Assigned to the 393rd Bomb Squadron, 509th Composite Group, it was used as a weather reconnaissance plane and flew over the city before the final bombing to determine if conditions were favorable for an attack. Pilot Claude Eatherly later expressed remorse, received psychiatric hospitalization, and engaged in anti-nuclear activism, and may be the origin of an urban legend that suggests that Enola Gay pilot Paul Tibbets (or other members of the crew) later went insane.
Straight Flush was one of the fifteen Silverplate B-29's used by the 509th in its deployment to Tinian. It was one of ten B-29s built at the Glenn L. Martin Company plant in Omaha, Nebraska, as a "block 35" B-29 but then designated "block 36" to denote its special configuration. It was flown from Omaha to the 509th's base at Wendover Army Air Field, Utah, on April 2, 1945, and assigned to Eatherly and crew C-11, and departed Wendover June 8, 1945, arriving June 13.
It was originally assigned the victor number 5 but on August 1 was given the triangle N tail markings of the 444th Bomb Group as a security measure and had its victor changed to 85 to avoid misidentification with actual 444th BG aircraft. It was named Straight Flush, purportedly based on a gambling penchant of Eatherly.
From June to August it flew 11 training missions, and six combat missions in which "pumpkin bombs" (five-ton TNT bombs with the same handling characteristics as the nuclear weapons) were dropped on Japanese industrial targets. Eatherly's crew bombed Tokyo (20th July), Otsu (24th July), Taira (26th July), and Maizuru (29th July) in Straight Flush, while Capt. Charles D. Albury and crew C-15 used it to bomb Koromo. On August 6, Straight Flush flew a mission over Japan as a weather patrol aircraft for the Hiroshima bombing; two days later, it made its final combat flight, a bombing raid on Yokkaichi.
One source (Campbell) states that on the first Pumpkin mission, on July 20, Eatherly attempted to bomb the Imperial Palace through overcast as a "target of opportunity" but missed, hitting a bridge called Gofukubashi. The attack was contrary to bombing restrictions (to protect the person of Emperor Hirohito) but apparently was not punished.
In November 1945 it returned with the 509th to Roswell Army Air Field, New Mexico. From March to August 1946 it was assigned to the Operation Crossroads task force, then rejoined the 509th BG at Roswell. In June 1949 Straight Flush was transferred to the 97th Bombardment Group at Biggs Air Force Base, Texas, then sent to Tinker Air Force Base in April 1950 for modification to TB-29 trainer specifications at the Oklahoma City Air Materiel Area.
Subsequent assignments were to:
Crew C-11 (regularly assigned to Straight Flush)