James Whitmore as Major Bill Uanna (Security Officer, Operation Silverplate) Larry Keating as Major General Vernon C. Brent (fictional stand-in for Major General Uzal Girard Ent) Larry Gates as Captain William "Deak"' Parsons, USN Marilyn Erskine as Marge Bratton Stephen Dunne as Major Harry Bratton, (fictional) co-pilot during B-29 tests Robert Burton as Brigadier General Samuel E. Roberts (Tibbets' fictional CO in Africa) Hayden Rorke as Dr. Norman Ramsey Lawrence Dobkin as Dr. Van Dyke (as Larry Dobkin) Jim Backus as Major General Curtis E. LeMay Christopher Olsen as Paul Tibbets Jr. (son) (as Christie Olsen) Sidney and Ernest Sittig as Baby Tibbets (son) Production The film was suggested by screenwriter Beirne Lay Jr., a Colonel in the Air Force Reserve, to General Curtis LeMay, then commander of the Strategic Air Command (SAC), who had discussed with Lay the problem of the high rate of divorce among flight crews. A film depicting the problems might help raise morale. Lay suggested a film based on the experiences of Colonel Paul Tibbets, commander of the 509th Composite Group during World War II. LeMay approved, and after writing an outline, Lay handed over scriptwriting duties to Melvin Frank and Norman Panama. Although Tibbets gave his full approval and support to the film, he felt he was too closely involved to be objective, and suggested Lt. Col. Charles F.H. Begg, commander of the nuclear ordnance squadron, and Charles Sweeney, pilot on the follow-up Nagasaki mission, as technical advisors. Ultimately, Begg, Major Norman W. Ray (ret'd.) and Major James B. Bean served as USAF technical advisors. Dore Schary of MGM said "It wasn't the yarn that intrigued me but the people and their problems in it." It was originally called Eagle on His Cap. Principal photography began on February 5, 1952, at the Culver City studios before transferring to Davis–Monthan Air Force Base that was predominantly utilized for the airfield scenes of Wendover Air Force Base, Boeing's Wichita testing area and even Tinian Island. The production wound up on March 26, 1952. For dramatic effect, some incidents were somewhat exaggerated, such as the scene in which the Hiroshima bomb is armed in mid-flight. The filmmakers added some turbulence to increase tension, although in fact the flight was perfectly smooth throughout. In addition, the entire mission was filmed in daylight, although actual takeoff from Tinian was in full darkness at 2:45 in the morning. However, the