Firepower

- To see and identify the target as a foe.
- To successfully aim, fire and hit the target.
- To generate enough damage on the target to neutralize it.
Of course, this must be done fast enough to avoid enemy fire.

Under clear conditions, basic systems like peri-telescopes and magnification binoculars for gunner and commander are the minimum basic requirement. Although, under bad weather, poor visibility (smoke, fog or dust)and night conditions; better systems are required. At the present, there are three systems available for the armored forces:


Infra Red projectors coupled to IR sights:
This allow for a 1000 m field of vision under clear conditions. Aiming is done in the conventional way. The drawback is related to the active source, which can be easily detected by the enemy. This device was typical for the tanks developed in the postwar and up to the '70s.
Typical examples of this is the peruvian T-55 with his L2AG Luna like IR searchlight, mounted on the right side of the main gun.



Low Light Level Television (LLLTV):
Is a highly sensitive device intended for vision and aiming. Because of his inherent non radiant nature is considered a passive device and do not expose the tank to the enemy. Is very efficient at night although it is limited under other poor visibility conditions like smog, dust or fog.
Best example in SA is the chilean Leopard 1v-Ch with his PZB-200, aiming and observation device, originally intended for the Leopard 2 prior to the availability of the newly developed thermal sight.


Thermal Sights:
Is the latest development in terms of passive sighting and aiming devices. It works as a very sensitive supercooled sensor for natural thermal radiation. This characteristic allow for day/night all-weather fighting without being exposed to the enemy. During "Operation Desert Storm", M1A1 gunners equipped with the TIS (Thermal Image System) could hunt enemy tanks under the cover of sand storm conditions witout being sighted by iraki armor because of the tecnological advantage of this system over the IR searchlight carried by former east block tanks.
Best example in SA is the brazilean M60A3 with his TTS (tank thermal sight).

The fire control system is the gunners aid for a better and sooner fire solution. In a simplified way, three subsystems are required:

Rangefinder: This device measures the distance to the target for gun elevation calculations. It can be found of the optic kind (stereoscopic/coincidence) or of the laser beam kind.
Although, there are still some very sensitive and effective optic devices in service (like the TEM-1A of the brasilean Leopard 1A1), the general tendency favors the laser rangefinder because of his simplicity, lower cost and better performance under low visibility conditions. The Chilean Leopard 1v features a unique configuration with a laser rangefinder integrated to the fire control system in addition to the original optical device, kept in stand by condition.

Gun Stabilization: This equipment allows the gun and sights to stay fixed on the target with independence of the tank movements. Some tanks rest only on a vertical stabilizer with acceptable results. Of course, only a two axis gyro-stabilized gun assures a high probability of hit while on the move over rough terrain.

Ballistic Computer: In order to make all the necessary calculations and corrections (tank movement, gun anomalies, gun powder temperature, atmosferic conditions, etc.) a fast computing device is required. Of course, a friendly interface and the degree of subsystem integration is vital to prevent from time losing and manual input errors.
Although, there are a lot of armor equipped only with basic aiming devices (like small caliber automatic guns), without a ballistic computer integrated firecontrol systems.
Technology in service for this kind of devices range from obsolete analog computers to the most recent and sophisticated digital computers and LCD displays.

Kinetic Energy Armour Piercing Projectiles:
These projectiles underwent a significant improvement since the introduction of the first hardened steel shots up to the current APDSFS concept. Most of the development occurred during WWII. While Germans had to rely mostly on armour piercing capped ballistic capped (APCBC) or rigid core capped (APCR) projectiles because of tungsten shortage; the British developed the discarding "sabot" principle in which a sub-caliber slug of tungsten carbide is sheathed in a light steel and then locked into a full diameter alloy sabot assembly. This allow the projectile to get more propellant accelerating power and once out of the gun the centrifugal effect liberate the sub-projectile from the sabot to continue to the target with a smaller drag, keeping a very high speed.
With the arrival of the smooth bore gun appeared the fin stabilized APDS projectile with his heavy long tungsten rod penetrator. The concept proved his effectiveness and soon was also adapted to common rifled guns like the british L7 and US M68. In this case, the projectile partially melts during his path through the armour plate, due to the high shear energy. So, the inflicted damage results from the combination of the heat, the piercing effect and eventually, a broken up, slug of armour fragmented inside the tank.
A slipping sealing ring on the sabot is necessary to absorb most of the the spin, since this effect reduce the penetration of the "arrow". Typical muzzle speeds for this kind of projectile are in the vicinity of 1400m/s.
The best example in SA is the DM33 APDSFS projectile fired by the L7A3 gun of the chilean Leopard-1v, originally designed specifically to beat modern ex-soviet tanks like the T-72A.

Other designations like HVAP or similar correspond typically to high velocity APDS ammunition with a steel/tungsten alloy rigid core penetrator like the USS M392(105mm) or russian BM-8(100mm) rounds.

Chemical Energy Warheads:
The performance of this kind of warheads do not depend on the striking velocity of the projectile. In fact, it rest on the chemical energy enclosed in the shell to beat the armour plate.
As in the case of the arrow rounds, spin and speed reduce penetration, but are needed for range and accuracy. That’s why, once better fire control systems became available and explosive technology improved, the HEAT round commenced to be used with antitank guns. This situation represented a mayor revolution in antitank warfare since a light armored vehicle with a short, large caliber gun (>75 mm) could beat even heavy armored tanks (right:a good example is the Scorpion/90). Typical muzzle speeds range between 800 and 1000 m/min.
To reduce the effect of CE warheads, compartmentalization and multilayer armor has been considered in modern tank design. Today, the tendency for MBT guns is going back to the arrow round since the new armour types like spaced, ceramic composite and explosive reactive has been successful in stopping them without adding to much weight.

According to the principle involved, the two main kind of warhead of this type are described bellow:

- High Explosive Anti Tank (HEAT):
Based on the principle discovered by Monroe in 1880, this warhead consist in an explosive charge with a cavity mostly conical in the front (also known as hollow charge). This round penetrate by blasting a high velocity narrow jet of high temperature gas and molten metal debris through armor with a pressure in excess of 300 tons/cm2 and more than 6000°C, allowing for a 3 to 6 times the gun caliber penetration path.

- High Explosive Squash Head (HESH):
This british postwar development, delivers a chunk of plastic explosive to the armor surface and then it is detonated, producing a violent shock wave and blasting off a large slab from the interior face of the plate. This slab, converted into a cloud of arrasing debris is known as the "spalling effect" and destroys enough inside the tank to neutralize it.
German designation is HE/P.

Right:Different types of 105 mm ammunition: HEAT, APDSFS & HESH.
Left: Cut of real APDSFS and HEAT ammunition.

Center: HESH
1=impact crater
2=inner wall after spalling

Right: HEAT
1=entry hole
2=inner wall entry hole
3=opposite wall jet exit "pin" hole

1st place: M60A3 TTS (best sighting technology)
2nd place: Leopard 1v-Ch & AMX-30B2

3rd place: Chinese revamped T-55 (active night vision)

4th place: SK105-A2 (no stabilizer), TAM VC'94 (no night vision)& Leopard 1A1-Br (no computarized FCS)
5th place: AMX-30B1 (no gun stabilizer, no computarized FCS), SK105-A1 (no computarized FCS, no gun stabilizer)
6th place: AMX-13/105 (no computarized FCS, no gun stabilizer, no night vision)