Vickers 40mm Class S Gun: Hard to aim at aircraft, but great for attacking tanks

The Vickers 40mm Class S gun was created in the late 1930s and was initially used as a defensive weapon for bomber aircraft during the Second World War.

Now one of these weapons sits in a massive collection of airborne artifacts at MOD Stafford, ready to go on display at the RAF Museum Midlands in Cosford.

It has a magazine that holds 15 rounds and can fire at a rate of two rounds per second, meaning it could empty its magazine in less than eight seconds.

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Ewen Cameron, the curator of the reserve collection at the museum, explained how there was an issue with the gun.

"The only problem is, it's great if you can hit an aircraft with your 40mm round, but it's not that easy to actually do," he said.

"So they start looking at putting this in turrets of larger aircraft."

However, the weapon was eventually put to good use against ground targets, including German tanks.

Mr Cameron said: "They're [German units] spearheaded by armoured columns and there's lots of concern on how do you actually stop this German armour.

"So they look at this weapon again, and it becomes used for anti-tank duties."

It was fitted to the Hawker Hurricane Mk IID and later fitted to the Mk IV.

He explained how it was fitted to the Hurricane, saying: "It's put into the pod underneath the wing so there'll be two of these cannons on the aircraft, one underneath each wing.

"There's not too many of these made, actually. There's only about 100."

Meanwhile, Rolls-Royce produced its own 40mm gun – the Type BH 40mm Aircraft Cannon.

Mr Cameron said: "Really, the idea behind this was could they get another 40mm weapon made very quickly when war is declared."

However, the Rolls-Royce version came with several issues.

He added: "One of the main problems with this weapon is when the round was being chambered, there was a terrible habit of the round actually exploding before it was fully into the chamber."

It was reassigned to Royal Navy vessels once that issue was resolved, and did not see operational service with the RAF.