In late 1939, just before the beginning of World War II, General Henry "Hap" Arnold received War Department approval to begin building a very long-range, very heavy four-engine bomber, and because of its success with the B-17 Flying Fortress, the Boeing Aircraft Company earned the first contract for its B-29 Model 245. The B-29 program became the second-largest industrial project in scope and cost during the war, exceeded only by the Manhattan Project, and produced 3,965 aircraft by the end of World War II. Powered by four Wright R-3350-23 Cyclone 18-cylinder radial engines, each with two General Electric B-11 superchargers, the Superfortress had 8,800 brake horsepower at takeoff and used four-blade Hamilton Standard Hydromatic propellers measuring 16 feet 7 inches, the largest in the world at that time. Its pressurized cabin, remote-control turrets with lead-computing sights, revolutionary wing, and AN/APQ-13 radar made it an advanced bomber that could carry 20,000 pounds of bombs and a crew of eleven. As the ultimate strategic bomber of World War II, it could fly higher, farther, and faster than any other large bomber, and its long range led to its exclusive use against Japan from bases in Guam, Tinian, and Saipan. After the war, some B-29s remained in active service while many were scrapped, and the Superfortress continued as Strategic Air Command's top bomber until 1948, later serving in the Korean War before being phased out during the 1950s and 1960s. This Boeing B-29A/Renton F-13A was delivered to the Army Air Corps on 11 January 1944 and, nicknamed the City of Lansford, flew from Guam in 1945 with the 314th Wing, 19th Bombardment Group, 28th Bombardment Squadron on mainly weather reconnaissance missions. Its crew received the Distinguished Flying Cross for flying through a typhoon on 29 June 1945 with only two engines. It is the only survivor of the 118 B-29A Superfortresses converted into Renton F-13A photo-reconnaissance models, which carried a crew of 11 and had an extended range of 4,000 miles. The B-29 was first reported in action on June 5, 1944, in an attack on railway yards at Bangkok, Siam, and on June 15 the first raid was made on Japan from bases in China, after which attacks on the Japanese mainland increased steadily, mainly from bases in the Marianas. The most famous Superfortress was the Enola Gay, which dropped the first atomic bomb on Hiroshima on 6 August 1945, and three days later Bock's Car dropped a second atomic bomb on Nagasaki, bombings that quickly led to Japan's surrender later that month.