The Aden Gun
Aden 30mm Gun
The Aden gun was developed to meet the need for greater firepower that became neccessary for aerial combat in the jet age, primarily due to the decreased time interval during which the gun could be brought to bear on a target. The high speed of jet fighters called for the destruction of the target at the first encounter. This required that a lethal blow be delivered in the very limited time available.
The Aden is an electrically-fired and controlled 30mm revolver cannon with a rate of fire of 1200/1400 rounds per minute. The gun is fully automatic in all respects once it is loaded and the first round has been fired. The gun must be loaded before take-off, no provision being made for loading in flight.
The gun is designed for belt feed, a disintegrating belt of open type links being used. The links are differently shaped from those previously used for belt feeds, being joined together by hooks and eyes. The feed mechanism is a part of the gun and this enables its timing to be definately controlled. Provision is made for left-hand and right-hand feed, and change from one hand to the other can readily be done by repositioning certain parts and changing others.
The Aden gun has a chamberless barrel, behind which is mounted a rotatable cylinder. This cylinder has five chambers equally spaced around its axis and is known as the breech cylinder. When the firing sequence is started, by pressing the firing button, this cylinder presents successive rounds to the barrel and when each round is aligned with the bore it is automatically fired. The Aden gun is mechanically operated and the motions are continuous after the first round has been loaded and fired.
The functioning of the gun can be compared with the basic features of a pistol revolver, only on a more elaborate scale. The pistol is limited to the number of rounds it can fire without reloading, whereas the Aden gun is belt-fed and, hence, limited only by the length of the belt and not upon the capacity of the cylinder.
The motive power for the automatic functioning of the Aden gun is provided by gas pressure. A portion of the propellant gas is bypassed through a vent in the barrel into a gas cylinder where it impinges upon a piston. The piston is driven to the rear by gas pressure every time the gun fires and is the source of all subsequent movements in the functioning of the gun.
In the Hunter, the gun installation consists of four Aden guns (two left-hand feed, two right-hand feed) carried, together with their ammunition, in a removable pre-armed armament package housed in the underside of the front fuselage. The gun barrels, which are detachable from the guns to allow removal of the package, extend forward in blast tubes below the cabin floor to apertures in the nose of the fuselage. Empty cartridge cases are ejected into the airstream through chutes extending aft from the rear of the gun package, two on each side, to apertures in the gun and radio access panels, while the belt links pass down chutes extending from the guns to collector tanks fitted beneath the fuselage. Whenever the guns are fired, the gun package is ventilated by the opening of a small electrically-operated air scoop in the gun bay starboard access panel. The guns are cocked pneumatically before flight from a ground supply.
Photo: A Hunter gun package at Tangmere Museum. Note the winches in the background and the removeable spigot lying on top. These spigots are screwed into the fuselage and the winches hung off them.
The Hunter can be rapidly re-armed by removing the gun package and winching in a replacement, complete with guns and ammunition.
Photo: A No.1(F) Squadron RAF Hunter being re-armed. Note three Type C bomb winches used to lift gun package. (Credit: Flight)