T12 Demolition Bomb
Twice the size of the 22,000-pound M110, this bomb was designed to create an earthquake effect by penetrating deep into the earth before exploding and thus causing the ground to heave up under the target. The bomb case is comprised of six separate sections welded together. The nose sections are extremely thick to permit deep penetration without deformation. The four tail fins are canted so as to impart a stabilizing spin to the bomb's trajectory. Only one plane in the US arsenal, the huge B36 "Peacemaker", could after a special modification to its bomb bay carry just two of these huge weapons.
The M-121, sometimes called the "Earthquake" bomb, was more often referred to as the "Grand Slam" bomb, a totally misleading nickname. Actually "Grand Slam" was the code name of a highly classified modification project strictly concerned with atomic matters. The "Grand Slam" modifications would allow the Convair B-36 to carry atomic bombs, which the Air Force believed might weigh more than 40,000 pounds. Since the 10,000-pound M-121, when properly dropped, could inflict the damage of a 40,000-pound bomb, curiosity and rumors most likely explained the ensuing confusion. As a matter of fact, the "Grand Slam" designation was also loosely applied to other conventional bombs of the M-121 category.
