The 509th Composite Group had been created in September 1944 when Major
General Leslie Groves, the man in charge of the Manhattan Project to construct
the atomic bomb, foresaw the need for a dedicated corps of men trained to drop
the bomb on targets in Japan. He chose twenty-nine-year-old Lieutenant Colonel
Paul Tibbets to assemble and command the group.
Groves provided Tibbets with fifteen Boeing Superfortresses and eighteen
hundred men, and ordered him to shape them into a self-contained, secret outfit.
Tibbets was to control his own maintenance, engineering, ordnance, medical,
radiological, and technical units, and his own set of troop transport aircraft
and military police. These provided the required self-sufficiency and with it,
the urgently demanded secrecy. If Tibbets ran into any bureaucratic problems, he
needed only to mention the code word "Silverplate," which revealed
nothing about the group's mission, but magically cut through red tape. If
thwarted nevertheless, he had direct access to Groves and if need be, to H. H.
"Hap" Arnold, commanding general of the Army Air Forces.
Tibbets's top secret mission was to forge a group to deliver an atomic bomb
to Japan and survive. For this he had to devise the means and train his crews to
drop this incredibly powerful bomb and escape before its terrible blast could
consume them. For months, he did not know when the bomb would be ready or
exactly how much it would weigh. But he knew it was going to be hard even to get
the loaded Superfortress off the ground. Whether she would be able to struggle
to an altitude of 30,000 feet with that bomb in her belly was anyone's guess.
Altitude was important. Tibbets and his crew would enter a hairpin turn
immediately after releasing the bomb and beat a retreat to gain added distance
from the point of explosion. If the B-29 could gain a few thousand feet of added
altitude, that would add time to the forty or forty-five seconds for the bomb to
fall to its detonation height. Every second gained meant added distance from the
blast and greater safety for aircraft and crew; the Army Air Forces had no
intention of making this a suicide mission.
The B-29s in which the 509th trained were not yet those they would need to
carry out their mission. New Superfortresses would have to be acquired and
modified for the task. On May 18, 1945, the Martin Aircraft factory in Omaha,
Nebraska, delivered aircraft No. 44-86292 to the U.S. Army Air Forces (USAAF).
She was one of 536 Boeing-designed B-29s to be assembled by the Omaha plant, and
one of four thousand Superfortresses to be built and delivered by Boeing,
Martin, and other companies for the war. This particular Superfortress had been
designed as a Model B-29-45-M0. Her wingspan of 141 feet 8 inches, length of 99
feet, and four Wright 2,200 hp, R-3350-57 Cyclone engines permitted her to take
off weighing sixty-seven tons fully loaded--about twice her weight empty of
fuel, crew, and bombs. With this takeoff weight, she could cruise at 190 to 200
miles per hour. The aircraft's ceiling, the maximum altitude she could reach,
was 35,000 feet, nearly seven miles above sea level.
For four weeks after leaving the factory, Superfortress 44-86292 was modified
to make her a "Special Mission" aircraft. Then, on June 14, she was
picked up by one of Tibbets's right-hand men, Capt. Robert A. Lewis, and ferried
to Wendover Army Air Force Base (AAFB), Utah, where the 509th had been training
in isolation for the past nine months. By June 27 Lewis and his crew were ready
to head for Tinian Island in the Marianas. Along the way, they stopped at Mather
AAFB in California and in Hawaii before reaching Guam on July 2. There, the
aircraft's bomb bay was further modified. Leaving Guam on July 6, Lewis first
headed to Kwajalein before finally taking off for Tinian, where the 509th
Composite Group was now assembling.
PRACTICING FOR PERFECTION
The next few weeks were spent on practice runs. On July 12 the aircraft
participated in a raid on Marcus Island, fully loaded with seven thousand
gallons of fuel and twenty 500-pound bombs, weighing the maximum sixty-seven
tons on takeoff. Like all the other 509th heavy bombardment air crews, Lewis and
his men were required to fly half a dozen missions to prepare for battle
conditions and their ultimate mission.
Though occupied with the many pressing problems of commanding the entire
group, Tibbets made time to fly on some of these practice missions. But he was
under strict orders not to go along on the flights over Japan. He knew too much
for the United States to risk his capture. Other members of the 509th, who had
been told little, could and did fly practice runs over the Japanese home
islands. They knew their mission was special; they knew the maneuvers they would
have to carry out; but they knew little else.