By 1944 the Willow Run Bomber plant was manufacturing as many as 25 four-engine B24 liberators a day.

One-Per-Hour

Production Miracle At Willow Run

Ford Motor Company History & the Origins of Lean Manufacturing

In January of 1940, America was being drawn into the growing war (WWII) and our military was unprepared. The Roosevelt administration asked Ford Motor Company to manufacture parts for the B-24 Liberator bomber. Charles Sorensen, Vice-President of Production for Ford traveled to San Diego to observe Consolidated Aircraft's operations (a company that was producing military aircraft at the time). After his visit he was convinced that Ford motor company could produce the bombers at a unthinkable rate of one per hour. Here is his description of the visit and how he conceived the Willow Run bomber plant that eventually manufactured 8,800 of these aircraft.

Willow Run is one of the greatest examples of LEAN MANUFACTURING. This is where it all started.

Charlie Sorensen's Story

Inside the (Consolidated) plant I watched men putting together wing sections and portions of the fuselage. The work of putting together a four-engine bomber was many times more complicated than assembling a four-cylinder automobile...

I really did have something in mind. To compare a Ford V-8 with a four-engine Liberator bomber was like matching a garage with a skyscraper, but despite their great differences I knew the same fundamentals applied to high-volume production of both, the same as they would to an electric egg beater or to a wrist watch.

First, break the plane's design into essential units and make a separate production layout for each unit.

Next, build as many units as are required,

then deliver each unit in its proper sequence to the assembly line to make one whole unit~ finished plane...

I saw no impossibility in such an idea even though mass production of anything approaching the size and complexity of a B-24 never had been attempted before.

But who would accept such a wild notion? And instead of one bomber a day by the prevailing method I saw the possibility of one B-24 an hour by mass production assembly lines...

As soon as I returned to my room at the Coronado Hotel, I began figuring how to adapt Ford assembly methods to airplane construction and turn out one four-engine bomber an hour...

Again I was practicing my production planning philosophy, which stemmed from my patternmaking days when I fashioned wooden models of Henry Ford's half-thought-out designs: "Unless you see a thing, you cannot simplify it. And unless you can simplify it, it's a good sign you can't make it.”

As I look back now upon that night, this was the biggest challenge of my production career...Now, in one night, I was applying thirty-five years of production experience to planning the layout for building not only something I had never put together before, but the largest and most complicated of all air transport and in numbers and at a rate never before thought possible.

Once again I was going on the principle I had enunciated many times at Ford: "The only thing we can't make is something we can't think about."

CD-3/C-47 Paratrooper Transport plane

Towards four o'clock, I was satisfied that my piles of paper were arranged in proper order and represented the most logical progress of units to the main assembly line; and I knew I could prove a construction rate of one big bomber an hour. Now I had something to talk about.

Standing over the papers, I roughed out on Coronado Hotel notepaper a pencil sketch of the floor plan of a bomber plant. It would be a mile long and a quarter mile wide, the biggest single industrial building ever...

The result of one night's hard work, it is the true outline of Willow Run, which took two years to build and came through on schedule with one four-engine Liberator an hour, 18 bombers a day, and by the end of the war a total of 8,800 big planes rolled off the assembly lines and into the air.

When I finished my sketch I went to bed, but was so carried away by enthusiasm for the project that I couldn't sleep. I was building planes the rest of the night.

At breakfast with Edsel (Ford) the next morning I was somewhat woozy as I showed him the sketch and outlined the bomber-an-hour proposition.

He was in complete accord and assured me that Ford Motor Company would build such a plant... We spent an hour together, getting set for a meeting in Major Fleet's office to shoot the works on a $200,000,000 proposition backed only by a penciled sketch.