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

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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.

 

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:

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.
 

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.
 
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.
 
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.
 

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:
(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
 
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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.

 

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

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.
 
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.
 
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.
 
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)
 

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

= 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:

 
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.
 
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