BUILDING THE B-29 – RACE FOR MASS PRODUCTION WWII

THE WAR PRODUCTION BOARD MANDATED THE MASSIVE COLLABORATION OF HUNDREDS OF MAJOR U.S. COMPANIES TO QUICKLY MASS PRODUCE THE B-29

By the time Boeing completed its first successful flight of the experimental prototype XB-29 in Sept. 1942, the U.S. government had already placed orders for 1665 production B-29s and spare parts, a number Boeing alone could not handle. Within the next four years an astonishing 3970 B-29s were mass produced under the authority of the new War Powers Acts. President Roosevelt created the War Production Board mandating the massive collaboration of hundreds of major U.S. peacetime companies to collectively cross-license, re-tool and re-train to quickly mass produce the B-29. In 1942, the U.S. was the world’s industrial and mass production powerhouse, being superior in manufacturing expertise, technology and manufacturing capacity (42% of total world capacity at the outset of WWII). Without this, the critical B-29 build-up that ended the war would not have been possible.

THE B-29 WAS FAR MORE MASSIVE AND COMPLEX THAN ANY PRIOR AIRCRAFT

The B-29 was far more massive and complex than any prior aircraft. It was twice the weight of a B-17 and its mechanical and electrical systems were far more intricate, making it the most challenging aircraft to produce during the war. It had

• 40,540 parts
• 12 tons of aluminum sheeting
• 600,000 rivets
• 9 miles of wiring with 586,000 connections, and
• 2 miles of tubing

for its construction.

LARGE COMPONENTS OF THE PLANE WERE BUILT BY MAJOR AUTO MANUFACTURERS

The War Production Board oversaw and funded the massive conversion, expansion, re-tooling and re-training of hundreds of civilian manufacturing facilities selected to build the component parts and assemblies of the B-29. Large components of the plane (fuselage, wings, tails, engines) were built by major subcontractors, principally auto manufacturers and industrial giants like Chrysler, Fisher Body, Hudson Motor, Goodyear and Briggs, and shipped by rail to four key aircraft assembly plants run by Boeing, Bell and Martin, respectively, for final assembly.

The huge final assembly plants were selected (or built) at decentralized sites leveraging existing aviation infrastructure and expertise, located away from attack-vulnerable coastal areas (except Renton, WA) and having readily available rail lines and large untapped workforces:

• Boeing, Wichita, KS
• Boeing, Renton, WA
• Bell Aircraft, Marietta, GA
• Glenn L Martin Company, Omaha, NE

The auto industry was selected to build large sub-assemblies of the B-29 because its existing mass-production infrastructure, skilled workforce and expertise in large-scale manufacturing made it perfectly suited for rapid conversion to large scale B-29 production. About 41% of aircraft assembly was done by subcontractors:

• Engines & Power:

• • Dodge (Chrysler) Chicago, IL: Produced majority of Wright R-3350 engines (over 18.000).
  • Frigidaire (GM), Dayton, OH: Made all Hamilton Standard propellers.

• Fuselage Sections:
  • Hudson Motor Car Co., Detroit, MI: Built rear fuselages, outer wings, and wingtips.
  • Fisher Body Div. (GM), Cleveland, OH: Supplied nose sections, outer wings, engine nacelles (housings), and complete tail sections.
  • Goodyear Aircraft, Akron, OH: Built two-bomb bay fuselage sections, entire tail assemblies and wing leading edges.
  • Chrysler (DeSoto), Warren MI: Produced engine cowlings.
• Wings & Control Surfaces:
  • Briggs Manufacturing, Detroit, MI: Supplied flaps, dorsal fins, and stabilizers.
  • Murray Corpoation, Scranton, PA: Built B-29 wings and wing edges
• Other Components:
  • Firestone: Provided the fuel tanks.

The highly complex B-29 nose sections were made by multiple manufacturers, along with Boeing’s own plants in Wichita and Renton, and Bell Aircraft in Marietta, GA. The nose section alone required over 50,000 rivets and 8,000 different parts.

The Wright R-3350 Duplex-Cyclone engines were built by the Wright Aeronautical Division of the Curtiss-Wright Company its developer, with major production during WWII handled by the Dodge-Chicago Plant (Chrysler) under license. The 18-cylinder, air cooled, turbo-charged engine was the most powerful piston engine of its time, providing the B-29 a cruising altitude, speed and range much greater than its predecessors.

The General Electric Company was the developer and primary manufacturer responsible for mass-producing the B-29’s revolutionary remote-controlled gun turrets and their associated central fire control systems.

Transformation of the hundreds of selected peacetime manufacturing companies (1400 total contracted) and their workforce to B-29 mass production was a monumental endeavor. Manufacturing and tooling engineers designed new and repurposed existing assembly lines at each plant to manufacture B-29 sub-assemblies and the thousands of B-29 parts. For final assembly, Boeing developed a revolutionary new “multi-line” assembly system to handle the complexity and size of production. Instead of one long line, B-29 factories used several parallel lines feeding into a central assembly area, allowing more workstations and flexibility for modifications.

HUNDREDS OF THOUSANDS OF WORKERS WERE TRAINED / RE-TRAINED TO MAKE THE B-29

Hundreds of thousands of workers were trained / re-trained to make up the B-29 supply chain and assembly workforce. This included massive upskilling for complex bomber production, using new techniques for new tech like pressurized cabins, remote turrets, and advanced engines. On-the-job learning, training films and dedicated schools (like at Pratt Army Field near Wichita) were used to quickly train workers. Underqualified, unskilled recruits became skilled workers through the process.

WOMEN COMPOSED NEARLY 40% OF THE TOTAL B-29 PRODUCTION WORKFORCE

Women and minorities entered the workforce for the first time to fill the void of the millions of working men called to active military service. Women composed nearly 40% of the total B-29 production workforce. They assumed critical jobs normally filled by men, being trained as assemblers and machinists, and were often made riveters because they were more likely to fit in tight aircraft spaces. The name “Rosie the Riveter” was affectionately given to all women production workers during the war.

BY MID-JANUARY 1944, 96 B-29S HAD BEEN BUILT, BUT ONLY 16 WERE AIRWORTHY

Boeing initiated all-out production of the B-29 in late 1943 at its Wichita plant, just a year after the first prototype flight. General H. “Hap” Arnold had demanded that at least 175 B-29s be combat ready by March of 1944 to begin long range bombing of Japan from bases in India and China. The timing was a promise made by Roosevelt to Chiang Kai-shek to keep China in the war. While all personnel working on the B-29 worked hard to meet Arnold’s demand, their efforts were hampered by the inherent complexity of the aircraft, especially engine issues, by slow delivery of key parts and a steep learning curve.  By mid-January 1944, 96 B-29s had been built, but only 16 of those were airworthy. Most of the aircraft were grounded at “Modification Centers” or in the delivery apron at the Wichita plant, pending urgent modification or parts.  The rush to design, produce and deploy the B-29 had taken an initial toll, as normal development times had been cut in half and shortcuts were taken to meet Arnold’s production deadline causing quality issues. The Wright R-3350 engine overheated and caught fire; the pressure seals around the cockpit windows and sighting blisters leaked; the remote-control turrets didn’t work properly; there were faulty electrical plugs; the cockpit glass had poor transparency and wing structures were inadequate. By the spring 1944 deadline, none of the produced B-29s were combat ready. Arnold was livid.

In what became known as the Battle of Kansas, General Arnold took control of B-29 production in a massive, two-month effort to modify 150 of the early B-29s to combat-ready status using five designated Kansas Army Airfields (Pratt, Salina, Herington, Walker, Topeka) as modification centers. Specialist USAAF ground crew and technicians were called in from all over the country and 600 production workers were pulled from the Wichita assembly lines. Subcontractors were told to stop all work on non-B-29 components until they had fulfilled their part commitments to the B-29.

WING SKINS WERE REMOVED, UNDERLYING STRUCTURES BEEFED-UP AND SKINS RIVETED BACK IN PLACE

Over the following five weeks, the B-29s underwent major modification. All of the R-3350 engines from already completed B-29s were pulled and modified to a new R-3350-23A “war engine” standard. This involved rebuilding them with additional airflow baffles, new exhaust valves and new rocker arms with drilled holes for better oil flow. Wing skins were removed, underlying structures beefed-up and skins riveted back in place. Rudders were replaced with strengthened units. Engine cowl flaps which cooled each engine were modified. Nose section glass panes were replaced with new distortion-free panes. Every electrical plug was removed, disassembled and resoldered – a total of 586,000 connections in each completed aircraft. Crews worked round the clock often in conditions so cold they were individually limited to 20 minute shifts due to the delicate nature of the work.

AT ITS PEAK, THE WICHITA PLANT PRODUCED FOUR B-29S PER DAY

By April 15, 1944, Arnold’s Herculean effort proved remarkably successful completing the 150 combat-ready B-29s for timely Asia deployment. This set in place a whirlwind of mass production. B-29s were produced in round-the-clock nine and ten hour shifts, six and seven days a week. By mid-1946, Boeing had built 2766 B-29s at its Wichita and Renton plants, Bell 668 and Martin 536 totaling 3970 aircraft, including XB-29, YB-29, B-29, B-29A and B-29B variants.  At its peak, the Wichita plant produced four B-29s per day. The workforce dramatically reduced man-hours per plane from 157,000 for the first 100 to just 17,000 for the last 100 B-29s produced at the Wichita plant. By the end of the war, peak production from all four assembly plants reached 375 aircraft per month.

The USAAF had originally ordered 9,052 B-29s. Orders for 5082 B-29s were cancelled upon Japan’s surrender. Once deployed, the game-changing B-29 put an early end to the war through utter devastation of the Japanese homeland and its military engine.

NO OTHER NATION CAME CLOSE TO MATCHING THE U.S. INDUSTRIAL MIGHT, ITS ENGINEERING, SKILLED WORKFORCE AND MANUFACTURING CAPACITY

One cannot overstate the importance of American leadership, ingenuity and manufacturing dominance in winning WWII. No other nation came close to matching the U.S. industrial might, its engineering, skilled workforce and manufacturing capacity. The massive industry transformation and workforce mobilization undertaken for B-29 mass production was repeated for the mass production of virtually all U.S. military hardware, including other aircraft, tanks, ships, vehicles, weapons and munitions, through combinations of many American companies. Critical also was self-possession and control of the raw materials, oil and ores, refineries and mills necessary to continuously supply these companies with essential materials like steel, copper, magnesium, aluminum and explosives at the enormous levels needed. This great American manufacturing engine allowed hardware lost or expended in battle to be readily replaced without attrition, allowing the U.S. and its Allies to overwhelm and outlast the Axis powers.