ADEN cannon


The Royal Small Arms Factory ADEN cannon is a 30 mm revolver cannon used on many military aircraft, particularly those of the British Royal Air Force and Fleet Air Arm. Developed post-World War II primarily to meet British Air Ministry's requirement for increased lethality in aircraft armament, the cannon is fired electrically, and is fully automatic once loaded.

Design and development

During World War II, the German firm Mauser began development of a radically new 20 mm autocannon using a motorised firing mechanism in order to improve the rate of fire. The weapon was designed for 20mm mine shell rounds.
However, production of the MK 213 never commenced due to development problems such as excessive barrel wear, not to mention the Allied Combined Bomber Offensive campaign against German industry. At the end of the war only 5 prototypes of either 20 mm MG 213 or 30 mm MK 213 were finished.
In the post-war era, the MK 213 became well known in armament circles, and a number of companies took up development. This included the Armament Development Establishment in the UK and GIAT in France. A common 30×111mm round was developed that offered a dramatic improvement in muzzle velocity from the MK 108's 500 m/s to the new design's. This was only slightly lower than contemporary 20 mm cannon like the Hispano Mk. V's, making the new round suitable for use during dogfights as well as against larger targets. The mechanism improved the rate of fire from the Mk. V's 750 rpm to 1,300 rpm, a significant improvement. The new weapon was quickly developed and production was set up at the Royal Small Arms Factory in Enfield. The name ADEN was created by combining the two first initials of Armament Development Establishment with the first two letters of Enfield, producing ADEN.
The ADEN cannon entered service on the British Hawker Hunter in 1954, and was subsequently used on every British gun-armed aircraft until the advent of the Panavia Tornado in the 1980s. The last version to see production was the Mk. 4. An improved version, the Mk. 5, incorporates a multitude of small changes to improve reliability and increase rate of fire to 1,500–1,700 rounds per minute. No new Mk 5s were built, but many older weapons were converted, being redesignated "Mk 5 Straden".
GIAT also introduced their version of the design as the DEFA cannon; the two weapons are very similar.

ADEN 25

The ADEN Mk 5 became the basis for the planned ADEN 25, which was to be a somewhat larger weapon at long and weighing firing the new range of 25×137mm NATO STANAG 4173 ammunition at a much higher muzzle velocity of. The lighter ammunition was also to produce a higher rate of fire, 1,650 to 1,850 rounds per minute.
The ADEN 25 was selected for British Harrier GR.5 aircraft. After initial weight problems and persistent difficulties in integrating the cannon with the pod, and the pod with the aircraft, the MoD considered the cost of fixing the problems excessive, and the project was cancelled in 1999. The Harrier GR.7 was cleared for emergency use of the ADEN 25, no attempt apparently having been made to retrofit the older ADEN 30 mm pods. Fleet Air Arm Sea Harriers retained the 30 mm weapon until their retirement in 2006.

Aircraft use

Built-in armament

The ADEN gun has seen use in several gun pods including:
The Aden is belt-fed using a disintegrating belt of open-type links.
  • Type: Single-barrel aircraft autocannon
  • Action: Revolver drum with 5 chambers
  • Operation: Gas operation
  • Cocking-system: Pneumatic
  • Priming: Electronic firing
  • Firing-system: Electrical 26 volts DC
  • Rifling: Progressive RH parabolic twist, 16 grooves
  • Cartridge: 30 × 113 mm
  • Calibre:
  • Weight of complete weapon:, with 200 rounds
  • Length of complete weapon:
  • Weight of barrel:
  • Length of barrel:
  • Recoil load: 31.4 kN
  • Rate of fire: 1,200–1,500 rpm, 1,500–1,700 rpm

    Ammunition

Ammunition for the ADEN included.
;High Explosive
  • Projectile type: "High-Explosive, High-Capacity"
  • Fuze type: Nose fuze
  • Explosive filling: Torpex 5
  • Cartridge weight:
  • Projectile weight:
  • Propellant weight:
  • CU-pressure: 2930 bar
  • Muzzle velocity:
;Armour-piercing
  • Projectile type: Armour-Piercing, Composite Rigid
  • Fuze type: None
  • Core type: Tungsten penetrator
  • Cartridge weight:
  • Projectile weight:
  • Core weight:
  • Propellant weight:
  • CU-pressure: 2930 bar
  • Muzzle velocity:
;Target practice
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