From the Museum

REME Museum

REME Special Devices part three: Flail tanks – the Baron

Scribe: Zoe Tolman, Assistant Archivist

Initially General Staff were reluctant to attach anti-mine equipment to tanks in case it impaired their fighting ability, however the mine problem was severe enough by 1941 that designs such as the spiked rollers (which we looked at previously) and flail tanks were brought back into serious consideration. This article will focus on one of the first two iterations of the flail tank - the Baron - though it is worth noting that many of these experimental designs were worked on at the same time, the final approved design borrowing from multiple initial trials.

The flail tank was the brainchild of Major Du Toit who posited that ‘the flexibility of the chains, combined with a point of strike well ahead of the drum’ would make the device comparatively indestructible by mines, particularly in contrast to the roller devices which received the direct force of each explosion. Whilst the Scorpion was trialled in the Middle East in battle, Major Du Toit was flown back to the UK to create and trial a flail tank under the Fighting Vehicle Division of the Ministry of Supply. This tank was soon known as the Baron.

Both tanks were built upon the Matilda II with a flail rotor attached several feet in front of the vehicle and powered by a separate engine mounted to the side of the tank; with the person controlling the engine also in this separate cabin. The flail rotor was essentially a large metal drum with chains attached at regular intervals and bobweights attached at the end. As the drum rotates, the chains and weights fly outwards and strike the ground in front of the tank, destroying any mines in its path.

Trialling the Baron was complex as there were many factors which affected its efficacy - speed and direction of rotation, length of chain, design of chain, chain material, number of chains, configuration of chains, distance from tank and from ground, speed of tank and, of course, terrain - and factors such as reliability and visibility still had to be considered alongside these.

Pic 25c

Direction of rotation was first considered as mines were occasionally thrown back by the flails onto the tank track. However, when the rotor was run in reverse, a greater length of chain was destroyed with each detonation, due to the fact that a link higher up the chain would make first contact rather than the end, and the earth thrown up by the flails had a tendency to bury undetonated mines ahead, protecting them from subsequent flailing. Rotation was therefore set so that the flail struck the mines ahead of the roller. During trials on a later Scorpion variant, the throwback problem resurfaced as dummy mines were thrown onto the driver’s visor by the flails. As these would have resulted in fatalities had they been real, wire netting was fixed to the front to prevent further throwbacks.

Visibility was an immediately noticeable concern as dust thrown up from the flails blocked most, if not all, vision from the operator’s periscope. Multiple schemes were tried to keep the periscope clean,

Baron MkIIIA (side elevation) Baron MkIIIA (front elevation)

Mine detonating efficiency (albeit of the later Scorpion)

including redirecting the exhausts to blast the dust clear, a small cover with a commercial windscreen wiper, a large scraper on a screen in front of the periscope, and even a piece of canvas placed over the flail similar to a bicycle mudguard. These helped alleviate the issue but none were deemed to have solved the problem satisfactorily. For example, the redirecting of the exhausts, after some tweaks, was fairly effective but had the downside of the exhaust getting drawn into the tank which made life very unpleasant for the crew, whereas the scraper method struggled with large quantities and could require manual use every 2 or 3 minutes in bad conditions.

The Baron went through multiple developments, the main ones revolving around the issues of power and cooling – at first a more powerful auxiliary engine was selected, which was then increased to two engines, and the cooling system for these was at one-point piggy-backed from the main tank but this was found to be insufficient. Ultimately however, it was too wide for landing craft and suffered from various mechanical defects so, whilst the Baron stayed in use as a training tool for future flail tank crew, developmental focus shifted to the Scorpion in 1943 (and our next article will do the same!) Information and images in this article are taken from E:05.0771.01 and E:08.0121.11