Geoffrey Sinclair
Staff Sergeant
- 932
- Sep 30, 2021
From mid 1941 until the end of 1942 and early 1943 the Luftwaffe day fighters in the west could pick when to engage, since the amount of damage the raiders could inflict on anything important was minimal, as the 8th Air Force built up it was realised that had to change but the priority for the first half of 1943 was the defence of Tunisia then Sicily and the Kursk offensive. The experience of the 1941/42 fighting had given the Luftwaffe a good ability to ignore fighter only operations, given the bombers cruised slower than the fighters it was a clue, and generally avoid poor tactical situations.
In July and August 1943 the Luftwaffe received a series of significant wake up calls, in date order, the "overnight success"
1) On July 5 the Kursk offensive begins, for the first time in the east the Luftwaffe is unable to secure air superiority where it wants it, the Red Air Force is able to intervene effectively. The air force needs to become bigger, given the Red Air Force largely ignores its opposite number the Luftwaffe can usually still operate.
2) 10 July the allied invasion of Sicily, in the air fighting before and during the invasion the Luftwaffe discovers the more aircraft it commits the higher the casualties without changing the overall situation. The air force needs to become much bigger or leave.
3) 27 July the firestorm at Hamburg.
4) 17 August the strikes on Schweinfurt and Peenemunde.
The next day the Luftwaffe chief of staff committed suicide.
Starting in July, after the failures of the Kursk and Sicily operations and with increased pressure on the home defences the Luftwaffe focus day fighters shifted to defending Germany, enabling the defeat of the unescorted day bomber but also making it easier for the allied forces in the "tactical" field. While the bomb damage started to really hurt the war economy.
Fighter Command did not change size much in the 1942/43 period in terms of number of day fighter squadrons, the quality went up but not the quantity. The big change in terms of pressure on the Luftwaffe was the USAAF, since it was totally dedicated to offensive operations while the RAF defended Britain as well, including the US airbases. As well as the numbers comes the availability and size of external tanks for the fighters. The British economy was fully stretched in 1943, getting a production line set up and quantity output was difficult even for something as relatively simple as the external tanks. First mission with a new size is one thing, adequate supply so all the fighters have access to them is another thing. From July 1943 and definitely after mid October 1943 the 8th Air Force stayed within the range of adequate fighter cover, operations in the period to around end February 1944 limited by the problems the P-38 and P-51 were having, plus there only being 2 P-38 and 1 P-51 groups operational end January, up to 2 and 3 by end February, so it meant staying mostly where the P-47 could go.
The Spitfire IX cannot go out to 400 miles without a major fuel tank upgrade, even the VIII needs more internal fuel. It is a false comparison to consider the Spitfire a long range fighter if the Mustang is present, it is medium range, like the P-47, if the mark VIII is used. What I do not have is the mission profile for the 8th Air Force combat range calculations, hence why the Spitfire ranges are nominal, until it can be compared with the actual profile the 8th Air Force was using.
In 1942 there are effectively no USAAF fighters in Britain and what drop tanks available were in the 30 to 60 imperial gallon range, assuming the Spitfires and P-47s could carry them. Sitting on enemy airbases requires numbers and range while France had plenty of fighter capable airfields. The 8th Air Force had a part operational fighter group in March 1943, up to 3 groups in April, 4 in August, 6 in September, by D-Day it had 15 groups. The 9th Air Force had 1 fighter group in November 1943, up to 18 groups by D-Day.
Put it another way for every 3 fighter sorties the USAAF could put up in April 1943 they could put up 33 in June 1944 and that is before the general expansion of fighter group strength. A 10 fold increase in offensive strength was far more than the Luftwaffe could handle even after concentrating forces in theatre.
Merlin Mustang time line, Rolls Royce began work on the two stage Merlin in 1940, expected late 1941.
N3297 the ex mark III prototype first flew with a Merlin 61 on 20 September 1941. Tests were so successful the call for production was being made before the type tests were done. On 12 November 1941 came the call to cancel all but Merlin 61 Spitfires. Merlin 60 production began in November 1941 according to Rolls Royce, 13 made that month and 13 more in December, 47 engines built by end February. Merlin 62 production from April 1942, Merlin 61 from May 1942.
Spitfire IX production from June 1942, mark VII from September, mark VIII from November.
The first Mustang arrived in Britain in October 1941, so airframe and engine are finally in the same area, 7 more in November, 24 in December. By 24 January the plan was to equip 10 Army Co-Operation squadrons.
Rolls Royce performance estimates, April 1942.
Air Vice Marshall Linnell informs the US that Merlin Mustangs a good idea, 9 June 1942.
3 Merlin Mustang conversions were ordered on 15 June 1942.
US/UK agreement for 1,200 Merlin Mustangs built January to October 1943, split half each, with the RAF releasing Packard Merlins from its order to the USAAF, 20 July 1942.
British order request for 120 engineless Mustang airframes a month for Britain and up to 200 a month for overseas theatres 27 August 1942. RAF talks about an order for 3,000 Merlin Mustangs, half for the RAF.
2 P-51 airframes officially accepted as XP-51B prototypes, August 1942, to await engines.
British request for bulk Merlin Mustangs 8 October 1942.
Mustang X first flight, 13 October 1942.
Churchill request to Harry Hopkins for Merlin Mustangs 16 October 1942, after 6 Mustang X test flights.
British request for 400 engineless Mustang airframes to be sent and converted to use Merlins. 5 November 1942.
XP-51B first flight 30 November 1942.
A Merlin XX engined Mustang would be one of the better 1942 fighters, but with the Merlin 61 so superior and in production why bother?
By 1943 the self defending bomber idea had an explicit in numbers added to it. The 8th Air Force considered 300 would be a big enough force to keep losses to acceptable levels, and it took until August and October for it to be abandoned. Until then there was little call for longer range fighters, nice to have but the priority was proving the bomber ideas. The everything that could fly mission on 24 December 1944 lost 12 bombers MIA and 23 written off, around half the 1943 long distance raids, but from 1,884 effective sorties. Even 30 lost from the 300 in 1943 would have been way too much, in 1945 thirty losses were well within acceptable levels. Also the early B-17F range as used by the 8th Air Force their radius of action was German border sort of distance and there was a certain make what you have work, the 3 fighter groups available April to August 1943 watched the bomber force grow from 5 to 16 groups, and that is with the B-24 groups on detached duty, end September the 6 fighter groups had 20 bomber groups to escort.
The allies firstly had to have the fighters in theatre, then a supply of tanks then enough pilot capable of being able to fly the distances, fight and return without many getting lost. Then use good tactics, like the 1944 escort ones As noted in Britain in 1943 but also in the US making changes in production came at a cost, both in terms of time to production and what had to be stopped to enable the new production.
As of mid 1943 only the Spitfire had shown to be able to match the best German fighter performance, and that required the latest versions after nearly a year where the German fighters were superior. Everyone was after the Spitfire, cutting production would be very unpopular.
To the Spitfire what if,
The allies have to decide the self defending day bomber is wrong earlier. The RAF have to decide the P-51 schedules are too optimistic both in time and numbers and increasing the Spitfire range is needed for bomber escort and general usefulness for the 1943 and 1944 operations. Furthermore the idea increasing efforts against Germany would pay off, the need for allied high performance fighters in the Mediterranean would drop as the Luftwaffe withdrew for example.
As part of mark XIV development, with a heavier thirster engine, specify a 30 to 40 gallon rear fuselage tank which the heavier engine should make an easier engineering task but also have the tank able to be used by the mark VIII, available about the time the mark XIV enters production in October 1943. Then during the Castle Bromwich mark V to IX change over, first IX in February 1943, last Vc in August, specify the Spitfire VIII internal fuel tankage, then later the rear fuselage tank, accepting the loss of production, using spare 60 series Merlins to convert more mark V to IX if necessary.
In early 1943, if the 90 gallon tank is available, the Spitfire can nominally match the August 1943 P-47 range, adding a 33 gallon tank nominally matches the February 1944 P-47 range.
In July and August 1943 the Luftwaffe received a series of significant wake up calls, in date order, the "overnight success"
1) On July 5 the Kursk offensive begins, for the first time in the east the Luftwaffe is unable to secure air superiority where it wants it, the Red Air Force is able to intervene effectively. The air force needs to become bigger, given the Red Air Force largely ignores its opposite number the Luftwaffe can usually still operate.
2) 10 July the allied invasion of Sicily, in the air fighting before and during the invasion the Luftwaffe discovers the more aircraft it commits the higher the casualties without changing the overall situation. The air force needs to become much bigger or leave.
3) 27 July the firestorm at Hamburg.
4) 17 August the strikes on Schweinfurt and Peenemunde.
The next day the Luftwaffe chief of staff committed suicide.
Starting in July, after the failures of the Kursk and Sicily operations and with increased pressure on the home defences the Luftwaffe focus day fighters shifted to defending Germany, enabling the defeat of the unescorted day bomber but also making it easier for the allied forces in the "tactical" field. While the bomb damage started to really hurt the war economy.
Fighter Command did not change size much in the 1942/43 period in terms of number of day fighter squadrons, the quality went up but not the quantity. The big change in terms of pressure on the Luftwaffe was the USAAF, since it was totally dedicated to offensive operations while the RAF defended Britain as well, including the US airbases. As well as the numbers comes the availability and size of external tanks for the fighters. The British economy was fully stretched in 1943, getting a production line set up and quantity output was difficult even for something as relatively simple as the external tanks. First mission with a new size is one thing, adequate supply so all the fighters have access to them is another thing. From July 1943 and definitely after mid October 1943 the 8th Air Force stayed within the range of adequate fighter cover, operations in the period to around end February 1944 limited by the problems the P-38 and P-51 were having, plus there only being 2 P-38 and 1 P-51 groups operational end January, up to 2 and 3 by end February, so it meant staying mostly where the P-47 could go.
The Spitfire IX cannot go out to 400 miles without a major fuel tank upgrade, even the VIII needs more internal fuel. It is a false comparison to consider the Spitfire a long range fighter if the Mustang is present, it is medium range, like the P-47, if the mark VIII is used. What I do not have is the mission profile for the 8th Air Force combat range calculations, hence why the Spitfire ranges are nominal, until it can be compared with the actual profile the 8th Air Force was using.
In 1942 there are effectively no USAAF fighters in Britain and what drop tanks available were in the 30 to 60 imperial gallon range, assuming the Spitfires and P-47s could carry them. Sitting on enemy airbases requires numbers and range while France had plenty of fighter capable airfields. The 8th Air Force had a part operational fighter group in March 1943, up to 3 groups in April, 4 in August, 6 in September, by D-Day it had 15 groups. The 9th Air Force had 1 fighter group in November 1943, up to 18 groups by D-Day.
Put it another way for every 3 fighter sorties the USAAF could put up in April 1943 they could put up 33 in June 1944 and that is before the general expansion of fighter group strength. A 10 fold increase in offensive strength was far more than the Luftwaffe could handle even after concentrating forces in theatre.
Merlin Mustang time line, Rolls Royce began work on the two stage Merlin in 1940, expected late 1941.
N3297 the ex mark III prototype first flew with a Merlin 61 on 20 September 1941. Tests were so successful the call for production was being made before the type tests were done. On 12 November 1941 came the call to cancel all but Merlin 61 Spitfires. Merlin 60 production began in November 1941 according to Rolls Royce, 13 made that month and 13 more in December, 47 engines built by end February. Merlin 62 production from April 1942, Merlin 61 from May 1942.
Spitfire IX production from June 1942, mark VII from September, mark VIII from November.
The first Mustang arrived in Britain in October 1941, so airframe and engine are finally in the same area, 7 more in November, 24 in December. By 24 January the plan was to equip 10 Army Co-Operation squadrons.
Rolls Royce performance estimates, April 1942.
Air Vice Marshall Linnell informs the US that Merlin Mustangs a good idea, 9 June 1942.
3 Merlin Mustang conversions were ordered on 15 June 1942.
US/UK agreement for 1,200 Merlin Mustangs built January to October 1943, split half each, with the RAF releasing Packard Merlins from its order to the USAAF, 20 July 1942.
British order request for 120 engineless Mustang airframes a month for Britain and up to 200 a month for overseas theatres 27 August 1942. RAF talks about an order for 3,000 Merlin Mustangs, half for the RAF.
2 P-51 airframes officially accepted as XP-51B prototypes, August 1942, to await engines.
British request for bulk Merlin Mustangs 8 October 1942.
Mustang X first flight, 13 October 1942.
Churchill request to Harry Hopkins for Merlin Mustangs 16 October 1942, after 6 Mustang X test flights.
British request for 400 engineless Mustang airframes to be sent and converted to use Merlins. 5 November 1942.
XP-51B first flight 30 November 1942.
A Merlin XX engined Mustang would be one of the better 1942 fighters, but with the Merlin 61 so superior and in production why bother?
By 1943 the self defending bomber idea had an explicit in numbers added to it. The 8th Air Force considered 300 would be a big enough force to keep losses to acceptable levels, and it took until August and October for it to be abandoned. Until then there was little call for longer range fighters, nice to have but the priority was proving the bomber ideas. The everything that could fly mission on 24 December 1944 lost 12 bombers MIA and 23 written off, around half the 1943 long distance raids, but from 1,884 effective sorties. Even 30 lost from the 300 in 1943 would have been way too much, in 1945 thirty losses were well within acceptable levels. Also the early B-17F range as used by the 8th Air Force their radius of action was German border sort of distance and there was a certain make what you have work, the 3 fighter groups available April to August 1943 watched the bomber force grow from 5 to 16 groups, and that is with the B-24 groups on detached duty, end September the 6 fighter groups had 20 bomber groups to escort.
The allies firstly had to have the fighters in theatre, then a supply of tanks then enough pilot capable of being able to fly the distances, fight and return without many getting lost. Then use good tactics, like the 1944 escort ones As noted in Britain in 1943 but also in the US making changes in production came at a cost, both in terms of time to production and what had to be stopped to enable the new production.
As of mid 1943 only the Spitfire had shown to be able to match the best German fighter performance, and that required the latest versions after nearly a year where the German fighters were superior. Everyone was after the Spitfire, cutting production would be very unpopular.
To the Spitfire what if,
The allies have to decide the self defending day bomber is wrong earlier. The RAF have to decide the P-51 schedules are too optimistic both in time and numbers and increasing the Spitfire range is needed for bomber escort and general usefulness for the 1943 and 1944 operations. Furthermore the idea increasing efforts against Germany would pay off, the need for allied high performance fighters in the Mediterranean would drop as the Luftwaffe withdrew for example.
As part of mark XIV development, with a heavier thirster engine, specify a 30 to 40 gallon rear fuselage tank which the heavier engine should make an easier engineering task but also have the tank able to be used by the mark VIII, available about the time the mark XIV enters production in October 1943. Then during the Castle Bromwich mark V to IX change over, first IX in February 1943, last Vc in August, specify the Spitfire VIII internal fuel tankage, then later the rear fuselage tank, accepting the loss of production, using spare 60 series Merlins to convert more mark V to IX if necessary.
In early 1943, if the 90 gallon tank is available, the Spitfire can nominally match the August 1943 P-47 range, adding a 33 gallon tank nominally matches the February 1944 P-47 range.