Friday, March 20, 2015

Matilda-based flail tank I

Known, initially, as the 'du Toit Winch', the Matilda-based flail tanks developed in Britain were rechristened 'Barons' in February 1942. Like its Middle Eastern counterpart, the British prototype retained its turret and mounted a separate engine compartment, in this instance containing a Chrysler unit, on the right side of the hull. The engine was housed in an armoured box, situated in line with the turret, from which a drive shaft extended forward into a small gearbox. Here motion was translated to a sprocket which, by means of a long loop of chain, activated another sprocket on the end of the rotating flail drum. The big difference from Scorpion was that the arms supporting the rotor drum could be raised hydraulically, using the turret traverse mechanism, to keep the chains clear of the ground when they were not needed.

It is worth recording that the prototype Baron was first demonstrated on 6 June 1942, not only two years to the day before D-Day but a good two months ahead of the prototype Scorpion in the Middle East. It was viewed by the General Staff and their impressions reported to the Commander-in-Chief Middle East, General Auchinleck, who was at least aware of it, even if Norman Berry was not. The difference was that with a major battle pending those in the Middle East were happy to go with what they had got and improve upon it afterwards, whereas in the UK they wanted something better before committing it to battle.

The immediate result of the prototype Baron demonstration, issued four days later, was a complaint that the Matilda seemed to be overloaded and that the flail drive engine was not powerful enough. Thus the tank was rebuilt, with a 73hp (54kW) Bedford MW engine instead of the Chrysler, and Cardan shafts replacing the chain. The hydraulic system (turret traverse) was retained and one source claimed that this enabled the operator to adjust the rotor height to suit different types of ground. However, another commentator was at pains to explain that this should not be seen as an early example of contouring. On both prototype Barons the complicated arrangement of bars and chains that made up the flails were limited to two sets, so that with every rotation the ground was only struck twice. The need for more flails was fully understood, but a good deal more power would have to be applied before this could be done.

Between June and November 1942 du Toit came up with the idea of a self-contained flail device, on rollers, that could be pushed across a minefield by any tank. A crude sketch is all that survives, but the official description claims that a form of box on wheels, propelled by the tank, contained two engines with an operator sandwiched between them. Some sort of boom extended forward from this box to a rotor, but the precise arrangement is not clear. Often referred to as a Perambulator Device it was, briefly, everyone's favourite and on a much higher priority than the conventional flail. It vanished just as swiftly at the design stage, as did a wheeled version of the Baron, presumably for armoured cars; it was noted at an Armoured Fighting Vehicles (AFV) Liaison Meeting of 9 November 1942 that: 'Baron on wheeled vehicle not to be proceeded with'.

Reading between the lines, it appears' that Rackham and du Toit differed on future flail development. Rackham, at least at this stage, probably favoured a dedicated mine-clearing vehicle, while du Toit seems to have preferred the perambulator system that could be applied to any tank. At least, in a statement released at the end of the war, the South African engineer implies that while he saw a future for the 'pram' he magnanimously put it aside in order to co-operate with Rackham.

The result was the Baron Mark III, about which we have very little information. All we are told is that in its production form, as the Baron Mark IIIA, it incorporated a number of improvements, particularly in respect of the hydraulic arrangements. Thus it seems safe to assume that in general appearance the two were much the same. It is fascinating to observe how certain trends appeared at the same time in both Britain and the Middle East and this one, of a dedicated mine-clearing device with no other offensive capabilities, is a case in point.

On the production version of the Baron IIIA the entire turret assembly of the Matilda was removed and replaced by a fixed superstructure, stepped upwards from the front, which housed the flail operator with the vehicle commander above and behind him. The flail operator had one forward-facing periscope, the vehicle commander had two, looking each way, but all three periscopes could be rotated and withdrawn into the vehicle for cleaning. Access for both operator and commander was via a two-flap hatch in the roof, but ahead of them in the usual place, sat the driver with his own hatch. The official handbook uses the term 'Pannier Fashion' to describe how the two Bedford engines, each with its clutch and modified gearbox, were mounted on either side of the tank, but it is worth remarking that although these units were contained within armoured covers, they were open to the air at the bottom to improve cooling and, presumably, to reduce weight.

The driver's main job during a flailing operation was to keep the tank on a dead straight course, creeping forwards at just 1/2mph (0.8km/h) and, through the muck thrown up by the flails and intermittent explosions, attempting to keep station on the other flail tanks of his troop. The commander's role was clearly one of overall supervision, but it was the flail operator who really had his work cut out. He probably had more controls to juggle with than the driver, in addition to operating the No.19 wireless set installed on his left. Even so, as the handbook points out, a close understanding between the three crew members was essential if the job was to be done properly.

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