WW2 British Prototypes

Arthur Janser’s 500-ton Battleship and Grasshopper Tanks

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

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

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

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

—Dr. Arthur Janser quoted 23rd April 1940.

Arthur Janser

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

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

—Memoirs of William ‘Bill’ Temple (2013).

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

The British Interplanetary Society

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

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

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

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

—Diary entry of William ‘Bill’ Temple, 10th November 1936.
Photograph of B.I.S. members at the inaugural meeting in 1936 in London. Professor A. M. Low is in the center at the front. Janser is in the back. A red dot has been placed above him to identify him in this photograph.
Source: Burgess

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

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

—Memoirs of William ‘Bill’ Temple (2013).

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

Members of the British Interplanetary Society meeting in London (probably at the B.I.S. convention) in 1938.
Left to right: J. H. Edwards, Eric Burgess, H. E. Turner, Midshipman C. Truax (USN), R.A. Smith, M. K. Hanson, and Arthur C. Clark.
Source: National Air and Space Museum

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

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

—Memoirs of Bill Temple (2013) recounting a meeting of the B.I.S. Technical Committee before the war in Janser’s flat.

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

The 1938 B.I.S. Moonship and lander – the culmination of the pre-WW2 work by the B.I.S.
Source: British Interplanetary Society

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

Barricading the Sky

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

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

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

—Diary entry of William ‘Bill’ Temple, 22nd October 1939.

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

The PAC rocket was a simple and effective anti-aircraft device.
Source: Secret Projects Forum

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

—Diary entry of William ‘Bill’ Temple, 4th May 1937.

Other Activities

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

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

Other Arms

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

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

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

The Enormous Tank

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

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

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

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

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

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

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

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

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

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

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

Robot Soldiers

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

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

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

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

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

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

The Grasshopper

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

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

Before and after of experiments with a Universal Carrier and rockets – not an optimal outcome.
Source: Pinterest


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

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

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

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

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

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

—Work of the BIS on Pathe in 1947.

Specifications Janser’s 500-ton tank

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


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