Watching a documentary about US production, if the US had used all of its car industry and similar making Sherman tanks, the whole of US steel production could have been turned into tanks, a very different problem to that faced by Germany, but a problem still the same.
WW II aircraft fatigue life
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Geoffrey Sinclair
Staff Sergeant
- 922
- Sep 30, 2021
M4 Sherman Production. The US made an assumption about the amount of tanks needed in 1943 that proved an over estimate.
8,017 in 1942
21,245 in 1943
13,179 in 1944
6,793 in 1945
Heavy Bomber Production
1940, 53 B-17, 7 B-24
1941, 144 B-17, 169 B-24
1942, 1,412 B-17, 1,164 B-24
1943, 4,179 B-17, 5,214 B-24
1944, 5,352 B-17, 9,519 B-24
1945, 1,552 B-17, 2,117 B-24
Total, 12,692 B-17, 18,190 B-24
Heavy bomber, cost of airframe ONLY, which represents around 50 to 60% of total cost.
28-Feb-43 B-17 $111,443 Costs based on weighted average of uncompleted contracts
28-Feb-43 B-24 $115,338 Costs based on weighted average of uncompleted contracts
31-Jul-44 B-17 $157,484 Costs are weighted average of all Army contracts from 1939 to date
31-Jul-44 B-24 $169,452 Costs are weighted average of all Army contracts from 1939 to date
31-Aug-44 B-17 $129,150 Costs based on uncompleted contracts
31-Aug-44 B-24 $138,585 Costs based on uncompleted contracts
30-Nov-44 B-17 $125,464 Costs based on uncompleted contracts
30-Nov-44 B-24 $114,951 Costs based on uncompleted contracts
USAAF Statistical Digest table 82, total cost.
Year B-17 B-24
1939/41 $301,221 $379,162
1942 $258,949 $304,391
1944 $204,370 $215,516
1945 $187,742 na
8th Air Force combat sortie loss rates, 1944
As noted before a higher percentage of 8th Air Force B-24 combat losses made it back to allied lines, how much of that is due to the B-17 being more crash worthy is unclear. B-17 were 68.8% of all sorties, 70.2% of effective sorties, 62% of mechanical aborts, 58.7% of weather aborts. Also as noted before B-24 production was cancelled before B-17.
Source Book of World War II Basic Data, Airframe Industry, Volume 1, man hours per aircraft
Fort Worth excludes knock downs. Ford invested a lot more in tooling and it shows, but the constant production changes made it very hard to recover the tooling costs.
8,017 in 1942
21,245 in 1943
13,179 in 1944
6,793 in 1945
Heavy Bomber Production
1940, 53 B-17, 7 B-24
1941, 144 B-17, 169 B-24
1942, 1,412 B-17, 1,164 B-24
1943, 4,179 B-17, 5,214 B-24
1944, 5,352 B-17, 9,519 B-24
1945, 1,552 B-17, 2,117 B-24
Total, 12,692 B-17, 18,190 B-24
Heavy bomber, cost of airframe ONLY, which represents around 50 to 60% of total cost.
28-Feb-43 B-17 $111,443 Costs based on weighted average of uncompleted contracts
28-Feb-43 B-24 $115,338 Costs based on weighted average of uncompleted contracts
31-Jul-44 B-17 $157,484 Costs are weighted average of all Army contracts from 1939 to date
31-Jul-44 B-24 $169,452 Costs are weighted average of all Army contracts from 1939 to date
31-Aug-44 B-17 $129,150 Costs based on uncompleted contracts
31-Aug-44 B-24 $138,585 Costs based on uncompleted contracts
30-Nov-44 B-17 $125,464 Costs based on uncompleted contracts
30-Nov-44 B-24 $114,951 Costs based on uncompleted contracts
USAAF Statistical Digest table 82, total cost.
Year B-17 B-24
1939/41 $301,221 $379,162
1942 $258,949 $304,391
1944 $204,370 $215,516
1945 $187,742 na
8th Air Force combat sortie loss rates, 1944
| Type | MIA | Cat E | credit sorties | MIA*100/credit | Lost*100/credit |
| B-17 | 1957 | 502 | 121882 | 1.61 | 2.02 |
| B-24 | 858 | 346 | 66154 | 1.30 | 1.82 |
As noted before a higher percentage of 8th Air Force B-24 combat losses made it back to allied lines, how much of that is due to the B-17 being more crash worthy is unclear. B-17 were 68.8% of all sorties, 70.2% of effective sorties, 62% of mechanical aborts, 58.7% of weather aborts. Also as noted before B-24 production was cancelled before B-17.
Source Book of World War II Basic Data, Airframe Industry, Volume 1, man hours per aircraft
| Type | B-17 | B-17 | B-17 | B-24 | B-24 | B-24 |
| Factory | Seattle | Long Beach | Burbank | San Diego | Willow Run | Fort Worth |
Jan-42 | 51,520 | |||||
Feb-42 | 44,800 | |||||
Mar-42 | 37,632 | na | na | 44,872 | ||
Apr-42 | 25,536 | na | na | 43,400 | ||
May-42 | 65,455 | na | na | 36,707 | ||
Jun-42 | 45,695 | na | na | 33,402 | ||
Jul-42 | 41,990 | na | na | 31,057 | ||
Aug-42 | 40,261 | na | na | 28,405 | ||
Sep-42 | 39,026 | na | na | 26,094 | 493,000 | |
Oct-42 | 37,050 | 151,082 | na | 24,082 | 187,920 | |
Nov-42 | 35,815 | 103,240 | na | 24,001 | 245,920 | |
Dec-42 | 32,851 | 90,233 | na | 24,303 | 222,024 | |
Jan-43 | 31,369 | 64,179 | 55,425 | 23,442 | 73,721 | |
Feb-43 | 29,393 | 58,209 | 50,554 | 24,429 | 44,824 | |
Mar-43 | 27,417 | 45,522 | 55,242 | 23,051 | 41,776 | 59,341 |
Apr-43 | 26,676 | 40,746 | 49,812 | 21,111 | 31,412 | 59,341 |
May-43 | 25,688 | 38,657 | 49,281 | 20,357 | 25,294 | 51,648 |
Jun-43 | 24,917 | 36,119 | 40,284 | 19,419 | 27,619 | 40,000 |
Jul-43 | 24,453 | 32,985 | 32,216 | 19,432 | 25,714 | 37,209 |
Aug-43 | 23,712 | 31,269 | 28,243 | 15,816 | 20,361 | 32,346 |
Sep-43 | 22,724 | 29,627 | 25,027 | 15,569 | 20,135 | 28,519 |
Oct-43 | 22,230 | 28,507 | 23,470 | 15,135 | 17,123 | 33,500 |
Nov-43 | 21,212 | 27,761 | 21,413 | 15,004 | 16,377 | 26,410 |
Dec-43 | 20,254 | 26,866 | 19,386 | 14,676 | 13,881 | 26,410 |
Jan-44 | 18,679 | 25,909 | 18,880 | 13,738 | 13,077 | 26,039 |
Feb-44 | 18,400 | 22,823 | 18,465 | 12,673 | 12,308 | 23,243 |
Mar-44 | 17,463 | 22,049 | 16,820 | 12,124 | 11,406 | 18,581 |
Apr-44 | 17,358 | 20,492 | 16,195 | 11,797 | 10,313 | 15,026 |
May-44 | 16,418 | 16,833 | 15,424 | 11,692 | 9,844 | 14,667 |
Jun-44 | 16,119 | 16,833 | 14,483 | 10,938 | 9,219 | 13,600 |
Jul-44 | 16,119 | 16,833 | 13,793 | 11,515 | 9,048 | 14,400 |
Aug-44 | 15,672 | 17,424 | 13,448 | 15,286 | 8,730 | 14,000 |
Sep-44 | 15,672 | 17,424 | 13,103 | 14,861 | 7,333 | 13,733 |
Oct-44 | 16,716 | 17,424 | 13,158 | 14,028 | 7,500 | 12,800 |
Nov-44 | 17,313 | 15,371 | 13,982 | 14,583 | 7,813 | 13,133 |
Dec-44 | 17,015 | 14,603 | 13,036 | 13,944 | 8,750 | 14,000 |
Jan-45 | 17,761 | 14,276 | 13,036 | 14,444 | 8,125 | |
Feb-45 | 17,910 | 14,793 | 13,091 | 14,085 | 8,281 | |
Mar-45 | 17,910 | 14,569 | 12,909 | 13,333 | 8,125 | |
Apr-45 | 20,896 | 14,172 | 12,727 | 13,235 | 8,047 | |
May-45 | na | 13,871 | 12,727 | 13,235 | 5,938 | |
Jun-45 | na | 13,776 | 12,545 | 12,206 | 3,750 | |
Jul-45 | na | 13,431 | 12,545 |
Fort Worth excludes knock downs. Ford invested a lot more in tooling and it shows, but the constant production changes made it very hard to recover the tooling costs.
B-24M production yes, it was end of life for that design.
However, 5,168 of the effectively 'new' B-24N were cancelled May 31 1945. It was going to built through 1945/46
The USAAF had already decided to redesignate the B-24 as a 'medium bomber' and standardise on it, with the B-29 becoming their standard 'heavy bomber'.
No B-17 Bomber Squadrons had a war to go to after VE Day, they were all to convert to the newer types. Orders were cancelled before VE Day and only penny packets were delivered as the lines were cleared, many never to be delivered to the USAAF who had no use for them.
The US cancelled over 5,000 B-29's after VJ Day along with 1,885 B-32's
Within a year of VE Day, the B-24, the most numerous bomber built, was no longer is use as a bomber with the USAF
When they captured some of the first Shermans, the Waffenampt and German industry was simply staggered at the high design and production standards - far in excess of anything they could manage - each German tank was effectively hand crafted. The double helix reduction gears in the final drive in particular astonished them - the best solution, but absolutely beyond the ability of Germany to mass produce - yet, an absolute breeze for US manufactures.
It was the car industry standards that were the Ace the US had. No parts were every to be hand fitted on a production line, every part from every one of a myriad suppliers had to be interchangeable. You could dismantle a Sherman picked at random from a couple of arsenals, shuffle the parts, and they fit back together first time. Compare that with a hard pressed German worker - He could spend hours hand filing and machining a 'new' part to get it to fit.
Exactly the same as with Merlin engines then?
Snautzer01
Honourably banned
- 42,932
- Mar 26, 2007
You do know than ford and gm had production lines in Germany and other european countries no?
Can you give a source for that hand crafting stuff of tanks?
Thumpalumpacus
Major
If by "dogfight" you mean "bear fending off a swarm of bees" ...
Americans never understand how hand filing replaced the long bow and knitting in European culture. If Tiger and Sheman tanks were not guarded around the clock, bored teenagers filed them down into pistons and crankshafts in a matter of hours.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Maybe within their sub-types, but the M4 varied greatly.
Some had larger hatches than others. Some had a radial engine, some had a twin-six diesel and some had a V-8 gas engine.
Then there's the difference in ammunition storage, hull design, suspension and on and on.
For anyone thinking that Sherman production is easy to understand, I recommend spending some time over on the Sherman Minutia site. You will quickly get a headache and wish you had never asked! It is a rivet counter's wet dream!!!
GrauGeist noted some of the major differences. But there were differences between factories producing the same model.
And some components fitted varied across the production life of a model, seemingly depending on availability when tanks were built. For example when Britain started to convert M4A4 Sherman V to 17pdr Firefly tanks they discovered not all had the same type of turret drive motor and decided only one type made the tank suitable for conversion.
GrauGeist noted some of the major differences. But there were differences between factories producing the same model.
And some components fitted varied across the production life of a model, seemingly depending on availability when tanks were built. For example when Britain started to convert M4A4 Sherman V to 17pdr Firefly tanks they discovered not all had the same type of turret drive motor and decided only one type made the tank suitable for conversion.
CAC Woomera
Airman
Been lurking in this thread for a while and got somewhat interested. I always assumed fatigue life was never really a concern in regards to a lot of ww2 aircraft and that extends to how I view warbirds. Warbirds seen today go through not even half of the stuff they'd have seen in wartime and I doubt many people in charge of 'em wanna throw them up a few Gs just for the sake of it. If you are interested though, a quick google search gave me this from the FAA although it's massive and I don't think it'd be entirely useful at all
Geoffrey Sinclair
Staff Sergeant
- 922
- Sep 30, 2021
To end August 1941 there had been 134 B-17 and 57 B-24 built, which is why I started the manpower details in 1942, neither type was really in mass production before than. So where does the man hour data come from and what is the definition of an early and late B-17 and B-24? The actual data shows Ford invested a lot more in tooling than anyone else giving significant man hour savings but no real cost savings. Most, but not all, of the man hours difference between the average B-17 and B-24 is down to Ford, the rest to a combination of original design features, design changes, workforce experience, management and tooling. The conclusion average construction man hours can be used to determine over building and engineering is junk as is the B-17 was more expensive and time consuming claim.
Actually the aircraft that return save a lot of highly trained aircrew, worth far more than the aircraft.
The final B-17 and B-24 program orders were placed under the J program, fiscal year 1944, approved June 1943, as of December 1944 it was 1,500 B-24 from Ford, 600 B-17 from Douglas and 700 B-17 from Lockheed. The two types kept being ordered in parallel, it did help the 8th Air Force would have preferred to be an all B-17 force. Within weeks of VE day all the 8th and 15th Air Force B-24 groups had been reassigned, most to the US to become B-29, the B-17 groups moved later or remained a part of the occupation forces. As far as I am aware there was no immediate plan to replace the B-24 groups already deployed against Japan. There were plenty of spare B-24 in the US, the RAF allocations of mid 1945 were being filled with aircraft built in late 1944, so the existing B-24 force still in combat had reserves. The early B-24 problems of a lack of commonality between the different models and factories had been significantly reduced with the J model.
From the documents I have I am struggling to find anything factually accurate in the above. There were 5,290 B-29 cancelled between August and November 1945, along with 115 B-32. You might want to consider your logic, if the B-24 was the throw away wartime only design then it would be the first to go as soon as the USAAF had something better and/or reduced need for combat forces, all those ex Europe B-24 groups to become B-29, while the B-17 stayed in service, including the new Air Sea Rescue versions.
USAAAF monthly RC-301 reports. Note when the numbers on order change. Starting with end December 1944, current orders,
B-17G Boeing, 309 out of an order for 4,035 outstanding, expected completion April 1945, Douglas 1,292 / 2,995 / January 1946, Lockheed 1,351 / 3,050 / January 1946
B-24M Consolidated 684 / 970 / July 1945, Ford 1,426 / 1,625 / July 1945, B-24N Ford, 3,476 on order / June 1946.
End March 1945,
B-17G Boeing, 32 out of an order for 4,035 outstanding, expected completion April 1945, Douglas 2,276 / 4,320 / July 1946, Lockheed 1,539 / 3,550 / January 1946
B-24M Consolidated 357 / 970 / July 1945, Ford 1,128 / 1,800 / July 1945, B-24N Ford, 3,976 on order / July 1946.
End April 1945
B-17G Boeing, orders completed, Douglas 1,105 / 3,270 / December 1946, Lockheed 949 / 3,050 / November 1946
B-24M Consolidated 173 / 916 / July 1945, Ford 421 / 1,801 / July 1945, YB-24N Ford, 7 on order / June 1945.
End May 1945
B-17G Douglas 578 / 2,847 / December 1946, Lockheed 74 / 2,250 / July 1945
B-24M Consolidated 71 / 916 / July 1945, Ford 119 / 1,677 / June 1945, YB-24N Ford, 6 / 7 / June 1945.
End June 1945,
B-17G Douglas 492 / 2,847 / December 1946, Lockheed 24 / 2,250 / July 1945
B-24 all orders complete.
End July 1945, all orders complete.
The Germans had a machine tool surplus, they did not need to run second shifts, it was one reason the bombing campaign had trouble reducing production. While the US was definitely ahead in mass production, the Germans were not hand crafting tanks.
If you look at the list of Sherman producers there were only 2 named as arsenals, they produced over half of all Shermans but little overlap in models,
Fisher M4A2(75), M4A2(75)D, M4A3(75)W, M4A2(76)W, M4A3(76)W, M4A3E2
Chrysler M4A4(75), M4 composite, M4A6, M4A3(76)W, M4A3(105), M4(105)
GregP
Major
Where would you get the idea the German were staggered by a Sherman tank? Any reference for that?They may well have been staggered by the number of them they encountered, but I've seen and been in a Sherman. The Planes of Fame has one that runs and is GREAT shape ( after considerable effort to make that so).
I've seen a Tiger at Fort Benning, Georgia.
I have to tell you, the Tiger is much more impressive.
GregP
Major
Most of the warbirds we see around Southern California don't get into classic dogfights every day, but they DO get a few g's now and then playing fighter pilot. If you are in a warbird and don't get the urge to bend it around a bit, you would be the only one in them so inclined.
Don't get me wrong, they don't load them up to 7-8 g's often, but they see 3-4 g's on almost every flight at least once or twice, probably in a loop somewhere away from track home eyes. If you can't play with a warbird, then why spend all that money? Go fly a Piper Cub and do similar things for a LOT less money, if considerably slower, too.
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It's amazing what 200,000 Germans with rasps, hand files and hammers could achieve
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
I have always been impressed by the delicately inlaid scrollwork.
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Thumpalumpacus
Major
... not to mention the Corinthian leather!
Not sure what armament Chrysler put on that tank.
I worked with a guy who took a trip to Italy with a group looking into the possibility of co-producing MB-339 trainers. He said that a lot of their drawings had notes to "fit perfectly". Of course, we know how that worked out for Italian mass production during WW2.
Corrosion is the big problem with most WWII aircraft, often triggered by galvanic action of dissimilar metals, i.e. steel bolt in aluminum fittings. Cables will corrode internally although they look good visually, usually failing around pulleys where stresses build up. Some places are near impossible to inspect or lubricate.
Rubber has a limited life, especially when exposed to liquids of all types which may interact. Gas tank self sealing bladders and de-icing boots are a special issue.
Remember a lot of wood was used and weathers badly ... and glues vary in longevity. I know of two accidents caused when a good looking wooden instrument panel suddenly fell apart due to engine vibration alone, and a BT-13 crashed when the wooden pilot seat collapsed in a moderate G manuver.
Don't trust any fabric more than 5 years old.
Remember, these craft were planned for a service life of max 5 years, and were expected to be obsolete by then.
Rubber has a limited life, especially when exposed to liquids of all types which may interact. Gas tank self sealing bladders and de-icing boots are a special issue.
Remember a lot of wood was used and weathers badly ... and glues vary in longevity. I know of two accidents caused when a good looking wooden instrument panel suddenly fell apart due to engine vibration alone, and a BT-13 crashed when the wooden pilot seat collapsed in a moderate G manuver.
Don't trust any fabric more than 5 years old.
Remember, these craft were planned for a service life of max 5 years, and were expected to be obsolete by then.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Most of the WWII Allied combat aircraft weren't expected to last 25 missions, let alone 5 years...
