35 mm/90 KDC (Gun)
GDM-A and GDM-C (Mountings)
The KD gun series were originally developed for army air defense and is considered one of the most successful post-World War II anti-aircraft defense weapons. Oerlikon and OTO-Melara have both produced naval versions.
Each gun has a device for measuring muzzle velocity and this data is fed back to the gun-laying computer. Each gun has two belt feeds and can be switched between belts in about two seconds. Muzzle velocity is electronically measured and fed back into the fire control computer.
Ammunition for these weapons is produced by at least fourteen countries, including the PRC.
|Designation||Gun: Oerlikon 35 mm/90 KDC|
|Ship Class Used On||Iran: Mark 7 frigate
Greece: Missile Boats
Japan: Patrol Boats
|Date Of Design||about 1965|
|Date In Service||1972|
|Gun Length oa||186.6 in (4.740 m)|
|Bore Length||Including muzzle break: 146.1 in (3.710 m)
Without muzzle break: 138.2 in (3.510 m)
|Rate Of Fire||550 rounds per minute per gun cyclic|
Weapons are completely interchangeable and can be assembled for left or right feed.
|Weight of Complete Round||HE-I: 3.48 lbs. (1.58 kg)
SAPHEI-T: 3.48 lbs. (1.58 kg)
APFSDS-T: 3.20 lbs. (1.45 kg)
FAPDS: 3.17 lbs. (1.44 kg)
AHEAD: 3.90 lbs. (1.77 kg)
|Projectile Types and Weights||HE-I: 1.21 lbs. (0.550 kg)
SAPHEI-T: 1.21 lbs. (0.550 kg)
APFSDS-T: 0.86 lbs. (0.388 kg)
FAPDS: 0.83 lbs. (0.375 kg)
AHEAD: 1.65 lbs. (0.750 kg)
|Bursting Charge||HE-I: 0.24 lbs. (112 gm)
SAPHEI-T: 0.05 lbs. (22 gm)
APFSDS-T: N/A (solid sub-caliber penetrator)
FAPDS: N/A (solid sub-caliber penetrator)
AHEAD: N/A (uses 152 3.3 gm sub-projectiles)
|Propellant Charge||0.73 lbs. (0.33 kg) NC 01 T 35 (single based)|
|Cartridge||35 mm x 288|
|Muzzle Velocity||HE-I: 3,850 fps (1,175 mps)
SAPHEI-T: 3,850 fps (1,175 mps)
APDS-T: 4,724 fps (1,440 mps)
FAPDS: 4,724 fps (1,440 mps)
|Working Pressure||24.6 tons / in2 (3,875 kg / cm2)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||1 2|
|Surface||8,700 yards (8,000 m)|
|AA||5,500 yards (5,000 m)|
Optical control or local control greatly reduces these figures.
|0.96 seconds||1,090 yards (1,000 m)|
|2.18 seconds||2,190 yards (2,000 m)|
|3.80 seconds||3,280 yards (3,000 m)|
|6.06 seconds||4,370 yards (4,000 m)|
|0.73 seconds||1,090 yards (1,000 m)|
|1.57 seconds||2,190 yards (2,000 m)|
|2.38 seconds||3,280 yards (3,000 m)|
|3.34 seconds||4,370 yards (4,000 m)|
|Designation||Single Mount: N/A 1a
Twin Mount: GDM-A 2a, GDM-C 3a 4a
|Weight||GDM-A: 10,500 lbs. (4,763 kg) without ammunition
GDM-C: 17,637 lbs. (8,000 kg) including ammunition
|Elevation||GDM-A: -15 / +85 degrees
GDM-C: -15 / +85 degrees
- ^The single gun version used by the Japanese was manually controlled and had a sidecar for the gunner.
- ^The GDM-A is the original Oerlikon design.
- ^The GDM-C version was developed as a joint project between Oerlikon and OTO-Melara. Requires two loaders plus a gunlayer if not in remote control mode. A US Navy Foreign Ordnance Review Team concluded about 1971 that this version was better suited to US requirements, but none were purchased.
- ^The GDM-C mount is gyrostabilized and requires a power source of 43 KW.
- "Jane's Pocket Book 9: Naval Armament" edited by Denis Archer
- "The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman
- "Jane's Ammunition Handbook: Ninth Edition 2000-2001" edited by Terry J. Gander and Charles Q. Cutshaw
- "Defense & Armament Heracles International" Issue #72, April 1988
Special help by Matthew Rodchenko