RAF starts early with 4-engined bombers: feasibility, plausability, consequences?

[stona]

That's true, but a more fundamental problem as far as the RAF was concerned was that there was no perceived need for such an aircraft, even had it been deemed technically possible. It's worth noting that the twin engine Whirlwind (a 1936 design I think) had exactly the same operational radius as a standard Hurricane.
The RAF's doctrine is at least as important as any technical considerations and that doctrine held fighter aircraft to be a defensive weapon.
Cheers
Steve

 

[R Pope]

The Windsor was pretty much a four-engined Wimpy, but years late for this topic (1943).

 

[nuuumannn]

Yep, agree, Shortround and Steve, the problem with the pre war RAF was that the Air Staff were entirely convinced that the heavy bomber concept would "always get through" as Stanley Baldwin put, it that the RAF never investigated such a thing as they thought it unnecessary. Once the RAF concentrated on night bombing there was thought of providing escort.

The Windsor was pretty much a four-engined Wimpy

The Windsor was not simply a four engined Wellington, although the two shared the same geodetic construction. It was however, designed as a Wellington replacement.

 

[Shortround6]

Wellington replacement or Warwick replacement??

Not that the Warwick actually did much of anything.

No disrespect to the crews but it's development was delayed and it was deployed late and in relatively small numbers in 'combat' roles so it tends to get over looked.

 

[nuuumannn]

Oops, I said thought of providing an escort; that should have been no thought of providing escort.

Wellington replacement or Warwick replacement?

Wellington replacement. Although the Warwick was intended initially as a Wellington replacement; it never served as such in Bomber Command as a result of its performance not being able to match the bigger four engined bombers that first flew at the same time as it did. The RAF struggled to find a suitable use for it as it was considered a failure as a bomber.

The Windsor was built to B.3/42, which was a merger of B.5/41 and the Wellington replacement project. B.5/41 was for a pressurised heavy bomber to which the Warwick III was projected; this was a pressurised four engined version of the Warwick that was never built. B.3/42 was more accurately referred to as a Lancaster replacement, which it did not do.

 

[Shortround6]

I believe the Warwick was supposed to compliment the Wellington not replace it. A way to get a "heavy bomber" (in 1935/36 terms) cheap and fast, used Wellington outer wing panels and a stretched Wellington fuselage, extra plugs being inserted.
Unfortunately the intended engines were, successively the Vulture (enough said), the Sabre ( all production allocated to the Typhoon and perhaps a good thing) and the Centaurus which was also much delayed. First Production versions used 1850hp P &W which were not big enough. Even 2000hp R-2800s were not big enough and when the Centaurus showed up late with 2500hp even that wasn't enough for the newer conditions.

 

[merlin]

I think if the Boulton-Paul design was picked instead of the Stirling, with less re-design 'complications' it's likely to get produced earlier.

I think the problem with 'escort' fighters, occurred when the commands were split up, no other aircraft were included in Bomber Command, apart from Bombers! With a more composite force it could have evolved. But the big problem was that the Air Ministry e.g. Portal didn't believe it could be possible - so didn't ask!

 

[mhuxt]

I think the problem with 'escort' fighters, occurred when the commands were split up, no other aircraft were included in Bomber Command, apart from Bombers! With a more composite force it could have evolved. But the big problem was that the Air Ministry e.g. Portal didn't believe it could be possible - so didn't ask!

That changed eventually, but without BC having done much to help the process.

 

[stona]

I think the problem with 'escort' fighters, occurred when the commands were split up, no other aircraft were included in Bomber Command, apart from Bombers! With a more composite force it could have evolved. But the big problem was that the Air Ministry e.g. Portal didn't believe it could be possible - so didn't ask!

I see and hear this a lot. Whether Portal or anyone else at the Air Ministry or in the RAF thought that a long range fighter was possible rather misses the point. It's a handy club for some with axes to grind to beat long dead corpses over the head with.
Almost nobody thought that a long range escort fighter was necessary. No government in its right mind is going to fund development of a weapon that its own military top brass can see no role for!
Cheers
Steve

 

[Shortround6]

There is also the question of timing. During the 30s and until 1940/41 Portal was right. An escort fighter that could take on short range interceptors was NOT possible. It became possible with with the better fuels and engines that showed up in 1942. Portal was guilty of not keeping up with the changes. But to claim he ( or other RAF brass) were guilty of ignoring what was not possible before then is not fair.

 

[OldSkeptic]

Actually SR and Stona there were experiments for LR (well at least MR) Spits in 1940. Even Douglas accepted the need for more range for the other theatres (such as the Med and North Africa), though he shut up when Portal was made CAS.

Even in the BoB Dowding and Park (and others of course) were turning their minds on moving to an offensive role later on, plus those other areas as well.

A properly planned move to an offensive role (plus those other requirements) would have pushed the RAF into improving range. In the Spit's case, make it a MR plane (combat radius of around 300 miles), then eventually a LR one. The work being done turning bog standard Spits into LR PR ones showed the technical possibility. That ended, except for PR ones, when Portal came into power.

In any organisation, when the boss says something, in fact puts their reputation on the line over it, then it isn't going to happen (otherwise your career prospects tend to disappear real fast).

Portal got himself into that position, he was so adamant about the impossibility saying to Churchill, right from the start that it was 'impossible', that he would have later had to have done an embarrassing climb down. A study of his record shows that he was not one of those 'big enough' people to ever admit that. Hence his fight against the USAAF on it (all documented). In fact he became a bit obsessional about it, judging by the time and effort he put into killing the idea.

I keep repeating that a up to a couple of months before the P-51B went operational he was still writing to Arnold lecturing him on the 'impossibility' of a LR fighter and that the USAAF should give up day operations and join the RAF in night ones. Now, he was not that stupid a person and he would definitely have known about the P-51B, but he had backed himself into a political corner. In the time honoured way of all politicians he preferred to double up on his position and just lie about it.

Nothing new about that sort of behaviour, you see it all the time (like how many people in the USAAF/USN are going to stand up and say the F-35 is a crock of rubbish, not many have the integrity and are prepared to throw away their careers like a John Boyd).

But, from one bad decision, a whole series of major strategic mistakes flowed on from that by the RAF.
One, which never gets much publicity, was was one of the absolute greatest and nearly lost the war for the Western Allies.
That was to repeatedly hit the German U-Boat bases in the Bay of Biscay, before they built all the reinforced pens in 41 and 42. Now the RAF could have done it and prevented the pens being built (which made them immune from bombing until the Tallboys came along). But it had to be done in the day (the RAF's night navigation was too bad) and that meant escorts.... which they didn't have because Portal said it was impossible. So one bad decision compounded into another. And that, at least, added a year to the war (and very nearly lost it).

 

[Shortround6]

Experiments are one thing, practical is another.

The Merlin gained About 45% in take-off power between the III and 61. And about 33% from the III to the XII and 45. Getting of the ground in an early Spitfire (MK III engine and 87 octane fuel) with 250-300 gals would have been a looong slooow processes. While a MK V Spit with a Merlin 45 engine offers a much more realistic take-off possibility what will an extra 350lbs (extra weight of fuel and tanks in a MK VIII ?)or so of weight do to combat performance at the needed radius? Doesn't sound like much but you are dealing with about a 7000lb fighter so even 350lbs is 5%.

Merlin 45 burns about 2.5 gallons a minute at 16lbs boost, so 12.5 gallons (imp) for 5 minutes, 22 gallons for 3000rpm and 9lbs for 15 minutes. About 15-20 gallons for 30 minutes or a bit more reserve at 1800rpm and low boost. SO around 50 gallons needed after what ever drop tanks are used are dropped and not including startup, warm up, take-off and climb to safe altitude to switch to drop tanks. A 300mph true airspeed cruise at 20,000ft can burn around 46 gallons an hour or more. Going to 335-350mph can burn 65-70 gallons a hour.

 

[Hop]

There is also the question of timing. During the 30s and until 1940/41 Portal was right. An escort fighter that could take on short range interceptors was NOT possible. It became possible with with the better fuels and engines that showed up in 1942. Portal was guilty of not keeping up with the changes. But to claim he ( or other RAF brass) were guilty of ignoring what was not possible before then is not fair.

Exactly. In the mid 30s Spaatz wrote to Arnold that a long range escort fighter could not fight a short range fighter on equal terms because of the compromises it would have to make to carry so much fuel. In Autumn 1941 the USAAF board looking in to long range escort fighters, they decided to build the YB-40 (a B-17 with extra armour and guns).

A properly planned move to an offensive role (plus those other requirements) would have pushed the RAF into improving range. In the Spit's case, make it a MR plane (combat radius of around 300 miles), then eventually a LR one. The work being done turning bog standard Spits into LR PR ones showed the technical possibility. That ended, except for PR ones, when Portal came into power.

Portal "came to power" in October 1940. His priority was more fighters for defence, not longer ranged fighters.

In March 1941 Spaatz and Hoyt Vandenburg turned down a proposal to equip the P-39 with drop tanks. Their reasons:

Additional range would ""provide opportunities for improper tactical use of pursuit types", and the changes "would tend to slow up production and reduce the combat effectiveness of the airplane."

The same reasons would be in Portal's mind. Indeed, they would have been more pressing for Portal. Whilst the USAAF was not yet in the war, the RAF was, and it was the only major air force standing against the Luftwaffe. Portal needed more Spitfires because it was the only fighter in the world at the time that could face the Luftwaffe on equal terms.

A properly planned move to an offensive role (plus those other requirements) would have pushed the RAF into improving range. In the Spit's case, make it a MR plane (combat radius of around 300 miles), then eventually a LR one. The work being done turning bog standard Spits into LR PR ones showed the technical possibility. That ended, except for PR ones, when Portal came into power.

No it didn't. The Spitfire VII and VIII were fitted with extra fuel to increase range. Sadly the Luftwaffe delayed them.

In 1940 the RAF needed more Spitfires desperately and didn't care about range.
In 1941 with the advent of the 109F the RAF desperately needed to get the Spitfire V into service in large numbers, to replace not just earlier Spitfires but the Hurricane as well.
In 1942 the RAF was supposed to begin switching to the Spitfire VII and VIII, with more fuel for increased range. Then the Fw190 came along and once again the RAF was desperate to get faster Spitfires, not longer ranged ones.

Long range Spitfires were a luxury the RAF simply couldn't afford for most of the war. And the RAF never had the urgent requirement that the USAAF faced in 1943, and that led to the modification of the P-51.

I keep repeating that a up to a couple of months before the P-51B went operational he was still writing to Arnold lecturing him on the 'impossibility' of a LR fighter and that the USAAF should give up day operations and join the RAF in night ones.

There was a lot of pressure on the USAAF to switch to night bombing in 1943. They had been at war for 18 months and had yet to begin bombing Germany in earnest. The politicians didn't want to wait another 6 months for an escort fighter that the USAAF was promising would be ready by the start of 1944.

That was to repeatedly hit the German U-Boat bases in the Bay of Biscay, before they built all the reinforced pens in 41 and 42. Now the RAF could have done it and prevented the pens being built (which made them immune from bombing until the Tallboys came along). But it had to be done in the day (the RAF's night navigation was too bad) and that meant escorts.... which they didn't have because Portal said it was impossible.

RAF navigation was fine for attacking coastal targets at night. In the Spring of 1941 they made a lot of attacks on German naval targets in France, with some success. That's what prompted the Germans to begin construction of the U boat pens in the first place.

Nobody seems to have considered the pens to be a worthwhile target during construction, perhaps because a building site manned with French labourers wasn't exactly high value to the Germans. Concrete is, after all, cheap.

The theory that the pens weren't attacked during construction due to a lack of range for escorts doesn't hold water. The largest German U boat pen was at Brest. The RAF flew 2 major daylight attacks on Brest in 1941.

In the first, on the afternoon of 24 July, 3 B-17s, 56 Wellingtons and 18 Hampdens attacked the Scharnhorst, Geneisenau and Prinz Eugen in Brest and La Pallice. They were escorted by 9 squadrons of Spitfires and Hurricanes.

The fighters claimed 3 aircraft for 2 losses. 16 bombers were lost.

There was another escorted daylight attack on the German ships in December. 11 squadrons of fighters escorted 47 Halifaxes, Manchesters and Stirlings. The fighters claimed 4 kills for 1 loss, 7 bombers were lost.

If the pens had been a priority they would have been attacked, night or day. They weren't. There were so many other priorities. But it certainly wasn't a lack of escorts that stopped them being attacked, as ships and submarines in those ports were attacked.

 

[stona]

Actually SR and Stona there were experiments for LR (well at least MR) Spits in 1940.

Once the war had started experience demonstrated that the pre-war doctrine was not sustainable and many officers started talking about longer legged fighters. That is utterly irrelevant to my post (and I think SR's) which apply to pre-war doctrine and thinking. Nobody foresaw the necessity for such aircraft.
Portal was not alone in doubting the British aviation industries ability to manufacture such aircraft. Despite increasing the range of some they already had they never did build what could accurately be described as a long range single seat fighter.

Without Portal we would not have the RAF as we know it today. It may well not have survived as an independent service. Nowadays it is The Royal Navy's air service that is in danger of extinction!

Cheers

Steve

 

[tomo pauk]

Hi, Hop, some remarks:

Originally Posted by Hop

...
Portal "came to power" in October 1940. His priority was more fighters for defence, not longer ranged fighters.

In March 1941 Spaatz and Hoyt Vandenburg turned down a proposal to equip the P-39 with drop tanks. Their reasons:

Additional range would ""provide opportunities for improper tactical use of pursuit types", and the changes "would tend to slow up production and reduce the combat effectiveness of the airplane."

The same reasons would be in Portal's mind. Indeed, they would have been more pressing for Portal. Whilst the USAAF was not yet in the war, the RAF was, and it was the only major air force standing against the Luftwaffe. Portal needed more Spitfires because it was the only fighter in the world at the time that could face the Luftwaffe on equal terms.

Could we say that those US generals were wrong the very second they made that decision, especially in the light of the BoB that ended only several months ago? Bf-109 was lacking mostly one thing - a drop tank facility - to extend it's legs over most of the England. Anyway, any fighter worth it's name get the drop tanks in 1941, US ones included.
If we take a look at USAFs priorities in late 1930s/early 1940s (bombers to bring the war to an enemy, fighters to defend US mainland, attack airplanes to help the Army at the ground), we can reckon the reasons for that US generals' decision.

No it didn't. The Spitfire VII and VIII were fitted with extra fuel to increase range. Sadly the Luftwaffe delayed them.

In 1940 the RAF needed more Spitfires desperately and didn't care about range.
In 1941 with the advent of the 109F the RAF desperately needed to get the Spitfire V into service in large numbers, to replace not just earlier Spitfires but the Hurricane as well.
In 1942 the RAF was supposed to begin switching to the Spitfire VII and VIII, with more fuel for increased range. Then the Fw190 came along and once again the RAF was desperate to get faster Spitfires, not longer ranged ones.

Fw-190 came along in 1941, and was recognized as a dire threat even back then.

Long range Spitfires were a luxury the RAF simply couldn't afford for most of the war. And the RAF never had the urgent requirement that the USAAF faced in 1943, and that led to the modification of the P-51.

The modification of the P-51 (from V-1710 to V-1650) happened in 1942, way before USAF admitted to themselves they need 'Berlin and back' escort fighter.
As for long range Spitfire being a luxury - the RAF bought 1000 BP Defiants, went for a two-engined Whirlwind, tried the Welkin, purchased Sabre-engined fighters, was buying (prior LL set in) US planes. Compared with that, a Spitfire with more fuel seems like a bargain.

 

[stona]

The Whirlwind wasn't a long range aircraft, as I posted somewhere else its official radius of action was exactly the same as a standard Hurricane. It was a means of getting four 20mm cannon airborne, something fighter command was keen to do. It was seen as a stop gap by Dowding until the new "Hawker fighter", meaning the Typhoon, came along. He didn't like it and he definitely didn't like Westland Aircraft Ltd.
Cheers
Steve

 

[Hop]

Could we say that those US generals were wrong the very second they made that decision, especially in the light of the BoB that ended only several months ago?

I don't know. The two points they raised were valid. Delaying production is obviously detrimental. Giving planes extra capability can be detrimental if they are then used for a different task.

I'd want to see a lot more information before saying that the commanders were wrong to want their planes as soon as possible, and that their fear that extra capabilities might mean the planes would be diverted elsewhere was unfounded.

Fw-190 came along in 1941, and was recognized as a dire threat even back then.

Yes. I mean the effect on Spitfire production was felt in 1942. The RAF planned to bring new Spitfires into service in 1942 with the 2 stage Merlin 60 series engine. Both the Spitfire VII and VIII had extra internal fuel. Because of the Fw190 threat, they instead fitted the Merlin 60 series to the Spitfire V airframe to produce the Mk IX. It could be in service quicker and in greater numbers than the VII and VIII.

It wasn't Portal's intransigence that caused the end of medium range Spitfire development, it was the absolute need to get a counter to the Fw190 in operation in large numbers as quickly as possible.

The modification of the P-51 (from V-1710 to V-1650) happened in 1942, way before USAF admitted to themselves they need 'Berlin and back' escort fighter.

The rear fuselage tank wasn't added until after the USAAF had sent an urgent request to Lockheed, Republic and NAA in August 1943 for extra fuel capacity in their fighters.

As for long range Spitfire being a luxury - the RAF bought 1000 BP Defiants, went for a two-engined Whirlwind, tried the Welkin, purchased Sabre-engined fighters, was buying (prior LL set in) US planes. Compared with that, a Spitfire with more fuel seems like a bargain.

It's not the cost it's the production delays. Buying Whirlwinds or Typhoons doesn't involve a delay to Spitfire production. Modifying Spitfires does.

There were all sorts of modifications that Supermarine came up with that would improve the Spitfire. Some of them even got built. But there was remarkably little change in the basic design of the Spitfires that were produced in bulk at Castle Bromwich. Castle Bromwich went from the Mk II to Mk V to Mk IX to Mk XVI. They all shared the same basic airframe.

 

[tomo pauk]

The Whirlwind wasn't a long range aircraft, as I posted somewhere else its official radius of action was exactly the same as a standard Hurricane. It was a means of getting four 20mm cannon airborne, something fighter command was keen to do. It was seen as a stop gap by Dowding until the new "Hawker fighter", meaning the Typhoon, came along. He didn't like it and he definitely didn't like Westland Aircraft Ltd.
Cheers
Steve

I was not implying that Wirly was a long range aircraft. My point was that RAF afforded it (paying for design, setting up the production line, paying to the RR for low-production engines, finally paying the airplanes themselves), unlike the long range Spitfires.

I don't know. The two points they raised were valid. Delaying production is obviously detrimental. Giving planes extra capability can be detrimental if they are then used for a different task.

A long range fighter was running in opposite direction vs. the current USAF mantra - bombers were to carve their way into enemy held airspace, by outpacing and overflying enemy fighters and AAA, while dispensing with MGs an odd fighter that might come close by. Fighters were to prevent the enemy doing the same to the USA, and, again, more fuel was not seen as an important thing for the fighters. Both things were proven wrong many times in the ww2, again - even before that order was issued.

I'd want to see a lot more information before saying that the commanders were wrong to want their planes as soon as possible, and that their fear that extra capabilities might mean the planes would be diverted elsewhere was unfounded.

Where might one divert the USAF fighters elsewhere?? All of the USA built fighters endured so many modifications prior they were considered combat capable (addition of armour, SS tanks, heavier/different armament etc) in the very 1941. One of modifications carried was the introduction of drop tank(s).

Yes. I mean the effect on Spitfire production was felt in 1942. The RAF planned to bring new Spitfires into service in 1942 with the 2 stage Merlin 60 series engine. Both the Spitfire VII and VIII had extra internal fuel. Because of the Fw190 threat, they instead fitted the Merlin 60 series to the Spitfire V airframe to produce the Mk IX. It could be in service quicker and in greater numbers than the VII and VIII.

Okay, now I know what you were meaning.

It wasn't Portal's intransigence that caused the end of medium range Spitfire development, it was the absolute need to get a counter to the Fw190 in operation in large numbers as quickly as possible.

Unfortunately, the fear from the Fw-190 did not ended until some time mid/late 1944, when the installation of additional fuel tanks was ordered for the Spit IX and Tempests.

The rear fuselage tank wasn't added until after the USAAF had sent an urgent request to Lockheed, Republic and NAA in August 1943 for extra fuel capacity in their fighters.

Ah, that modification.
BTW, Lockheed delivered the P-38J in September 1943, the greater internal fuel tankage being possible with change of intercooler type location - meaning they were doing the modification prior that USAF's request. P-51B was plenty capable to provide the escort radius of 500 miles, even without fuselage tank.

It's not the cost it's the production delays. Buying Whirlwinds or Typhoons doesn't involve a delay to Spitfire production. Modifying Spitfires does.

There were all sorts of modifications that Supermarine came up with that would improve the Spitfire. Some of them even got built. But there was remarkably little change in the basic design of the Spitfires that were produced in bulk at Castle Bromwich. Castle Bromwich went from the Mk II to Mk V to Mk IX to Mk XVI. They all shared the same basic airframe.

Maybe we could agree that an addition of the, say, 30 gal rear fuselage tank would impose negligible delays to the production of Spit VIII/IX, while providing the Allies with a far more capable fighter?

 

[stona]

Buying Whirlwinds or Typhoons doesn't involve a delay to Spitfire production.

I agree with much of your post but not this. It isn't how the British aircraft industry was organised, nor how it worked.

In December 1938 the Supply Committee had recommended a large order of 600 Whirlwinds be built at the Castle Bromwich Aircraft Factory. At the time CBAF was struggling to get the Spitfire into production and Nuffield and his senior production advisor, Oliver Boden were aghast at the prospect of having now to get another aircraft into full production. They blamed the Spitfire delays firmly on Supermarine and expected the same trouble with Westland. They had a meeting with Freeman (and Kingsley Wood) at the Air Ministry when they said that the Whirlwind order would result in a "substantial loss in total output" of Spitfires. Consequently the Supply Committee reported on 4th July 1939, that "the provisional order for 600 Whirlwinds from the Castle Bromwich factory should be cancelled, together with related orders for Peregrine engines."

It was the need for Spitfires that had effectively killed off the Whirlwind fighter and, to a large extent, the Peregrine engine.

Eventually, despite further blows from Freeman/Newall's the axe ( the Supply Committee reported in October that "orders for Whirlwind aircraft, Peregrine engines and allied equipment should be cancelled at once and all work on them stopped" and Rolls Royce were told to stop Peregrine production for the Whirlwind "at the earliest practical point") an order for 114 Whirlwinds was reinstated, principally to use up parts already made and to avoid waste.

CBAF went on to produce 12,000 Spitfires and not a single Whirlwind.

Cheers

Steve

 

[OldSkeptic]

Experiments are one thing, practical is another.

The Merlin gained About 45% in take-off power between the III and 61. And about 33% from the III to the XII and 45. Getting of the ground in an early Spitfire (MK III engine and 87 octane fuel) with 250-300 gals would have been a looong slooow processes. While a MK V Spit with a Merlin 45 engine offers a much more realistic take-off possibility what will an extra 350lbs (extra weight of fuel and tanks in a MK VIII ?)or so of weight do to combat performance at the needed radius? Doesn't sound like much but you are dealing with about a 7000lb fighter so even 350lbs is 5%.

Merlin 45 burns about 2.5 gallons a minute at 16lbs boost, so 12.5 gallons (imp) for 5 minutes, 22 gallons for 3000rpm and 9lbs for 15 minutes. About 15-20 gallons for 30 minutes or a bit more reserve at 1800rpm and low boost. SO around 50 gallons needed after what ever drop tanks are used are dropped and not including startup, warm up, take-off and climb to safe altitude to switch to drop tanks. A 300mph true airspeed cruise at 20,000ft can burn around 46 gallons an hour or more. Going to 335-350mph can burn 65-70 gallons a hour.

Quill, in his book, tells of doing a test. Mk IX, 75 (UK) gal tank, 90 gal drop tank. Flew the length of Britain and back. No problems. The VIII was a better airframe for because of the 26 gals in the leading edge of the wings..

But, and here is the but, from 1940 onwards PR spits were doing, first MR sorties, then LR sorties. They managed to fit fuel in everywhere. Wings, rear, under the seat (similar to the 109) and so on.
The issue wasn't getting the fuel in (it was done all the time), it was getting enough fuel in and having room for guns......

With a cannon Spit, drop the .303s, wing fuel (at least) 40 gals. 20 gals under the seat. 66-75 gals in the rear. Easier on a Mk VIII, IX, etc of course.

For a Mk V, 29 gals in the rear (actually done), with a 90 gal drop tank gives a combat radius of (checking my spreadsheet) of 250 miles, with a 14 (12%) gal reserve. No fuel in the wings at all.
Put 26 gals in the wings (already done with PR versions so the tech was well known) and you are up to 350 miles, with a 18% reserve.
That's enough to escort British bombers to do in the U-Boat pens .. before they hardened them, while wiping out the rump of the Luftwaffe left in France.

Note also that the early PR Spits didn't have the advantage of the later work on the improved elevator horn balances, which improved the CoG markedly, still managed to do the job though.

As for how you (say) plan a 'clear France' plan, you have mixes of Spit with no fuel in the rear supporting, for a distance, the fueled up ones. I mean by 42 the RAF had 75 squadrons of the things. They had them coming out their ears.

I can just see how Park would have done it, no 'leaning towards the enemy' nonsense for him, it would have been clear strategic and tactical plans. Probably would have won air supremacy over most of France (especially those important Bay of Biscay areas) within a couple of months in mid/late 41. Also he would not have been panicked when the 1st 190s came out (especially since the Germans had only a very few, buggy ones at first) as did Sholoto Douglas (LM was his usual 'what me?" self).

The Germans would have had to pull planes from elsewhere, stretching them even more. France, NA, Med, Russia. Could have brought forward the collapse of the Luftwaffe by a year.

Strategically there were 2 targets in France in 41/42/43 that the Luftwaffe could not ignore: (1) their own airfields, (2) the U-Boat pens. By 43 the U-boat pens had been hardened, but if they had been hit earlier before that happened they would have had to come up and fight ... on the RAF's terms. And an airwar of attrition would have taken place which the British could afford, but the Germans couldn't.