RAF daylight strategic bombing campaign results

[tomo pauk]

FWIW, here is the 'what and where' for the assets of the LW, for several dates of ww2:

Luftwaffe Orders of Battle 24 June 1941, 27 July 1942, and 17 May 1943

Wondering just how many fighters and bombers the RAF have had in Britain.

 

[Shortround6]

Some sources state that the Stirling was pulled from service at the end of 1943 due to losses from flak being higher than the losses suffered by the Lancaster and Halifax.
Flying them by daylight means higher losses before radar shows up and/or restricting bomb load to try to gain altitude.

There is little question the Luftwaffe fighter forces were stretched thin at this point in time but so were the British bomber forces. The Cologne 1000 bomber raid used several hundred planes manned by instructor and student pilots with planes drawn from training command. Worked OK for a publicity stunt but as an ongoing campaign it would fall into the same trap the Germans fell into. To few adequately trained pilots/crews coming in as replacements.
Shifting Luftwaffe AA assets is certainly do-able even if fighter assets are scarce.

 

[wiking85]

Some sources state that the Stirling was pulled from service at the end of 1943 due to losses from flak being higher than the losses suffered by the Lancaster and Halifax.
Flying them by daylight means higher losses before radar shows up and/or restricting bomb load to try to gain altitude.

There is little question the Luftwaffe fighter forces were stretched thin at this point in time but so were the British bomber forces. The Cologne 1000 bomber raid used several hundred planes manned by instructor and student pilots with planes drawn from training command. Worked OK for a publicity stunt but as an ongoing campaign it would fall into the same trap the Germans fell into. To few adequately trained pilots/crews coming in as replacements.
Shifting Luftwaffe AA assets is certainly do-able even if fighter assets are scarce.

Yeah, but you don't need 1000 bombers to hit specific industrial targets instead of incinerating cities.

 

[tomo pauk]

Stirling was introduced just in time to face the fire-control radars the German Flak arm introduced. Hence the altitudes, once perhaps recognized as 'safe from Flak', suddenly become dangerous. In 1941 the fire control radars are few and far between, but the daylight operations still mean that Flak will be a problem.

 

[stona]

Yeah, but you don't need 1000 bombers to hit specific industrial targets instead of incinerating cities.

Yes you do using WW2 technology and bombing by night in 1942/3. The original development of Bomber Command's large raid strategy was to ensure the destruction of such targets, though this soon became a pretence to cover the real objectives. By the time technology and tactics had developed to a point where accuracy was increased, in favourable conditions, such industrial targets were no longer the real objectives. Harris went on the record rating acreages of housing destroyed as more important than factories destroyed, but that was later.
Cheers
Steve

 

[Shortround6]

How many do you need?
That raid was a publicity stunt as much as anything else and is best viewed as a snapshot of what the RAF could muster for operational bombers on a given date. Tossing out the trainers and the more obsolete types and you have 292 four engine bombers including 88 Stirlings. You have an additional 46 Manchesters. Number of Wellingtons with Hercules engines is ?????

Now instead of a once a month or every coupe of weeks maximum effort try flying 2-3 missions a week with the approximately 400 first line aircraft available in the spring of 1942. Less said about the 1941 the better.

Weather conditions in the Ruhr valley were often not good. Modern day terminology would be SMOG. The coal fired industrial powerplants adding to the general confusion, purpose built smoke generators could also be brought into play.

And if you can see the ground then then guns on the ground can see the bombers. The Americans didn't do all that well with daylight bombing either. Granted it was higher up and therefor less accurate but it did cut down on exposure to the AA guns.

 

[Shortround6]

Stirling was introduced just in time to face the fire-control radars the German Flak arm introduced. Hence the altitudes, once perhaps recognized as 'safe from Flak', suddenly become dangerous. In 1941 the fire control radars are few and far between, but the daylight operations still mean that Flak will be a problem.

And there you have a big part of trying to conduct daylight bombing with medium altitude planes in 1941/42. IF you can see the ground to bomb accurately, the AA guns can see the bombers and don't need radar (although it helped) unlike night bombing were the AA guns either fired blind or tried to pick-out planes illuminated by searchlights. Some early radars guided the search lights.

You are only going to catch the defenses napping (un ready) a certain amount of times so individual raids are not a guide line for a campaign.

 

[stona]

Escorting bombers needs huge numbers of fighters. We didnt have the bombers or fighters to do it, sadly.

Nor did the Americans when they started, at least according to Lemay:

From 'Battles With the Luftwaffe - The Bomber Campaign Against Germany 1942-45'. Theo Boiten and Martin Bowman.

Cheers

Steve

 

[Shortround6]

There were major holes in theory as can be seen by the specifications issued.
B-26 and B-25 were supposed to carry 3000lbs of bombs 2000 miles and have top speed of over 300mph. They failed to meet the specification which was issued in the Spring of 1939 but it took a long, long time to get a single engine fighter to fly 2000 miles.
The 4 engine bomber specs really show how far off the idea of an escort fighter was.

Theory might have said there should be escort fighters but even the US didn't actually put out specifications for an escort fighter until around 1943.

 

[tomo pauk]

Re. LeMay excerpt - yes, it was a surprise, a rude one. The non-installation (prior mid-1943) of combat-worth drop tank installation in a 2000 HP fighter, that is going to be mass produced in three factories, is a reminder for the surprise. The lack of second source of the only long range fighter is another reminder. RAF Spitfires (and USAF Spitfires?) escorting the 8th AF bombers is yet another reminder for the surprise.
The USAF did not abolished attack aircraft either, the A-20 was produced, along the A-24 (granted, that one would've ill fared in the ETO, esp. without escort). However, attack aircraft will not be able to do Flak suppression 500 miles away from base.

 

[stona]

How many do you need?
That raid was a publicity stunt as much as anything else and is best viewed as a snapshot of what the RAF could muster for operational bombers on a given date.

It was very much a propaganda raid, all the 'millenium' raids were. Nonetheless they were a portent of things to come. The later raids comprising a few hundred Lancasters (and Halifaxes) delivered far more bomb tonnage than the earlier raids precisely because of the disparate and sometimes obsolete types employed.

To hit an average sized warehouse, given the aerodynamics and other factors contributing to the CEP of the iron bombs dropped required several hundred bombs if they were dropped from the right place. To be sure of hitting such a structure once navigational factors are added required literally thousands of bombs. All these calculations were made at the time, and that's why such large bombing forces were developed, even though the true objective of British bombing did change.
I can't give the exact figures and statistics as I'm away from home, someone else may have them.
Cheers
Steve

 

[Shortround6]

True but getting back to the original premise of the thread we have, in 1941,
Only a few hundred bombers at a time suitable for daylight operations even if escorted.
Escorts of short range, Ruhr valley is the BEST that can be hoped for. Even tweaking the Spitfire well beyond historical limits.
Bombers of rather low altitude capabilities leaving them vulnerable to visually aimed flak. Or the carriage of significantly lighter bombloads and higher altitudes which means many more sorties to get results.
Things improve the further into 1942 you get but not quickly.

One can look at the Lockheed Ventura raids of late 1942 and early 1943 to get an idea of what the likely results might have been. The Ventura was faster than any British bomber short of the Mosquito and these raids were against coastal targets, not 120-150 miles inland.

 

[stona]

True but getting back to the original premise of the thread we have, in 1941,
Only a few hundred bombers at a time suitable for daylight operations even if escorted.
Escorts of short range, Ruhr valley is the BEST that can be hoped for. Even tweaking the Spitfire well beyond historical limits.
Bombers of rather low altitude capabilities leaving them vulnerable to visually aimed flak. Or the carriage of significantly lighter bombloads and higher altitudes which means many more sorties to get results.
Things improve the further into 1942 you get but not quickly.

The inability of bombers designed in the 1930s to operate as planned in daylight came as a surprise to everyone, including the Germans. 'Bombing, States and Peoples in Western Europe 1940-1945' (Baldoli, Knapp, Overy) devotes several pages to what the Germans expected and the various ARP measures undertaken to protect the civilian population.

Cheers

Steve

 

[bobbysocks]

The long range spitfire just added an extra fuel tank behind the pilot seat

how big was this tank? and what part of the flight characteristics suffered due to its installation. anytime you mess with an AC's center of gravity you risk something. as in the case with the mustang you didnt want to do certain maneuvers or get into a dogfight with the fuse tank full ( which surprises me how well the guys at Y-29 did when attacked ). did the spitfire suffer the same way?

 

[Edgar Brooks]

Of course long range missions in 1941 with escorts are essentially impossible unless the Spitfire V is properly prepared. The Spitfire carried around 90 Imp gallons of fuel in tanks behind the engine which gave a range of around 400 miles. Historically 2 smaller tanks were fitted in the wing leading edges (4 in all) which increased internal fuel tankage by around 33% and range of some marks of Spitifre VII and VIII by around 50% (600 miles) over the Spitfire IX which lacked it.

As Tomo Pauk says, the VII, VIII XIV had a single tank in each wing. Two extra tanks (in the strengthened wings) were not fitted before the 20-series Spitfires.

Historically many spitfires also had tail tanks which tended to be regarded as ferry tanks only due to their destabilising effects in combat.

Only the XVI, in wartime, had a permanent fuselage tank; the removable 29-gallon tank could only be used with the 170 gallon ferry tank.

However if only 10 gallons (instead of 44-50 gallons) I'm sure the effect would be minimal and further range increases would be possible.

Totally wrong, and made worse by this apparent dream that we had loads of 170 gallon tanks that we could cheerfully chuck away, over France, a dozen at a time. When the ferry tanks were first used to get Spitfires to Malta (without the fuselage tank) pilots were told to avoid dropping them at all costs (except if combat was looming,) since they had to be returned to Gibraltar for re-use.

Of course the RAF lacked such a spolicy and Supermarines rang such a program only as a sideline.

Wrong on both counts, since the Air Ministry spent a lot of time and effort getting droptanks into service, and Supermarine (like all companies, especially during a war) did as they were told. They did not, in fact, make the tanks, which were made by a different company entirely. Supermarine manufactured the necessary plumbing, etc., to accommodate the tanks, that's all.
As well as the incorrect idea of the numbers of tanks available, there are some other pipedreams which need to be dispelled:-
1/. With the ferry tank in place, the pilot was restricted to straight and level flight, and gentle manoeuvres; if bounced, and he could not switch over the fuel flow, and drop the tank in time, he was dead.
2/. With the extra fuel, the Spitfire needed a larger oil tank, which was only available on tropical aircraft, with the Vokes filter (therefore extra drag.) Malta complained about just such a situation, with their deliveries, but were told it was that, or nothing.
3/. The extra fuel meant extra weight, which overloaded the airframe, so all guns and ammunition had to be removed, so what sort of fight are your "escorts" going to put up?

 

[Shortround6]

Fuel tank weights are all over the map due to shape (surface area) and construction. I have no idea what the 29 gallon tank in a Spitfire weighed, but the forward 37 US gallon tank in a P-40 weighed just about 100lbs empty. P-39s were about the worst and their tanks weighed almost 300lbs to hold 120 US gallons of fuel. British tanks may be a bit lighter due to different self-sealing set up?

British tried a number of different tank set ups on the Spitfire. Including the 40 gallon tank out on one wing, I am certainly not in love with the two small tanks in the wing set up as the more switching of tanks a pilot has to do the more chances of something screwing up. But the Supermarine engineers thought that was better than a single tank in the rear of the plane and that was on the planes with a much heavier engine and propeller than many here are proposing.

 

[kool kitty89]

To design a long range fighter in 1939/40 you must predict that they are needed, you must see the speed and economy of the Mustang before it is built and you must have available merlin engines that were produced in 1944. The mustang was a great design by a small manufacturer and had a charmed or even fated existence. Few saw the need of a long distance escort and even fewer saw the Mustang as that aeroplane. If the merlin did not slot in readily where the Allison had been it would never have happened.

Or to just not ignore designs with potential for such a role ... or fail to emphasize development of them for longer range. Granted, that even goes as far as shorter range aircraft (and pretty much all aircraft) lacking drop-tank support early on.

From the 1939/1940 standpoint, there were many fighters in development or even in service that could have developed into a long-range role. In England you had Gloster's F.9/37 twin engine fighter that had plenty of potential for the multirole/long-range fighter category, and possibly derivatives of a single-seat Defiant as well.

The US had the P-38, P-47, and F4U in development, all of which could have had more emphasis put on escort capabilities. Though none would have been really combat ready for 1941. (plus the P-38 had a whole list of problems, P-47 took a while to get large enough pressurized drop tanks and/or wing pylons, and the Corsair wasn't being persued for the USAAF) Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US. Accelerate development without Naval specific requirements and it might have entered service sooner. Good medium altitude performance, decent high alt (especially compared to contemporaries) good enough for US high alt bomber alts, and certainly at British bomber heights. (not P-47 turbo level power ceiling, but also lighter and more maeuverable)

There's an argument for the F4U making a better fighter-bomber than the P-47 too, but that's not pertanent here.

Germany had the likes of the Fw-187 on their hands too, though with most bombing ranges they worked with, drop-tank capable Bf-109s would have been good enough.


And, of course, Japan had heavy empahsis on exceptional long range capabilities pre-war, though achieved that in part by emphasizing lightweight construction, no self-sealing tanks, and no armor on top of large fuel capacity and fuel efficient engines.

On that note, the F2A Buffalo might have actually fit in reasonably well as a long-range fighter. Certainly the only pre-way US/British/German fighter in service witha range exceeding 1000 miles, let alone 1500. (technically, the P-40B could manage >1000 miles at minimum cruise, but that was slightly later and not in the same range class as the Buffalo)
The problem being that the performance was a bit mediocre ... manufacturing issues aside, between the lower rated refurbished engines on the Export models the British worked with and the heavier F2A-3, they'd have been ill suited to escorting bombers over Europe by the time the allies moved on to large scale offenssive raids.
That said, in the 1939/1940 context, it was probably the only thing remotely close to a serviceable single-engine escort fighters that the allies had, and performance wasn't far off from a similar vintage Hurricane. (and similarly up-armmed and armored, and more maneuverable -especially roll rate- along with lacking negative G fuel flow issues)

The F4F-3 with drop tanks might have been useful in this role too. (could go from F2A+F4F early war to F4U once it comes online)


Perhaps a P-40 derivative with cowl guns retained and wing guns reduced or elliminated in favor of more fuel would have been a useful early-war stop-gap too? (2x synchronized .50s is a bit weak, but strictly against other fighters it might have been marginally acceptable when nothing else could manage the range) That's assuming the gun bays were useful for holding fuel cells. (or that engineering space for wing tanks wouldn't be more difficult than the space for 6x .50s in the P-40D)

But really, once the Corsair hit the scene, that plane alone (in sufficient numbers) seems like it could have adapted to pretty much every role Allied fighters/fighter-bombers were called upon for in the ETO/MTO ... maybe not the super long-range capabilities of the P-38J/L exploited in the PTO, at least not without further expanded fuel. (perhaps a P-47N style wing redesign) Well that or some specific capabilities of the Beaufighter and especially Mossie.

A massive amount of luck resulted in a plane that could hardly be designed better for a job it was never actually designed for. It was so good that it is now easy to say the Brits were remiss in not designing one sooner but the Spitfire was designed around a 850HP engine, how would a Mustang/P51 perform with only 850HP?

The P-40 was adapted from the P-36 initially working with considerably weaker engines than the Merlin, yet expanded into a significantly longer-range aircraft than the Spitfire in spite of being closer to the Hurricane in original engineering date. (and flying slightly earlier)

I suppose that luck argument could apply to the P-36/P-40 too, though, given how well it developed ... and given Crutis's own difficulties in actually engineering something more capable than the existing airframe worked out to be.

 

[tomo pauk]

Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US.

That would certainly be the P-38? Very much feasible already in 1941. Few things might help out with P-38, though, like having a second source of production - for example, the P-47 was to be produced in 3 factories, ditto the F4U. Not crashing the XP-38 might've also helped to accelerate the testing, development production.

 

[Shortround6]

Or to just not ignore designs with potential for such a role ... or fail to emphasize development of them for longer range. Granted, that even goes as far as shorter range aircraft (and pretty much all aircraft) lacking drop-tank support early on.

For an escort fighter to work it has to be able to engage the interceptor fighters one a somewhat even level. Just getting a non-bomber with some guns along side the bombers doesn't work well. Germans found that out with Bf 110s trying to fly close escort.

A Mystery was the lack of drop tank support as many US fighters of teh late 20s and 30s used drop tanks and German Hs 123 used an external tank even if not often dropped.

From the 1939/1940 standpoint, there were many fighters in development or even in service that could have developed into a long-range role. In England you had Gloster's F.9/37 twin engine fighter that had plenty of potential for the multirole/long-range fighter category, and possibly derivatives of a single-seat Defiant as well.

We also have theory and intention hitting the brick wall of reality. The P-38 started with 400 US gallons in unprotected tanks, Fitting self-sealing tanks dropped fuel capacity to 300US gallons. The F.9/37 held 190 IMP gallons for it's two engines and more than likely the tanks were unprotected at that time. Fitting protected tanks will decrease capacity and increase weight, fitting more tankage increases weight. 190 IMP gallons might have worked for low powered engines in a light aircraft over short distances. It was nowhere near enough for escort work, think about it. A P-47 (early) carried 254 Imp gallons and that was nowhere near good enough. I rather doubt that the F.9/37 had less drag than the P-47 what with it's twin engines and bigger wing. Usefulness of the Defiant seems to be based of an estimate of an unflown proposal. Installation of the Merlin XX was not all that it could be in practice??

The US had the P-38, P-47, and F4U in development, all of which could have had more emphasis put on escort capabilities. Though none would have been really combat ready for 1941. (plus the P-38 had a whole list of problems, P-47 took a while to get large enough pressurized drop tanks and/or wing pylons, and the Corsair wasn't being persued for the USAAF) Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US. Accelerate development without Naval specific requirements and it might have entered service sooner. Good medium altitude performance, decent high alt (especially compared to contemporaries) good enough for US high alt bomber alts, and certainly at British bomber heights. (not P-47 turbo level power ceiling, but also lighter and more maeuverable)

We have been over this a number of times. F4U starts out carrying much less fuel inside than a P-47, has little or no advantage in drag and has to work it's engine harder even at 18-24,000 ft in high speed cruise than the P-47 does. Remenber that it doesn't really matter if the bombers are flying at 16,000ft or 24,000ft if the German interceptors are flying at 24-28,000 feet before diving down on the bombers. The escorts have to engage the interceptors before the interceptors are in a gun run. Shooting them down after the y make firing passes at the bombers means a lot of shot down bombers.

And, of course, Japan had heavy empahsis on exceptional long range capabilities pre-war, though achieved that in part by emphasizing lightweight construction, no self-sealing tanks, and no armor on top of large fuel capacity and fuel efficient engines.

And we know how that worked out in the long run.

On that note, the F2A Buffalo might have actually fit in reasonably well as a long-range fighter. Certainly the only pre-way US/British/German fighter in service witha range exceeding 1000 miles, let alone 1500. (technically, the P-40B could manage >1000 miles at minimum cruise, but that was slightly later and not in the same range class as the Buffalo)
The problem being that the performance was a bit mediocre ..

Once again, an escort fighter needs to be able to fight. Not just show up. F2A-3 began to come out of the factory in Jan 1941, about the time the First Bf 109Fs were showing up. F2As would have been in trouble against 109Es, against 109Fs in the summer of 1941 they would have been just so many more targets. Granted they may have saved bombers by having the 109Fs use up their ammunition shooting them down but sacrificial lambs is not a good long term strategy.

Perhaps a P-40 derivative with cowl guns retained and wing guns reduced or elliminated in favor of more fuel would have been a useful early-war stop-gap too? (2x synchronized .50s is a bit weak, but strictly against other fighters it might have been marginally acceptable when nothing else could manage the range) That's assuming the gun bays were useful for holding fuel cells. (or that engineering space for wing tanks wouldn't be more difficult than the space for 6x .50s in the P-40D)

A stop gap has to actually work, at least somewhat. P-40s needed Spitfires flying top cover in order to survive in North Africa. If you escorts need escorts that doesn't leave you much range for the bombing mission. And BTW "2x synchronized .50s is a bit weak" it was more than a bit weak. The US .50 probably took to synchronizing the worst of any gun that was successfully synchronized. British tests report a rate of fire of under 500rpm. One wing gun could fire almost 90% of the rounds that cowl guns could. Also you have to figure out which P-40 you are using. The D/E/F used engines that shifted the prop shaft upwards 6in. Maybe cowl guns would still fit, maybe they would need bumps/bulges to fit. Then you have to play games with the oil tank and CG. P-36s had the oil tank behind the engine and in front of the guns, ammo boxes. P-40-40C had the oil tank behind the behind the seat fuel tank. P-40D/E/F had the oil tank behind the engine near where the guns had been. This may have been in part to balance the plane. P-40 was 3 feet longer than the P-36, all due to engine but it means that 330lb (roughly) prop was 3 feet further in front of the CG than a P-36. You can't always just stick stuff where you want.

More later

 

[Shortround6]

But really, once the Corsair hit the scene, that plane alone (in sufficient numbers) seems like it could have adapted to pretty much every role Allied fighters/fighter-bombers were called upon for in the ETO/MTO ... maybe not the super long-range capabilities of the P-38J/L exploited in the PTO, at least not without further expanded fuel. (perhaps a P-47N style wing redesign) Well that or some specific capabilities of the Beaufighter and especially Mossie.

The F4U will not handle the long escort mission as well as a P-47, let alone the P-51. We have had threads on this before and with less fuel in the F4U and a higher fuel burn at the speeds and altitudes used it just isn't going to work.
You may want to look at the British twins again. They were very good at what the did do but that was NOT daylight air to air combat against high performance fighters.
American fighters were stressed for 12 G ultimate load at normal gross weight. British single engine fighters were stressed for 10 G. Mosquito was stressed for 6 G. Even if the controls will permit it you are going to break them trying to fling them about like a Spitfire or 109.