[Mike Cecil]

Nice crates.

According to a former user from the RAAC, the safest place to be when an ENTAC was fired was on the target.

I wrote an article about ENTAC about 20 years ago which may be of interest. It was first published in the Australian Army's monthly magazine 'Army'. Canada even gets a mention.

ENTAC IN AUSTRALIAN SERVICE

The Australia Army Buys its first ATGW

By Mike Cecil


Although the pioneering research and development undertaken by the Australian Department of Supply during the 1950s placed Australia amongst the world leaders in anti-tank guided weapons, the only sales were to Britain in the form of the heavy anti-tank missile, “Malkara”. (see Army Magazine issue ‘31) Other, smaller ATGW, suitable for infantry use, had been under consideration and some development work had been done on a small missile called “Toolondo”, but the advantage was never exploited, and the project was eventually shelved. The Australian Army had not shown much enthusiasm during the development phases for either large or small ATGW, preferring to simply keep an eye on developments.

By the early 1960s, however, the Army recognised an urgent need for an ATGW capability for both infantry and armoured corps, and subsequently released War Equipment Policy Statements (WEPS) Numbers 1 and 9 which detailed the requirements for each application. Malkara had already been rejected because such a large missile would not be suitable in South East Asia, which was considered to be the most likely operational environment. The Army therefore looked to overseas sources, and during 1961, initiated a study of available information on ATGWs which might prove to be suitable. There were several contenders, either in production or completing development trials, and most with rather colourful names. These were the AB Bofors “Bantam” from Sweden, “Mosquito” built by Contraves-Italiana SpA, the Italian subsidiary of the Swiss company Oerlikon-Contraves AG, the Messerschmitt-Bolkow-Blohm GmbH “Cobra” from Germany, Vickers-Armstrong’s (later British Aerospace) “Vigilant” from the United Kingdom, and Nord Aviation’s “ENTAC T581” and “SS-11” ATGW systems from France.

Vickers-Armstrong were quick to react to enquiries, arranging a demonstration firing in Australia of their “Vigilant” ATGW. This took place under adverse weather conditions at the Green Hills Range, Holsworthy, on 24 August 1961, when fourteen missiles were fired against stationary targets at various distances. Although additional information was collected about Vigilant during the ensuing months, the poor performance of the missile on this occasion - it scored only eight hits from the fourteen fired - appears to have cast a shadow during future considerations.

The evaluation on paper, together with several first hand reports by Australian Military personnel who attended demonstration firings of the likely contenders, quickly narrowed the field, and by April 1962, “Cobra” and “Bantam” had been deleted, to be soon followed in June by “Vigilant” and “Mosquito”. This left only Nord Aviation’s two systems, the ENTAC T581 and the SS-11.

Given the perceived operational urgency of equipping infantry and armoured units, a recommendation was made to procure the ENTAC system for operational use by the infantry and for training by armoured units, while the SS-11 system should be procured for operational use by armoured units, provided both systems satisfactorily completed a series of environmental tests.

This recommendation was partially accepted by the War Equipment Policy Committee: a quantity of about 150 ENTAC T581 missiles would be purchased for user and evaluation trials, but the SS-11 procurement was rejected on the basis that in view of the likely threat, the 106 mm recoilless rifle M40A1 would be adequate for countering enemy armour at longer ranges.

With the likely operational environment being South East Asia, there was particular interest in performance data under tropical and rough handling conditions. Various methods of obtaining this information were considered, but the most cost effective method was to have the manufacturer conduct the series of environmental trials in France, to Australian standards and under Australian supervision. These included drop and bump tests, vibration tests, hot-dry and solar radiation tests, and simulated tropical exposure tests, and were carried out over several months during 1963.

With the testing or adoption of both the ENTAC T581 and SS-11 by several countries, more extensive trials and testing reports progressively became available. While some of the conclusions may be seen as more nationalistic than objective (the Italian Army tests, for example, favoured their locally built “Mosquito” ATGW) they provided considerable firing and penetration data. Moreover, the US Army had introduced ENTAC into service during 1961, to be followed shortly after by Canada. As co-signatories of the ABCA agreement, their user information was also available, together with development work being carried out on various vehicle mountings.

This wealth of information, combined with local financial considerations, resulted in the decision in June 1963, to introduce ENTAC T581 into service use with the Australian Army without waiting for the final results from local trials or the environmental testing.

The ENTAC T581 ATGW derived its name from the contraction of the French description Engin Teleguide Anti-Char, and consisted of a shaped charge warhead containing 1.9 kg (4.2 pounds) of High Explosive mounted by a bayonet-type connection to a gyroscopically stabilized, four winged missile with a solid propellant motor. The firing impulse detonated a small charge in the head of an electrolyte container housed in the launcher, which forced the electrolyte into the battery in the missile. This then energised and fired the missile motor, the whole sequence taking about 1 second. As the missile left the launcher, the gyroscope was run up by a cord attached to the launcher box, and once the missile was clear, the missile rotated 45 degrees until the wings were oriented vertical and horizontal.

The missile was guided in flight by the operator, who would view the target through an optical sight while using a joystick controller to issue guidance commands to the spoilers on the trailing edges of the missile’s wings. These commands were transmitted to the missile as electrical pulses along two wires, spooled out from the body of the missile during flight.

A local trials and evaluation team was assembled from infantry and armoured Corps personnel in mid-1964. Based at the Armoured Centre, Puckapunyal, the team fired over ninety one missiles from ground mounts between 6 July and 21 August 1964. Further engineering evaluation firings were also undertaken at Woomera.

In the meantime, ADE were tasked with developing various vehicle mounts for ENTAC, including short wheel base Land Rover and M274 Mechanical Mule mounts for Infantry use, and a mounting for the Ferret Scout Car Mk.2 for use by armoured corps units. Much information on vehicle mounts was obtained from overseas, including those developed in Canada for the Ferret Mk.1, in the USA for the M151 MUTT and M113 APC, and in France for the Hotchkiss Jeep.

The M274 Mechanical Mule version was primarily abandoned when initial calculations showed the total weight of the system, including crew and stores, to be far in excess of the M274’s carrying capacity. The short wheel base Land Rover version for infantry use was also abandoned following an Army re-organization. However, since a French Hotchkiss Jeep ENTAC mounting had already been purchased, it was decided to use the mount in a single prototype long wheel base Land Rover. The vehicle was to be used for training at the Armoured Centre.

A mock-up mounting for the Ferret Scout car was completed by ADE before the end of 1964, and a trials version mounting a missile launcher on each side of the turret, together with spare missiles in transit cases fixed to the rear mudguards, was completed in 1965. ENTAC was also fired from an M113A1 during the late 1960s, as an unofficial trial by the Armoured Centre’s Regimental Technical Adjutant.

Although in use in Australia from 1964, the ENTAC T581 was not officially taken into service until 5 December 1967. It remained in service until superseded by the MILAN ATGW in 1982, and was eventually declared obsolete on 7 February 1985. The user opinions of ENTAC are varied, but were summed up recently by an experienced armoured corps Warrant Officer when he stated that “... the safest place with ENTAC was standing on the target!”





Technical Data

ENTAC T581

Manufacturer: Nord Aviation,
Chatillon-Sous-Bagneux, Hauts-de-Seine, France.
Variants in Aust Service: (1) Guided Missile, Anti-Tank;
(2) Guided Missile, Anti-Tank with Inert Head (Practice Missile);
(3) Sectioned Instructional Missile.
Warhead Type: High Explosive, shaped charge of 150/50 RDX TNT
Warhead Diameter: 130 mm
Explosive Weight: 1.9 kg (4.2 pounds)
Warhead Total Weight: 3.95 kg (8.7 pounds)
Warhead Fuze: Electric nose inertia fuze with base exploder
Minimum Arming Distance: 250 metres (when arming plug connects nose to exploder)
Missile Type: Gyroscopically stabilized, wire guided, solid propellant motor
Weight: 12.24 kg (27 pounds)
Length: 800 mm (31.5 inches)
Diameter: 150 mm (5.9 inches)
Wingspan: 376 mm (14.8 inches)
Range: 400 metres minimum to 2000 metres maximum
Velocity: 85.34 metres per second (280 feet per second)
Time of Flight: 24 seconds to 2000 metres
Penetration: 650 mm of 30 ton per square inch steel armour
(60 mm entry hole and 30 mm exit hole)
Maximum Impact Angle: 15 degrees
Operator Separation: Up to 110 metres from launcher
Mountings: Ground or vehicle