Oerlikon 35 mm twin cannon
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35 mm Oerlikon GDF-003
35 mm Oerlikon twin cannon
Type	Autocannon
Place of origin	Switzerland
Service history
Used by	Switzerland and others
Specifications
Weight	6,700 kg (with ammunition)
Length	7.8 (travelling)
Barrel length	3.15 (barrel)
Shell	35mm × 228
Caliber	35 mm
Carriage	4 wheels with outriggers
Elevation	+92° to -5°
Traverse	360°
Rate of fire	550 rounds/min (per barrel)
Muzzle velocity	1,175 m/s (HEI-T)
Effective range	4 km (vertical)

The Oerlikon 35 mm twin cannon is a towed anti-aircraft gun made by Oerlikon-Contraves. The system was originally designated as 2 ZLA/353 ML but this was later changed to GDF-001. It was developed in the late 1950s and is used by around 30 countries.

Design & development

The system uses 35 mm autocannons, which were originally designated 353 MK and are now designated as the KD series. The same KD series 35 mm cannons are used in the Leopard tank based Gepard and T-55 based Marksman self-propelled anti-aircraft guns. The system could be paired with the off-gun Super Fledermaus fire control radar, which in the late 1970s was upgraded to the Skyguard system.

In 1980 an upgraded model, the GDF-002 was produced, which featured an improved sight, and the ability to be directed by an off-gun digital control system. A few years later a third version of the system was being produced, the GDF-003, which was broadly similar to the GDF-002, but included some enhancements like self-lubricating weapons and integrated protective covers.

In 1985 a further upgraded model was produced, the GDF-005, which was introduced, featuring the Gunking 3D computer-controlled sight with an integrated laser range-finder and digital control system.

The guns are usually transported by a 5-tonne 6×6 truck.

Deployments

KD series cannons

An Austrian GDF-005 (FIAK85) gun system. Note the muzzle velocity measuring devices on the muzzle of both guns.

Development of the KD series cannon began around 1952, Oerlikon calculated that 35 mm was the optimum calibre for an anti-aircraft gun. The KD series cannons were a design adapted from the post-war 20 mm KAA 204 Gk cannon. Several designs were developed, including a water cooled design, designated Mk 352, which was tested by the U.S. Navy. The final design was the Mk 323, which was developed in two variants, a belt fed version the KDA, and a linkless version the KDC, fed by five round clips. Both designs are gas operated with a propped lock locking system. ¹

Super Fledermaus

A Gepard SPAAG of the German Army

The Super Fledermaus fire control system was designed and built by the then separate Contraves company. It consists of a towed trailer with an E/F band pulse doppler search radar with a range of around 15 km and a pulse doppler tracking radar operating in the J band, also with a range of 15 km. It was also used as the fire control system on the Gepard SPAAG.

Skyguard

An Oerlikon Contraves Skyguard Radar of the Austrian Air Force.

The Skyguard system is contained within a towed trailer, mounted on the roof of which is a pulse doppler search radar, a pulse doppler tracking radar and co-axial television. The trailer also houses the crew of two and a small petrol generator.

A typical battery using the Skyguard consists of two twin 35 mm gun platforms with a single Skyguard fire control radar.

History

• 1982 - The system was used by Argentine forces during the Falklands War. The Skyguard radar system was employed by the 601 Antiaircraft Artillery Group and the Super Fledermaus by the 1st Group of the Argentinian Air Force. The Skyguard succeeded in shooting down a Sea Harrier (XZ450) on 4 May 1982 at Goose Green. This resulted in a shift of tactics, so that British aircraft largely operated outside the weapons system's range. An RAF Harrier (XZ988) was shot down by the cannons again over Goose Green on 27 May.² The system was also employed in direct fire mode against British paratroopers during the Battle of Goose Green. The Skyguard radars were targeted by the RAF during Operation Black Buck on May 31 and June 3. One unit was destroyed as result. Another Harrier (XW919) was presumably hit by 35 mm splinters over Sapper Hill on June 12 and sustained heavy damage.^{3 4} The aircraft was later declared out of service. There was a further direct-fire mission conducted against British troops on Wireless Ridge, just hours before the Argentinian surrender.⁵. After being disabled by their operators the guns were captured by British forces. 15 guns and five Skyguard units were refurbished. 12 guns and 4 Skyguard radars were put into British service operated by the Royal Auxiliary Air Force based at RAF Waddington.⁶⁷

• 2007 - In South Africa, 9 defence force (SANDF) soldiers were killed and 14 injured by the system during a training exercise when the automated gun jammed, causing unspent rounds to detonate. Following the explosion, the gun began firing uncontrollably on the surrounding area.⁸

• January 2008 - The accident report by the SANDF blames "undetected mechanical failure - which the manufacturers of an anti-aircraft gun allegedly kept secret". The report says the gun malfunctioned because a spring pin, which is the size of a matchstick, sheared. Other sources blamed poor training and safety procedures in the SANDF.⁹

Ammunition

Designation:

• HEI — High Explosive Incendiary (-T — Tracer)
• SAPHEI — Semi-Armour Piercing High Explosive Incendiary
• FAPDS — Frangible Armour Piercing Discarding Sabot
• AHEAD — Anti-missile rounds, that fire "152 heavy tungsten metal sub-projectiles".
• TP — Target Practice (-T — Tracer)

Versions

A Japanese built version of the gun in travelling position.

Under tow, an Oerlikon 35mm twin cannon of the Republic of Singapore Air Force.

• GDF-001 / '2 ZLA/353 MK: XABA sight
• GDF-002: Introduced in 1980. Improved Ferranti sight and digital data bus. The gun has 112 rounds ready and 126 in reserve (238 rounds total)
• GDF-003: Minor enhancements including protective covers and automatic weapon lubrication.
• GDF-005: Introduced in 1985. Fitted with Gunking 3D computer controlled sight with a laser range finder and digital fire control system. Integrated power supply and diagnostics. 280 rounds on the gun and an automatic re-loading system.
• GDF-006: GDF-001/002/003 upgraded with AHEAD system.
• GDF-007: GDF-005 upgraded with AHEAD system.
• AHEAD: An upgrade for the GDF series guns built around a special projectile which explodes at a pre-calculated point in front of the target sending a shotgun-type blast of 152 tungsten sub-projectiles at the target. Used by Canada, Greece, Oman, Spain and Chile (unconfirmed).
• Gepard: Self propelled version of the system based around the Leopard tank.
• Marksman: Self propelled version of the system based around the Marksman turret, which could be fitted on numerous tank chassies. The only model that wen into production was a version based on the T-55 chassis for Finland, 10 systems in use.
• Type 87: Japanese SPAAG using the system.
• PZA Loara: Polish SPAAG based on the PT-91 tank
• Type 90: Chinese licensed copy of GDF-002

Operators

A swiss GDF-007 in shooting position

•  Argentina 50+ GDF-002 units
•  Austria 74 GDF-005 Army, Air Force 18 GDF-005
•  Bahrain Bahrain uses 12 GDF-005 units
•  Brazil 38 GDF-001 With Updated Super Fledermous FC radar
•  Cambodia
•  Canada 20 GDF-005 units, to be phased out. AHEAD modified.
•  Chile 24 GDF-005 units
•  China China uses licensed copy of GDF-002 as the Type 90, 100+ units with Skyguard FC radar¹⁰
•  Cyprus 30 GDF-005 units
•  Ecuador 30 GDF-003 units
•  Egypt 26 GDF-003 units used with Skyguard and Sparow SAM
•  Finland 16 units. known as 35 ITK 88
•  Germany On the Flugabwehrkanonenpanzer Gepard (self-propelled anti-aircraft gun)
•  Greece 44 GDF-002 units
•  Iran 92 GDF-002 units
•  Indonesia
•  Japan some 70 GDF-001 units, made under a joint venture with Japan Steel Works for the 35mm gun and Mitsubishi Electric Corporation for the rest of the system¹¹
•  South Korea 18+ GDF-003 units
•  Kuwait 12 GDF-005 units, used with Skyguard and Sparow SAM
•  Malaysia 28 GDF-003 units
•  Oman 10 GDF-005 units AHEAD modified
•  Pakistan estimated 200 GDF-002 units
•  Philippines Used by the Armed Forces of the Philippines
•  Romania 43 Flugabwehrkanonenpanzer Gepard systems and 72 GDF-007 units
•  Saudi Arabia 128 GDF-005 modified units
•  Singapore 34 GDF-002 units
•  South Africa some 100 GDF-002 + 48 modified GDF-005 units
•  Spain 92 GDF-005 units, being upgraded to 007 standard. Skydor and Skyguard FC radars ¹².
•  Switzerland 45 GDF-005 modified units (from Total of 264 GDF-001/002 units)
•  Taiwan
•  Turkey some 120 GDF-002 units
•  United Arab Emirates 30 GDF-005 units
•  United Kingdom Total of 15 GDF-002 35mm twin guns were captured during the Falklands War along with 6 Skyguard and 1 Super Fledermous FC Radars. One of the Skyguard radars was damaged from a Shrike missile strike during the conflict. Currently the fire control systems for these guns 4 x (Skyguard) are being used to catch UK military aircraft exceeding flight restrictions over residential areas¹³

See also

• List of artillery
• List of anti-aircraft artillery
• List of artillery of Germany
• List of artillery of Switzerland

Notes

Cited

General

• Weapons: Robot Cannon Goes Berserk, Kills 9

References

• Jane's Land-Based Air Defence 2005–2006, by James C O'Halloran, ISBN 0-7106-2697-5
• RAF Harrier Ground Attack-Falklands, by Jerry Pook, ISBN 9781844155514
• The Machine Gun, Volume V, George M. Chinn
• Rheinmetall page on 35 mm ammo
• La Artillería Argentina en Malvinas, by Horacio Rodríguez Mottino. (Spanish)
• (Russian) Skyguard-Sparrow
• Iran mass produces 35mm anti-aircraft gun, Press TV. January 15, 2008.