RAF daylight strategic bombing campaign results

[tomo pauk]

For the F4U to work as a long range fighter, it will need to have a drop tank facility much earlier than historically. The 1st F4U with single fuselage rack plumbed for fuel tank was accepted by USN at October 4th 1943. That would make 237 gals of protected fuel, 124 gals of non-protected fuel in 2 wing tanks total, and up to 175 gals in the drop tank. IF the F4U can warm up, take off, climb and cruise some time on wing fuel alone, that would mean it has all of the protected fuel available before entering combat.

Compared to that, the early P-47D has 305 gals of protected fuel, and can carry a tank under belly. Problem is the size of belly tank - mostly it was used the 75 gal, or 110 gal tank there, due to ground clearance. Seem that the 1st people that managed to get a pressurized belly tank of bigger volume were at 5th AF of Gen Kenney, the tanks produced in Brisbane by Ford of Australia.
The combat radius for the such P-47D with 75 gal tank was 340 miles, per AHT; with 110 gal DT instead it will do ~375 miles of combat radius. The F4U will probably not be able to better those values. Once the P-47 is plumbed for wing drop tanks, it will do 425 miles of combat radius, per USAF table via AHT. Unless the F4U gets much more of protected internal fuel and second drop tank, it won't come close. And, an escort fighter of under 400 miles of radius will not going to do the trick for the USAF in last 24 months of ww2.

The P-47D of early 1944, with 370 gals of protected fuel in fuselage, really outdistances the F4U as an escort fighter with 600 miles of combat radius. All figures for the P-47 are for USAF requirements - 25000 ft cruise, 20 min combat, ~310 mph TAS.

 

[tomo pauk]

Another thing that would've plagued the, presumably, hi-alt operations needed by 8th AF: compressibility. Prom America's hundred thousand, pg. 517:

- August '43: Navy Squadron VF-17, in testing out their new Corsairs, dives them from high altitude and encounters some compressibility problems; they are shedding elevator fabric and loosing control in the dives . Vertical dives from above 20000 feet are banned in Squadron VF-17

The wing profile was 23018 at root, ie. thickness was 18% of chord. That is one thick wing (even the P-38 was at thinner percentage with 23016 profile at root), and with the 'classic' NACA 230 series it will be entering compressibility quick - meaning LW fighters will have no problems to disengage with split-S when needed.

 

[kool kitty89]

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.

Hence why I didn't refer to any British twin that actually reached operational status. (though I mentioned the Mosquito would have a tough time due to G-limits and maneuverability)

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??

I'm not thinking of something exceptional, but something closer to an indiginous British P-40 possibly with a bit more room for growth in internal tankage. (the P-40 itself was much better in the long-range role than the Spitfire or Hurricane ... just not good enough to manage the extreme ranges heavy Bombers were pushing over Europe)

So perhaps not potential to be a deep penetration fighter capable of staying with the bombers on their longest routes, but a hell of a lot closer than anything else the British had in production.

And the F.9/37 was more in terms of potential growth ... it might not have worked out, but given the dimensions and design of the airframe (and provisions for a second crewman), it seems a fair bet that it had lots of potential for expanded internal fuel tankage (unlike the Whirlwind) while being a more practical day fighter than the Mosquito (G-limits among other things).
Modified Mosquitos MIGHT have made sense too, but between maneuverability and stress limits of the airframe, it seems less likely.

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.

Faster level flight, acceleration, and climb rates at low/mid altitudes than early P-47s (prior to boost limits being raised), lower weight, greater roll and turn rates, and I'm assuming use of the wing tanks. (and replacement with self-sealing tanks on later models rather than deletion)

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.

True, and by the time the F2A-3 arrived, better aircraft were on the horizon anyway ... and drop-tank eqipped F4Fs probably would have fared better. (barring hypotheticals like an F2A fitted with the 2-stage R-1830 of the Wildcat)
Even so, with equal pilots, the F2A-3 may have fared better than the Hurricane at least. (similar speed and climb, but more maneuverable -especially at high speeds)

The 1939/1940 argument is a bit limited here since allied bombing wasn't really significant until after that point, so the really early fighters with the necessary range are only really relevant when there was no serious need for them. (one could argue for the Germans being better off with F2As or especially P-40s during the battle of brittian, but drop-tank equipped Bf-109Es would have been perfectly suited to the short ranges involved there ... albeit P-40s, Buffalos, and Wildcats ... and P-39s for that matter all made better fighter-bombers due to range/fuel load compared to contemporary 109s)

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.

Like the Buffalo and F4F, I'm speaking mostly very early war (before the P-38, P47, or F4U could be ready) so it'd be P-40B/C/Tomahawk. (the C is actually a bit too late for the early-war requirement) But the allusion to the P-40 D/E wing did imply later use as well, so those factors are valid from that standpoint.

As to the armament, nose guns have concentration of fire, lack of convergence zone limits, and effectiveness round per round over wing mounting. (both the British and Americans seemed to actively ignore/decry this advantage when the Soviets, Germans, and Finns seemed to recognize it much more -including Soviets removing the P-39 wing guns and Finns noting the nose mounted .50 brownings of the F2A were more efficient than the wings in spite of the much lower RoF -and opted for 4x nose mounted .50s in their indiginous fighter development -while the P-51 had its pair of nose guns deleted -or removed in the field on the A-36- ... as did the F4F)
Nose guns are pretty definitively more affected, but realistically (looking at historical US/British doctrine/tendencies) this argument is largely compromised if for no other reason than due to preference over utility.

That whole argument may be superfluous anyway if the P-40's wing was ill suited for fuel in/around the gun bays. (just keep the wing guns ... or even consider adding the nose guns to later models if possible -again ... doctrine/preference seems to nix that idea regardless of technical feasibility)


It's also worth noting that compared to the 8 gun Spitfire and Hurricane, 2 500~600 RPM .50 BMGs still managed better than half the firepower of 8x .303 brownings. (and the 4x .30-06 brownings + 2x .50s had more firepower than the 8 gun british fighters) At very least using these metrics for firepower The WWII Fighter Gun Debate: Gun Tables
(in fact roughly 130% the firepower of an 8-gun spit/hurricane)




There's also one other thing relating to the P-51, especially relevant when comparing the P-40 to Spitfire and 109. Not only was it a 'lucky' design to fit the long range category, but was just an exceptional all around performer lucky enough to NOT have the enemy challenge it with a similarly advanced short-range interceptor. (As the spitfire and 109 were to the P-40) Unless you count the jets but those came too later and too few to matter.

 

[kool kitty89]

The wing profile was 23018 at root, ie. thickness was 18% of chord. That is one thick wing (even the P-38 was at thinner percentage with 23016 profile at root), and with the 'classic' NACA 230 series it will be entering compressibility quick - meaning LW fighters will have no problems to disengage with split-S when needed.

According to The Incomplete Guide to Airfoil Usage the F4U's wing root was a 23015. The critical mach number figures for the F4U I've seen (.73 mach in wind tunnel tests) also correspond more to 15% chord than 18%.

http://www.ww2aircraft.net/forum/flight-test-data/ww2-fighter-critical-mach-speed-802.html
I recall there being a more recent thread to bring this up too, but the F4U's mcrit discussed there is higher than the P-47's. (granted, critical mach alone doesn't say how detrimental the high speed handling is -buffeting, loss of control, shift in center of lift -extreme on the P-38, etc)

For the F4U to work as a long range fighter, it will need to have a drop tank facility much earlier than historically. The 1st F4U with single fuselage rack plumbed for fuel tank was accepted by USN at October 4th 1943. That would make 237 gals of protected fuel, 124 gals of non-protected fuel in 2 wing tanks total, and up to 175 gals in the drop tank. IF the F4U can warm up, take off, climb and cruise some time on wing fuel alone, that would mean it has all of the protected fuel available before entering combat.

Drop tank is going to be the big bottleneck there. It's going to need 300+ gallons externally AND the internal wing tanks to be really useful. Better than the existing P-47 prior to wing mounted drop tanks, but that's about it.

This argument mostly hinges on the F4U being able to receive belly racks for drop tanks quickly ... more quickly than the P-47 got wing pylons and certainly more quickly than the late P-47D's expanded internal fuel capacity. (upgrading to protected wing tanks on the F4U would have been significant too, but less so than being able to cary half its fuel externally)

Further, the more general point on the F4U being (potentially) the only fighter the US needed over Europe also hinges on featuring ALL of those elements. (internal fuel capacity, drop tank capacity, plus bomb and rocket capacity for the fighter-bomber role) The historical USN/USMC F4U-1 in 1942/43 would NOT have been that plane. (but I'll maintain that the F4U design would have been more capable in covering the P-38/47/51's historical roles than any ONE of them would -not better than where those other A/C excelled, just good enough to be a better multi-role machine than them ... perhaps sans the P-38 -unless maybe you took more cost effectiveness into account ... but then simplified turbo-less fighter-bomber derivatives might mitigate some of that too, so lots of variables)

(more detailed argument below)

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.

Maybe. Looking at the P-38, P-47, and F4U stricly from a USAAF long-range fighter point of view:

P-38 needs to solve cockpit heating issues (not QUITE as extreme at RAF bomber heights), terminal dive control issues, maneuverability issues, turbo/intercooler issues, and be drop-tank capable. (the latter was pretty straightforward, and lacking cockpit heating could arguably be lived with -but compromise health/awareness of pilots, especially on such long flights- the engine performance and maneuverability were critical for being adequate in fighter vs fighter combat, and the dive issues could be avoided by a good pilot and the emergency dive-flap/break solution probably could have been applied much earlier without need of extensive research -it IS a reasonable interim solution, unlike actually trying to solve the buffeting and pitch-down+heavy stick issues aerodynamically -the former solved by carefully designed wing/body fillets, the latter never cured only better avoided)

There's not that many quick fixes on the P-38 that'd get it working well as a high-altitude escort fighter. (it COULD reasonably have been optimized in the short-term as a more effective and more cost effective low/medium altitude fighter/fighter-bomber by deleting the turbos and streamlining the design for low/mid-alt roles -lighter, more power at low alt compared to pre-J models, warm enough for cockpit heating issues to be ignored, warmer denser air avoiding high mach number dives, and easier to maintain)

The P-47 was primarily limited (once service ready) by lack of high capacity drop tanks. If they'd been able to carry around 300 US gallons of external fuel on the belly shackle, things would have been very differnt. I'm not sure there's a quick fix here, but I suppose heavy emphasis on the need of the P-47 as an escort fighter would have accelerated development of larger capacity pressurized tanks. (limited internal fuel capacity was an issue too, but not the primary bottleneck until after it could carry over 200 gallons of fuel externally)
It wasn't until the P-47 was carrying 300+ US gallons on wing pylons that the early models actually showed their limitations due to internal fuel capacity. (and slightly more so due to added drag from the pylons -plus added weight increase if comparing the C to early D models)

The F4U mostly just needed to be drop tank equipped and possibly have the wing tanks replaced with self-sealing fuel cells. (likely closer to 50 gallons each) Similar to the P-47, the ability to carry 300 US gallons externally would have been the big factor. (the higher clearange of the F4U's centerline would have allowed a much greater variety of tanks to be employed, making fitting the actual pylons+plumbing to the F4U the main limiting factor rather than sheer availability of suitable tanks) I may be mistaken, but I think the F4U's belly pylons also affected performance less than the P-47's wing+belly pylons.

I do realize that you need fuel for warmup, time to target, combat, and time home+landing, and am not expecting a full half of range to be covered by external fuel, but half of total FUEL is not the same as half the total range. (external stores burned off first would get the worst fuel efficiency due to weight and bulk adding to drag, so the ability to carry significantly more than half your total fuel stores externally might not be useful for combat, but the ability to carry close to or exactly half your total fuel externall IS significant) Likewise the P-38's ability to carry a pair of 150 gallon drop tanks was significant, while its added ability to carry a pair of 300 gal tanks wasn't particularly combat relevant. (more relevant for the late models, but still a bit overkill aside from ferry flights)
Fuel consumption increase due to weight and higher engine output on later models is also a factor. (though improvements to cruise efficiency sometimes come into play too)

 

[tomo pauk]

According to The Incomplete Guide to Airfoil Usage the F4U's wing root was a 23015. The critical mach number figures for the F4U I've seen (.73 mach in wind tunnel tests) also correspond more to 15% chord than 18%.

I'm afraid that honorable gentleman is wrong. The data tables for the F4U clearly state the 23018 as a profile at root: link1, link2 (page 2)

http://www.ww2aircraft.net/forum/flight-test-data/ww2-fighter-critical-mach-speed-802.html
I recall there being a more recent thread to bring this up too, but the F4U's mcrit discussed there is higher than the P-47's. (granted, critical mach alone doesn't say how detrimental the high speed handling is -buffeting, loss of control, shift in center of lift -extreme on the P-38, etc)

At 20000 ft, the dive limit for the P-47D was 350-400 mph IAS, for the F4U was 335 kts IAS (385.5 mph IAS); at 30000 ft, it was 250-300 mph IAS for the P-47D vs. 255 kts IAS (293.5 mph IAS) for the F4U. Hmm - the F4U indeed looks at least as capable as the P-47D, if not better, until the P-47D got dive flaps. That also means it is a considerably better than P-38.

Drop tank is going to be the big bottleneck there. It's going to need 300+ gallons externally AND the internal wing tanks to be really useful. Better than the existing P-47 prior to wing mounted drop tanks, but that's about it.
This argument mostly hinges on the F4U being able to receive belly racks for drop tanks quickly ... more quickly than the P-47 got wing pylons and certainly more quickly than the late P-47D's expanded internal fuel capacity. (upgrading to protected wing tanks on the F4U would have been significant too, but less so than being able to cary half its fuel externally)

The bottleneck are both drop tanks and protected tanks for the F4U. Unless it does not have above 300 gals of internal fuel in s-s tanks, it will be ill able to provide escort much beyond 400-420 miles, no mater how much fuel it carries in DTs.
The P-47 was ferried by using wing tanks in August 1943 via Island to the UK, so it only takes enough of will early enough to have those installed. The Australian-made belly tanks were of 200 gals capacity, too bad that solution was not adopted in 1943 for the ETO Thunderbolts.
The s-s wing tanks were installed on the 'Super Corsair', that brought protected fuel to 309 gals. Good, but it would still mean under 450 miler of radius.

Further, the more general point on the F4U being (potentially) the only fighter the US needed over Europe also hinges on featuring ALL of those elements. (internal fuel capacity, drop tank capacity, plus bomb and rocket capacity for the fighter-bomber role) The historical USN/USMC F4U-1 in 1942/43 would NOT have been that plane. (but I'll maintain that the F4U design would have been more capable in covering the P-38/47/51's historical roles than any ONE of them would -not better than where those other A/C excelled, just good enough to be a better multi-role machine than them ... perhaps sans the P-38 -unless maybe you took more cost effectiveness into account ... but then simplified turbo-less fighter-bomber derivatives might mitigate some of that too, so lots of variables)

I've always thought that P-47 would do better than a F4U derivative

More later, got to cook some lunch

 

[Edgar Brooks]

. I have no idea what the 29 gallon tank in a Spitfire weighed,

According to the A.P., the 30-gallon droptank, when made of vulcanised fibre instead of tinned steel, weighed 40 pounds. As the 29 gallon tank was flexible (otherwise it would never have gone into the fuselage,) it's possible that it was the same material, and therefore weight.

 

[Koopernic]

RAF daylight shallow penetration missions into German airspace (The Ruhr eg Dusseldorf) means a range of 300-350 miles. No RAF fighter can achieve this, the Allison Mustangs don't become available for combat til mid 1942. Hence daylight bombing campaign requires engineering. In a What if hindsight scenario what might have plausibly been achieved with simple basic "sheet metal" engineering that didn't require advances in fuels, engines and aerodynamics.

Assume that the RAF had a daylight bombing strategy that had come to accept 'lessons learned' from analysis of what happened to their enemy, the Luftwaffe, over the Battle of Britain.
1 Bombers will be intercepted in force due to the defenders use of radar
2 and that the Germans had good radar. (Seems to have been somewhat of a problem)
3 Long Range Escorts are necessary.
4 Night bombing was unacceptable. (Assume Lindeman didn't exist)

This means decisions to produce an interim long range escort are made by October 1940, near the end of the BoB. Specifications are issued then. Priority is given.

I see only two options:

1 Improve the capacity of the Spitfire III and V by essentially introducing the "C" wing early. Historically the C wing is introduced on the Mk V and is used on the Mk IX but it is only the MK VII, VIII and latter Griffon variants that receive the wing with an in built 15-18 gallon fuel tank. The basic spitfire has a 85 gallon tank increased to 95 gallons.

The 85 Imperial gallon internal capacity in two fuselage tanks, one above the other. Range described as "allowed for take-off, a climb to altitude, 1.65 hours cruising and 15 minutes combat at full bore".

A later re-design of these internal tanks increased their capacity by 10 gals. Installation of wing tanks added a total of 36 gals capacity.
Internal tankage capacity for the latest Mks was therefore 85 + 10 +36 = 131 gallons.


The tail tanks I think can be ignored due to their destabilising effects unless only a very small tail tank is added (say 10 gallons, 42L enough for 6 minutes of full bore combat)

2 Take the P-40 and overcome its power to weight ratio problem and its Allison engines low critical altitude by fitting the single stage Merlin 20 series with two speed supercharger.
Main tank 50 gallons [62.5 gal U.S]
Fuselage tank 47 gallons [58.75 U.S.]
Reserve tank 33 gallons [41.25 U.S.]
Total 130 gallons [162.5 U.S.] (Note some sources state 134 gallons)

Historically such an aircraft was built, the P-40F with Packard Merlin V-1650-1 but only in 1943. The two speed Merlins were available pre was and production was being wasted on the Hurricane in 1941.

Combined with drop tanks a substantial range can be achieved to reach more than 50% of German airspace.

I think its worth noting that the only nation which had a passable long escort fighter in 1939,1940 and 1941 was Germany with the Me 110. The exchange ratio against RAF Hurricanes and Spitifires was in fact slightly favourable.

 

[Glider]

The rear tank on the Spitfire was an option. I recognise that it didn't do the handling any favours but by using it first the handling issue would have gone before combat was reached. The other comments re the earlier introduction of the C wing I agree with.
The P40 was outclassed by the 109 and no matter what you do with it that will not be altered. The earlier comment about the F2A apply here, it has to be able to take on the defending fighters on equal or near equal terms to work, just turning up will not suffice.
The Me110 was not up to taking on equivalent single engine fighters, that was proven many times in combat.

 

[tomo pauk]

I'm not the greatest fan of the P-40F as an escort fighter that would be able to go against LW and do very much. 1st delivered on January 1942, it was at least 40 mph slower than LW fighters of same era.

 

[Balljoint]

The P40 was outclassed by the 109 and no matter what you do with it that will not be altered. The earlier comment about the F2A apply here, it has to be able to take on the defending fighters on equal or near equal terms to work, just turning up will not suffice.

The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.

 

[Shortround6]

The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.

P-40 is always about a step behind the 109. P-40s are being built when the 109E was, P-40Cs are being built when 109Fs are coming into service. P-40Es start coming out of the Factory when 109-F-4s start showing up in service units (P-40s have to shipped 3,500-6000 miles to service theaters). P-40Fs start to roll out of the factory when 109Gs start to show up.

Granted in takes a number of months to see large numbers of a new type to really appear in service but trying to depend on P-40s to take on 109s doesn't look good.

IF you have other fighters that can force the 109s down to the better altitudes for the P-40 the P-40 could (and did) give a better account of itself but that is NOT what is being talked about here.

And I repeat, the escort fighter used has to be able to prevent, or at least interrupt, attacking fighters from diving on the bombers from 3-8,000 ft above.

 

[Glider]

The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.

The P40 was never as good as the Me109 and as pointed out was always at least a generation behind the Me109 and FW190.
In the C Shores book Fighters over Tunisia there is a section where a number of allied fighter pilots were asked which were the best allied fighters of the period. There was almost unanimous agreement that went Spit IX followed by Spit V and P38, followed by P40 and Hurricane. Most people agree that the Fw190 was as good as the Spit IX and the Me109G2 was of a similar class. There is no way that the P40 could make such a leap in performance.

 

[kool kitty89]

The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.

Up-engined to what? The 9.6 supercharger geared Allison or Merlin?

P-40 needed more fuel to get the range needed for full penetration escort in Germany and would have been outperformed in most aspects. (aside from range and dive/high speed maneuverability performance)

Aerodynamically it might have been in the same class as the spitfire, 109, or 190, but to manage that range AND be a competent (not just marginal) fighter against those contemporaries, it needed to be able to perform well in SPITE of being capable of more than double the combat radius. (or maybe not quite that extreme compared to the 190 with drop tanks)

With the P-51 B/C/D's engine and fuel expanded wherever practical, it might have gotten by well enough ... a turbocharged P-40 might have managed that too if they could somehoe figure out how to cram a turbo+intercooler AND enough fuel into the ship. (granted, turbo improves fuel efficiency somewhat, potentially, but you'd still need more fuel than the P-40E/F/M carried)


At British bomber alts, the V-1650-1 or 9.6 supercharged Allisons might have been adequate too, but more fuel is still needed.

P-40 is always about a step behind the 109. P-40s are being built when the 109E was, P-40Cs are being built when 109Fs are coming into service. P-40Es start coming out of the Factory when 109-F-4s start showing up in service units (P-40s have to shipped 3,500-6000 miles to service theaters). P-40Fs start to roll out of the factory when 109Gs start to show up.

From the P-40 through P-40E (aside from WER at low alt), performance of the P-40 consistently DECREASED compared to earlier models due to gains in weight and drag without much/any improvement in engine performance. (figures for the prototypes and acceptance trials show some speed gains in the E over the B/C, but actual service performance figures show a much more consistent degradation in top speed and climb)

Of course, the P-40 was more akin to the very early war Spitfire/Hurricane/109E lacking self sealing tanks and pilot armor and the B wasn't as heavily armored as the C (and lacked the bomb/drop tank rack).

Besides that, as above, the P-40 always carried much more fuel than the 109 or Spitfire, though closer to the 190. And aside from being built heavier, also had to deal with (often) carrying more weight in armament and using similar or lower performance engines. (P-40F with reduced armament and fuel might be reasonably close to Spitfire V and early 109Gs, P-40M probably slightly worse, N perhaps slightly better ... probably close in top speed, weaker in climb, and better controlled at high speeds)



With any given engines available, the P-40 as a basic airframe would be more paractical to configure with enough fuel to be a useful escort fighter compared to the Spit or 109 ... maybe better than the 190 maybe similar hard to tell. (put the 109's engine in the 190 and try to cram in more fuel if there's practical space for tanks without hurting CoG and it might manage it too -likely won't manage it with the BMW in there)




With equal technology, intercepting fighters are always going to have superior performance to escorting ones, aside from short-range low/medium altitude tactical escorts. You need significantly superior technology in a long-range escort fighter to manage combat on equal or better terms ... on a one to one basis. (granted, tactical advantage of managing to drop on intercepting fighters from above and maintain a good bit of zoom energy and take advantage of coordination and numerical superiority -even if 1:1 performance is weaker- could make marginally adequately performing long-range fighters good enough)

 

[Shortround6]

Has anybody established an 'actual' desired timeline or date here?

1941-42 is pretty squishy as by the end of 1941 there had only been 138 Mustangs built and due to shipping distance the British don't even test fly one at Boscombe Downs until Jan 1942. They have four squadrons in service in Aug 1942 and 15 squadrons in service in Jan 1943. There are only going to be enough Mustangs to support a daylight bombing campaign in the last few months of 1942.
And that is with historic production, no modifications, no waiting for better/different engines.

Stripper P-40s, as done historically are useless. One of the mods was yanking out a fuel tank. While yanking the #5 and 6 guns may have been a good idea, limiting the remaining guns to 200-201 rpg isn't such a good idea for an escort fighter.

The P-40 with a pair of .50cal guns in the cowl with 200rpg and one .30cal in each wing with 500rpg, no armor, no self sealing tanks, grossed 6800lbs. Spitfire II grossed 6172lbs, 109E-3 was 5875 and a 109F-2 was 6173lbs(?)
The P-40 weighed 5357lbs empty (no guns, no trapped oil, no gun sight, no oxygen equipment), unless you cut structure you can't get a P-40 light enough by just leaving out equipment.

 

[Freebird]

The answer to this is already well known and you only need to look at Sholto Douglas' 'Leaning into France' to witness RAF losses over the continent at that time. It was a roundly criticised campaign with high losses for Fighter Command at the hands of mainly Bf 109Fs, which were superior to Spitfire Vs. The appearance of the Fw 190 compunded the problem. Night bombing offered protection against German fighters, until the Nacht Jagd became numerous and effective enough.

And when the "real" combat losses vs enemy aircraft were tallied it went from high losses to extreme.
The RAF Fighter Command under Douglas and Leigh-Mallory overclaimed g German losses by an astounding 7-1

 

[Balljoint]

The P40 was never as good as the Me109 and as pointed out was always at least a generation behind the Me109 and FW190.
In the C Shores book Fighters over Tunisia there is a section where a number of allied fighter pilots were asked which were the best allied fighters of the period. There was almost unanimous agreement that went Spit IX followed by Spit V and P38, followed by P40 and Hurricane. Most people agree that the Fw190 was as good as the Spit IX and the Me109G2 was of a similar class. There is no way that the P40 could make such a leap in performance.

Just what an up-engined P-40 could be is a bit nebulous. And, with enough fuel to get home, so is performance. But the P-40 could well be superior in the vertical in that it maintained rather good roll rate ate high speeds while ME-109 had high roll control forces and suspect structural integrity at speed. Thus the P-40 might well be able to reach more favorable altitudes for escape or combat.

Overall, the P-40 had been bypassed regarding performance. But, with select tactics taking advantage of the LW fixation on the bombers, the P-40 would have been better than no help at all during the early days.

 

[kool kitty89]

Stripper P-40s, as done historically are useless. One of the mods was yanking out a fuel tank. While yanking the #5 and 6 guns may have been a good idea, limiting the remaining guns to 200-201 rpg isn't such a good idea for an escort fighter.

Modest weight saved by omitting a single pair of guns would probably be the only practical compromise there, yes. (similar armament to P-51A/B/C)

The P-40 with a pair of .50cal guns in the cowl with 200rpg and one .30cal in each wing with 500rpg, no armor, no self sealing tanks, grossed 6800lbs. Spitfire II grossed 6172lbs, 109E-3 was 5875 and a 109F-2 was 6173lbs(?)
The P-40 weighed 5357lbs empty (no guns, no trapped oil, no gun sight, no oxygen equipment), unless you cut structure you can't get a P-40 light enough by just leaving out equipment.

Could the Spitfire or 109 be practically modified to carry enough fuel to be competitive with the P-40 range-wise? And could it do so in a manner that was reasonably stable in flight? (degradation to speed and climb/turn rate is unavoidable, but actual handling characteristics in terms of stability are still critical -an overweight but stable A/C can at least rely on dive and zoom tactics to gain an advantage)

And equally importantly, could a 109 or Spitfire carry a large enough drop tank to have that cover for close to 1/2 the range.

For the 1941/42 period, in the context of British daylight raids, modified long-range Spitfire Vs might have been adequate ... but that's only IF they could safely carry enough fuel.

 

[Shortround6]

in reverse order.

For the 1941/42 period, in the context of British daylight raids, modified long-range Spitfire Vs might have been adequate ... but that's only IF they could safely carry enough fuel.

MK V Spits were getting hammered on the "lean into France" missions. That is attacking targets or escorting planes attacking targets in coastal areas. Asking them fly to targets another 100-125 miles inland is certainly not going to help things. Especially if the "long range planes" are heavier.

Could the Spitfire or 109 be practically modified to carry enough fuel to be competitive with the P-40 range-wise? And could it do so in a manner that was reasonably stable in flight? (degradation to speed and climb/turn rate is unavoidable, but actual handling characteristics in terms of stability are still critical -an overweight but stable A/C can at least rely on dive and zoom tactics to gain an advantage)

And equally importantly, could a 109 or Spitfire carry a large enough drop tank to have that cover for close to 1/2 the range.

The problem is NOT getting in. It is getting out. A few 109 recon planes carried a tank under each wing (usually without wing guns?) Spit might carry a 90 gallon drop tank (might go larger, 170 gallon ferry tank is out), both planes may/would need larger oil tanks.
For a mission profile on the way in you have engine warm up and take off taking up fuel plus climb to altitude and forming up. SPits could top off fuselage tanks I think. Pump and piping would solve problem for 109 if not already fitted.
That solves getting IN. Getting OUT has the combat allowance (how many minutes at combat power, how many minutes at max continuous or max climb or? ) and a high enough cruise speed back to the coast to help keep from being bounced. For a Spit V using 16lbs of boost in combat every minute was worth 5 minutes at most economical cruise.
Us planners figured how much fuel was needed to get back after dropping tanks, that was the practical radius and then they figured how to get enough external fuel on the planes to get to the radius distance. Plane limitaions sometimes got in the way on early planes. Please note that the external 52 gallon tank on the P-40 (and the under fuselage tank on the P-39) were to restore fuel capacity after fitting self sealing tanks.

Modest weight saved by omitting a single pair of guns would probably be the only practical compromise there, yes. (similar armament to P-51A/B/C)

Modest weight savings won't get you want you want/need. And while the armament is similar at first glance P-51Bs carried more ammo. 250 rounds for the inboard guns and 350 rounds for the outboard guns. Stripper P-40s carried 201 ( why the 01?). Regular P-40s carried a total of 1410 rounds. (235 per gun but I don't know if all guns had the same amount.) .50 cal ammo is about 30lbs per 100 rounds so adding ammo back in for a 4 gun version can quickly use up the weight savings. Some P-51Ds pulled the center gun of the three(?) and increased ammo. Some planes carried 500rpg (not always filled?) for 4 guns and others (later ones changed ammo trays) to 400 for inboard gun and 500 round for outboard gun.

 

[Koopernic]

The original poster, Viking, wanted to examin daylight raids from 1941 onwards. To me that means January 1941.

If the RAF wants to run precision daylight raids into Germany proper it needs an escort fighter. The only aircraft that is available that can do the Job is the Curtiss P-40B (Tomahawk IIA) and it most certainly can do the job being the first P-40 with acceptable armour and protection. The P-40B is available from May 1941.

It has a range of 730 miles on internal fuel, 1270 if throttled back. That is 75% more than the Me 109F or Spitfire III or V. With a 75 gallon drop tank it has even more range.

The aircraft is over maligned. It can out dive both the Me 109 and the Spitfire by a substantial margin, it can out roll both by a substantial margin, particular at speed. It can out turn the Me 109 at low altitude and could probably give the Spitfire a run for its money. A well trained pilot has some strengths he can play to. The P-40 made aces against all the axis power, Clive Callwell being one.

The P-40's problem is that its larger airframe and relatively weak Allison V-1710 engine gave it an inferior power to weight ratio to the Spitfire and Me 109F2 which was worsened by the relatively low full throttle height of the Allison.

A power to weight ratio problem can be fixed by fitting a more powerful engine, such an engine was the Merlin, which was easy to fit. The Merlin XII, Merlin 45 and Merlin XX are all available in 1941 (the XX which had a two speed supercharger and was latter know as the 20 series) Historically the P-41F with Packard built V-1650-1 "Merlin 20" became available a scant 8 months latter in Jan 1942. The Merlin would improve the power to weight ratio of the P-40B by between 10% to 20%.

The RAF can have an even more effective escort fighter before mid 1941 by bringing forward the installation of the Merlin into the P-40 by 9 months. Having said that I believe that Allison engine P-40/Tomahawk IIA would have been effective in substantially protecting the bombers by diverting the Luftwaffe's interceptors. It has to be remembered the Luftwaffe is stretched then as well.

The main opponent would be the Me 109F2 with its 1270hp DB601N which at 369mph is slightly faster but able to climb much faster. The Allison is producing 1040hp, latter in 1941 1140hp, about 10% less with lower critical altitude. German C3 fuel is only rated at 92/110 in this period, raising to perhaps 93/115 in that year. Latter in 1941 the Me 109F4 appears with the more powerful DB601E engine (running on lower grade B4 87 octane fuel) but with substantially more power due to variable length inlet ports and the Me 109F4 with a speed of 380 to 390 mph for a short time perhaps even eclipses even the Spitfire V.

The Allies have a substantial fuel advantage with their fuel rapidly jumping from octane/PN 100, 100/110, 100/125, 100/130 by 1942. The German fuel lagged, not even reaching 100/130 even by mid 1944 though close enough (but then the allies were using 100/150.

The Middle of 1942 sees the early Allison P-51A Mustang I/II come into service. This is an incredibly fast aircraft below 15000ft that outclasses all other fighters but at 20000ft its speed is 380mph versus the Me 109G1 400mph. Again the Merlin 20 ie Packard V1650-1 would close of this gap.

There is one further possibility. Wikipedia states that in 1938 Supermarine was told to develop suspended 20mm canon for the Spitfire. Joe Smith objected and the guns were built into the wing. However had he not done so the leading edge tanks used in the Reconnaissance Spitfires (which added 66 gallons each wing) could have been used on the fighter spitfires with a pair of suspended 20mm Hispano's.

We know that a pair of suspended canon "gondola guns" on the Me 109G impacted speed less than 1%. (See Kurfurst.org) and so I argue that the impact on spitfire speed would have been negligible since the guns were being moved (not added as in the German case).

Such a Spitfire would substantially out range even the P-51D with tail tank.

 

[Glider]

The P40 was significantly outclassed by the Me109 and suffered heavy losses when they met in combat, any analysis of the actions in the Mediterranean area will prove that. The P40 had no speed advantage over the 109F, dive advantage was marginal and to be of use you have to have a height advantage which is a major problem with the P40, as compared to the 109F it has a miserable climb performance. It was also poorly armed. The LMG were of little effect against the 109 and the 0.5 had their rate of fire significantly reduced as they had to fire through the propeller.

The quickest and simplest way of giving the RAF a decent long range fighter in this period was to develop drop tanks for the Spitfire. At Malta they installed 2 x 45 gallon drop tanks under the fuselage of the Spit V (they were cast offs from those fitted to Hurricanes) and with a bit of imagination this could have been developed.

However I do agree that the Spit V was outclassed by the FW190 and losses would have been heavy. That said all fighters of the period were outclassed by the FW as it was by far the best fighter of the period anywhere. Nothing is going to get around that.