Term of the day

Road Wheels

The wheels bearing the weight of a land vehicle onto the ground or its own tracks.

Term of the day

Monocular, Biocular, and Binocular Sights

Monocular sight is an optical system with a single objective lens and a single eyepiece. Biocular sight is an optical system with one objective lens and two eyepieces, in which the same image is presented to each eye. Binocular sight is an optical system with an independent channel for both eyes. Each channel has its own objective lens and eyepiece, so that the images presented to the eyes are slightly different.

Term of the day

Top Roller (Track Support Roller, Track Return Roller)

It is a small wheel supporting the top run of the track.

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Rolled Homogeneous Armour (RHA)

In order to achieve the best possible strength, it is essential to have armour plate with the same hardness and structure throughout. The production of armour plate involves a rolling process to bring it to the correct thickness and to induce some desirable metallurgical properties. The expression 'rolled homogeneous armour' is used as a measure of the ability of a penetrator to defeat armour. Usually measured in millimetres, the rolled homogeneous armour can be used to assess one type of armour against another, i.e., spaced armour and monoblock (solid) armour.

Term of the day

Composite armour

Composite armour is a term used to describe armour which uses a number of different techniques to defeat the anti-armour threat, e.g., rolled homogenous armour, explosive reactive armour, spaced armour.

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Explosive Reactive Armour (ERA)

Is is a form of armour in which explosive is sandwiched between two thin armour plates. The force of the penetrator hitting the front armour plate causes the explosive to detonate, reducing penetration. ERA is more effective against high-explosive anti-tank projectiles.

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Cleft Turret

It is a type of turret where the gun is set between the two turret crewmen, one either side.

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Turbocharger

A turbocharger is an exhaust gas-driven compressor used to increase the power output of an internal-combustion engine by compressing air that is entering the engine thus increasing the amount of available oxygen. A key advantage of turbochargers is that they offer a considerable increase in engine power with only a slight increase in weight.

Term of the day

Oscillating Turret

The oscillating turret is a two-piece turret where the bottom half allows a 6400 mils (360 degrees) rotation on a conventional turret ring, but the upper half is mounted on trunnions at either side. The gun is fixed in the upper part of the turret and gun elevation and depression is obtained by tilting the whole of the upper part of the turret.

Term of the day

Self-entrenching device

A small dozer blade attached to the front of an armoured vehicle to enable the vehicle to dig itself in, in order to give better protection.

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Coaxially Mounted Machine Gun (Coaxial Machine Gun)

It is a machine gun that is mounted alongside the main armament and used against suitable targets in order to save main armament ammunition.

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External Gun Tank

It is an unconventional tank in which the gun is mounted in a separate mini-turret above the hull. The crew, usually three, in order to accommodate an autoloader, is located in the hull and hence all surveillance and target acquisition have to be accomplished by the use of remote viewing devices.

Term of the day

Hull-down Position

It is a fire position for a tank where the barrel and upper part of the turret is visible from the front, i.e., everything from the 'hull down' is protected behind cover.

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Panoramic Sight

It is a sight that can be rotated to enable an operator to observe the scene throughout an azimuth angle of 6400 mils (360 degrees).

Term of the day

Male and Female Tanks

During the First World War, the British Mark 1 tank was armed either with guns or machine guns. If it was fitted with two 6-pounder guns, it was called 'Male tank'; if it was fitted with machine guns only, it was called 'Female Tank'. So, the term 'Male Tank' has no significance other than to distinguish this tank from a Female Tank.