Sherman Firefly

Sherman Firefly
Sherman Firefly during the Battle of the Bulge, 1944
Type	Medium tank
Place of origin	United Kingdom
Production history
Designed	1943
No. built	~2,000
Specifications
Weight	34.75 long tons (35.3 tonnes)
Length	19 ft 4 in (5.89 m); 25 ft 6 in (7.77 m) overall
Width	8 ft 8 in (2.64 m)
Height	9 ft (2.7 m)
Crew	4 (Commander, gunner, loader / radio-operator, driver)
Armour	89 mm (turret front)
Main armament	QF 17-pounder (76.2 mm) gun, 77 rounds
Secondary armament	Flexible .50 in (12.7 mm) Browning M2 machine gun (generally not mounted); coaxial .30 in (7.62 mm) Browning M1919 machine gun, 5000 rounds
Engine	Multibank or radial engine petrol engine depending on chassis used 425 hp
Power/weight	12 hp (9 kW) / tonne
Suspension	Vertical volute coil spring
Operational range	120 miles (193 km)
Speed	20 mph (32 km/h) sustained 25 mph (40 km/h) at bursts

The Sherman Firefly was a tank used by the United Kingdom and some Commonwealth and Allied armoured formations in the Second World War. It was based on the US M4 Sherman, but fitted with the powerful 3-inch (76.2 mm) calibre British 17-pounder anti-tank gun as its main weapon. Originally conceived as a stopgap until future British tank designs came into service, the Sherman Firefly became the most common vehicle mounting the 17-pounder in the war.

Though the British expected to have their own new tank models developed soon, British Major George Brighty championed the already rejected idea of mounting the 17-pounder in the existing Sherman. With the help of Lieutenant Colonel Witheridge, and despite official disapproval, he managed to get the concept accepted. This proved fortunate, as both the Challenger and Cromwell tank designs experienced difficulties and delays.

After the difficult problem of getting the gun to fit in the Sherman's turret was solved by W.G.K. Kilbourn, a Vickers engineer, the Firefly was put into production in early 1944, in time to equip Field Marshal Montgomery's 21st Army Group for the Normandy landings. It soon became highly valued as its gun could almost always penetrate the armor of the Panther and Tiger tanks it faced in Normandy. In recognition of this, German tank and anti-tank gun crews were instructed to attack Fireflies first. Between 2,100 and 2,200 were manufactured before production wound down in 1945.

The idea of fitting a 17-pounder gun into a Sherman tank had initially been rejected by the Ministry of Supply's Tank Decision Board. Although the British Army had made extensive use of the American-built Sherman tank, it was intended that a new generation of British tanks would replace it in the anti-tank role. First, there was the Cromwell tank, which was expected to use the Vickers High Velocity 75 mm gun; this gun would have had superior anti-tank performance to the US 75 mm and 76mm guns that were mounted in the Sherman. The second was the A30 Challenger, which was based on the Cromwell but with the even more powerful 17-pounder gun. These two tanks—and their successors, the Comet and the Centurion, which were already on the drawing board—were to have replaced the Sherman in British service, and so the prospect of diverting resources to mount the 17-pounder on the Sherman seemed undesirable.