A handful of nice prototype machining china photos I discovered:
Steven F. Udvar-Hazy Center: B-29 Superfortress "Enola Gay" panorama
Image by Chris Devers
Quoting Smithsonian National Air and Space Museum | Boeing B-29 Superfortress "Enola Gay":
Boeing’s B-29 Superfortress was the most sophisticated propeller-driven bomber of World War II and the initial bomber to property its crew in pressurized compartments. Even though designed to fight in the European theater, the B-29 found its niche on the other side of the globe. In the Pacific, B-29s delivered a variety of aerial weapons: standard bombs, incendiary bombs, mines, and two nuclear weapons.
On August 6, 1945, this Martin-built B-29-45-MO dropped the first atomic weapon used in combat on Hiroshima, Japan. 3 days later, Bockscar (on display at the U.S. Air Force Museum near Dayton, Ohio) dropped a second atomic bomb on Nagasaki, Japan. Enola Gay flew as the advance climate reconnaissance aircraft that day. A third B-29, The Fantastic Artiste, flew as an observation aircraft on each missions.
Transferred from the United States Air Force.
Country of Origin:
United States of America
General: 900 x 3020cm, 32580kg, 4300cm (29ft 6 five/16in. x 99ft 1in., 71825.9lb., 141ft 15/16in.)
Polished general aluminum finish
Four-engine heavy bomber with semi-monoqoque fuselage and higher-aspect ratio wings. Polished aluminum finish all round, normal late-World War II Army Air Forces insignia on wings and aft fuselage and serial number on vertical fin 509th Composite Group markings painted in black "Enola Gay" in black, block letters on reduce left nose.