Manufacturing times:
Spitfire: 13,000 man hours
Hurricane: 5,200 man hours
Bf 109: 4,000 man hours
So where did the figures come from? Are they meant to be airframes only, or complete aircraft? As of early 1939 the German export prices for ordering 201 or more airframes were Bf109E 70,000 RM each, Bf110C 140,000, He111 205,000, HS126 85,000, Ju52 118,000, Ju87B 88,000 Ju88A 167,000. So if the Bf109E really did take 4,000 man hours either it was being sold at super profit levels or all German airframes were similarly economical to build. If you wanted complete Bf109E then ordering 201 or more would cost you $130,000 RM each. Engines quoted at 47,000 RM.
The basic rule is the longer the production run the more tooling can be used. Hawker were given an initial contract for twice the number as Supermarine and had been building larger numbers or aircraft for years. Ford discovered aircraft have small production runs and large numbers of modifications, making it hard to do their idea of tooling economically.
Firstly a diversion, Liberty ships were relatively low technology, built using well established methods by multiple yards, The 2,648 Emergency Cargo (Liberty) cost an average of $1,827,000 each. In terms of the ship yards, the following applies, table is ship yard, ships delivered, average cost,
Alabama / 20 / 1,958,000
Bethlehem-Fairfield / 361 / 1,755,000
California / 306 / 1,858,000
Delta / 128 / 1,939,000
Jones-Brunswick / 85 / 1,993,000
Jones-Panama City / 66 / 2,020,000
Kaiser-Vancouver / 2 / 2,703,000
Marinship / 15 / 3,012,000
New England / 228 / 1,892,000
North Carolina / 126 / 1,544,000
Oregon / 330 / 1,643,000
Permanente-Richmond #1 / 138 / 1,875,000
Permanente-Richmond #2 / 351 / 1,667,000
Rheem / 1 / 7,191,000
St Johns / 82 / 2,099,000
Southeastern / 88 / 2,043,000
Todd-Houston / 208 / 1,833,000
Walsh-Kaiser / 10 / 3,923,000
Firstly showing the advantages of mass production but also the efficiencies of the different yards. If you take a minimum of 50 ships delivered as the cut off point then average costs vary between 1.5 and 2.1 million dollars each.
Much of the cost of an aircraft is non airframe, engines etc. So as of 31 July 1944, costs, weighted average of all contracts, airframe cost, percentage of total cost.
| Type | Airframe | %cost | Type | Airframe | %cost |
| B-29 | $ 478,180 | 63.17 | C-48 | $ 91,229 | 67.71 |
| B-32 | $ 540,305 | 70.52 | C-49 | $104,870 | 72.24 |
| B-17 | $ 157,484 | 57.91 | C-50 | $ 97,273 | 72.86 |
| B-24 | $ 169,452 | 60.00 | C-51 | $100,689 | 76.18 |
| B-25 | $ 93,690 | 56.46 | C-52 | $105,052 | 73.46 |
| B-26 | $ 140,735 | 58.03 | C-53 | $107,124 | 74.03 |
| B-34 | $ 108,558 | 57.66 | C-60 | $ 91,978 | 75.06 |
| A-20 | $ 75,448 | 60.69 | C-76 | $135,489 | 78.53 |
| A-26 | $ 112,264 | 56.75 | C-82 | $427,244 | 89.47 |
| A-28 | $ 91,499 | 72.95 | C-45 | $ 39,667 | 59.81 |
| A-29 | $ 89,262 | 70.12 | C-78 | $ 16,818 | 49.76 |
| A-30 | $ 110,586 | 72.14 | C-43 | $ 18,687 | 70.02 |
| A-24 | $ 35,922 | 63.66 | C-61 | $ 7,611 | 55.77 |
| A-25 | $ 67,492 | 68.66 | C-64 | $ 26,336 | 71.37 |
| A-31 | $ 65,852 | 72.96 | AT-7 | $ 43,504 | 63.94 |
| A-35 | $ 56,166 | 68.26 | AT-8 | $ 25,646 | 61.50 |
| A-36 (P-51) | $ 36,706 | 60.97 | AT-9 | $ 27,927 | 62.64 |
| P-38 | $ 73,607 | 63.63 | AT-10 | $ 26,886 | 61.57 |
| P-59 | $ 128,961 | 60.55 | AT-11 | $ 47,429 | 59.16 |
| P-61 | $ 191,831 | 64.50 | AT-17 | $ 20,968 | 64.44 |
| P-70 | $ 79,865 | 55.82 | AT-18 | $ 83,890 | 69.33 |
| P-82 | $ 86,540 | 65.38 | AT-21 | $ 62,381 | 61.91 |
| P-39 | $ 32,824 | 51.05 | AT-6 | $ 14,188 | 52.84 |
| P-40 | $ 29,515 | 52.74 | AT-19 | $ 22,793 | 67.59 |
| P-47 | $ 61,699 | 58.48 | BT-12 | $ 29,159 | 68.87 |
| P-51 | $ 28,984 | 49.26 | BT-13 | $ 12,657 | 51.90 |
| P-63 | $ 28,551 | 48.95 | BT-15 | $ 13,741 | 57.43 |
| P-72 | $ 153,672 | 85.61 | PT-13 | $ 6,054 | 55.21 |
| P-75 | $ 83,585 | 61.73 | PT-17 | $ 5,756 | 60.93 |
| F-3 (A-20) | $ 103,627 | 63.58 | PT-18 | $ 5,943 | 60.53 |
| O-52 | $ 24,558 | 57.73 | PT-19 | $ 7,340 | 64.71 |
| OA-10 (PBY) | $ 158,941 | 71.34 | PT-23 | $ 10,632 | 70.80 |
| C-54 | $ 262,501 | 75.16 | PT-26 | $ 9,668 | 67.19 |
| C-69 | $ 534,331 | 81.31 | L-1 | $ 18,341 | 72.15 |
| C-74 | $ 949,740 | 87.26 | L-5 | $ 6,763 | 70.40 |
| C-87 | $ 196,474 | 73.56 | R-4 | $ 46,826 | 91.55 |
| C-46 | $ 197,639 | 74.71 | R-5 | $ 50,586 | 83.65 |
| C-47 | $ 73,749 | 62.49 | R-6 | $ 41,142 | 85.73 |
The US did a lot of measuring, with airframe build efficiency in WWII it seems productivity followed a curve that said it took 16 to 18 man hours per pound of aircraft for the first production example, dropping to around 7 man hours by aircraft 10, 3 by aircraft 100, 1.2 by aircraft 1000 and 0.52 man hours per airframe pound by aircraft 10,000. Now name a US production line that actually turned out 10,000 aircraft of the same design.
British figures. Cost of 201st production aircraft, estimated man hours, Lancaster 74,319, Halifax 98,246, Stirling 129,944. As of 22 December 1941 a Hurricane IId was estimated to take 19,560 man hours, a Spitfire Vc as of 23 April 1942 19,086 man hours. The early estimate for the Hawker Typhoon had 28,756 man hours using present methods and 22,349 man hours using full advantage of best available manufacturing methods. In May 1942 a Lancaster was estimated to cost 84,800 pounds ready to be sent to a combat unit, a Stirling in June 1942 140,800 pounds. In March 1941 4 Hurricanes "absorbed from Dominion orders" were costed at 8,500 pounds each, the proposed Spitfire order had a unit cost of 10,123 pounds each, the proposed Typhoon order 16,700 pounds, Lancaster 44,500 pounds, and the Oxfords at 7,200 pounds each.
Figures from Buying Aircraft by Halley,
There was a real trade off between production line changes and modification centre effort, to install a P-38 wing fuel tank on the line took under an hour, in a modification centre 300 hours. At one time one small aircraft design took 9,000 hours to build and 8,000 hours in the modification centre. In the end 25 to 50% of the man hours turning out military aircraft were performed at the modification centres. Nearly all bombers and transports needed modification, along with 30 to 50% of fighters. Some 58,741 AAF aircraft were reworked.
Time and dollar costs encountered while making 73 modifications to a group of 1,000 P-38,
P-38F-5, 10,450 engineering hours, 6,200 tooling hours, $4,650
P-38G-1, 23,250 engineering hours, 23,760 tooling hours, $18,000
P-38G-3 to 5, 5,000 engineering hours, 4,000 tooling hours, $3,000
P-38G-10, 19,200 engineering hours, 18,480 tooling hours, $13,800
B-25 direct engineering hours to give an idea on how often design change actually was
1940 - 329,415 hours
1941 - 419,060 hours
1942 - 695,488 hours
1943 - 461,213 hours
1944 - 200,321 hours
Ford Willow run began production in September 1942, as of January 1943 it took 5.03 direct man hours per pound of airframe accepted, it was 2.52 in February and 1.03 in May, 0.56 in January and May 1944, and 0.32 in September 1944.
Republic Farmingdale in January 1943 had a ratio of 3.82 direct man hours per pound of airframe accepted, that was down to 1.9 in May 1943, and 1.02 in September 1944, it then spiked to 1.61 in December 1944. Hello M and N models.