Mark 82 general-purpose bomb

The most common bomb in the world

If one weapon stands for air-to-ground ordnance, it is the Mk 82. At a nominal 500 lb it is one of the smallest bombs in current service and one of the most common air-dropped weapons anywhere. [1] Its actual weight runs from about 510 to 570 lb depending on what is screwed into it, and the body itself is simple: a streamlined steel case holding 192 lb of tritonal. [1]

The shape goes back to 1946, when Ed Heinemann of Douglas Aircraft studied how to carry bombs on fast aircraft with as little drag as possible. The result, the Aero 1A shape, is about eight times as long as it is wide, and every Mk 80 bomb uses it. [8] The FAS describes the series as developed in the 1950s for exactly that reason: earlier bombs produced too much drag. [3] The Mk 80 bombs did not see combat until Vietnam, but they have since replaced most earlier American general-purpose bombs. [8]

One body, many tails

What makes the Mk 82 so adaptable is that the bomb body stays the same while the fins, fuzesFuze GlossaryWeapons: A device that causes the detonation of an explosive charge at the proper time after certain conditions are met. A bomb fuze is mechanical or electrical, and is classed by what sets it off (impact, mechanical time… and kits change. Navy ordnance training lists a conical fin for ordinary free-fall delivery and the Mk 15 Snakeye, a retarding fin made for the 500 lb bomb. [2] [9] The Snakeye’s four spring-loaded blades can stay shut, so the bomb falls as a low-drag weapon, or spring open at release, so it slows sharply. The manual explains why: in a low-level attack the aircraft and an unretarded bomb arrive over the target at the same moment, and the aircraft could be damaged. Retarding the bomb lets the aircraft clear the area first, so the retarded modeRetarded delivery GlossaryWeapons: A bomb delivery in which a retarding fin, such as the Snakeye, opens to give a high-drag configuration, used in low-level bombing. Unretarded, the same bomb falls free in a low-drag configuration; with the in-flight… is used for low-level bombing. The pilot can choose between the two in flight. [4] The later BSU-86/B fin gives the same choice of high or low drag. [5] A third way to slow the bomb is the ballute, an inflatable cross between a balloon and a parachute; F-111s dropped Mk 82 AIR bombs fitted with them. [7]

Add a guidance kit and the Mk 82 becomes something else entirely. It is the warhead of the GBU-12GBU-12 Paveway II laser-guided bomb OrdnanceThe 500 lb laser-guided bomb that was the F-111F's tank buster in Desert Storm and is now one of the most used guided weapons. laser-guidedLGW GlossaryWeapons: Laser-guided weapon. A weapon that uses a seeker to detect laser energy reflected from a laser marked/designated target and through signal processing provides guidance commands to a control system, which guides the… bomb and the GBU-38 JDAMJoint Direct Attack Munition OrdnanceThe GPS/INS tail kit that made ordinary bombs accurate in any weather, and its laser-seeker version for moving targets., and the Air Force’s 2021 budget describes its BLU-111 version as delivered in high- and low-drag modes with ground-burst, delay or air-burst fuzing. [1] [6]

Built for carrier decks

A fire on a carrier deck is the nightmare that shaped the Navy’s bombs. A safety board set up after the 1967 fire aboard USS Forrestal found that a Mk 82 caught in a fire would cook off in about two and a half minutes. [1] The Navy’s BLU-111A/B adds a thermal-protective coating to resist fuel fires, and the textured insulation shows clearly on bombs loaded aboard ship. [1] [8] Later variants trade blast for precision: the BLU-126/B carries a smaller charge with inert ballast so that it flies like a standard bomb, and the BLU-129/B’s composite case breaks up instead of fragmenting, to limit damage around the target. [1]