| FH 70 howitzer | |
|---|---|
Towed FH-70 of Japan Ground Self-Defense Force |
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| Type | Close support gun |
| Place of origin | UK, Germany, Italy |
| Service history | |
| In service | 1978–present |
| Used by | see text |
| Production history | |
| Manufacturer | Vickers Ltd, Rheinmetall, OTO Melara |
| Specifications | |
| Weight | 7,800 - 9,600 kg (17,196 - 21,164 lbs) |
| Length | Travel: 9.8 m (32 ft 2 in) |
| Barrel length | 6 m (19 ft 8 in) L/39 |
| Width | Travel: 2.2 m (7 ft 3 in) |
| Height | Travel: 2.5 m (8 ft 2 in) |
| Crew | 8 |
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| Caliber | 155 mm (6.10 in) |
| Carriage | Split trail, sole plate, auxiliary power unit and hydraulics |
| Elevation | -5° to +70° or -100 to +1,250 mils |
| Traverse | 56°or 500 mils left and right |
| Rate of fire | Burst: 3 rounds in 15 seconds Sustained: 3-6 rpm |
| Muzzle velocity | 827 m/s (2,713 ft/s) |
| Effective range | 24 - 30 km (15 - 18 mi) depending on ammo[1] |
The FH-70 (Field Howitzer for the 1970s) is a towed howitzer in use with several nations.
Contents |
In 1963 NATO agreed a NATO Basic Military Requirement 39 for close support artillery, either towed or tracked. Subsequently Germany and UK started discussions and design studies and in 1968 established Agreed Operational Characteristics for a towed 155 mm close support gun. Italy became a party to the agreement in 1970.
Key requirements were a detachable Auxiliary Power Unit (APU), an unassisted range of 24 km, 30 km assisted, a burst capability of 3 rounds in 15–20 seconds, 6 rounds per minute for a short period and 2 rounds per minute sustained. The gun was to fire all 155 mm munitions in NATO service and have a new range of ammunition.
The two national authorities had overall responsibility for R & D, and Vickers Ltd was the co-ordinating design authority. They were also the design authority for the carriage and Rheinmetall GmbH was the authority for the elevating mass, including the sights, and for the APU. There was a further breakdown at a more detailed level and production worksharing. The UK Royal Armament Research and Development Establishment (RARDE) was responsible for designing the HE projectile and the charge system. Germany was responsible for Smoke, Illuminating, Minelet and extended range HE, although development of the last two was not completed in the program.
The intention was for FH70 to replace M114 and equip general support battalions in German divisional artillery regiments and to equip three (two Territorial Army (TA)) British general support medium regiments replacing the 5.5 inch gun. In the event it actually equipped UK regular regiments in direct support of infantry brigades until after the end of the Cold War, and only replaced the L118 Light Gun in two TA regiments, 100th (Yeomanry) Regiment Royal Artillery and 101st (Northumbrian) Regiment Royal Artillery (Volunteers) from 1992 to 1999.
FH 70 had several interesting features including:
The barrel was 39 calibres long giving 827 m/s standard maximum MV. It had a muzzle brake giving 32% efficiency.
Other conventional features included a split trail and turntable sole plate. Initially it had assisted loading but became an early user of flick-ramming. In accordance with long-standing UK practice it used one-man laying. All this meant the gun could be operated by a minimum detachment of only 4 men (commander, layer and 2 loaders). The burst fire rate was 3 rounds in 15 seconds. It was also fitted with a direct fire telescope.
There were a number of design flaws that became apparent in service. The equipment entered full operational service in the UK in 1980, and it became clear that there were significant difficulties with the tube feed system in anything but ideal conditions. 1st Regiment RHA, a unit who had conducted the Troop trials, evolved their own procedures to cure the problems, which related to dust contamination, and this process became established in official manuals in due course. More significantly, the trails of the gun proved to be weak at the point where maximum stresses incurred when the equipment was towed. and this resulted in modification work on the UK guns in 1987. There were continual problems with the drive train on the flat-4 VW APU, and the hydraulic system was always vulnerable to the obvious problems posed by external, non-armoured hosing, in combat conditions. In addition, the complex dial sight carrier was vulnerable to damage.
By the mid-1990s, the gun, in the UK, was being superseded by events, and more modern equipments. The writer of this section, who worked the equipment for a number of years, considers the gun to have been a design compromise - properly fought, with an experienced detachment, and with ready repair facilities to hand, the equipment was calpable of high-speed rates of fire, surprising degrees of mobility in deployment - including being air-portable under a CH-47 Chinook - and could be brought into action and worked with as few as a single crewman. Against that, it was quite clear that the gun suffered from the interface between the different nations and manufacturers involved in production. One could conclude that the equipment was a useful demonstration of the final throes of towed medium artillery.
The new projectiles conformed to the Quadrilateral Ballistics Agreement between US, UK, Germany and Italy. In essence this meant a shell with the same shape and dimensions as the US M549 rocket-assisted projectile. The standard HE shell (UK designation L15) is a thin wall design weighing 43.5 kg and containing 11.3 kg of HE. This remains the largest HE load for a standard 155mm shell.
The propellant system comprises 3 different bagged cartridges with triple-base propellant. Cartridge 1 gives charges 1 & 2, Cartridge 2 give charges 3 - 7 and Cartridge 3 is charge 8, which gives a maximum range under standard conditions of 24.7 km.
Each nation developed its own fuses and ammunition packaging. In UK's case this led to the Unit Load Container carrying 17 complete rounds, including shells with fuzes fitted - a novelty for 155 mm.
Standard US pattern 155mm ammunition can also be fired, although US primers proved problematic for the primer magazine and feed due to their variation in size.
RB Pengelley FH 70 - Europe's first multi-national artillery program International Defense Review Vol 6, No 2 April 1973