# ADEN cannon

The Royal Small Arms Factory ADEN cannon (ADEN being an acronym for "Armament Development, Enfield") 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 was fired electrically and is fully automatic once it is 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 (designated the Mauser MG 213 and for 30mm rounds (the Mauser MK 213). 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 (V1 to V5) 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 790 m/s (2,600 ft/s). This was only slightly lower than contemporary 20 mm cannon like the Hispano Mk. V's 840 m/s (2,800 ft/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 90 in (2.3 m) long and weighing 203 pounds (92.1 kg) firing the new range of 25x137mm NATO STANAG 4173 ammunition (as developed for M242 Bushmaster) at a much higher muzzle velocity of 3,445 feet per second (1,050 m/s). 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 issues and persistent problems integrating the cannon with the pod, and the pod with the Harrier GR.5 aircraft, the MoD considered the cost of fixing the problems excessive, and the project was cancelled in 1999. 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 BAE Sea Harriers retained the 30 mm weapon until their retirement in 2006.

## Aircraft use
### Built-in armament

* CAC Sabre
* English Electric Lightning
* Folland Gnat
* Gloster Javelin
* HAL Ajeet
* HAL Marut
* Hawker Hunter
* Saab Draken
* Saab Lansen
* SEPECAT Jaguar
* ST Aerospace A-4S Skyhawk
* Supermarine Scimitar
* Supermarine Swift

### As external armament

The ADEN gun has seen use in several gun pods including:
* British Hawker Siddeley Harrier and BAe Sea Harrier, as well as the US Marine Corps AV-8A/Cs, carried two 30 mm ADEN gun pods below the fuselage of the aircraft.
* The FFV 30 mm [sv] and Matra SA-10 gunpods produced for Swedish Air Force by collaboration with FFV and S. A. Engins Matra used on Saab AJ 37 and Saab Sk 60B/C attack aircraft during the early 1970s used guns taken from scrapped Swedish Saab J 32Bs and Hawker Hunter J 34s. The FFV pod has also been sold to the Austrian Air Force for use on their Saab 105Ös.
* A centreline gun pod containing ADEN gun and 100 rounds on the BAE Systems Hawk in RAF service. It is still in active service with, among others, the South African Air Force.

## Specifications

The Aden is belt feed 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 × 111 mm
* Calibre: 30 mm (1.18 in)
* Weight of complete weapon: 87.1 kg (192 lb), 196 kg (432 lb) with 200 rounds
* Length of complete weapon: 1,590–1,639 mm (5 ft 2.6 in – 5 ft 4.5 in)
* Weight of barrel: 12.25 kg (27.0 lb)
* Length of barrel: 1,080 mm (3 ft 6.5 in)
* Recoil load: 31.4 kN
* Rate of fire: 1,200–1,500 rpm (ADEN Mk. 4), 1,500–1,700 rpm (ADEN Mk.5)

### Ammunition

Ammunition for the ADEN included.

#### High Explosive (High Explosive Mk.3Z)

* Projectile type: "High-Explosive, High-Capacity"
* Fuze type: Nose fuze
* Explosive filling: 52.5 g (1.85 oz) Torpex 5 (Hexotonal)
* Cartridge weight: 440 g (15.5 oz)
* Projectile weight: 220 g (7.76 oz)
* Propellant weight: 46 g (1.62 oz)
* CU-pressure: 2930 bar
* Muzzle velocity: 795 m/s (2,610 ft/s)

#### Armour-piercing (30 mm pprj m/55 Sweden)

* Projectile type: Armour-Piercing, Composite Rigid
* Fuze type: None
* Core type: Tungsten penetrator
* Cartridge weight: 511 g (18.0 oz)
* Projectile weight: 270 g (9.52 oz)
* Core weight: 150 g (5.29 oz)
* Propellant weight: 47 g (1.66 oz)
* CU-pressure: 2930 bar
* Muzzle velocity: 795 m/s (2,610 ft/s)

#### Target practice (Practice Mk.2Z, UK )

* Projectile type: Inert solid metal plug in place of fuze and explosive charge
* Cartridge weight: 440 g (15.5 oz)
* Projectile weight: 220 g (7.76 oz)
* Core weight: 80.5 g (2.84 oz)
* Propellant weight: 46 g (1.62 oz)
* CU-pressure: 2930 bar
* Muzzle velocity: 795 m/s (2,610 ft/s)

## Users
### Australia

* Royal Australian Air Force

### Bahrain

* Royal Bahraini Air Force

### Belgium

* Belgian Air Component

### Chile

* Chilean Air Force

### Denmark

* Danish Air Force

### Finland

* Finnish Air Force

### Iraq

* Iraqi Air Force

### India

* Indian Air Force
* Indian Naval Air Arm

### Indonesia

* Indonesian Air Force (TNI-AU)

### Jordan

* Royal Jordanian Air Force

### Kenya

* Kenyan Air Force

### Kuwait

* Kuwait Air Force

### Lebanon

* Lebanese Air Force

### Netherlands

* Royal Netherlands Air Force

### Malaysia

* Royal Malaysian Air Force

### Oman

* Royal Air Force of Oman

### Peru

* Peruvian Air Force

### Qatar

* Qatar Emiri Air Force

### Rhodesia (now Zimbabwe)

* Royal Rhodesian Air Force (later to Air Force of Zimbabwe)

### Saudi Arabia

* Royal Saudi Air Force

### Singapore

* Republic of Singapore Air Force

### South Africa

* South African Air Force

### Republic of Korea

* Republic of Korea Air Force

### Somalia

* Somali Air Corps

### Spain

* Spanish Naval Air Arm

### Sweden

* Swedish Air Force – designated 30 mm akan m/55

### Switzerland

* Swiss Air Force

### Thailand

* Royal Thai Navy Flying Unit

### United Arab Emirates

* United Arab Emirates Air Force

### United Kingdom

* Fleet Air Arm
* Royal Air Force