Armoured Car, Humber Mark IV
Design and service history:
The Humber Armoured Car was one of the most widely produced British armoured cars of the Second World War with over 2000 examples being constructed by the time production ended in 1945 with the cessation of hostilities. The Humber armoured car was to replace the subpar Humber Light Reconnaissance Car on production lines and remained in service with Commonwealth forces until the end of the war and with some nations into the early 60s, which is rather impressive when one realizes that the Humber armoured car came into being as an unplanned necessity of the struggling British war economy at the start of 1940.
The inception of the Humber Armoured car came when it became clear that the Guy company lacked the sufficient production capacity to produce the required number of Guy Armoured Cars as well as other vehicles to meet demand after the losses at Dunkirk. Because of this, shortly after the outbreak of the war, the Rootes Group were approached for the request of an armoured car, which at the time was termed a “Tank, Light (Wheeled)” for use by the army. Using the Guy design as a base, Karrier designed a vehicle using the basis of their KT 4 artillery tractor chassis, which was already in production for the Indian army, mated with the armoured body of the Guy armoured car. In order to accommodate this, Karrier moved the KT4 engine to the rear of the chassis and fitted the welded bodies and turrets provided directly by Guy. Due to the fact the new vehicle was fully based on proven elements, trials and prototypes passed without serious issues, and an order for 500 vehicles was placed in late 1940, with the first deliveries made in 1941.
At this time the Karrier name was dropped to avoid confusion with the British Universal Carrier tracked vehicle, and instead, the armoured car was designated the “Armoured Car, Humber Mk 1” using the name of Humber Limited, which was another member of the Rootes Group, even if the production would be carried out by the Karrier plant at Luton. This fast-production turnaround meant that the first Humbers were more or less identical to the Guy armoured car down to faults in the armour, though these weaknesses were soon rectified as production went into full effect after around 300 MK 1 Humbers had been produced.
In terms of design, the Humber was a relatively standard armoured car, possessing a rectangular chassis frame with a rear-mounted engine. The gearbox was mounted to the front of the engine and fed a centrally mounted transfer box, which distributed power to both the front and rear axles. These rigid axles were mounted on leaf springs in the front and hydraulic dampers for the rear axle. The welded armoured hull was then mounted upon this chassis at four points, one front, one rear, and one on either side, giving some flexibility, with precautions in place to prevent excessive movement of the hull on the chassis.
For forward vision, the driver was equipt with a flap in the front of the cab, similar to light tanks in service with the army at the time. This would later become part of the glacis from the Mark II onwards, though the function remained the same, as the flap could be shut during combat while maintaining visibility through a Triplex bulletproof glass block. This block could be replaced when damaged and was supplemented by a pair of flaps on the sides of the driver’s position. In order to see what was behind though the driver needed to use a combination of a flap in the rear bulkhead between the fighting compartment and engine bay, along with a mechanism to manually raise the engine cover in order to see. In the MK 1 Humber, the turret was armed with one 15mm and one 7.92mm Besa machine gun, in a hand-traversed turret, with the vehicle commander acting as the wireless operator.
This armament and design was deemed successful, leading to the production of 300 Humber armoured car MK.1’s, though the Rootes Group were keen to improve the design of the base vehicle and were fast to begin producing the Humber Mark 2 armoured car. The most logical read for improvement was the modification of the main hull, which included a new front glacis plate housing the driver’s cab, and the rear radiator armour now being of a louvred design. This design was deemed successful but the Rootes Group saw room for improvement, which lead to the next major variant the MK.III.
The mark 3 retained the engine, modified KT 4 chassis and the hull of the Mark 2, along with the main and secondary armament. However, the MK 3 saw a major change in the fact it was equipt with a new larger turret able to accommodate an extra crew member, who would serve as a wireless operator, a role previously assigned to the commander of the vehicle, reducing his workload. The revised turret is easy to spot both due to its increased size and its sloping sides compared to the Mark 2’s straight and parallel sides. This design was deemed fit for service, though the lack of firepower was deemed an issue, resulting in the development of what would become the final major derivative of the Humber armoured car the Humber MK IV.
The Mark 4 succeeded all previous Humber derivatives, though it used the same engine, modified KT 4 Field Artillery Tractor chassis and hull of the earlier Mark 2 & 3 vehicles, as well as retaining the larger turret mounted on the Mark 3. The big difference however was the fact that the Mark 4 was up-armed with the US-produced M6 37mm Cannon instead of the previously mounted 15mm BESA gun. Due to the addition of this larger gun, the crew size again dropped back down to three, despite the larger Mark 3 turret being used. This design was deemed a success and would instead outlive its planned replacement the Coventry armoured car with a production of almost 2000 vehicles, which would go on to serve into the mid-60s with various nations, along with seeing extensive service in ww2 with British, exile and commonwealth forces.
Mass 5 t
Length 15 ft 1.5 in (4.610 m)
Width 7 ft 3 in (2.21 m)
Height 7 ft 10 in (2.39 m)
Armour 15 mm (0.59 in)
Main armament M6 37 mm high velocity gun
Secondary Armament 1 x 7.92 mm Besa machine gun
2 x .303 Vickers K machine guns
Engine Rootes 6 cylinder petrol engine 90 hp (67 kW)
Power/weight 18 hp/tonne
Suspension Wheel 4x4, rigid front and rear axles, rear-wheel drive with selectable four-wheel drive
Operational range 200 mi (320 km)
Maximum speed 50 mph (80 km/h)
- Humber Armoured Car - Wikipedia (Wiki page for vehicle class)
- https://www.dday-overlord.com/en/material/vehicles/humber-armoured-car (More info on chassis)
- Besa machine gun - Wikipedia (Info for the besa machine gun)
- WarWheels.Net-Humber Mark 4 Armored Car Index (Additional historical sources)