[.041 Safety Wire]

The 9700-pound bomb was released over Hiroshima on August 6, 1945, at 9:15 am. The bomb fell at a speed of 700 miles per hour, or 1138 feet per second. Within a 1-km radius of the hypocenter, the thermal energy contained in that single moment's flash was intense enough to cause internal organs to evaporate, boiling off intestines in less than a fraction of a second. Birds ignited in mid air; telegraph poles, trees, clothing, thatched roofs, wooden buildings, household pets, and entire streetcars spontaneously combusted; steeled framed buildings liquefied; rubble and bone fused together in a single amorphous mass. Watches and clocks suddenly stopped, their hands permanently burned into their faces, forever recording the precise moment of detonation. Hundreds of fires sprang up simultaneously all across the city. In some cases, individuals were so completely incinerated that nothing remained but their shadows. More than 200 radioactive isotopes spewed out of the bomb's core and into the dust cloud. After the flash came the shockwave, ripping out from the hypocenter at 7200 miles per hour, 10,000 feet a second, producing a wall of high pressure that smashed through doors, windows, houses, offices, temples, hospitals, shops, stalls, restaurants, factories, buses, schools, animals, and people. The shockwave slammed through the city with an initial force of nearly 7 tons per square meter, destroying almost 60,000 buildings in its wake. It killed perhaps 80,000 people in those very first seconds. The plane returned to Tinian 12 hours and 13 minutes after take-off after covering a distance of 2960 miles. The USSR declared war on Japan 3 days later.

General characteristics

Crew: 11 (5 officers, 6 enlisted): (A/C)Airplane Commander, Pilot, flight engineer (a rated pilot),[28][29] bombardier, navigator, radio operator, radar operator, blister gunners (two), CFC upper gunner, and tail gunner
Length: 99 ft 0 in (30.18 m)
Wingspan: 141 ft 3 in (43.06 m)
Height: 29 ft 7 in (8.5 m)
Wing area: 1,736 sq ft (161.3 m²)
Empty weight: 74,500 lb (33,800 kg)
Loaded weight: 120,000 lb (54,000 kg)
Max takeoff weight: 133,500 lb (60,560 kg) ; 135,000 lb plus combat load (144,000 lb on record[14])
Powerplant: 4× Wright R-3350-23 and 23A turbosupercharged radial engines, 2,200 hp (1,640 kW) each
Zero-lift drag coefficient: 0.0241
Drag area: 41.16 ft² (3.82 m²)
Aspect ratio: 11.50
Performance

Maximum speed: 357 mph (310 knots, 574 km/h)
Cruise speed: 220 mph (190 knots, 350 km/h)
Stall speed: 105 mph (91 knots, 170 km/h)
Combat range: 3,250 mi (2,820 nmi, 5,230 km)
Ferry range: 5,600 mi (4,900 nmi, 9,000 km, (record 5,839 mi, 5,074 nmi, 9,397 km[14]))
Service ceiling: 33,600 ft (10,200 m)
Rate of climb: 900 ft/min (4.6 m/s)
Wing loading: 69.12 lb/sqft (337 kg/m²)
Power/mass: 0.073 hp/lb (121 W/kg)
Lift-to-drag ratio: 16.8
Armament


Guns:

10× .50 in (12.7 mm) caliber Browning M2/ANs in remote controlled turrets
2 x .50 in and 1× 20 mm M2 cannon in tail position (the cannon was eventually removed as it proved unreliable in service )
B-29B-BW – All armament and sighting equipment removed except for tail position; initially 2 x .50 in M2/AN and 1× 20 mm M2 cannon, later 3 x 2 x .50 in M2/AN with APG-15 gun-laying radar fitted as standard.
Bombs: 20,000 lb (9,000 kg) standard loadout