I recently saw a documentary featuring Paul Tibbets, the pilot of the B29 (Enola Gay) which dropped the atomic bomb on Hiroshima. Paul Tibbets (Gen, USAF Ret.) stated he dropped the bomb and immediately turned, exiting the area as quickly as he could. He reported that the crew saw the bright flash of the detonation when the aircraft was 9 miles from the drop point, some 45 seconds after releasing the weapon.
I have two questions. The first concerns the terminal velocity of the egg-shaped bomb free falling from an aircraft. The atomic bomb released from the Enola Gay fell from 31000 feet, to 1900 feet above Hiroshima, (elev. about 26 m) in 45 seconds. That’s over 5 miles in less than a minute. Is that actually possible for a free falling object?
Wiki’s report differs slightly from what Gen Tibbets reported.
The release at 08:15 (Hiroshima time) went as planned, and the gravity bomb known as “Little Boy”, a gun-type fission weapon with 60 kilograms (130 lb) of uranium-235, took 43 seconds to fall from the aircraft flying at 31,060 feet (9,470 m) to the predetermined detonation height about 1,900 feet (580 m) above the city. The Enola Gay traveled 11.5 miles (18.5 km) before it felt the shock waves from the blast.
The second question concerns the speed of the B29 after releasing the bomb. The B29 traveled 9 miles (when the flash was observed) in 45 seconds. This seems to be an impossible speed for the B29, even in a controlled dive. Not to mention a 270 degree, 60 degree bank turn, immediately after release. All this seems rather remarkable for a piston powered aircraft. Were these reported speeds possible for a B29, even in a dive? The published speed of the B29 is 365 mph (mach 0.55) in level flight. http://www.globalaircraft.org/planes/b-29_superfortress.pl