A Critical Analysis of the RAF Air Superiority Campaign in India, Burma and Malaya in 1941-45

[Schweik]

If I'm reading this right only the bottom front tank on the Spit IX was self-sealing. Using the rear fuel tanks sounds dicey and required the area commander sign off.

It also introduces the issue of fuel tank pressurization, which may be needed in the CBI if you wanted to fly at a reasonably high altitude.

 

[Milosh]

That is from a post WW2 manual.

 

[RCAFson]

According to that datasheet you posted, the Spit VIII could fly 940 miles with "aux tanks full". With "permanent tanks full" (143 IG) it could manage 740 miles but doesn't that mean a full rear fuel tank which makes the thing unstable? Realistically the actual range is ~650 miles after dropping the tanks and that includes a bit of margin for landing, weather etc. but doesn't, I believe, include WEP or military power time for combat.

Also, in your scenario, you were suggesting that they fight with the external tank in place. Not only would that put a Spit VIII or IX at a disadvantage against a Fw 190 or late model 109G, it would create a variety of hazards.

If the external tank is indeed self sealing then I'll retract that from the list of additional perils that it would bring to a dogfight but I'd really like to see some proof of that before I signed off. I don't believe any Amercian made external tanks were. But aside from those issues, there are reasons why it was generally considered a bad idea to get into combat with external tanks on - especially against other fighters where hard maneuvering may be required. You still have the weight and drag, and stability effects of an external tank. I think you might find even worse effects than the dreaded vokes filter.

In short, I think it's very unlikely the Spit VIII could fly a Schweinfurt raid escort, and Berlin is just grasping at straws.

If they actually could then they would have done so, in my opinion, because in a dogfight a Spitfire is a bit better than a P-51, depending on the models.

The Spitfire8 data sheet is for a Spitfire with the standard 124IG internal fuel with no CoG restrictions. Adding a 75IG rear fuselage tank would extend range considerably. As I have repeatedly pointed out the limitations on CoG due to the rear fuselage tank were the same on the Mustang, yet they managed to use them with great success.


The 30 and 45IG tanks were SS, per Morgan and Shacklady but a variety of slipper tanks were developed, and AIUI, not all were SS. The Fulmar 60IG slipper tank was SS (as per the Pilot's Notes), for example. A combat trial was done between a Spit Mk 14 with a combat rated 90IG slipper tank and:

About 20mph knocked off maximum speed...turning circle still within those of FW190 and Me109G... Conclusions. Even with the 90 gallon long range tank the Spitfire 14 can equal or outclass the FW190 (BMW801D) and Me109G in every respect...
Price, The Spitfire Story.

And the same would apply to a Mk8, albeit, with lower max speed. The slipper tanks had more drag than a torpedo tank (still not that much in total), but they had the advantage of being very near the CoG and their shape made it relatively easy to design in SS. Hence they could be retained in combat.

 

[RCAFson]

If I'm reading this right only the bottom front tank on the Spit IX was self-sealing. Using the rear fuel tanks sounds dicey and required the area commander sign off.

It also introduces the issue of fuel tank pressurization, which may be needed in the CBI if you wanted to fly at a reasonably high altitude.

View attachment 549410

The Forward fuselage tanks are the standard fuel tank arrangements as used on all Spitfires. All SS tanks that are pressurized will have some impairment of their SS properties and this is true for the Mustang as well.

I think LR escort is one of the "special operations" where the rear fuselage tank could be used, and as we've discussed the Mustang had CoG restrictions as well when using the rear fuselage tank. But your typical spitfire pilot wasn't fully trained in their use.

 

[Schweik]

I just don't buy the idea of fighting with the external tank. I don't believe it's self sealing either. I think you are comparing the slow crawl range at minimum cruise speed with the 400 mph cruise of the Mustang... which can fly a lot further at slower speeds and lower altitudes. I think you are grasping at straws. Like I said before, it's out of reach mate.

But we probably have to agree to disagree, because it will just go on forever.

 

[Schweik]

That is from a post WW2 manual.

So what?

 

[Milosh]

So what? Restrictions were added that would not have been so in WW2.

 

[Shortround6]

I have seen in several places that some of the 30 gallon drop tanks were self sealing, apparently there were several different styles/methods of construction. I wasn't sure on the 45 (or they came both ways?) while the 90 gallon tank was pretty much a plain tank and the 170 gallon was never sealing. that is my understanding anyway.

Both the Spitfire and the Mustang had restrictions placed on them post war for rear tank usage.

 

[RCAFson]

I just don't buy the idea of fighting with the external tank. I don't believe it's self sealing either. I think you are comparing the slow crawl range at minimum cruise speed with the 400 mph cruise of the Mustang... which can fly a lot further at slower speeds and lower altitudes. I think you are grasping at straws. Like I said before, it's out of reach mate.

But we probably have to agree to disagree, because it will just go on forever.

Spitfire VIII self sealing tanks:

Fuel. 100 octane.
Capacity Fuselage (upper) 47gals, lower 49, wing leading edge 2
x 14. Total 124gals. Plus 30, 45, 50 and 90 0/ld tanks. All tanks
except l/edge self seal. Fuel system pressurised. At 20,000ft self
sealing impaired.
M&S, page 290

OK, let I'll Spitfire pilots tell you:

MkXII

F/O C. R. Birbeck of 41 Squadron recorded in his Combat Report for 27 April, 1943:

I was Blue 2 on a weather recco to Calais and the Somme area. We flew down the French coast at zero feet, climbing North of the Somme to about 2,000 feet. Controller then told us to steer 330 degrees and we were just turning on to this course, West of the Somme Esturary, when I saw two F.W. 190's approaching from three o'clock at our height. I warned Blue 1, who turned towards them. I dived down to the deck, pulling up in a steep turn towards the E/A. One of these, which I saw through thin cloud, was climbing. I climbed after him and fired a full beam shot at him, giving him a six seconds cannon and m/g burst, starting at 700 yards and closing to 300 yards. The E/A did a gentle turn towards the French coast and I saw flames on the port side which seemed to be coming from just in front of the cock-pit. I broke away and was pursued up the French coast by another F.W. 190 for about five minutes. This E/A kept firing from about 600 yards, missing to port. I was taking violent skidding evasive action on the deck and he was just about holding me at 340 I.A.S. I had not jettisoned my extra tank. He finally abandoned the chase and turned towards France. I claim one F.W. 190 Destroyed.​

Mk9

S/Lr. G. Hill, D.F.C. and Bar of 111 Squadron recorded in his Combat Report for 11 July 1943:

We were patrolling Acid at about 10,000 feet and were just leaving the patrol when enemy aircraft were sighted by W/Cr. Smith, who was flying with 126 Squadron. We turned back and saw about 5 190s going down to bomb what looked like a large building. I followed the last one of those down and caught him up in a dive, but was unable to close even though I was in a IX, because I forgot to release my jettison tank.​

I fired a burst at the tail end 190 with no result. I turned and climbed back towards the dog fight which was going on and saw a Macchi 200 on the deck going West. He still had his bombs on. I closed in and opened fire at 100 yards closing in until I was forced to break away. The aircraft caught fire and dived into the ground where it exploded.​

CLAIM: 1 Macchi 200 destroyed.​

MK14
F/O Harry Walmsley of 130 Squadron recorded in his Combat Report for 8 December, 1944:

On 8th December I was Yellow 3, and my squadron had been detailed on armed recce to cover Dulmen, Hamm, Munster. There were 9 aircraft airbourne at 1409 and W/Cdr. Keefer was leading. About 1505 we approached Burgstein. Red and Blue sections went to one side of the town and my section went to the other. We saw a locomotive with about ten trucks. We had made one attack on the loco. and two on the trucks and were preparing to make another when about a dozen aircraft appeared from the east and they dived straight past us as if they wre joining in the attack on the train. These aircraft had cigar-shaped drop tanks slung under the centre of the fuselage and I thought at first they were American aircraft. I then saw the crosses on the wings and I could see that they were Me 109's and FW 190's. A dog fight started with everyone milling round. After about five minutes I found myself alone. I saw another train pulled up in a station so I went down and had a squirt at it and saw strikes on the locomotive. When I pulled up I saw a Spitfire in trouble. It was smoking and the undercarriage partly down. I joined up with it to protect it. There were five Spitfires there. I do not know what happened to the damaged Spitfire for suddenly six e/a probably some of the ones I had first seen came diving down out of cloud. They had obviously climbed and reformed after the initial attack. This second attack made from 10/10th. cloud at 1,500 feet was obviously directed against the damaged Spitfire. Some of the others in the Squadron chased them off. I went for two which were making an attack. I made a quater attack on one of them, an Me 109, closing to 300 yards and giving a two second burst with all guns. I saw strikes behind the cockpit the e/a dived straight into the ground. I found I was being fired at by two e/a so I used full evasive tactics for about five minutes and finally got away into cloud. I landed at Heesh as I was short of petrol and made my claim to the Intelligence Officer there. I then returned to base. I claim this Me 109 destroyed.​

I am sure that on the sides of the fuselage there where white roundels. The e/a were very persistant, the leaders certainly were very well clued up, I have never seen Huns fight so well. Their tactics were good in that obviously after the first attack they climbed to cloud and reformed. They definately caught us by surprise. I think they had either been on patrol, or had been scrambled, and when they saw smoke from the train they knew where we were and attacked out of cloud. The Spitfire XIV is definitely better than the 109 as I could do a better climbing turn even with my tank on. With my tank on the e/a could almost follow me but could not get a deflection shot at me. The e/a were using tracer and self-destructing ammunition. The camouflage was earth green and brown and blended well with the cloudy weather. 64​

F/Sgt. G. W. Hudson of 130 Squadron recorded in his Combat Report for 8 December 1944:
On 9th December (actually the 8th) I took off with the squadron (nine aircraft) on G.C.17 (armed recce. to Dulmen, Munster and Hamm). I was yellow 2. Near Burgstein we found a train and my section which was led by F/L. Hume and which comprised F/L. Walmsley and myself went down to attack. I was last to attack and as I flew through the smoke my windscreen became badly covered. I flew around for awhile and then I saw some aircraft coming from the S.E. at about 500 feet and they were diving on the train. I could not see very well and at first I thought they were Mustangs. They looked as if they were camouflaged silver-gray. Someone then called up and said they were Huns. I looked round and found that one of them was on my tail firing at me. I did a steep climbing turn to the right and evaded them by getting into cloud. I flew above cloud for a minute or two and then came down again but could see nothing of the e/a. I then heard some one call again saying "There are Huns up here". I went up but saw nothing. By this time my windscreen had cleared so I came down again and then saw a dog fight going on about two miles away behind me on my port side. I saw two Me 109's going away on the deck. I could now see they were 109's. They had black spinners and there appeared to be a black ring behind the propeller. I went after them and I attacked what appeared to be the No. 1 of the section. I came in from the starboard side and fired from about 300 yds., but my first burst was behind. My angle of deflection had been about 35°. I pulled the stick back hard and my next burst of about 1 1/2 seconds from 200 to 250 yards. at an angle off of 25-30° hit him. I saw strikes all over the wings and the fuselage. The e/a broke left and the other broke right. The one I had attacked was wobbling very badly. I nearly overshot as he broke and I got above him. I could see the machine wobbling, the pilot had the hood open, there was smoke coming from the starboard side and I could see the holes in the wings where I had hit him. I broke away to the left as the No.2 was now attacking and I climbed away into cloud.
I claim this Me 109 as probably destroyed, as when I last saw it it was wallowing around and appeared out of control at about 150 feet.
I could not get rid of my drop tank at first, but I found that even with the tank on I could turn inside the e/a. 65

F/Lt. H. Walmsley of 130 Squadron recorded in his Combat Report for 13 March, 1945:

I was flying as Spinner Blue 1. We had passed South of Munster heading east at 11,000 feet when I saw 8 plus aircraft flying South at 2,500 feet. I called up and went down after them, intercepting over Hamm, and, finding that they were long nosed FW 190's, engaged the one on the extreme left. He broke down and proceeded due East at zero feet. After chasing him for 10 miles, firing occasional short bursts, I hit him around the cockpit with several cannon shells and quite a bit of debris came away. The range was 200-250 yards; angle off 5°. He pulled up steeply to port and the pilot baled out at 1,500 feet, the aircraft crashing close to where the pilot landed and lay on the ground without releasing his parachute. Both the e/a and I had long range tanks, neither of which were dropped, and at no time did I have to go "through the gate" in order to stay on his tail. 85​

F/Sgt Clay of 130 Squadron recorded in his Combat Report for 13 March, 1945:

I was flying as Spinner Blue 3 at 11,000 feet South of Munster, heading East, when F/Lt Walmsley led us down on 8 long-nosed FW 190's which were flying South at 2,500 feet. I had no time to jettison my tank, but the Hun I attacked dropped his as I was closing in from behind and slightly below. He started to weave gently when I was about 500 yards behind. I opened fire at 400 yards closing right in; he turned sharply to port and I followed, still firing. Then I had to slide over to port to avoid hitting him as he slowed up very suddenly. His hood flew off and his aircraft was wallowing badly, out of control. We were now down to 700 feet and suddenly he nosed straight in and blew up in a railway siding in or very near HAMM. I could not see my strikes owing to a sheet of oil which covered my windscreen as soon as I went through the gate. My ringsight was almost obscured and sighting was difficult.​

Immediately after the E/A crashed, I was hit in the port wing by a cannon shell from a 190 which appeared on my tail with his No.2. I broke hard to port and they did not press home their attack, so I returned to base. I claim one e/a destroyed. 86​

P/O P. J. Coleman of 41 Squadron recorded in his Combat Report for 20 April, 1945:

I was flying as Kudos Blue 5 on an Armed Recce in the area south of the MURITE LAKE. The section was flying north of a point about 32 miles up the BERLIN / WITTENBERGE road, when W/O Boscow reported an aircraft below at three o'clock. I saw the aircraft on a northerly course and recognized it as a long nosed FW 190.​

Blue 3 and 4 peeled down but overshot and were attacked by the FW 190, I followed down and using a gyro- sight fired a short burst from 40° astern to port at 200 yds seeing strikes. The FW 190 turned hard to port and I followed switching on my camera which I had omitted to do losing distance in the turn. I closed easily and opened fire from dead astern. At 300 yds at 1,000 ft, a 2 seconds burst, during which he flick rolled on to his back and baled out.​

The aircraft plunged into the BINENWALDE LAKE (U 3907) and the pilot landed in the trees of a wood to the S.E. and verge of the lake.​

I did not jettison my 45 gal. tank.​

FW markings and camouflage as usual.​

I claim one F.W. 190 destroyed. 117​

F/Lt. D. J. Reid of 41 Squadron recorded in his Combat Report for 2 March, 1945:

I took off from B.80 at 0702 as Blue 1 with F/Sgt Kelly as Blue 2, to patrol Nijmegan. At approx. 0735 Planet reported a Jet aircraft N.E. of Weert. I flew towards Weert in thin layers of cloud, then returned towards Nijmegen still between cloud layers. On emerging near Nijmegan saw a single aircraft about one mile in front and about 1000 ft. above. I immediately gave chase instructing my No. 2 to slow down and drop his jet tank, being unable to do so myself due to high speed. The E/A turned slightly to Starboard and continued towards the North East, weaving slightly from time to time. I kept out of the enemy pilot's view by keeping under his tail plane and slowly overhauled him at an I.A.S. of 340 m.p.h. at 8/9000 ft. Whilst astern of the E/A I was only able to say it was jet propelled and not an Me.262 (or Meteor). I closed to 100 yards or less, firing with .5 M.G. and cannon whilst still overtaking. I saw strikes on the Port wing, Port jet engine and fuselage. E/A immediately emmitted dense clouds of brownish smoke, possibly jet exhaust. I continued firing and saw flshes in the smoke, breaking away at extremely close range, and being hit in the port radiator by debris. I next saw E/A going down in a wide spiral to Starboard with white smoke or vapour pouring from holes all along the Port wing, and dark smoke from the fuselage. I could then see the long nose of the a/c and the straight tapered wings with rounded tips and identified E/A as an Arado 234. A large piece of E/A suddenly flew off, and one person baled out, parachute opening. E/A steepened its dive and crashed somewhere near Enschede, being completely destroyed by explosion. Some fire from the ground was seen at this time. I returned to patrol being rejoined by my No. 2 who witnessed the destruction of this enemy a/c.​

I claim one Arado 234 destroyed. 168​

http://www.wwiiaircraftperformance.org/130_Clay_13march45.jpg​

http://www.wwiiaircraftperformance.org/130_Clay_13march45.jpg​

(Above from WWII Aircraft Performance encounter reports)

So pilots could engage in violent manoeuvring combat with their slipper tanks in place. Of course they typically dropped them (max drop speed was 300mph IAS which was not a limitation on high altitude missions). Testing on the Mk IX gave these results:

Morgan and Shacklady give results of a Mk V Trop fitted with/without a 90IG slipper tank. Vmax = 354/337.5 mph at 17.4k ft

 

[RCAFson]

I think you are comparing the slow crawl range at minimum cruise speed with the 400 mph cruise of the Mustang... which can fly a lot further at slower speeds and lower altitudes.

Spitfire 9 HF range at max weak mixture with 85IG internal and 170IG external = 800 miles. Versus 880 for the Mustang with 221IG (Pilots notes states 224IG) internal:

http://www.wwiiaircraftperformance.org/mustang/mustang-III-ads-7.jpg

Of course carrying the fuel all internal caused considerably less drag for the Mustang. So a Mk VIII with 200IG internal (75IG fuselage tank) and a 30 or 45IG slipper tank would do considerably better than the Mk IX with a 170IG slipper tank and would probably get about 850 miles.

 

[wuzak]

In short, I think it's very unlikely the Spit VIII could fly a Schweinfurt raid escort, and Berlin is just grasping at straws.

If they actually could then they would have done so, in my opinion, because in a dogfight a Spitfire is a bit better than a P-51, depending on the models.

They didn't because the development hadn't been done and the RAF weren't pushing for LR escorts.

 

[wuzak]

Because the Mustang could fly 900+ miles on internal fuel (in protected tanks) and do so at close to 400 mph. That way it could fly out to a target say, 600 miles away, drop it's external tanks when attacked, fight for a while and then fly home with fuel to spare.

To get that range they wold have to fly much slower.

I think it was posted in this thread earlier that the maximum range for the Mustang III/P-51B was at a cruise speed of ~265mph TAS, compared to the Spitfire's ~225mph.

 

[Schweik]

Most of those encounters you listed described decreased or severely decreased performance with the extra tank on - couldn't catch the FW, etc. If I cared enough about it I'm sure I could find plenty of anecdotes where the degradation of performance (especially with anything larger than a 30 gal tank) actually caused losses.

You are clearly dead set to believe your theory and we very clearly read the exact same data completely differently. Kudos for persistence, but you haven't come close to convincing me, there was no long range Spitfire it's a joke to pretend there was or could have been. Yes they can reach Calais, but deep into Germany from England? Not operationally. And the notion that they didn't need a long (or even medium) ranged Spitfire during the war is also a joke. Of course they needed it and they could and would have equipped bombers for daytime operations if they had them. There was certainly a desperate need for them in the Med and they got the most of the Mk VIII when they arrived even though their range wasn't that great either.

 

[Schweik]

They didn't because the development hadn't been done and the RAF weren't pushing for LR escorts.

Even Mosquitoes could have benefited from escorts - they were pretty good at surviving but hardly invulnerable. They did also have to use Lancasters for daylight operations sometimes and would have loved to have escorts available. Daytime bombing is always more accurate than night bombing, and particularly needed for Tactical and Operational targets not just Strategic.

 

[Schweik]

To get that range they wold have to fly much slower.

I think it was posted in this thread earlier that the maximum range for the Mustang III/P-51B was at a cruise speed of ~265mph TAS, compared to the Spitfire's ~225mph.

According to this, (I have Americas 100,000 five feet away as I write this but can't be bothered to walk over there for this ridiculous conversation) cruise speeds and ranges are

P-51B/C
325 mph @ 10K for 1180 miles (internal)
294 mph @ 20K for 1900 miles (with drop tanks)

 

[RCAFson]

Most of those encounters you listed described decreased or severely decreased performance with the extra tank on - couldn't catch the FW, etc. If I cared enough about it I'm sure I could find plenty of anecdotes where the degradation of performance (especially with anything larger than a 30 gal tank) actually caused losses.

You are clearly dead set to believe your theory and we very clearly read the exact same data completely differently. Kudos for persistence, but you haven't come close to convincing me, there was no long range Spitfire it's a joke to pretend there was or could have been. Yes they can reach Calais, but deep into Germany from England? Not operationally. And the notion that they didn't need a long (or even medium) ranged Spitfire during the war is also a joke. Of course they needed it and they could and would have equipped bombers for daytime operations if they had them. There was certainly a desperate need for them in the Med and they got the most of the Mk VIII when they arrived even though their range wasn't that great either.

The encounter reports show some decreased performance, but as the tests show, it was not a severe decrease, only amounting to about 14mph for the Spit9 with a 30IG slipper tank and 20mph for the Spitfire14 with a 90IG tank. By late war the Luftwaffe had some very high performance aircraft, including jets, so naturally pilots wanted all the performance they could get...as long as it meant they didn't have to walk home, hence the desire in some cases to retain the tanks, which were SS and fully stressed for combat. Spitfires were using DTs from 1941 and all slipper tanks were tested to 7G to which, amongst other things, allowed for catapult TO from carriers.

The first production Spitfire VIIs (basically a pressure cabin version of the Mk VIII) were built in Sept 1942. Given production and development priority there could have been LR escort spitfires available in time for the Schweinfurt raids.

You are basically admitting that no amount of evidence is going to sway you, and that's OK because I did this research for my own benefit.

This is from Morgan and Shacklady, from their chapter on the SpitfireV when the RAF began large scale development of extended range mods for the Spitfire in 1941:

Spitfire V potential escort and ferry ranges:

 

[Schweik]

You are basically admitting that no amount of evidence is going to sway you, and that's OK because I did this research for my own benefit.

No, yet again it's a fine distinction you are missing here - I have yet to see any evidence that you posted in this thread that has convinced me. That is a far cry from "no amount of evidence" - you are just not as convincing here as you think you are. You read that article you linked and got something out of us none of the rest of us did. I also get the sense that you are indifferent to reality and evidence, I think you actually do believe the Spitfire potentially had the range, or better than the range of a Mustang. Which is ludicrous.

But I'm not ruling out the possibility could exist that somebody could show me something that actually did convince me of this, I've certainly learned a lot on this forum so while I'm highly dubious I wouldn't rule it out. Somebody might capture Bigfoot tomorrow too.

 

[slaterat]

Looking at the data cards RCAFson makes a very valid point. You have two single engined fighter planes here, with essentially the same engine. The Mustang is aerodynamically cleaner, but heavier. The Spit 8 is a bit more draggy, but is lighter and a better climber. Both planes have flight limitations with a full internal rear tank.
The Spit 8 holds 200 IG internal and the Mustang 221 IG, thats pretty close with a 10% advantage to the Mustang. As Shortround6 has already pointed out carrying more fuel in your drop tanks then you do in your internal fuel tanks is not of much value for extending operational range on a combat mission. The exception is if your external tanks are stressed for combat. I know that the Hurricane could carry 2x 45 IG tanks that were self sealing and fully stressed for combat but they were not jettisonable. The 45 and 90 IG drop tanks were not stressed for combat.

It seems that RCAFson has shown that the slipper tanks on the Spit 8 offer the best of both worlds being , pressurized, self sealing stressed for combat and jettisonable.

Does anyone know the details of how the Mustangs external tanks worked?

 

[RCAFson]

Some more info regarding the USAAF mods to the Spitfire IX in performed at Wright field in early 1944, from M&S:

Boscombe Down 6 July 1944. MK210. Effect of two
underwing drop tanks on level speed performance and position-
al error correction. Modifications installed at Wright Field,
USA (1) 43gal tank behind pilot (2) two leading edge tanks of
16.5gal (3) two Mustang type drop tanks of 62 gal. Auw with
drop tanks empty 8,2651b; without tanks 8,155.

mph without tanks / with tanks
Full throttle height
MS gear 363 @ 9400ft / 333 @ 8800
FS gear 392 @ 20,350ft / 359 @ 19,600

Boscombe Down August 1944. MK210. Handling trials
underwing drop tanks and tank dropping tests. Auw fuel tanks
full 9165lb. Handling satisfactory. Starboard dropped @
200mph. It swung clear of aircraft, bracing swept along wing
undersurface but cleared tailplane. Port tank @ 250mph, Tank
and bracing fell away clear. Starboard tank @ 300mph. Tail of
tank forced up and dented undersurface of wing; bracing swept
close to undersurface of tailplane.

= 161IG internal fuel. Adding a 30/45/90IG slipper tank gives 191/206/251IG of SS fuel. changing the rear fuselage tank to 76IG and the 30/45IG slipper = 221/236IG of SS fuel.

High speed, high altitude, cruise fuel consumption on the Mk V:

 

[Kevin J]

The encounter reports show some decreased performance, but as the tests show, it was not a severe decrease, only amounting to about 14mph for the Spit9 with a 30IG slipper tank and 20mph for the Spitfire14 with a 90IG tank. By late war the Luftwaffe had some very high performance aircraft, including jets, so naturally pilots wanted all the performance they could get...as long as it meant they didn't have to walk home, hence the desire in some cases to retain the tanks, which were SS and fully stressed for combat. Spitfires were using DTs from 1941 and all slipper tanks were tested to 7G to which, amongst other things, allowed for catapult TO from carriers.

The first production Spitfire VIIs (basically a pressure cabin version of the Mk VIII) were built in Sept 1942. Given production and development priority there could have been LR escort spitfires available in time for the Schweinfurt raids.

You are basically admitting that no amount of evidence is going to sway you, and that's OK because I did this research for my own benefit.

This is from Morgan and Shacklady, from their chapter on the SpitfireV when the RAF began large scale development of extended range mods for the Spitfire in 1941:

Spitfire V potential escort and ferry ranges:
View attachment 549431

Interesting chart for a Spitfire V. Norwich to Berlin, 441 miles, escort range; London to Brest, Belarus, 1015 miles, reinforcing range, so must be a 90 IG slipper. Seafire III, navalised Spitfire V had a combat radius of 100 miles clean and 185 with a 60 IG torpedo tank. Whilst theoretically, with a 90 IG you could fly escort Norwich - Berlin, realistically you can't because you're flying too slow, you're flying over hostile territory, and finally manoeuvres are restricted with that big 90 IG slipper; it's just not going to happen. Longest Spitfire raid in Europe is SW England to La Palice, all over water in 1944, 370 miles in the Mk VII, so yes you could do that out and back at econ cruise perhaps with only a 45 IG slipper, and likewise you don't want the 90 IG slipper if at all possible because manoeuvres are restricted. The Australians did Darwin to East Timor return, 884 miles, only possible with a 90 IG slipper, but it's all over water, no other land anywhere in sight, unlike the La Palice raid. IIRC the LF XVI had an effective combat radius of 230 miles over Europe; I'm assuming this is using 66/75 IG rear fuselage and 45 IG slipper, but again over hostile territory.