A couple of good prototype machining china pictures I located:
Steven F. Udvar-Hazy Center: B-29 Superfortress “Enola Gay” caption
Image by Chris Devers
See more images of this, and the Wikipedia post.
Information, quoting from 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 very first bomber to house its crew in pressurized compartments. Though developed 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 range of aerial weapons: traditional bombs, incendiary bombs, mines, and two nuclear weapons.
On August 6, 1945, this Martin-constructed B-29-45-MO dropped the initial atomic weapon utilised in combat on Hiroshima, Japan. Three 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 Excellent Artiste, flew as an observation aircraft on both missions.
Transferred from the United States Air Force.
Manufacturer:
Boeing Aircraft Co.
Martin Co., Omaha, Nebr.
Date:
1945
Nation of Origin:
United States of America
Dimensions:
Overall: 900 x 3020cm, 32580kg, 4300cm (29ft 6 5/16in. x 99ft 1in., 71825.9lb., 141ft 15/16in.)
Supplies:
Polished all round aluminum finish
Physical Description:
4-engine heavy bomber with semi-monoqoque fuselage and high-aspect ratio wings. Polished aluminum finish all round, standard 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.
Long Description:
Boeing’s B-29 Superfortress was the most sophisticated, propeller-driven, bomber to fly for the duration of World War II, and the very first bomber to residence its crew in pressurized compartments. Boeing installed quite sophisticated armament, propulsion, and avionics systems into the Superfortress. In the course of the war in the Pacific Theater, the B-29 delivered the 1st nuclear weapons used in combat. On August six, 1945, Colonel Paul W. Tibbets, Jr., in command of the Superfortress Enola Gay, dropped a highly enriched uranium, explosion-sort, "gun-fired," atomic bomb on Hiroshima, Japan. 3 days later, Main Charles W. Sweeney piloted the B-29 Bockscar and dropped a highly enriched plutonium, implosion-kind atomic bomb on Nagasaki, Japan. Enola Gay flew as the advance climate reconnaissance aircraft that day. On August 14, 1945, the Japanese accepted Allied terms for unconditional surrender.
In the late 1930s, U. S. Army Air Corps leaders recognized the need to have for really lengthy-range bombers that exceeded the performance of the B-17 Flying Fortress. A number of years of preliminary research paralleled a continuous fight against those who saw limited utility in establishing such an high-priced and unproven aircraft but the Air Corps issued a requirement for the new bomber in February 1940. It described an airplane that could carry a maximum bomb load of 909 kg (two,000 lb) at a speed of 644 kph (400 mph) a distance of at least eight,050 km (5,000 miles). Boeing, Consolidated, Douglas, and Lockheed responded with style proposals. The Army was impressed with the Boeing style and issued a contract for two flyable prototypes in September 1940. In April 1941, the Army issued an additional contract for 250 aircraft plus spare parts equivalent to yet another 25 bombers, eight months ahead of Pearl Harbor and almost a year-and-a-half just before the first Superfortress would fly.
Amongst the design’s innovations was a lengthy, narrow, high-aspect ratio wing equipped with big Fowler-kind flaps. This wing style permitted the B-29 to fly quite quick at high altitudes but maintained comfortable handling traits throughout takeoff and landing. A lot more revolutionary was the size and sophistication of the pressurized sections of the fuselage: the flight deck forward of the wing, the gunner’s compartment aft of the wing, and the tail gunner’s station. For the crew, flying at intense altitudes became much far more comfortable as stress and temperature could be regulated. To shield the Superfortress, Boeing developed a remote-controlled, defensive weapons technique. Engineers placed 5 gun turrets on the fuselage: a turret above and behind the cockpit that housed two .50 caliber machine guns (four guns in later versions), and another turret aft near the vertical tail equipped with two machine guns plus two much more turrets beneath the fuselage, each equipped with two .50 caliber guns. One of these turrets fired from behind the nose gear and the other hung further back near the tail. An additional two .50 caliber machine guns and a 20-mm cannon (in early versions of the B-29) had been fitted in the tail beneath the rudder. Gunners operated these turrets by remote manage–a true innovation. They aimed the guns utilizing computerized sights, and every single gunner could take control of two or much more turrets to concentrate firepower on a single target.
Boeing also equipped the B-29 with sophisticated radar equipment and avionics. Based on the type of mission, a B-29 carried the AN/APQ-13 or AN/APQ-7 Eagle radar method to help bombing and navigation. These systems have been precise adequate to permit bombing via cloud layers that fully obscured the target. The B-29B was equipped with the AN/APG-15B airborne radar gun sighting method mounted in the tail, insuring correct defense against enemy fighters attacking at night. B-29s also routinely carried as numerous as twenty diverse varieties of radios and navigation devices.
The very first XB-29 took off at Boeing Field in Seattle on September 21, 1942. By the finish of the year the second aircraft was prepared for flight. Fourteen service-test YB-29s followed as production began to accelerate. Building this advanced bomber necessary huge logistics. Boeing built new B-29 plants at Renton, Washington, and Wichita, Kansas, whilst Bell built a new plant at Marietta, Georgia, and Martin built one in Omaha, Nebraska. Both Curtiss-Wright and the Dodge automobile firm vastly expanded their manufacturing capacity to build the bomber’s powerful and complex Curtiss-Wright R-3350 turbo supercharged engines. The plan necessary thousands of sub-contractors but with extraordinary work, it all came together, despite key teething problems. By April 1944, the 1st operational B-29s of the newly formed 20th Air Force began to touch down on dusty airfields in India. By Could, 130 B-29s were operational. In June, 1944, significantly less than two years right after the initial flight of the XB-29, the U. S. Army Air Forces (AAF) flew its 1st B-29 combat mission against targets in Bangkok, Thailand. This mission (longest of the war to date) called for one hundred B-29s but only 80 reached the target area. The AAF lost no aircraft to enemy action but bombing final results were mediocre. The very first bombing mission against the Japanese principal islands considering that Lt. Col. "Jimmy" Doolittle’s raid against Tokyo in April 1942, occurred on June 15, again with poor outcomes. This was also the 1st mission launched from airbases in China.
With the fall of Saipan, Tinian, and Guam in the Mariana Islands chain in August 1944, the AAF acquired airbases that lay several hundred miles closer to mainland Japan. Late in 1944, the AAF moved the XXI Bomber Command, flying B-29s, to the Marianas and the unit began bombing Japan in December. However, they employed higher-altitude, precision, bombing techniques that yielded poor benefits. The higher altitude winds were so powerful that bombing computer systems could not compensate and the climate was so poor that rarely was visual target acquisition attainable at high altitudes. In March 1945, Significant Common Curtis E. LeMay ordered the group to abandon these tactics and strike alternatively at night, from low altitude, using incendiary bombs. These firebombing raids, carried out by hundreds of B-29s, devastated a lot of Japan’s industrial and financial infrastructure. But Japan fought on. Late in 1944, AAF leaders selected the Martin assembly line to make a squadron of B-29s codenamed SILVERPLATE. Martin modified these Superfortresses by removing all gun turrets except for the tail position, removing armor plate, installing Curtiss electric propellers, and modifying the bomb bay to accommodate either the "Fat Man" or "Little Boy" versions of the atomic bomb. The AAF assigned 15 Silverplate ships to the 509th Composite Group commanded by Colonel Paul Tibbets. As the Group Commander, Tibbets had no particular aircraft assigned to him as did the mission pilots. He was entitled to fly any aircraft at any time. He named the B-29 that he flew on 6 August Enola Gay right after his mother. In the early morning hours, just prior to the August 6th mission, Tibbets had a young Army Air Forces upkeep man, Private Nelson Miller, paint the name just below the pilot’s window.
Enola Gay is a model B-29-45-MO, serial number 44-86292. The AAF accepted this aircraft on June 14, 1945, from the Martin plant at Omaha (Positioned at what is nowadays Offut AFB close to Bellevue), Nebraska. Soon after the war, Army Air Forces crews flew the airplane for the duration of the Operation Crossroads atomic test system in the Pacific, despite the fact that it dropped no nuclear devices during these tests, and then delivered it to Davis-Monthan Army Airfield, Arizona, for storage. Later, the U. S. Air Force flew the bomber to Park Ridge, Illinois, then transferred it to the Smithsonian Institution on July four, 1949. Despite the fact that in Smithsonian custody, the aircraft remained stored at Pyote Air Force Base, Texas, in between January 1952 and December 1953. The airplane’s final flight ended on December 2 when the Enola Gay touched down at Andrews Air Force Base, Maryland. The bomber remained at Andrews in outdoor storage until August 1960. By then, concerned about the bomber deteriorating outdoors, the Smithsonian sent collections staff to disassemble the Superfortress and move it indoors to the Paul E. Garber Facility in Suitland, Maryland.
The staff at Garber began operating to preserve and restore Enola Gay in December 1984. This was the biggest restoration project ever undertaken at the National Air and Space Museum and the specialists anticipated the perform would call for from seven to nine years to complete. The project truly lasted nearly two decades and, when completed, had taken about 300,000 function-hours to complete. The B-29 is now displayed at the National Air and Space Museum, Steven F. Udvar-Hazy Center.