The M117 is an air-dropped demolition bomb used by United States military forces. The weapon dates back to the Korean War of the early 1950s. Although it has a nominal weight of 750 pounds (340 kg) its actual weight, depending on fuze and retardation options, can be around 820 pounds (372 kg). The bomb’s explosive content is typically 386 pounds (175 kg) of Tritonal or 377 pounds (171 kg) of Minol in the case of the M117A1E2due to their higher density and detonation velocity compared to TNT. Demolition bombs rely on time delayed fuzes which allow the bomb to burrow into a building or other structure before detonating. The M117 can be configured with a conical low-drag tail for medium and high altitude deliveries or a high-drag tail fin for low-altitude drops, delaying the bombs hitting their targets ensuring fighters are out of the blast zone before detonation. The M117 was the basis for the BOLT-117 the world’s first Laser-guided bomb.
From the 1950s through the early 1970s the M117 was a standard aircraft weapon, carried by the F-100 Super Sabre, F-104 Starfighter, F-105 Thunderchief, B-57 Canberra, F-111, F-5, A-1 Skyraider, A-4 Skyhawk and F-4 Phantom. The M117 series was used extensively during the Vietnam War, and B-52G Stratofortress aircraft dropped 44,600 M117 and M117R bombs during Operation Desert Storm.
The B-52 Stratofortress was the last aircraft to use the bomb; tactical aircraft had mostly switched to using the Mark 80-series bombs, particularly the Mark 82 (500 pounds (227 kg)) or Mark 84 (2,000 pounds (907 kg)) bombs and their guided equivalents. On 26 June 2015, the last Mk 117 in PACAF inventory was dropped by a B-52H crew on an island near Andersen AFB, Guam.