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Beyond-Armour Effect is a term coined by Försvarets Fabriksverk (FFV),〔FFV is now part of Saab Bofors Dynamics〕 a semi-governmental Swedish defense firm, while developing the AT4. From the 1980s this phrase was used in its brochures, press releases, weapon instruction manuals and other documentation to denote the ''post-penetration effect'' of the AT4's HEAT anti-armour warhead against the interior and occupants of armoured vehicles. The phrase now has become more or less standard in modern military terminology.〔Hewish, Mark "FFV's Lightweight AT4, first of a new family of Swedish anti-armour weapons", International Defense Review, 5/1982, p. 70〕〔Not to be confused with ''Behind-the-armor effect'' or ''After-armour effect'' which is a term sometimes used to describe the effects of armour piercing shells fired by tanks, antitank cannons and naval warships that have a small high explosive charge in the rear of the projectile that explodes after penetrating the armour plating〕 ==History== During World War II, man-portable antitank weapons using shaped charge warheads, more commonly known today as HEAT projectiles, came into widespread use with almost all armies. These warheads have the advantage of not being affected by the projectile's velocity. They penetrate armour by an explosive charge fitted in a liner in the shape of a cone or, more precisely, an ogive. The liner often is made of a soft metal, such as copper. Burning of this shaped charge turns it into a highly focused stream moving forward at extreme speeds. These warheads also have the same effect as medium and high velocity solid shot armour piercing projectiles: spalling on the interior of the armoured vehicle's armoured plate.〔The second being solid shot AP projectiles impacting other items inside the armour vehicle and a massive transfer of kinetic energy to the object(s) impacted〕 A problem with shaped charge warheads is that if the ogive shaped liner is deep, it will have more penetration, that results in a smaller hole, that is less effective inside the armoured vehicle. Research on shaped charge warheads has shown a hole the size of a large coin on the outside of a tank turret, but an inside hole the diameter of pencil lead. If, on the other hand, the ogive is shallow, it will have less penetration, but cause a larger hole on the inside which will result in a massive spalling.〔A rule of thumb for infantry antitank weapons is that if a HEAT warhead has to use more than two-thirds of its official penetration capability, it will have less effect on the interior of the vehicle.〕 In 1954, during the siege of Dien Bien Phu, France had dismantled and flown in a number of M-24 Chaffee light tanks. Their thickest armor was only 25.4 mm. The Viet Minh's main infantry antitank weapon was the old World War Two U.S. 2.36-inch bazooka, captured from Nationalist Chinese forces and supplied by Communist China. During the siege the French launched counterattacks using the M-24 in support of their infantry. One Chaffee took seven hits from 2.36-inch bazookas and still continued to fight, demonstrating that portable rocket launchers were hardly a flawless tank-killer.〔John Keegan, "Dien Bien Phu", page 110, Ballantine Books, 1974〕 Other examples became evident during the Vietnam War. The North Vietnamese and their allied forces in South Vietnam were equipped with two types of light anti-armour weapons. One was the 1950s era B-40, which was a Chinese manufactured version of the Russian RPG-2, and the other was the newer RPG-7. The RPG-2 had a shallow cone and the RPG-7 a deep cone. The B-40 had a maximum penetration against armour of approximately 150 mm while the RPG-7 penetration was more than double that of the B-40. But to the surprise of the North Vietnamese, the B-40, while not effective against heavy tanks, was far more effective than the RPG-7 in killing or wounding the occupants of light armoured vehicles, and in igniting the ammunition storage or the vehicle's fuel, including the more modern M113 APC which U.S. and South Vietnamese forces at that time operated in large numbers. In addition, the B-40 proved more effective than the RPG-7 against non-armoured targets, like the bunkers at fire base camps. There are many stories from U.S. Vietnam veterans of the enemy attacking or ambushing with the dreaded B-40.〔John Weeks "Small Arms Profiles #21 - Recoilless Anti-Tank Weapons", Profile Publications, 1973〕 The U.S. Army also discovered that in combat, with rare exceptions, more than one hit by the M72 LAW rocket was required to disable or kill the North Vietnamese PT-76 light tank.〔William R. Phillips, Night of the Silver Stars, pg 80, Naval Institute Press, 1997〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Beyond-armour effect」の詳細全文を読む スポンサード リンク
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