Extracts from Willow Run  (Warren Benjamin Kidder)

Plant location:

 

Henry Ford’s grandfather, John, cleared and lived in land near Dearborn, Michigan.  Henry Ford was born on this land in 1863 and in the late 1920s started buying large areas of land throughout Michigan for what became known as the Ford Farms.  On some of the land he maintained two camps to help sons of World War One veterans work live off the land.  One of the camps was located east of Ypsilanti near Willow Run stream.

 

In December 1940 Henry Ford was asked to build airplanes for the US defense programme.  On the 8th January 1941 a team from Ford’s, led by Charles Sorensen, Ford’s executive vice-president, visited Consolidated’s plant at San Diego.  That evening Sorensen conceived the idea to mass produce B-24s.  Consolidated could not supply the thousands of B-24s needed because the plant at San Diego could not be enlarged and modernised for mass production.  Before the Ford team left San Diego they learned that Consolidated did not have a complete set of blueprints for their bomber.  Changes made within the last six months to facilitate production had not been recorded but had been left to the discretion of the relevant shop foreman.

 

Sorensen examined the viability of using the land under cultivation by the Ford Farms east of Ypsilanti as the location for the B-24 production factory.  Ford owned large parcels of land in both Wayne and Washtenaw counties.  It was decided that the Ford B-24 plant, which would include an airport and factory, would be built in this area   Other families who owned land around the Ford Farm were moved out.

 

Plant layout:

 

On March 11th 1941 a group of 200 Ford engineers, production experts and draftsmen arrived at Consolidated’s plant in San Diego.  A model of the proposed Willow Run plant was made and divided into bays representing 40 by 60 feet manufacturing area and 40 by 150 feet assembly area.  Paper templates of machinery and other facilities were made  and moved on the layout board to determine the most advantageous location.  The layout board also showed the installation of electric cables, cranes etc.  The size and weight of material to be used in a machine were important factors in determining location.  Adequate toilet facilities for both men and women, locker rooms and large lunchrooms all being close to employees work stations were also taken into account.  

 

The Willow Run complex was designed by Albert Kahn who had designed Henry Ford’s buildings for thirty years.  Working against the natural slope of the site the constructors set to work on a seventy four mile drainage system, the first drainage crew began digging trenches for the sewer lines on the 13th August 1941.  The airport was located on 1434 acres.  It  had six runways all 160 feet in width and ranging in length from 6363 feet to 7286 feet.  2.3 miles of taxiway, 80 feet wide, was laid.  On the 3rd May 1941 the first structural steel was erected on its concrete foundation and footings.  

 

The total area of the factory floor was 80.4 acres, the concrete flooring being covered with creosoted wood block flooring.  The factory was ‘L’ shape to avoid crossing from Wayne county to Washtenaw county with the longer leg running 3200 feet and the shorter leg being 1279 feet.  The assembly line was 5460 feet long.  

Engineering changes:

 

Consolidated, like all aircraft manufacturers at that time, were using zinc based dies to stamp out aluminum plate.  The Ford engineers argued that under high volume production these dies would become dull and disfigured and hence hard metal dies should be used.  William F. Pioch, who was in charge of Ford’s tooling, looked closely at the way Consolidated made the B-24 centre wing section.  It was taking Consolidated 550 man hours to manufacture the centre wing section.  Pioch felt it could be constructed by ‘putting it in a machine and machining it up’.  When the centre wing machining fixture was made it cost $168500.     

 

Starting production:

 

Before the plant and assembly lines were completed at Willow Run B-24 parts were being manufactured and being shipped to Consolidated and Douglas.  Initially these components were taken by road in specially designed trailers hauled by dual engine Ford V8 trucks.  The road shipments commenced on the 31st March 1942 and ended in August 1942 when the trucks were taken off the road and shipment continued by rail.  

 

The biggest problem in getting production started was in trying to obtain an experienced workforce.  Of the three hundred thousand experienced aircraft workers in America, Fords were allocated four hundred.  Training schools were set up within the Willow Run complex.  The workforce, which containing many women and young men, not only lacked aircraft experience but also had no industrial experience.  When the young men became old enough they entered military service.  Fords made an unsuccessful plea for deferments.  Given the inexperienced workforce and the pressure the Ford aircraft inspectors were under to get mass production under way it was almost inevitable that the initial B-24 components shipped to Consolidated and Douglas were badly constructed.  Towards the end of 1942 there was a marked improvement in the quality of the B-24 components being manufactured.  These improvements were orchestrated by Charles Lindbergh, the famous aviator, who from March 1942 till March 1944 was Ford’s engineering consultant.

 

Another major problem to commencing production at Willow Run was the large number of engineering changes required initially due to the fact that Consolidated had not updated their original design templates.  When the design of an original part was complete a steel template was made which was used as the ‘master’ for production of that particular part.  If the original part was modified a new ‘master’ template was made.  

 

Master templates for production at Willow Run were made by Ford’s most experienced template makers from Consolidated’s master templates.  It was discovered that many changes in Consolidated’s original design had not been recorded on their templates.  This required not only making a whole new set of templates but major reworking of all tooling that had resulted from the layout of the original Consolidated templates.    

 

Field modifications:

 

As the war progressed, field experience resulted in engineering changes being requested by the USAAF, these changes would affect the lives of the men who flew the B-24.  Making changes reduced production.  An agreement was reached that changes would be incorporated at certain intervals and that Liberators without those changes would be accepted by the Air Force until those time periods came due.  The first aircraft in each new design group was designated the Master Change Ship and the groups varied in size from 200 to 400 aircraft.  The production team at Willow Run were not always assisted in making these changes.  In August 1942 General Arnold had a meeting with Charles Lindbergh to discuss the concern of the USAAF with regard to the lack of armour plating on the B-24.  A month later Lindbergh flew to Wright Field to discuss ways in which to improve the armour plating on Liberators.  The armaments officers at Wright Field were indifferent.  

 

The major field experience change related to the need to improve the defensive fire power in the nose of the B-24.  In the first hundred B-24s the nose contained a single gun, in 101 - 400 a second gun was added, in 410 - 800 a third gun was incorporated.  It soon became clear that a nose turret similar to the rear turret was needed.  A field version by two officers, Lieutenant Colonel Arthur Rogers and Major Marion Unrah of the 90th Bomb Group was being examined.  These officers worked with the engineering staff at Willow Run.  Unrah was reassigned to the Seventh Air Force in Hawaii and continued to develop the installation of a nose turret.  Rogers returned to the 90th Bomb Group and also continued to work on the fitting of a nose turret with the engineering modification being carried out in Brisbane, Australia.  Unrah, who had been promoted to Lieutenant Colonel, became the first person to install a nose turret in a B-24.  In February 1943 the USAAF asked Consolidated for fifty nose turret Liberators to be delivered within four months (June 1943) and to pass on to Willow Run by the end of February the production changes required.  In March Willow Run was asked by Wright Field if they could incorporate the changes requested of Consolidated without receiving engineering from Consolidated and informed that fifty Emerson turrets would be available in May.  Ford production and engineering worked together to design a completely new nose assembly, attachable directly to the front fuselage, using the same mounting hole as the current assembly thus eliminating structural modification to the fuselage.  A half size clay model of the front of the fuselage was made from which full scale plans and a model of the assembly were laid out.  A full size wooden die was made from which the experimental assembly was produced by hammering out parts by hand over the wooden model.  

 

The first blueprint was released to production on the 10th April.  The Emerson turret was wider than the original nose, requiring a corresponding increase in the size of the front assembly.  The turret moved on a circular track supported on a support shaped like a bucket.  The bomb aimers compartment, with bomb sight mountings and the bomb release equipment was moved to the underneath slope of the front fuselage.  The first aircraft to receive the Emerson turret was ‘801’.  She entered station one of final assembly on the 24th May.  By the end of June there were forty four Emerson turreted B-24s in final assembly, six more outside on the ramp and a further six delivered to Flight.  Consolidated went into production at San Diego with their front turreted B-24 at the beginning of September.  Fort Worth went into production two weeks later.      

 

Housing:

 

On the 8th December 1941,  though the Willow Run factory was unfinished, parts for the B-24 began to be manufactured.  On the 1st December, six days before Pearl Harbor (7th December) the hiring of many thousands of people had begun.  In order to avoid a major traffic problem the Michigan Highway Department routed to Willow Run a four lane divide expressway under construction from Detriot to Chicago. The housing programme for the Willow Run work force was totally inadequate.  It was not until February 1943 that the first government housing (‘Willow Village’) become available.  In June 1943 when the factory employed over forty two thousand people there was only sufficient government accommodation for just over 3000 people.  Six months later when the workforce had diminished due to production being slowed down, ‘Willow Village’ was opened providing accommodation for 2500 families.  The lack of housing produced a high turnover and low employee morale.  The squalid conditions created by families living in tents, trailers and shacks became a national disgrace.

    

Production:

 

In front of the beginning of the assembly line and to one side of the assembly line there were over fifty manufacturing and assembly areas.  The large press shop made 120000 pieces every day using 345 presses, the machine shop produced 25000 pieces ever day, the draw bench where wing stringers were manufactured employed 300 people, the small parts assemblies occupied more than an acre of floor space.  Over 300000 rivets were used in every B-24, over 500 different types of rivet were manufactured and in 1944 the rivet department made nearly two billion rivets.

Assembling the centre wing section took Consolidated many hours.  It was believed, by aircraft manufacturers,  that it was not possible to rivet the skin and stringers together at a location other than where they were joined to the bulkhead and spar.  The Ford engineers felt that provided the preliminary operations were properly oriented and fitted in relation to those that followed, the resulting parts should fit where ever they were assembled.  

 

At Willow Run the centre wing skin and stringer assembly commenced with fixtures holding the long skin segments for both the upper and lower surfaces of the wing while they were riveted together.  The long stringers, which had been made in one of the manufacturing areas, were laid out on steel benches.  As the wings tapered so to did the stringers.  The thickness of skin varied from an eighth of an inch to one fortieth of an inch.  Locating points and jigs on the tables allowed workers to follow the different angles and junctions for supporting the stringers.  Ten rectangular skin sections were riveted together on special curved fixtures to form the upper wing surface, to allow for Bernoulli’s principle of lifting forces the upper surface rivets were countersunk.  Forty four pieces of skin were required for the wing lower surface.  After the skin surfaces were joined together and the stringers properly prepared they were placed in a vertical fixture (70 feet long, 18 feet high and 13 feet wide) designed to hold them both while they were riveted together.  Through holes already pierced in the stringers, workers drilled from the stringer side through the upper skin surface while another crew working on the other side countersank the holes.  Over 78000 rivets were used to attach the skins to the stringers.  Prior to the centre wing being moved from the vertical fixture by overhead crane four reference blocks were secured to the bottom and rear spar.  The  centre wing was carried to the vertical machining and boring fixture.  Seven operators carried out forty two machining operations (thirty two related to the engine mounting pads and ten related to the landing gear needle bearings) in just over half an hour.

 

The centre wing then moved horizontally through twelve stations.  At each station components were added to the wing, at station ten the main landing gear was installed.  While the centre wing was being assembled the workers in the parallel bay along the north wall of the factory were assembling the fuselage and its component sub assemblies.  At what was referred to as the transfer bay the two major sub assemblies crossed over to the final assembly lines.     

 

The final assembly lines commenced with two 150 foot wide assembly bays which initially provided four assembly lines where the fifty five foot centre wing was mated with the fore and aft sections of the fuselage.  These four lines started from station one through to station fourteen.  There was direct routing of parts and sub-assemblies at each station.  At station one the top fuselage deck above the wing was installed, at station two the front and rear bomb racks, catwalk and side panels were added.  At station seven the nose wheel was fitted.  

 

At station eight the fuselage was mated with the centre wing.  Mating of the fuselage section  with the centre wing was spread over several work stations.  A heavy duty fixture was developed which allowed the fuselage to be aligned and ‘mated’ with the centre wing section.  Four cast iron towers were arranged in pairs and set far enough apart to allow the fuselage to pass between them and low enough so that the centre wing section could pass over them.  The centre wing was lowered on to the towers which located with the four reference blocks that had been bolted in place before the wing was moved to the vertical machining and boring fixture.  

 

The wing was then adjusted to a flight angle of incidence of three degrees twenty six minutes.  The four towers were mounted in reinforced concrete which had been poured to a depth of eighteen feet to ensure they did not move out of alignment.  From this point each Liberator was moving on its own wheels.

 

On later models at station eleven the Emerson front turret was fitted.  The two assembly bays were equipped with an overhead crane to assist in the movement of parts to the four production lines.  Each of these four lines fed partially assembled aircraft into the centre of the bay where at station fifteen the four lines became two allowing the two 150 foot bays to provide sufficient space for attaching the outer wings giving the Liberator its total wing span of 110 feet.  The ailerons and flaps were added, engines and propellers installed and the two B-24s being assembled side by side began to become complete aircraft as they moved through from stations fifteen to twenty.  Between stations 20 and 21 the B-24s were moved on to a turntable and turned ninety degrees to prevent the factory from being built in Washtenaw county.  At station twenty four the B-24s from one side were moved sideways and integrated with the B-24s being constructed beside them with the result that the two assembly lines became one.  Final assembly was complete at station twenty eight.  Each B-24 then took on fuel and oil and had their compasses calibrated.  The guns on every fifth Liberator was checked on the Gun Butts.  Prior to delivery every B-24 was flight tested.  Delivery  from Willow Run was undertaken by the men and women of Ferry Command operating from Romulus, Michigan.

 

Willow Run after the war:

 

After World War Two the Kaiser-Frazer Corporation purchased Willow Run.  They used the factory to build cars and during the Korean war aircraft.  In 1953 the corporaton ceased operating due to financial difficulties.  In the same year a fire destroyed General Motor’s Hydra-matic transmission facility at Livonia, Michigan.  General Motors took over Willow Run and within two months got Hydra-matic production up and running.  The plant is still in use with General Motors.  On the site of the original training school the headquarters of the Yankee Air Force museum is located.       

Dates:

 

1941:  28th March; site clearance begins at Willow Run.  20th April; first concrete poured in foundation footing.  3rd May; first piece of structural steel framework erected.  25th June; first concrete floor poured.  12th August; first machinery installed at Willow Run.  22nd August; first concrete poured on runways in airfield.  2nd October; first official airport landing.  8th December; first horizontal milling machine put in to operation and first part produced at Willow Run.  

 

1942:  15th January; centre wing fixture ready for production.  18th February; centre wing leading edge for No 1 ship started.  19th March; pilot’s floor for No 1 ship completed.  23rd March Charles Lindbergh engaged as engineering research consultant.  31st March; first shipment of sub assemblies sent to Douglas.  15th April; centre wing for No 1 ship taken out of fixture.  15th May; first Willow Run assembled B-24 turned over to Flight Department.  12th July; first KD kit shipped to Douglas.  3rd October; centre wing No 59 assembled in 93.25 hours.  31st October; seventh B-24 delivered to Flight.  7th November; first shipment to North American.  8th November; first B-24 delivered to Fort Worth.  27th November; centre wing No 145 assembled in 37.83 hours.  23rd December; centre wing No 178 assembled in 19.17 hours.

 

1943:  7th January; ship No 100 entered final assembly line.  15th February; first unit of Willow Run housing facility (‘Willow Lodge’) opened.  14th April; 500th centre wing section commenced in vertical fixture.  24th April; ship No 200 delivered to Flight.  28th April; ship No 300 entered final assembly line.  22nd May; ship No 400 entered final assembly line.  9th June; centre wing No 800 completed in vertical fixture.  10th July; centre wing No 1000 completed in vertical fixture.  13th July; ship No 500 delivered to Flight.  1st September; ship No 700 delivered to Flight.  17th September; centre wing No 1500 in vertical assembly fixture.  20th October; centre wing No 1800 in vertical assembly fixture.  27th October; ship No 1000 enters stations at final line.  6th November; centre wing No 2000 started in vertical fixture.  4th December; orders issued from Wright Field to discontinue camouflage.  

 

During 1943 1300 B-24s flown away from Willow Run in addition  1106 KD’s kits transported to Douglas and Consolidated.

 

1944:  28th January; centre wing No 3000 started in vertical fixture.  4th February; ship No 1600 completed in final assembly line.  24th February; 10000th student graduated from AAFTTC school at Willow Run.  By the end of February 1824 ships had been assembled at Willow Run in addition 657 KD kits were shipped to Douglas and 809 KD kits were shipped to Consolidated.  18th March; ship No 2000 completed in final assembly.  Single tail prototype started.  During March 322 ships assembled at Willow Run in addition 78 shipped to Douglas and 62 shipped to Consolidated (overall 462 B-24s produced).  

 

7th April; ship No 2200 completed in final assembly.  By the end of April total production so far was 2483 ships assembled at Willow Run in addition 801 B-24s shipped to Douglas and 923 Liberators shipped to Consolidated.  

 

During April 1944 four hundred and fifty five Liberators were made in four hundred and fifty hours, a rate on one every 59.3 minutes.  

 

10th May last KD kit shipped to Consolidated.  17th May; centre wing No 4600 entered vertical fixture.  31st May; ship No 2800 left final assembly line.  During May only 18 KD kits shipped to Consolidated.  16th June; centre wing No 5000 started.  28th June; ship No 5000 completed in final line.  During this month 387 ships assembled at Willow Run in addition 66 B-24s shipped to Douglas.  7th July last KD kit shipment to Douglas.  1st August; single tail ship fixture and tool design begun.  15th August ship No 3800 finished in final line.  19th August; first test flight Ford bomber crash (near Almont, Michigan).  21st August; centre wing 6000 started in vertical fixture.  31st August; 6000th ship entered line number four of primary assembly.  11th September 6000th ship off the line.  21st October; single tail prototype fuelled.  During October 348 B-24s manufactured.  5th November; first flight of single tail prototype.  13th November; Departments 940A and B (fuselage) placed on one shift.  16th November; centre wing 7000 started in vertical fixture.  During November 318 B-24s built.  26th December; directive received from Wright Field requesting 206 ships without ball turrets also 55 ships without tail turrets, all to be delivered by the end of January 1945.  During December 296 Liberators built.

 

On the 28th June 1945 production ceased.  The last Liberator built was a B-24M (44-51928).  8685 B-24s had been built at Willow Run, of these 1893 were KD kits.

 

Facts:

 

Aileron:  41.55 square feet of area, covered with grade A cotton with six coats of dope, travel up 20 degrees, down 20 degrees.

 

Battery:  Two 24 volt batteries in each B-24, weight 75 pounds each, served as emergency supply.  Each engine driven generator (one on each engine) supplied up to 200 amps.  APU had a capacity of 70 amps and 27 volts, driven by 3hp motor, weighed 122 pounds.

 

Cables in B-24:  226 cables per B-24, longest piece fifty three feet three inches, shortest piece eight inches, seven types used.

 

Camouflage:  Weight per aircraft 90 - 120 pounds.  Increase in speed of 8 - 12 mph when camouflage not applied.

 

Empennage.  Tail height twelve feet, width from one tail fin to the other twenty six feet.  Elevator area 67.06 square feet.  Area of fin 123 square feet.  Area of rudder aft of hinge 64.3 square feet.  Built to withstand 25g.  During perfect landing a force of 1 - 2g would be applied.

 

Flaps:  Raised at 750 pounds pressure, lowered at 450 pounds pressure.  Maximum travel forty degrees.  Could not be lowered if aircraft speed was in excess of 150 mph.  When extended the lift of the wing increased by 55% but its drag increased by 70%.

 

Fuel cells:  Twelve in centre wing section, overall capacity 2372 gallons.  Three tanks in each of the two outer wings, overall capacity 348 gallons.  Total of 2720 gallons gave an approximate weight of 16320 pounds.  Each cell of three layer self sealing construction.  

 

Hydraulics:  System capacity 18 gallons.  Accumulators ten inch diameter, 900 - 1000 psi.  Fluid circulated by displacement pump fitted to number three engine, output approximately 7 gallons per minute.  If hydraulic pump (or number three engine) failed electrically operated pump mounted on right bomb bay side panel could be used.  If both pumps failed hand pump mounted on floor beside co-pilot.

 

Midgets:  Ten employed to install stiffener rods in auxiliary fuel cells and attach outer wing assembly to centre wing section at splice joint.

 

Oil:  142 gallon tank for each engine.

 

Propeller:  Eleven foot six inch diameter.  Weight, including governor, 473 pounds.  Blades made of drop forged aluminum ally, hub made of steel.

 

Tabs:  Area of single elevator tab (there were two) 1.2 square feet, all metal construction.

 

Bottom turret:  Sperry retractable.  Controlled by gunner, operated by Power-Vickers electro-hydraulic unit.  Forty volts.  Sight- Sperry automatic computing type.  Diameter of turret forty four inches.  Height of turret and hanger assembly 104 and one eighth inches.  When lowered, extended from retracted position by twenty seven and a half inches.  360 degrees rotation in azimuth, depression of guns 85 degrees from vertical.  Ammunition stored in containers attached to hanger assembly outside of turret.  Weight of turret 780 pounds.  Side pressure in hand grips gave azimuth rotation, forward or back pressure moved turret up or down.

 

Nose turret:  Emerson Electric Type A-31D.  Controlled by gunner, electrically operated. 27.5 volts.  Sight - ring reticle reflector type.  Bullet proof glass and armour plate in front of gunner.  Diameter of turret forty two inches, height sixty nine inches, weight 720 pounds.  Azimuth rotation 150 degrees, elevation of guns sixty degrees above horizontal, depression of guns fifty degrees below horizontal.  Ammunition stored in boxes outside of turret on each side of nose fuselage.

 

Tail turret:  Army A-6-C.  Manufactured by Southern Aircraft Corporation.  Hydraulically operated, no armour plate.  K-10 compensating sight.  Diameter forty inches, height fifty eight inches, weight 550 pounds.  Ammunition stored in bins located in aft section of fuselage.  Azimuth rotation 122 degrees, elevation of guns seventy one degrees above horizontal, depression of guns forty degrees below horizontal.  Side pressure on gun grips actuated a rack and pinion (located under gunner’s seat) which rotated the turret.  Forward or backward pressure actuated hydraulic jack (in front centre of turret) which moved the guns in a vertical plane.

 

Top turret:  Glenn L Martin type A-3D.  Controlled by gunner, electrically operated.  27.5 volts.  Sight - ring reticle reflector type.  Armour plate below ring in front of gunner.  Diameter forty two inches, height sixty inches, weight 564 pounds.  Azimuth rotation 360 degrees, elevation of guns eight five degrees above horizontal, depression eight degrees below horizontal.  Ammunition stored in containers suspended from turret ring in front of gunner.    

 

Turbo:  General Electric.  180hp generated from each turbo.  Temperature of super charger air 400 degrees F.  Lubrication jet and splash system.  Each R-1830 required 135 pounds of air per minute at seal level.  Speed up to 28000 rpm.  Built by Fords at River Rouge plant until October 1944.  52244 produced.            

  

 

Willow Run

 

Henry Ford’s grandfather, John, cleared and lived in land near Dearborn, Michigan.  Henry Ford was born on this land in 1863 and in the late 1920s started buying large areas of land throughout Michigan for what became known as the Ford Farms.  On some of the land he maintained two camps to help sons of World War One veterans, one of the camps was located east of Ypsilanti near Willow Run stream.  

 

In December 1940 Ford’s was asked to build airplanes.  Charles Sorensen, Ford’s executive vice-president, visited Consolidated’s Liberator plant at San Diego.  Sorensen conceived the idea to mass produce B-24s.  San Diego could not be enlarged and modernised for mass production so a decision was made to build the Ford B-24 plant, which would include an airport and factory, on the Ford camp located near Willow Run stream.

 

In early March 1941 a group of Ford engineers, production experts and draftsmen arrived at Consolidated’s plant in San Diego.  A cardboard model of the proposed Willow Run plant was made and divided into bays representing 40 by 60 feet manufacturing area and 40 by 150 feet assembly area.  Paper templates of machinery and other facilities were made and moved on the layout board to determine the most advantageous location.  

 

The plant would require a seventy four mile drainage system, digging trenches for the sewer lines began on the 13th August 1941.  The total area of the factory floor was 80.4 acres, the concrete flooring being covered with creosoted wood block flooring.  The factory was ‘L’ shape to avoid crossing from Wayne county to Washtenaw county with the longer leg running 3200 feet and the shorter leg being 1279 feet.  The assembly line was 5460 feet long.  

Willow Run airport:

 

The airport was located on 1434 acres.  It  had six runways all 160 feet in width and ranging in length from 6363 feet to 7286 feet.  2.3 miles of taxiway, 80 feet wide, was laid.  On the 3rd May 1941 the first structural steel was erected on its concrete foundation and footings.  

 

Prior to delivery every B-24 was flight tested by flight crews employed by Fords.  Delivery  from Willow Run was undertaken by the men and women of Ferry Command operating from Romulus, Michigan.

Centre wing section:

 

Consolidated were taking 550 man hours to manufacture the B-24 centre wing section.  

 

At Willow Run fixtures were manufactured which held the long skin segments for both the upper and lower surfaces of the wing while they were riveted together.  The thickness of skin varied from an eighth of an inch to one fortieth of an inch.  Locating points and jigs on the tables allowed workers to follow the different angles and junctions for supporting the stringers.  Ten rectangular skin sections were riveted together on special curved fixtures to form the upper wing surface.  Forty four pieces of skin were required for the wing lower surface.  

 

After the skin surfaces were joined together and the stringers properly prepared they were placed in a vertical fixture (70 feet long, 18 feet high and 13 feet wide) designed to hold them both while they were riveted together.  Through holes already pierced in the stringers, workers drilled from the stringer side through the upper skin surface while another crew working on the other side countersank the holes.  Over 78000 rivets were used to attach the skins to the stringers.  The  centre wing was then carried by crane to the vertical machining and boring fixture.  Seven operators carried out forty two machining operations.  From start to finish the manufacture of the centre wing took less than one hour.

 

Workforce:

 

Of the three hundred thousand experienced aircraft workers in America, Fords were allocated four hundred.  A training school was set up within the Willow Run complex.  The workforce of many women and young men lacked aircraft  and industrial experience.

 

On the 1st December, six days before Pearl Harbor (7th December) the hiring of many thousands of people begun.  In order to avoid a major traffic problem the Michigan Highway Department routed to Willow Run a four lane divide expressway under construction from Detriot to Chicago.

 

The housing programme for the Willow Run work force was totally inadequate.  It was not until February 1943 that the first government housing (‘Willow Village’) become available.  In June 1943 when the factory employed over 42000 people there was only sufficient government accommodation for just over 3000 people.  Six months later, when the workforce had diminished due to production being slowed down, ‘Willow Village’ was opened providing accommodation for 2500 families.  The lack of housing produced a high turnover and low employee morale.  The squalid conditions created by families living in tents, trailers and shacks became a national disgrace.

 

Initially B-24 components were badly constructed.  Towards the end of 1942 there was a marked improvement in the quality of the B-24 components being manufactured.  These improvements were orchestrated by Charles Lindbergh, the famous aviator, who from March 1942 till March 1944 was Ford’s engineering consultant.

 

(The photograph shows protection worn by the female workforce ... were these the first ever ‘boob tub’!)

Field modifications:

 

The major field experience change related to improving the defensive fire power in the nose of the B-24.  In the first hundred B-24s the nose contained a single gun, then a second gun and finally a third gun was incorporated.  It soon became clear that a nose turret similar to the rear turret was needed.  A field version was fitted by two officers of the 90th Bomb Group.  These officers worked with the engineering staff at Willow Run.  Ford production and engineering designed a nose assembly that could be attached directly to the front fuselage, using the same mounting hole as the original assembly thus eliminating structural modification to the fuselage.  The turret moved on a circular track laid on a support shaped like a bucket.  The bomb aimers compartment, with bomb sight mountings and the bomb release equipment was moved to the underneath slope of the front fuselage.  The first aircraft to receive the Emerson turret was ‘801’.  She entered station one of final assembly on the 24th May 1943.  By the end of June there were forty four Emerson turreted B-24s in final assembly, six more outside on the ramp and a further six delivered to Flight.  Consolidated went into production at San Diego with their front turreted B-24 at the beginning of September.  Fort Worth went into production two weeks later.      

Production (1):

 

Surrounding the assembly line were over fifty manufacturing and assembly areas.  The large press shop made 120000 pieces every day using 345 presses, the machine shop produced 25000 pieces ever day, the draw bench where the wing stringers were manufactured employed 300 people.  Over 300000 rivets were used in every B-24 with over 500 different types of rivet being manufactured.

 

The centre wing having been manufactured, moved through twelve stations.  At each station components were added to the wing, at station ten the main landing gear was installed.  While the centre wing was being assembled the workers in the parallel bay along the north wall of the factory were assembling the fuselage and its component sub assemblies.  At what was referred to as the transfer bay the two major sub assemblies crossed over to the final assembly lines where the fifty five foot centre wing was mated with the fore and aft sections of the fuselage.  

Production (2):

 

The four production lines became two.  The ailerons and flaps were added, engines and propellers installed and the two B-24s being assembled side by side began to become complete aircraft as they moved through from stations fifteen to twenty.  Between stations 20 and 21 the B-24s were moved on to a turntable and turned ninety degrees to prevent the factory from being built in Washtenaw county (avoid taxes).  At station twenty four the B-24s from one side were moved sideways and integrated with the B-24s being constructed beside them with the result that the two assembly lines became one.  Final assembly was completed at station twenty eight.  Each B-24 then took on fuel and oil and had their compasses calibrated.  

Willow Run after the war:

 

After World War Two the Kaiser-Frazer Corporation purchased Willow Run.  They used the factory to build cars and during the Korean war aircraft.  In 1953 the corporaton ceased operating due to financial difficulties.  In the same year a fire destroyed General Motor’s Hydra-matic transmission facility at Livonia, Michigan.  General Motors took over Willow Run and within two months got Hydra-matic production up and running.  The plant is still in use with General Motors.  The Yankee Air Force museum is located on the site of the original training school.       

Production figures:

 

1942:  15th May first Willow Run assembled B-24 turned over to Flight Department.  12th July first KD kit shipped by specially designed Ford trucks to Douglas.  31st October seventh B-24 delivered to Flight.  7th November first shipment of KD kit to North American.  8th November first B-24 delivered to Fort Worth.  27th November centre wing No 145 assembled in 37.83 hours.  23rd December centre wing No 178 assembled in 19.17 hours.

 

1943:  7th January ship No 100 entered final assembly line.  24th April ship No 200 delivered to Flight.  10th July centre wing No 1000 completed in vertical fixture.  13th July ship No 500 delivered to Flight.  1st September ship No 700 delivered to Flight.  6th November centre wing No 2000 started in vertical fixture.  4th December orders issued from Wright Field to discontinue camouflage.  

 

1944:  28th January centre wing No 3000 started in vertical fixture.  24th February 10000th student graduated from AAFTTC school at Willow Run.  18th March ship No 2000 completed in final assembly.  In March 322 ships assembled at Willow Run in addition 78 shipped to Douglas and 62 shipped to Consolidated.  

During April four hundred and fifty five Liberators were made in four hundred and fifty hours, a rate on one every 59.3 minutes.  

 

28th June ship No 5000 completed in final line.  11th September 6000th ship off the line.  13th November; Departments 940A and B (fuselage) placed on one shift.  

 

On the 28th June 1945 production ceased.  The last Liberator built was a B-24M (44-51928).  8685 B-24s had been built at Willow Run, of these 1893 were KD kits.

Ball Turrets

 

Sperry retractable.  Controlled by gunner, operated by Power-Vickers electro-hydraulic unit.  Forty volts.  Sight- Sperry automatic computing type.  Diameter of turret forty four inches.  Height of turret and hanger assembly 104 and one eighth inches.  When lowered, extended from retracted position by twenty seven and a half inches.  360 degrees rotation in azimuth, depression of guns 85 degrees from vertical.  Ammunition stored in containers attached to hanger assembly outside of turret.  Weight of turret 780 pounds.  Side pressure in hand grips gave azimuth rotation, forward or back pressure moved turret up or down.