Wartime Willow Run

America was being drawn into the growing world war and our involvment was an almost certainty but militarily we were woefully unprepared. The Roosevelt administration asked the Ford Motor Company to manufacture components for the B-24 Liberator bomber, but before parts could be manufactured a plant needed to constructed and that task fell to Charles Sorensen, Vice President of Production for Ford Motor Company.
In 1940 Sorensen visited the Consolidated Aircraft Company in San Diego, California to observe production of the B-24 (the prototype XB-24 made its first flight in December 1939). He noted that the
B-24′s final assembly was made out-of-doors under the bright California sun and on a structural steel fixture. The heat and temperature changes so distorted this fixture that it was impossible to turn out two planes alike without further adjustment. If Ford were to produce parts (which would be uniform in measurements) for Consolidated and ship them to be assembled in the California out-of-doors they would not fit properly and would slow up production. Something different had to be done. After a night of barnstorming and rough sketching an idea of how mass producing the B-24 (automotive industry style) could be done Sorensen presented his idea to Edsel Ford and the decision was made that Ford would not only produce parts for the B-24 but they would produce the entire airplane!

Willow RunClick to see full view… Willow Run on mapClick to see full view…

The Willow Run Farm owned by Henry Ford was selected as the site to build the airport and manufacturing facilities. Since the farm was personally owned by Ford the problem of land acquisition was averted and service via main roads and rail lines connecting Detroit with Ann Arbor made this the perfect choice. Easements were acquired from landowners across the county line in Ypsilanti Township where the Liberator plant (and eventually the airport terminal) would be built.
Architect Albert Kahn designed the main structure of the Willow Run bomber plant, which had 3,500,000 square feet (330,000 m2) of factory space, and an aircraft assembly line over a mile long. It was thought to be the largest factory under one roof anywhere in the world. The Willow Run plant featured a large turntable two-thirds of the way along the assembly line, allowing the B-24 production line to make a 90° turn before continuing to final assembly. Construction began April 1941, the airport was finished December 4, 1941, and the factory was completed January 1942.

Assembly Line B-24′sClick to see full view… Knock Down Parts B-24′sClick to see full view…

Willow Run’s Liberator assembly line ran from September 1942 through May 1945, building 47% of the 18,482 Liberators produced. There were initial start up problems due to different techniques of automotive production vs. aviation production plus there were quality control issues but eventually the bugs were worked out of the manufacturing processes and by 1944 Ford was rolling a Liberator off the Willow Run production line every 63 minutes, 24 hours a day, 7 days a week.
At its peak Ford produced 650 B-24′s per month and a total of 6,972 Liberators were built at Ford, with an additional 1,893 knock-down parts provided for other manufacturers.
The mass production process reduced the cost to build a B-24 from $297,627 to $137,000 per airplane. In addition, the B-24 holds the distinction of being the most produced heavy bomber in history. Ford produced the B-24E, B-24H, B-24J, B-24L, B-24M, and B-24N variants. The delivery of seven YB-24Ns by Ford in June 1945 marked the end of Liberator production at Willow Run.
Here is a video about Willow Run:

Specifications B-24J

• Crew: 11 (pilot, co-pilot, navigator, bombardier, radio operator, nose turret, top turret, 2 waist gunners, ball turret, tail gunner)
• Length: 67 ft 8 in (20.6 m)
• Wingspan: 110 ft 0 in (33.5 m)
• Height: 18 ft 0 in (5.5 m)
• Empty weight: 36,500 lb (16,590 kg)
• Loaded weight Loaded weight: 55,000 lb (25,000 kg)
• Max takeoff weight: 65,000 lb (29,500 kg)
• Powerplant: 4 × Pratt & Whitney R-1830-35 or -41 turbosupercharged radial engines, 1,200 hp (900 kW) each
• Fuel capacity: 1,750 gals. (6620 L.)

Performance

• Maximum speed: 290 mph (250 kn, 488 km/h)
• Stall speed: 95 mph (83 kn, 153 km/h)
• Cruise speed: 215 mph (187 kn, 346 km/h)
• Range: 2,100 mi (1,800 nmi, 3,400 km)
• Service ceiling: 28,000 ft (8,500 m)
• Rate of climb: 1,025 ft/min (5.2 m/s)

Armament:
• Guns: 10 × .50 caliber (12.7 mm) M2 Browning machine guns in 4 turrets and two waist positions
• Bombs:
Short range (˜400 mi): 8,000 lb (3,600 kg)
Long range (˜800 mi): 5,000 lb (2,300 kg)
Very long range (˜1,200 mi): 2,700 lb (1,200 kg)