The Devil's Chariots
Page 11
Crompton was appointed technical adviser to the committee with instructions to produce alternative designs for the wheeled and tracked machines. He was given virtually a free hand, with no more detailed specification to work from than Dumble’s verbal brief. He was an accomplished innovator. After founding his electrical engineering company, Crompton & Co., in 1878, he had introduced generating plant of very advanced design and began installing arc lighting to such major sites as Kings Cross station and Glasgow’s St Enoch’s and North British Railway stations. He was awarded the first gold medal for an electric lighting generator the following year. In 1887 Crompton introduced mains electrical distribution to West London. By 1889 only two licences for electric mains supply had been taken out in England and Crompton held one of them.
A drawing office was set up in the attic at Thriplands. Needing an expert on internal combustion engines and transmissions, he recruited his friend Lucien Legros, a meticulous and distinguished 50-year-old engineer and past President of the IAE. Legros had designed the first petrol-engined tram cars in England in 1895–98 and later engineered and built Iris motor cars.
Crompton turned to Pedrail Transport Ltd for tracks for the ‘B’ Type. He confirmed at the time that no other crawler system was in production in Britain.12 Indeed, there appeared to be no tracklayer in the country save the army’s Hornsbys and a pair of Holts. It is not entirely surprising that despite Macfie’s entreaties the Landships Committee never considered a Holt machine, arguably the most efficient tracklayer of its day. Holden had only recently refused to lend one to Sueter. Any fresh approach to the army or even to Holt’s agents at that stage would risk disclosure of Churchill’s hand and shutdown of the project.
Diplock and James Lowe, his draughtsman, showed Crompton the design work which they had begun on Sueter’s 25-ton machine. A turret for a 12-pdr gun topped the DAD’s torpedo-shaped 38ft hull. It was to be mounted directly over two broad Pedrail track bogies set in tandem, each 13ft long and independently driven and steered. The machine would have lacked steering if it had had only a single track. Crompton retained the layout but increased payload to 70 men and the gun was discarded. A low 40ft hull devoid of turrets straddled the two in-line tracks. The engines and control gear lay along its central axis and there was a two-man crew. On either side a narrow detachable wing overhung the tracks rather like an iron saddlebag, providing a pair of standing-room corridors for the assault party. The two tracks were set close to the extremities of the hull, the underside of which was angled upwards at each end in a cutaway to aid climbing. Its great length relative to an underbody clearance of only 18in left the machine seriously prone to grounding. The same problem would arise laterally from the platform’s overhang if the machine rocked unduly over rough ground. Twin engines gave a top speed of 4.5mph. At 80ft, the turning radius can only be described as generous.
Crompton went to Lincoln on 26 February to discuss the wheeled ‘A’ Type with Tritton. The committee had approved the colonel’s proposal that Foster’s howitzer tractor should be nearly tripled in length by extensions fore and aft to enable it to carry 50 men, with some means of trench crossing less complicated than the bridging machine’s. Tritton still favoured his experimental ‘bridger’ as a lightly armed and crewed support weapon mounting two or four machine guns. He showed it to the colonel and urged retention of its semi-tricycle layout for the troop-carrier version. Rather surprisingly, Crompton agreed despite the visible lack of stability with upwards of 12ft of laden extension platform behind the rear axle and some 24ft ahead of it perched over the in-line steering wheels. However, he seems to have had misgivings on arriving home, likening the design to a skate. Legros was sent to Lincoln with instructions to bring away drawings of the front-end layout. The scholarly and quietly spoken engineer received a chilly reception:
I found Mr Tritton working at a War Office scheme for bridging trenches, and that he had no belief whatever in the chain-track system. He received me rather rudely, wanting to know why Colonel Crompton and myself were butting into this when he was already working at a scheme for a War Office committee. He stated that he had experience in building and running chain tracks of his own make (termed Centipedes) and that caterpillar tracks were no good for such work as was in view, namely trench taking.13
Tritton shared Holden’s opinion on chain traction and his view was possibly hardened by the lack of commercial interest in ‘Centipede’, his answer to the ‘Caterpillar’. Centipede was a semi-track version of Tritton’s very successful wheeled petrol tractor. Foster’s appears to have built only one – to special order in 1913 for a Paraguayan sugar plantation. Unlike the rigidly locked camber of Roberts’ track, ‘Centipede’s’ track could be profiled from flat to any camber to suit ground conditions.
Legros returned home with a drawing of Tritton’s first ideas. It was clear that the platform would have to be scaled down to carry 30 men at most, as the already lengthened tractor frame would distort under a greater load. He also brought a letter from Tritton which displayed not only his lack of enthusiasm for the troop-carrying idea, but also considerable personal hostility towards Crompton. In a statement to the Tanks Awards Committee in 1918 Tritton spoke about this meeting:
Mr Legros asked if I would place all my information at Colonel Crompton’s disposal. I said NO [sic] and I gave Mr Legros a letter to take back to Colonel Crompton. I had already had many dealings with Colonel Crompton and I had all the work and he had the credit… I very politely told him that if his committee or department wanted my assistance it was freely at their disposal.14
Tritton’s and Crompton’s paths had almost certainly crossed on two previous occasions. They were rival engineers during the electrification of London: the colonel operated a power station in Kensington, and Tritton was appointed Chief Assistant Engineer with the Metropolitan Electric Supply Company in 1899. Tritton then joined Foster’s as Works Manager in 1905 just after they had fitted a steam tractor with Diplock’s third set of Pedrail wheels. The tractor went to Aldershot for trials that year with the MTC, of which Crompton was still a member. He was also advising Diplock, and Tritton would have met him in one or other capacity.
Crompton and Legros spent the morning of 4 March with Diplock and Lowe at Wyfold Street, preparing a drawing for what became the regular Friday Landships Committee meeting at 5pm in the DNC’s office. The very able Dale Bussell from Admiralty Contracts Department attended, doubling as committee secretary. Col Dumble had departed to join Sir W.G. Armstrong, Whitworth & Co. Ltd at their Openshaw gun factory in Manchester. Crompton’s diary entry that day reads: ‘Decided to press Caterpillar type landship very carefully.’ He reported little progress with the wheeled ‘A’ Type, noting that Tritton was unable to fit a platform even for 30 men without overstressing the narrow chassis. Crompton and Lowe tabled the Mk I ‘B’ Type design. Their crawler presented a much lower hull profile and centre of gravity than Tritton’s machine. Its floor trap exit was replaced by large armoured side doors which could be swung open to shield men while they cleared wire obstacles, details of which had been discreetly obtained from the Royal Engineers. Crompton was asked to finalize drawings for the ‘B’ Type and place construction contracts through Bussell. The heavy ‘C’ Type was dropped. Churchill minuted ‘Press on.’
At Sueter’s request, Diplock had got Lowe to complete an elevation drawing of the DAD’s original turreted design. Lowe had hurried over to Thriplands that morning and secured Crompton’s approval for it to be produced at the meeting. It was Sueter’s final throw. His half-submarine design was rejected.15 This marked the end of Murray Sueter’s creative involvement with landships, though he retained administrative control of the committee. Sueter had been the first by a few days to commission the design of a tracked trench destroyer. His concept machine was, significantly, a modestly crewed gun platform rather than the lightly armed troop carrier which the Landships Committee was now pursuing.
Because of the problems with Tritton’s machine, C
rompton was instructed to approach other firms, including Foden’s, with an invitation to design and construct a big-wheeler. He had privately concluded that it was pointless to continue with wheels, and Tritton’s attitude rankled. Crompton left Foster’s to pursue a wheeled solution on their own. He spent the next day at Foden’s lorry works at Sandbach, Cheshire, arranging for the firm to take on the framing and final assembly of his ‘B’ Type. The limited resources of Diplock’s Pedrail company meant that construction of the track assemblies would have to be contracted out through the Admiralty. There were problems too with the twin transmissions. Crompton wanted the machine to be drivable from either end, as fast in reverse as in forward gear. He was trying to adapt automobile gearboxes which were incapable of such work. Without identical ratios in forward and reverse he would have stripped standard boxes, so purpose-built transmissions were ordered from light locomotive builders McEwan, Pratt & Co. Ltd of Burton on Trent, Staffordshire. As for engines, Legros, who was now working full time at Thriplands, had earmarked three Rolls-Royce armoured car units. Foden’s appointment as lead contractor was approved on 12 March. Track design would be sub-contracted to Pedrail.
Foster’s abandoned work on the tricycle ‘A’ Type. Its frame was inadequate for the load. With a flourish Tritton instead showed the committee a model of a radically new design on 19 March. The ‘Foster Trench Tractor’ was an articulated big-wheel landship. A 20ft tractor and its 28ft trailer were each mounted on a single axle between a pair of 15ft wheels. The trailer could carry a powerful gun or, Tritton claimed, transport an assault party of 70 men – exactly the complement planned by Crompton for the ‘B’ Type. To expect to pack so many fully armed men into the narrow trailer’s 150sq ft was wildly optimistic. A fixed turret on top of the trailer provided an arc of fire directly rearwards, the gun being blinded in all other directions by the wheels or the tractor ahead. Steering was from the trailer via a manually operated brake on each wheel. Tritton must have known that the design was unstable at only 8ft 6in wide, and the huge bulk of the set would make it an easy target. He later admitted that the 36-ton monster with its 105hp engine was underpowered and ‘inherently bad’.
Tritton promised to put the first machine on the road within three months at a cost of £2,000–3,000 subject to swift approval. He ended with a swipe at Crompton’s ‘caterpillars’, alleging that they were liable to ‘scrounching’ – his word for the nutcracker tendency of adjoining track plates to grip wire and stones with resultant damage. Inexplicably, d’Eyncourt accepted the design without comment, seeking permission next morning to order one each of the two types. Churchill called him in before summoning Hetherington, Crompton and Legros for the first of several meetings at the Admiralty that day. They ended with an evening session at which the First Lord increased the numbers to 12 Pedrail crawlers with the necessary 24 Rolls-Royce engines plus three spares, and six big-wheel machines. He marked the folder ‘Most urgent. Special report to me in case of delay. Estimates of time and money.’ Expenditure totalling £70,000 was approved on 26 March.16
Churchill wrote across the file cover in his customary red ink ‘Proceed as proposed and with all despatch. On account of secrecy this may be taken as full sanction.’ ‘Secrecy’ included concealment from the Treasury. The committee’s expenditures were charged to (or interred in) Admiralty vote 8 111 B – an obscure fund covering auxiliary machinery for contract-built ships.
The landships contractors were wired at once to proceed, with contracts to follow. Government munitions contracts were generally based on payment of approved costs plus 10 per cent, an unavoidable formula for new work entailing unknown expenditure, though it encouraged cost inflation by the supplier. Dale Bussell had little choice as no working drawings were available from which to estimate quantities and labour. Delivery of the first big-wheeler was expected by the end of June; the first Pedrail machine was to follow a fortnight later. Meanwhile, Foden’s were running into a serious labour dispute. Crompton and Foden had attended a fruitless meeting of the Labour Conciliation Board on 23 March. By the time Bussell’s confirmatory telegram reached Sandbach three days later the factory was already crippled. Of the workforce of 1,100, around 400 were on strike and threatening to move to better paid mining and munitions jobs. After a dispiriting visit on 14 April Legros contacted Dudley Docker’s Metropolitan Carriage, Wagon & Finance Company in hopes of finding alternative capacity there. He was directed to Metro’s subsidiary, The Patent Shaft & Axletree Co. Ltd at Wednesbury which was able to take over the work. Available pressing and drop-forging capacity was very short nationally by then, but Shaft’s Old Park Works could undertake this and similar work for the Pedrail machine, and the company was appointed main contractor.
The committee engaged Crompton as its design and consulting engineer. He and Legros were to work full time for four months backdated to 1 March, Crompton at £130 and Legros £72 per month. Sueter withdrew some of Crompton’s earlier freedoms: all questions of design were to be considered in committee; Crompton could no longer give firms instructions unsupported by official orders; Hetherington would assist him and oversee construction, submitting all drawings and purchasing requests through Boothby.
A search for armour began. Hetherington and Lt Albert Stern his assistant went over to Paris on 2 April to interview M. Berjery Dérocle, inventor of a compound which he claimed to be bullet-resistant if used as a filling between two sheets of steel plate. They brought back a sample. The gelatine was packed into a 38mm gap between two plates, respectively 4mm and 2mm thick. Test firings literally shot Dérocle’s idea to bits. Legros now toured the Sheffield plate mills which were overwhelmed with orders.
Crompton’s hull was of unitary construction to keep down weight; he omitted structural framing. Its final design depended on the size of available sheet armour, the wider the better, to minimize joins. Legros was looking for hardened steel plate, but because of its relative thinness it required exceptionally heavy pressure in the rolling mill. Unfortunately there were few pairs of rolls in the country able to turn out such plate larger than 4ft x 2ft. Vickers (and Wm Beardmore in Glasgow) could go to 6ft x 4ft. The plate also had to be rolled dead flat to ensure rivet holes married tightly at the joining of sheets, and needed to be finished to true edges to minimize the need for grinding, a difficult and slow operation on hard steels. Legros had to reveal his purpose during visits to John Brown, Hadfield’s, Flather’s, Firth’s, and Vickers. He found them all anxious to help.
He learned that the Germans were now reversing the normal rifle bullet to improve penetration. In that position its lead filling first came into contact with the plate and for a millisecond it welded the nose of the round to the surface, absorbing some of the shock before the hard core punched on through. Legros was asked for a German rifle and ammunition for trials. When he wired Wormwood Scrubs he was assured that he was covering old ground, they had all the results and no test was necessary. However, the RNAS trials data only covered Beardmore’s plate and the findings did not hold true for steels of variable hardness from other mills. The misunderstanding led to a later increase from 8mm to 12mm in the thickness of the landships’ flank armour, imposing a severe weight penalty and resultant power loss.
Unknown to the Admiralty, Kitchener ordered heavy armoured cars to be built in support of a fleet of 700 London buses which were earmarked for requisition, should an evacuation or other emergency arise in the capital.17 Several vehicles were built at Woolwich Arsenal on AEC ‘B’ Type bus chassis. The turretless hull fully enclosed the engine and driver compartments, with an open-top fighting platform behind. Sliding shutter rifle ports surrounded the cab and platform in place of mountings for fixed weapons.
Woolwich did not tap into the navy’s recently acquired knowledge of light armour until the cars were built, at which point Sueter was contacted and asked if his expert on the subject could come over to the War Office. Briggs was away so Hetherington went, probably on 12 April.18 The newly promoted major found himse
lf before Kitchener, von Donop and Guthrie-Smith. Hetherington favourably impressed ‘The Chief’ who questioned him closely on the RNAS tests and much else before sending him on to Woolwich to inspect the finished cars. Hetherington found the plate was only bullet-proof at ranges over 300yd, useless for armoured car work, and reported accordingly. The War Office was aware of Sueter’s experiments with thin armour and could have obtained the necessary data at any time.
Pedrail’s broad sleeper-track gave a performance over wet ground which was exceptional even by the standards of conventional crawlers. The devil lay in the system’s complexity and the need to scale up track length to 18ft from the Colonial wagon’s 6ft. No practical machine anywhere had got near that and every Pedrail component would have to be redesigned to support greatly increased loads and the higher demands of the engines. Legros was having difficulty finding available plant for some of the work. A 2-ton stamp was needed for the slippers carrying the track feet, which neither Vickers nor Firth’s could release from other government work in hand.
Diplock began to miss deadlines for finished drawings, and without working drawings the builders were stalled. They could not leave plant idle, so the tightly scheduled time slots for landship assemblies were threatened. Diplock resented Crompton’s insistence that Lowe should move full time into the Thriplands drawing office and, pressed to complete the drawings in ten days, he replied on 12 April that he hoped to finish them in three or four weeks. Crompton and Legros hurried over and discovered gross errors in the design of the foot carriers which meant that they could not be riveted up. Diplock gave way and Lowe moved to Thriplands next day, but a cloud of doubt had formed over Pedrail Transport Ltd.