FV433 Abbot SPG

FV433 Field Artillery, Self-Propelled "Abbot"  is the self-propelled artillery variant of the British Army FV430 series of armoured fighting vehicles, using much of the chassis of the FV430 but with a fully rotating turret at the rear housing the 105 mm gun and given the vehicle designation of FV433.

Its correct designation was "Gun Equipment 105mm L109 (Abbot)"; L109 was little used, probably to avoid confusion with 155 mm M109 that entered UK service at about the same time. The name "Abbot" continued the World War 2 style of naming self-propelled artillery after ecclesiastical titles. The FV433 used a different configuration of power pack to other vehicles in the FV430 series.

Ammunition
A completely new ammunition family, comprising shells, fuzes and cartridges, was designed for Abbot, designated 105 mm Field (105 mm Fd), was designed for Abbot's L13 ordnance. It uses electrical instead of percussion primers, and compared to US 105 mm M1 type ammunition has longer shells. The widely used US M1 type round was called "105 mm How" in UK service. The 105 mm Fd came in two marks, both separate loading (shell and cartridge loaded separately). The 105 mm Fd Mk 1 was used initially, it had a UK-produced 105 mm How shell, mostly US pattern fuzes and reduced charge 105 mm Fd cartridges with their electrical primers (105 mm M1 uses percussion primers).

The Mark 2 adopted a new projectile design including an improved lethality HE shell (heavier with more HE) and full charge cartridges. Its shell types include HE, Smoke, Coloured Marker (Red and Orange), Illuminating, and HESH for direct fire against enemy armoured vehicles. Direct Action, Controlled Variable Time (CVT) and Mechanical Time (MT) fuzes were available for HE and Coloured Marker shells.

Initially there were three cartridges. Sub-zones 1 and 2 were only used to provide short range in high angle fire, and were soon replaced by a plastic spoiler slipped over the shell ogive. Normal cartridge gave charges 1–5, each bag being a different colour in accordance with established UK practice, Mk 1 normal cartridge only went to charge 4. Both marks had charge Super, a single charge cartridge, although the charge was reduced in Mk 1. Charges 5 and Super used extended "bags" that projected beyond the metal cartridge case. The 105 mm Fd uses double (often internationally called triple) base propellants designated N in UK service instead of the single based FNH propellants favoured by the US. The 105 mm Fd Mk 2 is still used with L118 Light Gun.

Gun
Maximum range with 105 mm Fd Mk 1 ammunition was 15 km, the Mk 2 gave 17.4 km. Maximum rate of fire was 6–8 rounds per minute.

The gun was able to elevate to 70 degrees and depress to -5 degrees, sufficient to engage enemy AFVs if necessary. Traverse and shell ramming were powered by electrical servo mechanisms, elevation and cartridge ramming were by hand.

Due to the number of charges and its compact turret the Abbot did not have calibrating sights. Instead the sight mount had both Tangent Elevation (TE) and Angle of Sight Scales and a separate Gun Rule to convert range into TE, corrected for the muzzle velocity variation from standard. The dial sight had all scales internal, illuminated and viewed through a single eyepiece.

Communications
The Abbot was fitted with both line and radio (Larkspur B48, then Clansman UK/PRC 352) communications to its battery command post, which used the Apparatus Loud Speaking No. 23, this enabled the gun No. 1 to acknowledge his fire orders merely by clicking his pressel switch. Initially it also used induction loop communications for the turret and external crew.

Shortly after the Field Artillery Computer Equipment (FACE) entered service in the early 1970s the Gun Rule was removed and Artillery Weapon Data Transmission System (AWDATS) installed. AWDATS displayed firing data transmitted from FACE in the battery command post via either line or radio.

Mobility
The Abbot was able to swim across water, having a flotation screen fixed around the hull which was raised to provide buoyancy. The action of the tracks was sufficient to drive it forward at about 3 knots (see also DD Tank). Each Abbot was supported by a fully amphibious Stalwart Mk 2 High Mobility Load Carrier that carried additional ammunition.

Service history
The Abbot was replaced by the AS-90 self propelled gun in the mid 1990s. It is still in service with the Indian Army though they are looking for a replacement.

Ammunition

 * 105mm Field Mark 1


 * L32 Cartridge 105mm Field, Normal (Charges 1–4)
 * L34 Cartridge 105mm Field, (Charge Super)
 * L33 Shell 105mm Howitzer, HE
 * L32 Shell 105mm Howitzer, WP
 * L51 Shell 105mm Howitzer, Smoke
 * L55 Shell 105mm Howitzer, Illuminating
 * L43 Shell 105mm Howitzer, HESH
 * L44 Shell 105mm Howitzer, Practice


 * 105mm Field Mark 2


 * L35 Cartridge 105mm Field, Normal (Charges 1–5)
 * L36 Cartridge 105mm Field, Super
 * L31 Shell 105mm Field, HE
 * L36 Shell 105mm Field, Smoke
 * L37 Shell 105mm Field, Marker, Red
 * L38 Shell 105mm Field, Marker, Orange
 * L34 Shell 105mm Field, Illuminating
 * L42 Shell 105mm Field, HESH
 * L41 Shell 105mm Field, Practice

Variants
A simplified Value Engineered Abbot without flotation screen, NBC defence equipment, power traverse, elevation or loading, a simplified dial sight and communications fit was exported to India for use in their armoured divisions. A small number were purchased by UK for use at the British Army Training Unit Suffield (BATUS) in Alberta, Canada.

Use

 * British Army Royal Artillery regiments (1965–95)
 * Since decommissioning from British Army service, Abbots have become popular for "tank-driving" adventures, proving much more economical to buy and run than the genuine article.
 * Still in service in the Indian Army Regiment of Artillery. They currently operate around 80 guns.
 * The comedian Ross Noble revealed on the 3 July 2011 edition of BBC motoring show Top Gear that he owns and operates an FV433. He also provided the interesting fact that the vehicle is exempt from the London congestion charge.
 * The vehicle is used in the TV series Gary: Tank Commander from BBC Scotland as the "Tank".
 * The vehicle was also used in the final episode of British TV series, Spaced.