have £80 million for materials and ammunition. While the Territorial Army would receive £9 for training equipment, there was no increase in their budget for war equipment or reserve. The agreement by the Cabinet the previous month that the Territorial Army should be trained on the same equipment as the Regulars meant that the extra funding would have to be approved. The War Office hoped that the extra funding for training equipment would eventually work through to having the equivalent of two full regular division’s worth of equipment by April 1940. Much of the increased funding was not so much for immediate army requirements, but for what was described as measures to increase the industrial facilities for armament production or the technical phrase to “augment the war potential.”

    The ordering of 107 Mark VIB light tanks from Vulcan Foundry during 1936 was part of that programme. The decision to award the contract for the A12 to Vulcan required that the company should have some knowledge and experience of building tanks. The light tanks would be a simple exercise in preparing them for the much more complex responsibility of designing and building an infantry tank. The Royal Ordnance Factory at Woolwich was the only other facility, besides Vickers-Armstrong who had any experience of producing tanks. Woolwich, however, was focussed primarily of orders for the Admiralty and Air Ministry, so their ability to build tanks was limited.

    With Nuffield Mechanisation and Aero taking on the specification for the A13 that meant another company joining in the expansion of the ‘war potential’. Vickers, however, that was the only company currently capable of building and delivering tanks in any numbers. Within their own subsidiaries, Vickers was looking at the possibility of outsourcing some of the work that was hopefully coming their way. The A11, with its thick armour, would probably have to be built in-house. The company were looking at Harland and Wolff in Belfast to take on some aspects of building the A9 if contracts were awarded. Likewise, they were also approaching the Birmingham Railway Carriage & Wagon Company and Metropolitan-Cammell Carriage & Wagon Company for work on the A10.

    One of the problems with the increased armour in the A10 over the A9 was how it was going to be fixed. One school of thought was to build the hull from thinner plate, riveted to the structural frame, then screwing outer panels to the shell to create the required thickness. This kind of ‘composite’ armour had various advantages, it was economic in the use of hardened plate, and it would be easier to assemble. However, Sir John Carden was aware that a single thickness of armour would give better protection, and ultimately this was the reason for the War Office specification of an inch of armour. When the prototypes of the A10 were being built one had been made using rivets and bolting plates together. The other had been welded. This had saved weight on the tank, but the management had been unhappy at using such an expensive method. The welders, borrowed from the shipbuilding part of Vickers-Armstrong, had found some of the welds difficult, there were some cramped and awkward spaces they had to work in. Overseeing this work had given Carden an appreciation of the work welders did, and some thoughts about when designing something considering how it would be put together.

    The two prototypes for the A10 were nearing completion but were overdue to be transported to Farnborough. The design and production team had had to take make the same changes to the A10’s suspension that had fixed the problems in the A9’s trials. As well as the spacing of the bogies, the tracks had to be wider to spread the increased weight. The obvious deficiencies in the ‘lubricated’ tracks on the A9 had meant that a different design of track had had to be worked on, which added to the delay of the project. The difficulty of having to shoehorn the large Rolls-Royce Eagle engine into one of the prototypes had also caused delays, but with help from Rolls-Royce engineers, the old engine was running smoothly and providing the kind of horsepower and torque that Carden had hoped it would. The engine compartment of that prototype looked very untidy, and the team were a bit concerned with the temperatures that the engine was reaching when working hard.

    The decision had been taken to put the AEC engine into the slightly lighter welded prototype, in the hope that it would help with the power to weight ratio. If Farnborough pushed for a timely arrival of the A10E1 tank, then Vickers could send off this tank first, it was judged to be just about ready to be put through its trials.
    20 April 1937. 16:00hrs. Farnborough, England.
  • 20 April 1937. 16:00hrs. Farnborough, England.

    The testing of the A9E2 had been completed and as the tank was driven off to the depot there was a general feeling of cheerfulness around the team from Vickers. The changes to the engine and suspension had solved the problems of the previous model, it was able to maintain the top speed of 25mph on the road, and an average of 15mph cross country. The suspension had behaved itself over the roughest country, and the gunner was confident that it provided a stable enough platform for firing on the move. The tracks had been tinkered with and, while still more fragile than desirable, they were far less likely to come off or break than previously.

    The single machine-gun position in the hull, rather than the two turrets, was generally thought of as an improvement, and the company had added a little more armour to the turret and forward hull to improve it to 0.75 inch. The army had been unhappy with the positioning of the radio in the hull, but Vickers had used an internal intercom system borrowed from the Vickers Wellington bomber aircraft that was currently under development. The system gave the tank commander and the hull gunner/radio operator the ability to communicate clearly, likewise with the driver and the loader. There would have to be some training and testing to see if this would actually work in practice. There were also questions about the training of radio operators, this generally had been reserved to tank commanders, nobody wanted to have to have one crew member from the Royal Signals rather than the Royal Tank Corps. On the other hand, there were quite a few people who thought that relieving the tank commander from yet another role would be helpful.

    Sir John Carden had asked what radio sets for tanks were under development, if space was needed for bigger sets this would be important to get right. The current radio systems, No 2 and No 7 Wireless sets were used in the Medium and Light tanks respectively. The No 2 had a range on R/T (voice communications) of about 12 miles, though the tank had to be stationary to achieve this. The No 7 set had only about 3 miles range, and since they were still new, the majority of Light tanks were making do with modified No 1 sets. He was informed that new sets, designated No 9 and No 11, were under development at the Signals Experimentation Establishment. A request was made that the tank designers should be involved, or at least kept up to date, in that development process as the space and power needed for the radios was an important part of a successful tank design. The A9E2 would be equipped initially with the No 2 Wireless Set until the No 9 was available.

    What pleased the team from Farnborough was that the tank had travelled over 1000 miles with no major breakdowns. The engine had red-lined a few times in steep climbs, it was just at the limit of what it was capable of. The changes to suspension had evened out the ride of the tank, and the five-man crew were relatively comfortable. The tracks had improved but were still capable of further work. There were a number of little niggles that could easily be put right in the production model, the Vickers team had already taken note of many of these. The recommendation of the Mechanisation Experimental Establishment to the War Office was that the A9E2 had successfully passed its trials, and should be put into production.
    1 June 1937. 10:00hrs. London, England.
  • 1 June 1937. 10:00hrs. London, England.

    Sir Hugh Elles, the Master General of Ordnance, chaired the meeting at which Sir Harold Brown, as Director General of Munitions, brought together the work of his department regarding placing orders for tanks. Brown’s department had two main directorates: Industrial Planning and the Directorate of Progress. This was a relatively new set up for the army and it was worth beginning the meeting with a review of the current situation regarding contracts for the production of tanks.

    Since 1934 a number of orders had been made to various companies to provide tanks for the Cavalry Regiments that were undergoing mechanisation. Vickers had received the first order for twenty Mark V light tanks in January 1934. Fifteen Mark IV light tanks had been ordered from Royal Ordnance Factory Woolwich in May 1934, along with another fifteen Mark IVs from Vickers. The first 40 Mark VI had been ordered in July 1935 from Vickers, with five more in December 1935 and five from Vulcan Foundry in February 1936. The largest orders of tanks had been given in November and December 1936 when Vickers was awarded a contract for 110 Mark VIB light tanks; Vulcan Foundry’s contract was for 100 Mark VIAs; and then another 100 Mark VIA were ordered from Vickers.

    Since the beginning of 1937 North British Locomotive Company and the agricultural vehicle engineers, Ruston & Hornsby had each received orders for 50 Mark VIB Light tanks. These were two new companies to the manufacture of tanks and the Directorate of Progress was keeping an eye on how they were responding to the challenge. A further 100 Mark VIBs had been ordered from Vickers-Armstrong. Altogether, over six hundred tanks had been ordered since 1934. A tank regiment would normally have around 60 tanks, so there were enough tanks on order to equip ten regiments. The designated regiments for the Light Tanks were the Cavalry Regiments currently undergoing mechanisation.

    The question that had to be resolved now was what to do about the Royal Tank Corps, whose Medium IIs were in dire need of replacing. There were currently two heavy tanks in development, the A11 and A12. The changes that Vickers has made to from the A11E1 to the A11E2 had increased the cost per tank over what had originally been called for. The A11E2 was believed to be better for the improvements and the results of the tests at Farnborough were positive. Brown recommended ordering 60 of the A11 from Vickers immediately, this would provide one of the RTC battalions with a replacement for their worn-out vehicles and allow training on the new type to commence. The A12 mock up by Vulcan Foundry had been seen and approved for the next phase of building an A12E1 prototype. Realistically the Directorate of Industrial Planning couldn’t see this tank entering production until late 1938 at the very earliest. Overall, the A12 was likely to be the better choice for an infantry tank in the long term, but the needs of the RTC were extreme. Brown suggested it might be prudent to consider a second order for 60 A11s in the 1938 budget, providing a second battalion’s worth of tanks. Then they could count on ordering an initial 60 A12s in 1938, and 180 in 1939 when the budget was expected to bigger again, to equip four battalions of the RTC with the A12. This would provide two complete Army Tank Brigades with Infantry tanks.

    The A9, as a direct replacement for the Medium tanks, had also been successfully tested and was ready to go into production. Both Vickers and Harland and Wolff would be able to build these if contracts were given. However, the new type of fast tank based on the Christie suspension, the A13E2 was due at Farnborough in October. This was considered more desirable by the RTC, but wouldn’t be available for production until well into 1938. Likewise, Vickers’ A10 was due shortly for testing, and if the omens were read correctly, then it may well be worth investing in it for the RTC, as it would be more likely to be ready for production before the A13.

    The problem was having five new types of tanks all coming along at the same time and a limited budget. The two Infantry tanks were straightforward, the A11 would be a stopgap until the A12 could come along in large enough numbers. It would seem therefore that the same logic should apply to the A9/A10 and A13 tanks. By ordering 60 A9s now, and 60 A10s in 1938, the last two of the eight battalions of the RTC would be equipped with modern tanks. Brown recommended splitting the order for 60 A9s between Vickers (30) and Harland and Wolff (30).

    The problem in the 1938 Budget was that there would also be the need for another 600 Light Tanks for the next tranche of mechanisation of the Cavalry Regiments. It has been calculated that the army would need 1,182 Light Tanks by the end of 1939 to equip twenty cavalry regiments. The plan to increase the battalions of the RTC to eight and equip them would need 480 medium and infantry tanks.

    The current cost of a Mark VIB light tank was £4000. It was expected that the A11 would cost nearer £8000 than the originally planned £5000. The A9 was expected to cost £12700 and the A10 would be over £13000, while the A13 was expected to be closer to £12000. The A12 was provisionally costed at £18000. The cost of 1182 light tanks would be £4.75 million. The heavier tanks were likely to cost over £6 million. The need for the budget to increase to allow this to be in place by the end of 1939 was becoming critical.

    Both the Directors for Industrial Planning and Progress were unsure whether it would be possible for the current state of tank production to actually produce all these tanks for the end of 1939. Currently only the Mark VIB was in production and the A9 was almost ready to go into production. There were a lot of companies who were starting from scratch, especially Vulcan Foundry and Nuffield designing and building the A12 and the A13 respectively. There were many foreseeable problems that could well delay the implementation of the desire to acquire an extra 1000 tanks in 30 months. The only company with anything like the capacity and experience was Vickers-Armstrong. A suggestion was put forward to scale back the numbers of light tanks to be ordered from Vickers to allow more production allocation to be made to the A9 and A11. It might be better if Vickers could make a start on these types in the next twelve months, giving the RTC four battalions worth of tanks by the end of 1939.

    The contracts for Mark VIA and VIBs given to Vulcan Foundry, the North British Locomotive Company and Ruston & Hornsby earlier this year were so that these would acquire the experience and skills for building tanks, starting with something quite straightforward. Other companies, such as Harland and Wolff (working with Vickers on the A9), Birmingham Railway Carriage & Wagon Company and Metropolitan-Cammell Carriage & Wagon Company could also be brought on to the War Potential program, perhaps working with Vickers to produce the A10. Once Vulcan Foundry and Nuffield had developed the A12 and A13 all these other companies, with a year’s experience on the light tanks, might be in a better position to make the more sophisticated models.

    Giffard Martel noted that A13’s potential was such that the A9 and A10 would merely be stopgap tanks, just like the A11 would be for the A12. It may well be the case that what the Cavalry Regiments needed was this kind of fast tank, with a proper gun, rather than the light tank. If the decision was made in 1938 to order only 300 Mark VIBs instead of 600, and slow the process of mechanising the cavalry regiments for an extra year or two, £1.2 million budget saving could be invested in 100 of the A13 fast tanks, but that would mean converting only seven cavalry regiments instead of the planned ten. Providing either five of those regiments each with a squadron’s worth of A13s (18 tanks), or three regiments with almost two squadrons, would make them a bit more capable of doing more than simply reconnaissance. Once the A13 was in full production, if the budget allowed, ordering more of them could replace squadrons of light tanks in the previously mechanised cavalry regiments, would allow these to be more rounded in their capability.

    While General Elles agreed with most of Sir Harry Brown’s recommendations, he did feel the need to ask a question. If the A11 costs £8000 and the A12 will cost £18000, wouldn’t it make more sense to order an extra 60 A11s? From the description of the A11E2, it was certainly less capable that the proposed A12, but not by as much as the original A11E1 would have been. If Vickers was asked to concentrate more on the A11 and less on the Mark VIB, it might mean that three battalions of the RTC would be fully equipped with Infantry tanks by the end of 1939 instead of two. If the A12 wouldn’t enter production in any numbers until mid-1939, as suggested by the Director of Industrial Planning, then the RTC would be at 50% of its required inventory of Infantry tanks by the end of 1939 instead of 30%.

    What General Elles proposed was ordering 120 A11s immediately; then order another 60 in 1938 along with the first 60 A12s; then order another 120 A12s in 1939 once they were in production. This would provide the RTC with three battalions of infantry tank A11 by the end of 1939 and three with the A12 by the end of 1940. In addition to the infantry tanks, ordering 120 A9s this year would give the other two RTC battalions the tanks they desperately needed, and hopefully be fully equipped by the end of 1939.

    Elles agreed with Martel’s idea of cutting the numbers of Mark VIBs to be ordered, and slow the process of mechanising the cavalry regiments. He went further, in his opinion, it would be better to order only 240 of the planned 600 light tanks next year and freeze this year’s number at about the same. If the A13 was everything that Martel hoped it would be, and if the tests were satisfactory, then an initial order for 100 A13s could be made in 1938. If these were delayed in coming into production, which was highly likely going by the fact they were a completely new design from an unexperienced firm, then they could order 60 of the A10 from Vickers in 1938. If the A10 had problems, then this could easily be changed to the A9. With sixty each of A13s and A10s ordered in 1938, then increase the A13 order to 120 per annum for the cavalry regiments along with 240 light tanks, mechanising six regiments per year.

    The idea of providing mixed squadrons of tanks to the cavalry regiments for their different roles was sensible, but would increase the problems of training. Having a regiments worth of gun tanks as quickly as possible might make it possible for a troop’s worth to be given to each regiment to become familiar with while they await their full allocation.

    Sir Harry Brown could see the logic of this, but wondered at the political backlash that would come from slowing the process of mechanisation of the cavalry regiments. Nobody wanted to say that Brown’s background in the Royal Navy meant that he probably didn’t realise that a good number of the old boys of the Cavalry Club were resisting giving up the horses. Delaying the inevitable would probably play better in political circles than was expected. If the deal was sweetened with something like promising the A13 as a proper cavalry tank, then so much the better. The other thing that Brown noticed was that the A10, with its thicker armour, would probably better a better fit for the RTC battalions than the A9. Elles and Martel agreed that perhaps as the A9 and A10 started appearing, that some reassignment of vehicles could be made, but a bird in the hand was currently worth more than two in the bush.

    For comparison: OTL
    21 October 1937. 16:00hrs. Farnborough, England.
  • 21 October 1937. 16:00hrs. Farnborough, England.

    The A13E2 had spent the last week undergoing testing. With 14mm of armour the total weight of the tank was 14 tons. The suspension, based on the Christie model, was judged capable of being stiffened up allowing it to take more weight. The designers at Nuffield however had built the suspension close to the design weight, so as it stood it would struggle to deal with any improvements.

    Unlike the A13E1, the original Christie machine brought from the USA, the nose of the A13E2 had been squared off, though no hull machine gun had been added. The driver’s position was in the center of the hull, with the box shaped head cover for the driver sticking out above the glacis plate. The turret, with the 2-pdr and co-axial Vickers .303 was the same style as the A9 and was riveted, though it differed from the A9 as it had a large drum-shaped cupola added.

    The transmission differed from the Christie model to include a constant mesh gearbox, and the tank was powered by Nuffield’s re-worked Liberty engine, achieving 411bhp at 2000rpm. Amal flame traps had been built into the air intakes to protect the air-cleaners. The suspension spacing had been rearranged to suit the new hull shape and shock absorbers built by Newton and Bennet has been added to soften the rebound effects. The tank ran on the original Christie size track and sprockets, though the second prototype (A13E3) was promised with a new type of double link track.

    Most of the problems that had been identified during the testing stemmed from the ability of the tank to exceed 35mph, most of which could be solved by governing the engine to not exceed 30mph. The engine's power was judged to be very good, and this model's engine worked well. The A13E3 would take on board many of the criticisms and make the necessary changes before production would be contemplated. For the school of thought that Giffard Martel had been promoting since seeing the Soviet BT2s in action, the A13E2 looked like the answer to a prayer.

    Below is the link to the Tank Museum's Tank Chat about the A13. All this is as OTL.
    30 October 1937. 11:00hrs. Magdeburg-Buckau, Germany.
  • 30 October 1937. 11:00hrs. Magdeburg-Buckau, Germany.

    Chassis number 80101 rolled off the production line Krupp-Grusonwerk. This was the first Panzer IV Ausf.A of the thirty-five ordered. The company expected the order to be completed by the end of March 1938. The hull was divided into the rear engine compartment, the central crew compartment and the forward-mounted transmission and enclosed driving compartment, the separation between the three compartments was made with a fire resistant and gas-tight armoured firewall.

    The hull was topped with a superstructure that was wider than it to provide sufficient protection for the crew members as well as satisfactory working space and ammunition storage. It was made of four welded plates with a visor port on each side. The front plate had the driver plate protruding out, providing the driver with a better view to the front and sides when driving.

    The panzer had an auxiliary DKW gasoline engine which provided power the electric engine that was used to traverse the turret. At the rear of the turret, the commander’s cupola was a simple drum shape and eight small vision slits, the commander entered through a two-piece hatch door which also provided a good all-around view when not engaged in combat. The turret ring with a diameter of 1680mm. Its main armament of was the 7.5cm KwK 37 L/24 with an internal gun mantlet. The gun’s role was primarily meant to destroy soft skin targets, anti-tank positions etc. and was thus mostly equipped with high explosive and smoke rounds. An armour piercing round was provided which could penetrate 41mm of armour at 100m. At ranges of 500m, the penetration dropped to 38mm.

    A variety of suspension types had been tested but Krupp’s chief tank designer insisted on using a self-dampening leaf spring suspension. The suspension consisted of eight small wheels on each side, suspended in pairs and placed on four bogie assemblies. The small road wheels were suspended by leaf-spring units. For a vehicle weighing 18 tonnes this suspension system was considered adequate. Its engine was the Maybach HL 108TR which produced 230 hp at 2600 rpm giving a maximum speed of 32 km/h (or 10 km/h cross-country). The transmission was five-speed (and one reverse) transmission was connected to the engine by a drive shaft that ran through the bottom of the fighting compartment.

    The general armour protection ranged between 8 to 16mm and was designed primarily to provide protection from armour piercing bullets. There were two 7.92 mm MG 34 machine guns, one mounted in a ball mount in the hull operated by the radio operator, the second machine gun was placed in a coaxial configuration with the main gun and was fired by the gunner.

    This is mostly a summary of this article.
    1 December 1937. 15:00hrs. Newcastle-upon-Tyne. England.
  • 1 December 1937. 15:00hrs. Newcastle-upon-Tyne. England.

    The A10E1 and A10E2 were back at Elswick Works after testing at Farnborough. The A10E1 was the welded version powered by the AEC engine. This tank turned out to be a good ton heavier than the A9. Without a hull mounted machine gun, and therefore one less crewman and the associated weight of the gun and its ammunition, the extra armour on the A10E1 didn’t completely overwhelm the AEC engine’s power, but it came close. The tank was between five and ten miles per hour slower than its A9 stablemate on the road, but not that much discernibly slower on the cross-country parts of the trials. The tests noted that the fuel capacity was limited and recommended an increase in fuel tank volume.

    What had been interesting for the Vickers team was the reaction to the welded armour. When the A10E1 was examined it was noted that the angles that the armour was mounted, especially on the front hull made it extra effective. The absence of rivets or bolts was also noted, it was judged that this meant the crew would have better protection, since the rivets wouldn’t be knocked out by a strike against the armour. The question came back to overall cost per tank, and whether the welding workforce would be big enough to produce the tanks in a timely manner. It had also been noted that the armour thickness of about an inch (30mm) wouldn’t protect it from the 2-pdr gun, and therefore conceivably from any enemy anti-tank gun at 500 yards. The sloped armour helped, but the thickness of the armour would have to be considered, for all tanks under consideration. It raised questions about wisdom of the half an inch (14mm) armour thickness on the A9 and the planned A13.

    The A10E2 differed from the A10E1 by being longer and having a raised engine deck to contain the Rolls-Royce Eagle aero-engine. With the bigger engine and more traditional riveting, the whole tank was 15 tons, two tons heavier than the A9 and one ton more than A10E1. However, the engine was producing 400hp, which moved the tank at a faster speed than the A9, reaching over 30mph in some trials. It came at a cost however. Despite improvements to the tracks, they weren’t up to the kind of punishment that the greater mass and higher speed put on them. The suspension coped with the increased weight, but there wasn’t too much room for growth. During the test the tank was weighted to take the tonnage if it was to be given the same level of protection as the A11 infantry tank, over 2 inches (60mm) of armour. While the engine would be capable of keeping the speed up to about 25mph on the road, the suspension and the tracks would have to be improved, the suspension wouldn’t be far from its limit under that weight.

    The large engine had been adapted to take the normal petrol that was used by the army, but had lost some power in the process. It proved to be thirsty, and while extra fuel storage had been added as part of the lengthening of the hull, it wasn’t satisfactory enough in terms of the tank’s road radius. The higher power of the engine also meant that extra effort had to be made with the cooling system. This had been noted for reference with the Liberty engine powering the A13.

    With the much the same turret as the A9 and A10E1 there was little to separate it from the others regarding its fighting prowess, though the absence of a hull mounted machine gun was noted. The A10 was expected to work more with the infantry and so the extra machine-gun might be considered useful. One of the things that Sir John Carden had done with this particular turret, designed to fulfil the role of Close Support, was to add geared elevation apparatus, rather than the shoulder balanced system for the 2-pdr. He had also fixed the the co-axial machine-gun to the movement of the main gun. This simplified the process for the gunner, who only had to control one set of movement for traverse and elevation rather than two separate systems for each weapon. The report on this had noted it as being an innovation worth further examination.

    The A10E2 hadn’t been ordered by the War Office, it was being seen by them basically a Vickers commercial proposition. The fact that the larger engine could shift a heavier tank was noted, after all the Liberty engine was designated for the A13 for the same reason. Certainly, the information gained from the test would be passed to Vulcan Foundry for their work on the A12. At this point however, the plan to order 60 A10s based on the A10E1 model was affirmed, asking Vickers to begin planning to put this tank into production, but adding the stipulation that a hull mounted machine-gun be added. Vickers noted that the extra weight would overtax the engine, slowing the tank substantially, as well as delay production while the front hull was redesigned. They also noted that the A13 design did not include a hull mounted gun, so perhaps it wasn’t essential. The War Office said they would consider these arguments, but perhaps a redesign, similar to the A9 front hull might be expedited, before the order was confirmed.

    When advised that Sir John Carden was currently working on a using the A10E2 as a basis for an alternative design for the A12 specification, the War Office accepted the offer of looking at the design, but at this point would not commit to it. Therefore, they did not assign a specific A (tank) classification to it, but would look on it as an alternative A12. Vickers stated that they hoped to have a mock up of the design by spring and a mild steel prototype by the end of the year. The fact that Vulcan Foundry’s A12 design was proposing using a diesel engine to power it was noted, and Vickers was asked, if it were to produce an alternative, to consider using the same type of engine.
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    20 January 1938 11:00hrs. Farnborough. England.
  • 20 January 1938 15:00hrs. Farnborough. England.

    Leo Anderson shivered and kicked the wheel of the tank, which just added a sore toe to his tale of misery. His boss, Walter Christie had designed this new tank, the M1938, and since the Limeys had bought the last one, he’d been certain they’d buy this one too. So certain in fact, that he’d invited the French over too.

    The big show had got off to a bad start the day before. Anderson had been harassed all the time by his boss who wanted this done and that done pronto. In all the hullabaloo Anderson hadn’t checked everything, and sure enough after a few miles driving through the MEE range the thing seized up. The oil in the gearbox should have been changed after the sea voyage, so as driver, Anderson had had to spend the freezing cold night in the middle of nowhere with the tank. Meanwhile Christie hared around the place trying to find an engineering firm who could supply replacement gears. Being the home of testing British tanks, miracle of miracles, sure enough he succeeded. Having spent the morning fixing the tank, they’d knocked the limeys’ socks off clocking 64.3mph on a flying quarter mile.

    When an official looking car turned up, Christie thought the Frenchies had arrived, but it was a couple of State Department goons from the Embassy. They had taken Christie aside and were giving him a verbal going over. If there was one thing that Walter Christie couldn’t deal with well, it was getting a public dressing down from a couple of cheap suits. All hell broke loose. The limeys of course seemed terribly amused, though as oily as all get out when the Embassy car drove off.

    The sales pitch had obviously died a death, it seems the Embassy goons had made it clear to Christie that it was illegal for an American citizen to export war materials. The limeys had come over all sympathetic, but Anderson could see they weren’t too impressed anyway. After all the M1938 didn’t have any kind of weapons, Christie didn’t believe in all them “high in the sky turrets.” Some limey called Martel, who seemed like a big cheese in the gang, was impressed enough with the speed coming from the Curtiss D12 aero engine. You should have seen his face when informed it was rated at 670bhp at 2600rpm, his imitation of a big bass was a sight to behold. That was one of the few highlights of a very cold and unhappy couple of days.

    An offer to store the M1938 was made by the Farnborough team, while Christie organised shipping back to the States. Anderson was worried that he’s be left behind to guard the thing from British meddling, but thankfully he could ship home with Christie. Once the shipping across the pond was sorted, the limeys would deliver the tank to Southampton, then it’d be back to business as usual.

    25 February 1938. 10:00hrs. London, England.
  • 25 February 1938. 10:00hrs. London, England.

    The letter from the Secretary of State for War (Leslie Hoare-Belisha) was the subject of much discussion. Ever since he took office the Secretary of State it seemed that he had come under the influence of Basil Liddell Hart, some had taken to calling it ‘The Partnership’. It seemed to many in the War Office that Hoare-Belisha was trying to use Liddell Hart’s book “Europe in Arms” as the blue print for the future of the army. There had been in December 1936, while Duff Cooper was Secretary of State for War, an expectation that should war break out on the Continent that the initial response of sending five Regular Divisions would be backed up with twelve Territorial Divisions, two of which would be fully equipped for the job initially. In a written memorandum Mr Cooper had explicitly stated that a future war would not be fought under conditions of ‘limited liability.’ Liddell Hart on the other hand had advocated that Britain should avoid becoming involved in a continental land war and rely on the Royal Air Force as its offensive arm. When Field Marshall Cyril Deverell, as Chief of the Imperial General Staff (CIGS) had expressed opposition to this view, Hoare-Belisha had fired him. Liddell Hart had suggested John Dill and Archibald Wavell as replacements, both of whom had been interviewed, but the decision was made to make Lord Gort, his former military secretary, CIGS.

    Nobody in the War Office were under any illusions that as the demands of air defence were becoming insistent and the cost of naval programmes was mounting, the prospects of an army adequate for war in Europe were going to be continually reassessed. With financial limitations paramount, a policy favouring the Air Force at the expense of the Army appeared to be inescapable. In December 1937, the Minister for Coordination of Defence, Sir Thomas Inskip, had come to the conclusion that the policy of continental commitments no longer suited Britain's circumstances and that a number of recent events in the international field justified this change of policy. He gathered that France no longer looked to Britain in the event of war to supply an expeditionary force on the scale hitherto proposed in addition to her all-important cooperation on the sea and in the air. He argued that Germany had guaranteed the inviolability and integrity of Belgian territory and there seemed good reasons for thinking that it would be in Germany's interests to honour that agreement.

    Inskip’s chief argument was since resources were limited, rearmament must be concentrated on the vital objective. Most vital of all was, in his opinion, the survival of Great Britain herself from air attack. Next came the preservation of the trade routes and, in the third place, the defence of British territories overseas. The fourth objective, which could only be provided for after the other objectives had been met, was cooperation in the defence of the territories of any allies Britain might have in war. On the basis of this policy 'the continental hypothesis' ranked fourth in order of priority. The primary role of the Regular Army became 'the defence of imperial commitments, including anti-aircraft defence at home'. The role of the Territorial Army was to be adjusted accordingly. Instead of providing reinforcements for the expeditionary force on the Continent, it would merely be called upon to assist in anti-aircraft defence and to perform ‘duties in connection with the maintenance of order and of essential services in this country in time of war’.

    Knowing full well the policy of 'limited liability' meant that Hoare-Belisha’s memorandum came as less of a shock. Just as the War Office was formulating the first really ambitious plans of reequipment, it confirmed that in matters of supply all war plans should be based on what might be termed a war of 'limited liability', and from the end of 1937 to the spring of 1939 the equipment of the five divisions was geared down to the level of 'colonial warfare in operations in an Eastern theatre'. An army thus equipped could not be used in Europe except in a defensive role and could not be brought up to full fighting efficiency without a large increase in ammunition, a partial reequipment of tank forces, and other material changes.

    Therefore, the Secretary of State for War found it necessary to issue this special warning to the General Staff that potential allies should be left in no doubt as to the possibilities of direct assistance on the part of Great Britain. There-in lay the problem for the War Office. It was bad enough having to warn their liaison officers in friendly countries and allied governments, that Britain’s response to hostilities would come primarily from the Royal Navy and the Royal Air Force. The Regular army’s five Divisions would need much longer to be in a position to move to a war footing, and that of the Territorial Army would be even worse.

    One of the few saving graces from this state of affairs was that the decision to affirm that one of the five Regular Divisions would be a Mobile Division, rather than a Cavalry Division. Having been formed the previous year, General Alan Brooke, appointed General Officer Commanding, reported The Mobile Division was formed from two Mechanised Cavalry Brigades, the Army Tank Brigade, with attached artillery, engineers and signals. Its paper strength was 620 armoured fighting vehicles but 7⁄8 of these were reconnaissance vehicles and some were simulated by trucks. The tank brigade was to be made up of heavier tanks but only had obsolete medium tanks currently. With the ‘limited liability’ measures in place, although the tanks for the Division were part of the allocated funding, the possibility of an expansion of the Mobile Division was remote at best.
    1 March 1938. 15:00hrs. Shoreham-by-Sea, England.
  • 1 March 1938. 15:00hrs. Shoreham-by-Sea, England.

    Harry Ricardo had successfully adapted a Rolls-Royce Kestrel engine into a diesel engine. That engine had successfully powered ‘Flying Spray’, driven by George Eyston, to three land speed records in April 1936. He had decreased the bore by a quarter inch to 4.75 inch. He put a single sleeve valve around each cylinder, each sleeve valve was driven from the rear of the engine by a gearset that ran along the outer side of each cylinder bank. A cylinder head featured a vortex-type combustion chamber with a fuel injector positioned vertically on to of the chamber. Displacing 1170 cu (19.2L) it produced 340hp at 2400rpm. With this engine, Eyston set the diesel flying km (.6 mi) record at 159.10 mph (256.05 km/h), and the flying mile (1.6 km) record at 158.87 mph (255.68 km/h).

    When John Carden had visited Ricardo back in the autumn of 1937, he wanted to know was whether the Ricardo Diesel could be mass produced to be used in a tank. Ricardo knew tank engines well, he had designed the engine for the Mark V tank, which had also been used on the British version of the Mark VIII as well as Mark IX during the Great War. The challenge was that Rolls-Royce’s aero-engines were in great demand by the Air Ministry as the expansion of the RAF picked up speed. Carden had already been in discussion with Rolls-Royce who’d felt it would be too expensive to produce an engine for tanks, given the small numbers being ordered.

    Ricardo had understood the difficulty and the two men had talked over alternatives. Nuffield were taking up the American Liberty aero-engine for their A13 designs. London, Midland & Scottish Railway were thinking of getting into the tank business with the A14 design, which they were hoping to use a Thornycroft RY12 marine diesel, producing 500hp, which had been used in the A6E3, the Vickers’ 16-tonner. Carden wasn’t sure that LMS would be able to bring their design to production, it was likely to be too big and too complicated for a company with no experience building tanks. Likewise, Nuffield were experimenting with a heavier version of the A13, which had received the designation A16. Carden thought that while the Christie Suspension could handle something heavier, Nuffield were proposing using their Liberty engine again, though attempting to increase its power. Lastly, Vulcan Foundry were putting in two of AEC’s diesel bus engines, which Ricardo had a hand in designing, into the A12.

    With the expansion of the RAF the primary driver of aero-engine development and production, any tank engine would really need to be coming out of either an engine that hadn’t been accepted for aircraft use, or from a different source altogether, such as Thornycroft or AEC’s diesels. Giffard Martel had looked at Napier’s Lion engine as an alternative to the Liberty, and those were available, and with it being used to power High Speed Launches, as the Sea Lion, there was still a production line. The offer to buy up the spare Lions hadn’t gone through, with the Liberty being procured instead. That meant that some 500 of these machines were available, but would need to be reconditioned for tank use. Ricardo had questioned was whether it was worth transforming these into diesel engines when the power they were capable of producing was more than adequate for Carden’s needs.

    The experiments with the Rolls Royce Eagle in the A10E2 had indeed proved that an aero-engine could adequately power a tank. Carden however had noted that cooling was going to be a problem. Putting a large engine inside an armoured compartment was a recipe for over-heating. The cooling system was going to have to be really robust, especially if the tank was going to be used in places like India or the Middle East. He wondered if using a diesel engine wouldn’t be a better choice for a tank, as the torque produced would be in some ways more important than the horse power. The diesel engine was also likely to be more fuel efficient, and that would help give the tank a decent radius of action that didn’t need huge fuel tanks. That was why he’d asked Ricardo to do to the Napier Lion what he’d done successfully on the Kestrel. When Ricardo had approached Napier with Carden’s proposal they were keen to show off the Culverin diesel engine which they were working on. It was a German design, based on the Junkers Jumo 204, which they had a license for.

    Ricardo told Carden that he’d looked the Culverin over, but hadn’t been terribly impressed overall. It was almost twice the weight of the Lion, but ended up with a slightly worse power to weight ratio. There was plenty to like about it, but the power from the two opposing crankshafts had to be geared together, which added weight and complexity, something that was best avoided in a tank. Having got hold of a Lion engine he had set about doing the same to it as he had to the Kestrel in 1936. He wasn’t sure if it was everything that Carden hoped for, but he reckoned that it fitted the bill in terms of power, torque, fuel consumption and endurance.

    What was helpful was that it didn’t look like the Culverin would win any orders from the Air Ministry, who were unconvinced that the future of flying involve the use of diesel. However, it meant that Napier had some familiarity with diesel engines, and Ricardo had had their help in transforming a Lion into a diesel engine. Meanwhile Napier were keen to see what Ricardo had done with the sleeve-valves, which they were starting to experiment with. If Vickers-Armstrong wanted to negotiate with Napier, Ricardo Consulting Engineers would be happy to continue to be involved in the process.

    Carden and Ricardo shook hands over the offer, it would be up to the various companies to actually work out the deal, but Carden liked what he had seen of the bench test of the Ricardo Lion Diesel. It was being boxed up for delivery to Newcastle-upon-Tyne, where it would be married to the A10E2 for further experiments. The plans for a Vickers alternative to Vulcan’s A12 were progressing nicely.
    15 March 1938. 11:00hrs. London, England.
  • 15 March 1938. 11:00hrs. London, England.

    The three men pored over the latest reports from Spain. As they did every week, all sources were scoured for any intelligence on the tactics and weapons being employed by both sides. As well as his reports for publication in newspapers, Colonel ‘Boney’ Fuller also passed on more complete accounts of what he was seeing. Part of the problem was that he was so enamoured with the Nationalist cause, that the team looking at them had to take some of what he was saying with a pinch of salt.

    They were looking again at the various descriptions of what was happening with tanks. Fuller’s reports of the Panzer I being used by the Condor Legion were all very positive, but what was puzzling was why the Nationalists were trying to capture as many Soviet made T-26s as possible in running order. Reading between the lines, it seemed that the machine-gun armed German machine wasn’t able to deal with its Soviet counterpart. The T26 was based on the Vickers 6 tonner, and was armed with a 45mm cannon. This gun was more than capable of penetrating the Panzer, while the 7.92mm machine gun wasn’t able to deal with the T26. The Italian tanks, CV33 and CV35 suffered from the same problem. Fuller had remarked that efforts were being made to replace the MG13 on the Panzer I with a Breda 20mm autocannon, which would be able to penetrate the Soviet machine.

    What British military intelligence made of this was that the Vickers Mark VI light tanks, which were similar to the Panzer I in armour and armament, would suffer from the same problems. An enemy armed with anything more that a rifle cartridge would be a serious threat to the light tanks. It was believed that the Panzer II was armed with a 20mm cannon, and the standard German anti-tank gun was fired a 37mm round. And since the light tanks were only armed with machine guns, though the Vickers .5-inch machine gun might be a bit better than the .303, they too would be unable to deal with any enemy machines. Vickers was working on a Mark VII light tank, designated A17, which had the standard 2-pdr gun in a turret. However, it was designed with the same 14mm armour thickness as the Mark VI. What was becoming clear from the Spanish Civil War was that tankettes and light tanks had very limited value.
    1 April 1938. 10:00hrs. War Office. London, England.
  • 1 April 1938. 10:00hrs. War Office. London, England.

    The hand-over was a formality, Major General Lewis was being replaced by Colonel Campbell Clarke as Director of Artillery. The two men had worked closely together, Clarke having been on the Ordnance Committee since 1936. In all that time he had been urging for a design to eventually replace the 2-pdr anti-tank gun which was now in full production. With the advent of the A11 and A12 infantry tanks with 60-80mm of armour, the 2-pdr was going to struggle to penetrate that kind of armour thickness on any equivalent enemy tank. However, it had appeared that he was a voice crying in the wilderness. Maj General Lewis however on handing over the reins was able to say to him ‘now you can get on with your gun.’

    One of the problems that Clarke faced was that the design department at Woolwich was understaffed and busy with other designs, and a replacement for a gun just entering service was low on the list of priorities. The only other design department with the experience and staff for designing a gun was Vickers-Armstrong. Within days of taking office Clarke had written to them asking them to begin exploratory work on an anti-tank gun, ‘following generally the specification which governs the production of the 2-pdr.’ Getting the funding for such development work wasn’t going to be easy. It was noted that in the Vickers alternative to the A12 specification that the turret would be designed to take a bigger gun when it became available. This gave Clarke the grounds for making funds available to Vickers to begin the exploratory work for an improved gun for a tank. He added that it would have to be capable of penetrating tanks with armour of up to 90mm (3.5 inches), which would be about as thick as could be imagined. As Director of Artillery, he was primarily concerned with a ground mounted anti-tank gun, as with the 2-pdr. It made sense to him that just as the 2-pdr had proven capable of being mounted on a tank, so a gun designed for tank use could as easily be adapted for use in the ground mounted role.