Although it was a very inefficient weapon, it was considered to be such reliable design that it had not been tested. The bomb was 120 inches (3.048 meters) long with a diameter of 28 inches (0.711 meter).
It contained 64 kilograms (141.1 pounds) of highly-enriched uranium. This was a 9,700-pound (4,400 kilogram) “gun type” fission bomb, the Mark I, code-named Little Boy. Tibbets, Jr., was carrying Bomb Unit L-11, the first nuclear weapon to be used during war. The Martin-Omaha B-29-45-MO Superfortress, 44-86292, under the command of Colonel Paul W. Colonel Paul Warfield Tibbets, Jr., United States Army Air Corps, Commanding Officer, 509th Composite Group, and aircraft commander of the B-29 Superfortress, Enola Gay. Air Force)Ħ August 1945: At 0245 hours, a four-engine, long range heavy bomber of the 509th Composite Group, United States Army Air Forces, took off from North Field on the island of Tinian in the Northern Mariana Islands, on the most secret combat mission of World War II. Silverplate Martin-Omaha B-29-45-MO Superfortress 44-86292, “Dimples 82,” at Tinian, Marshall Islands, August 1945.
