Why did British aircraft production stagnate a bit during the war?

In 1941 the British produced 20k military aircraft to Germany's 11.7k and Japan's 5k, yet in 1944 Britain only made 26.4k (a measly increase of 0.75% from 1943) whereas Germany produced 39.8k and Japan produced 28.1k, was it because of the American sleeping giant and changes in Britain's Minister of Aircraft Production?

Reasons.
Yearly figures hide what was going on.
Like the US, British Aircraft production peaked in Q1/1944. The allies were moving from too few to too many aircraft.
There was a shift in categories, more heavy bombers, less trainers (Trainer Misc types in 1942 was 5,932, down 1,000 from 1941, in 1944 it was 2,877)

UK Statistical Digest Figures.

anetos05 said:

In 1941 the British produced 20k military aircraft to Germany's 11.7k and Japan's 5k, yet in 1944 Britain only made 26.4k (a measly increase of 0.75% from 1943) whereas Germany produced 39.8k and Japan produced 28.1k, was it because of the American sleeping giant and changes in Britain's Minister of Aircraft Production?

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As noted by G. Sinclair above, it was a shift towards the 2- and 4-engined aircraft that made the difference. A Lancaster will 'demand' perhaps 4 times as many manours than a Spitfire or a Battle. So the more correct metric, IMO, is the 'airframe weight', rather than 'number of aircraft' if we want to make the more realistic comparisons. Number of V12 and 2-row radial aero engines produced is also a good metric, but also the total weight of the engines.

We can note that Germans all but abandoned the 2- and 4-engined aircraft production by 1944, while neither the Soviets nor Japanese were making any 4-engined types (bar prototypes) in 1944.

tomo pauk said:

We can note that Germans all but abandoned the 2- and 4-engined aircraft production by 1944, while neither the Soviets nor Japanese were making any 4-engined types (bar prototypes) in 1944.

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Some grumbling: in 1944 the Soviets produced 18 4-engine Pe-8s, 16 of them in bomber version (14 with M-82s, 2 with ACh-30Bs).
Of course, that's an absolutely negligible number, but still not zero - and they weren't prototypes.

In addition: how many H8K were manufactured in 1944?

What the Commonwealth was short of in Europe was infantry not aircrew by 1944 and especially 1945. Aircrew were being re roled into infantry to keep up the numbers. Even coal miners were being considered for military service despite the demand for coal. Not needing more aircrew reflecting more efficient aeroplanes for the required tasks. The RAF in 1944/5 was delivering more bang than ever with much the same staff as late 1943.

As above the weight of production is a better measure than numbers. Somewhat like the RAF counting bombing weight rather than number of sorties which was the common US measure.

I'd think that in 1941 production was likely running at full capacity, and that means further growth relied upon building more plant, which will probably slow down the growth.

anetos05 said:

In 1941 the British produced 20k military aircraft to Germany's 11.7k and Japan's 5k, yet in 1944 Britain only made 26.4k (a measly increase of 0.75% from 1943) whereas Germany produced 39.8k and Japan produced 28.1k, was it because of the American sleeping giant and changes in Britain's Minister of Aircraft Production?

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Just picking on the 3rd quarter of 1941 and 1944 from Mr. Sinclair's provided numbers
Q3/41.........................5,376.................................23.51.........................4373
Q3/1944....................6,145.................................50.40.........................8202
increase.....................14.5%................................114%.........................87.5%


Increase in production was very large.
And then there is everything else, Tanks/Artillery/Ammunition for the army. Transport ships/Escorts/Landing craft for the Navy.
The British (and Americans, the US had limits) had to balance a lot of different needs.

Hi
The book 'The Air War 1939-1945' by R J Overy, page 150, has some comparisons:

Mike

As many have mentioned before, just looking at total numbers can be rather deceptive.
For the US this is especially true as the US had a huge civilian market in the late 30s and 1940.
The Numbers for 1939 and 1940 (and 1941?) include thousands of Piper Cubs and competitors. Not war planes. Piper Cub (and other grasshoppers) continued through out the war but not in the quantities of the 1939/40 deliveries.
To show how off the numbers can be in 1940 the US built 1685 fighter planes out of the 12,804 plane total. That is ALL fighter production both domestic and foreign delivers, Prototypes and even 6 of the NA P-64s (single seat AT-6?). US bomber production was probably under 100 for the USAAC with hundreds of Hudsons, DB-7 and Martins going overseas. Chances of over 1000 total is slim. So what were the other 10,000 planes?
US Army and Navy were buying a lot of trainers in 1940 but not 10,000 of them.

tomo pauk said:

As noted by G. Sinclair above, it was a shift towards the 2- and 4-engined aircraft that made the difference. A Lancaster will 'demand' perhaps 4 times as many manours than a Spitfire or a Battle.

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I've seen very, very different figures for particular aircraft re: man hours, I assume each document/author uses different criteria ... but below are figures from one that had the most types in one place ('44 Air Ministry document):

Production cost in man months (1 man month = 195 man hours)

Lancaster - 1,160
Halifax - 1,380
Stirling - 1,940
Wellington - 860
Mosquito - 450

When British coal production became a problem young men were given the option of mining or infantry and kept choosing infantry, they had to be drafted into the mines.

The USSBS says 66 H8K in 1943 and 77 in 1944. Fw200 76 in 1943 and 7 in 1944

USAAF Statistical Digest, USAAF, USN and Foreign military aircraft production (all twelve or more seat transports counted as military aircraft even if for civil customers.)

1940 1941 Year
6,028 19,445 Total
0 1 Very Heavy Bombers
61 318 Heavy Bombers
95 865 Medium Bombers
1,038 2,935 Light Bombers
1,689 4,421 Fighters
123 727 Reconnaissance
290 532 Transports
2,731 9,376 Trainers
1 270 Communications

Civil production is put at another 6,785 aircraft in 1940 and 6,844 in 1941, giving totals of 12,813 and 26,289. There are a number of US production figures for 1940/41, slightly different, splitting things into different categories.

Man hours per aircraft was not static, the number decreased over the production run provided the design remained stable enough, bombers in particular were prone to increases in electronics, all types tended to experience weight gains. The US did a number of studies, the first of a type at a factory tended to require 15 man hours per pound, the 10th about 7 hours, 100th 3 hours, 1000th under 1.5 hours. As well there is the reality most aircraft factories were assembly plants using large numbers of sub contractors and their effort needs accounting for, supplying Willow Run were 965 subcontractors located in 287 cities in 38 states.

P-47 orders, 1941 to 45, 773 @ $113,196, 6,447 @ $98,033, 2,500 @ $96,475, 5,347 @ $85,448, 614 & $84,897

The Civil Aeronautics Administration thinks the US Aviation Industry, airframe, engine, propeller, glider, modification centres (after February 1943), sub contractors, Government Furnished Equipment and Special Purpose, had 97,600 people in January 1940, 253,135 in January 1941, 618,356 in January 1942, 1,609,256 in January 1943, 2,079,836 in January 1944 and 1,683,772 in January 1945 (peak 2,101,552 in November 1943)

The British Ministry of Aircraft Production had a wider remit than the US figures cover, like repairs, 1,627,200 people in January 1943, 1,821,500 in January 1944, which was the peak.

So about 1200 bombers instead of my 1000 plane guess

What is more impressive is the that the US was making over around 6000 2 seat wooden/fabric aircraft with 65hp or under engines in 1940 so the increase in larger war planes is even larger than it looks at first glance.

bf109xxl said:

In addition: how many H8K were manufactured in 1944?

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1940: (1) H8K1 - prototype
1941: (2) H8K1 - pre-production
1942: (14) H8K1 - production
1943-1945: (112) H8K2 - production
1943-1945: (36) H8K2-L - production
1944: (2) H8K3 - prototype
1945: (2) H8K4 - prototype

tomo pauk said:

As noted by G. Sinclair above, it was a shift towards the 2- and 4-engined aircraft that made the difference. A Lancaster will 'demand' perhaps 4 times as many manours than a Spitfire or a Battle. So the more correct metric, IMO, is the 'airframe weight', rather than 'number of aircraft' if we want to make the more realistic comparisons. Number of V12 and 2-row radial aero engines produced is also a good metric, but also the total weight of the engines.

We can note that Germans all but abandoned the 2- and 4-engined aircraft production by 1944, while neither the Soviets nor Japanese were making any 4-engined types (bar prototypes) in 1944.

Click to expand...

While I agree in general with your statement I totally disagree with A Lancaster will 'demand' perhaps 4 times as many manhours than a Spitfire because the Spitfire was a massively manpower hungry design. I have never seen manhours for the Lancaster but the manhours for the Spitfire were far above the manhours for the Dakota and about four times the manhours for building the Mustang and Kittyhawk.

On the Lancaster each wing rib section was a single stamping requiring very few manhours as the ribs were cut to shape in lots of 10 to 30 depending on the metal thickness. They were then stamped to shape one at a time, had any stiffeners required added and were then essentially finished. The fuselage components were equally well designed for mass production using minimal staff.


The typical Spitfire wing rib is made of many dozens of small parts, each individually cut to size, and then the profile extrusions have to be shaped one by one in a stretch press followed by the whole mess fitted to a jig and then riveted and bolted together, in many cases with tubular spacers. Note section AA (top left) includes machined spacers which add even more manhours and tooling types to the production time.



Likewise on the fuselage the Lancaster was designed for ease of production.

Note that the stringers (the thin strips that run from end to end) are single full length pieces.

On the Spitfire they used dozens of intercostals instead of a small number of stringers. Intercostals run from frame to frame and are attached to the frame by an angle bracket at each end - usually with five rivets on the angle bracket. Lots more manhours again to make and fit the angle brackets.

Castle Bromwich, dedicated to mass production of limited models, is reported to have had twice the productivity of Supermarine while overall productivity was heavily dependent on the amount of tooling which in turn depended on size and stability of orders, throw in quality of management and how modern the assembly plant was.

AVIA 10/267, man hour estimates, memo dated 21 October 1942
129,944 Stirling I, Short Swindon, for 201st aircraft
74,319 Lancaster I, Avro, for 201st aircraft
98,246 Halifax II, Handley Page, for 201st aircraft
53,969 Wellington Ic, Vickers Weybridge, date of estimate 19 November 1941.
34,813 Blenheim IV, Bristol, date of estimate 22 December 1939
36,605 Beaufighter I, Bristol, date of estimate 31 July 1941
37,933 Beaufighter II, Bristol, date of estimate 31 July 1941
19,560 Hurricane IId, Hawker, date of estimate 22 December 1941
19,086 Spitfire Vc, Supermarine, date of estimate 23 April 1942
28,756 Typhoon Ia, Hawker Kingston/Gloster, date of estimate 26 January 1942 (Preliminary estimate, assuming current methods)
22,349 Typhoon Ia, Hawker Kingston/Gloster, date of estimate 10 January 1942 (Preliminary estimate, assuming full advantage of best manufacturing methods)
40,418 Beaufort I, Bristol, date of estimate 5 September 1940
123,556 Sunderland III, Blackburn Dumbarton, date of estimate 28 February 1942 (Preliminary estimate)
24,852 Albacore, Fairey Hayes, date of estimate 20 August 1941
27,052 Barracuda, Fairey Stockport, date of estimate 15 June 1942 (Preliminary estimate)
24,787 Fulmar II, Fairey Stockport, date of estimate 11 April 1941

AVIA 15/950 all up cost estimates as of 31 July 1941
£41,400 Lancaster, Armstrong Whitworth
£43,600 Lancaster, Metropolitan Vickers
£52,100 Sunderland, Short
£60,100 Sunderland, Short Harland.

Mixture of cancelled and current orders, unit costs,
£13,671 for 170 Blenheim from Rootes
£14,887 for 622 Blenheim from Avro
£42,978 for 450 Lancaster from Avro
£43,595 for 257 Lancaster from Metro-Vickers
£7,530 for 500 Master from Phillips & Powis Reading
£7,530 for 300 Master from Phillips & Powis Doncaster
£7,658 for 400 Master from Phillips & Powis South Marston

Air 20/1981 UK fighters cost between around £8,000 for a Hurricane to around £21,000 for a Beaufighter, cost plus freight to UK for P-39 about £16,700, P-40 about £15,500.

AVIA 15/2389 covers the sale of RAF aircraft to France in 1945/6, including serial numbers, one point is the prices (costs) quoted, complete aircraft,
£37-40,000 Lancaster I
£40,000 Halifax
£15,000 Mosquito VI
£16,000 Mosquito 30
£16,000 Mosquito PR XVI
£16,300 Mosquito PR.34
£10,000 Spitfire IX
£9,700 Spitfire XIV
£13,650 Typhoon
£26,000 Wellington XIII
£25,000 Wellington XIV
£55-65,000 Sunderland III

Spare engine prices,
£1,530 Merlin 22
£1,460 Merlin 24
£3,830 Hercules 100
£1,480 Merlin 25
£1,840 Merlin 76
£1,840 Merlin 67, 72 etc.
£1,900 Merlin 114
£1,800 Merlin
£2,300 Griffon
£5,550 Sabre II
£3,180 Hercules XVII
£1,596 Pegasus XVIII
My but Rolls Royce were cost effective.

Ministry of Aircraft production Price Books, Unit prices,
Lancaster, monies paid to Avro
£22,000 aircraft 1 to 252
£17,600 aircraft 253 to 862
£17,500 aircraft 863 to 1,312
£17,000 aircraft 1,313 to 1,993
The final price is made up of £8,000 materiel, £1,700 sub contractors, £2,500 Labour, Overheads £4,125 and profit (3.5%) £575.

Lancaster, monies paid to Armstrong Whitworth
Cost plus £350, first 10 aircraft
£37,778, next 40 aircraft
£33,048, next 50 aircraft
£27,898, next 100 aircraft
£23,548, next 100 aircraft

And so on.

Addition, due to P-51 mention in next post, it comes back to what workers are counted. Inglewood August 1944,

1,454,000 direct hours on P-51D
1,000 direct hours on P-51H
149,000 direct hours on other work
1,646,000 total direct hours
8,229 direct workers at 200 hours worked in month = 1,645,800 direct hours
17,662 total employment at say 200 hours worked in the month = 3,532,400 hours

470 P-51 accepted for month,
1,454,000/470 = 3,094 direct hours per P-51
3,532,400/470 = 7,516 factory worker hours per P-51

Magic.
That puts the Spitfire as needing almost five times the manhours of the Mustang. Some of that will be from the dispersed manufacturing but most comes back to the design of the structure.

Just a side reflection.
I don't need Google, DuckDuckGo, ChatGPT, Copilot, Claude, etc for aviation statistics... as long as Geoffrey Sinclair is on this forum.
Seriously, Geoffrey's contribution can hardly be overestimated.

MiTasol said:

Magic.
That puts the Spitfire as needing almost five times the manhours of the Mustang. Some of that will be from the dispersed manufacturing but most comes back to the design of the structure.

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Only if the manhours are calculated in exactly the same way and cover completion of the airframe, and ancillary components, to the same level.

An exercise in trying to understand what is being measured.

Source Book of World War II Basic Data Airframe Industry
Volume 1 Direct man Hours, Progress curves
Volume 2 Area, Shift, Time Cycle and Labor Requirements

Prepared by Industrial Mobilization office, Research and Development, Procurement and Industrial Mobilization (T-3), Air Material Command, Army Air Forces, Wright Field, Dayton, Ohio.

Volume 1,

Direct man hours, represent direct man hours actually charged to production of planes of the model for the given month, including in feeder plants and manufacture of spare parts.

Total employees, average calculated by start of month plus end of month numbers divided by 2. Nett figures excluding people on leave and people at the factory whose work was charged to other locations, but includes people at other locations whose work was charged to the factory.

Volume 2
Direct man hours, represent direct man hours actually charged to production of planes of the model for the given month. Including machining, processing, fabricating, assembling and installing airframe structure, flight operations and rework prior to acceptance. Excluded are work on raw stock and equipment items, spare parts manufacture and rework after acceptance.

So spare parts counted in 1, not counted in 2. Volume 1 reports feeder plants, volume 2 separates out feeder plant times.

North American Inglewood, direct work hours, which only count a minority of the people employed at the factory.

Firstly the end of non P-51H production, acceptance figures are P-51D for the month, airframe weight is 4,800 pounds, total worker hours from volume 1, per unit from volume 2.


This gives the efficiency at the end of a long production run. It also shows the volume 2 figures are not monthly, rather they are for the block of airframes where the final one of the block was completed in that month. Note the word completed, airframes/aircraft were completed, then accepted (official production measurement point) then delivered.

Direct worker hours on P-51H, Total Worker Hours is from Volume 1 and do not easily reconcile with the numbers from volume 2 which are reported in unit hours to cumulative plane number in the table, Completed and Accepted are from the USAAF Delivery Logs and are for the calendar month.


First point is how long it took and how expensive it was to set up the P-51H line, 374,000 hours to end February less the cost of 2 aircraft completed, others partly assembled, component manufacture etc., it is around 670 hours per each of the 555 P-51H built.

By end June 1945 there were 170 P-51H completed, 128 accepted. March to June volume 1 says 1,805,000 P-51H direct worker hours, volume 2 says the first 150 completions come to 1,138,590 worker hours, another 20 completions pushing it towards 1,250,000 worker hours.

Using the volume 1 man hours and the actual number of completions per month, March to June 1945, unit worker hour costs for the 4 months were 25,300, 27,467, 11,280, 6,194. The trend shows the volume 2 figure is people actually assembling the aircraft in the period, volume 1 includes those working on non assembly tasks.

Volume 1 says to end June 1945 it was 2,179,000 hours for 170 complete airframes, 12,800 hours per completed unit, then account for the non direct workers, most of whom were supporting the P-51D line until mid/late July 1945, and subtract the hours worked on partially complete airframes.

Using volume 2 the 450 completed airframes came out at around 5,460 hours each, which clearly excludes much to most of the preliminary work and, again, the non direct workers.

How many worker hours per P-51H again? And this is the airframe, add in the engine, instruments, radio etc.

For the Mustang family at Inglewood (excluding the P-51H), worker hours per completed airframe, Inglewood built 10,077 Mustang/P-51/A-36, 11 experimental, there are 44 others missing from the table below, 4,500 pounds airframe weight raised to 4,800 pounds in January 1945, overall average 3,725 direct worker hours per completed airframe. Time wise it took until month 34 out of 48 production months to go below the long term average, numbers wise about 40% of the run. I read the data as airframe 1 20,000 hours, airframes 2 to 7 17,000 hours each. Inglewood B-25 production ended in July 1944.