So did the Mk VIII really had 2100 miles range ?

[VO101_Isegrim]

Nashwan in the other topic states that his Spitfire Mk VIII with Merlin 66 had 10 miles per gallon fuel economy.

This plane carried 120 gallon fuel internally, and according to Nashwan, 90 gallon tank was very widespread in service. That woud gives 2100 miles range with 210 gallon fuel.

I wonder why these allegadly hyper-long range Spitfires didn`t blackended out the skies over Berlin, and all over Germany since they were already available in 1943.

There was no need for the Mustang at all, with these really long range Spitfires around.

I am not sure about what the P-51`s milage wa, but wouldn`t that 10 mpg put it into ashame? Since they had the same engine, this really speak about aerodynamics.

[Karnak]

I seriously doubt it.

I cannot see any way that it could have that kind of efficiency.

[VO101_Isegrim]

Personally I don`t believe either, mostly I do see 6-7 mpg figures for the MkIXs, including one report with Merlin 61 engined one. Were there big improvements over the 61 in the 66 for fuel economy?

But Nashwan appears to be quite sure that this is a correct figure, and this leads to the 2100 miles figures (120+90)*10. But in this case, 2100 miles must-be possible, it`s labeled "a.m.p.g" iirc, in other words, it`s an avarage value.

In fact, AFAIK from him, even 170 gallon tanks were used, and that would mean some 2900 miles, plus there was a rear tank, too, which would raise the Spitfire Mk VIII`s range to well over 3000 miles.

If this is true, this would change the POV on WW2 air war quite radically, and would set a series of questions, ie. why didn`t the Brits used MkVIII as escort fighter in Europe in place of the Mustangs they also got, why the birth of the Mustang at all, wouldn`t it be simplier and even better to produce Spits instead of them?

I mean, even 2100 miles would mean that you can do 1-way sorties not only to Berlin, but Kiev...

[Nashwan]

The tests say yes. Isegrim's anecdotal evidence says no.

[Guppy35]

Originally posted by VO101_Isegrim
Nashwan in the other topic states that his Spitfire Mk VIII with Merlin 66 had 10 miles per gallon fuel economy.

This plane carried 120 gallon fuel internally, and according to Nashwan, 90 gallon tank was very widespread in service. That woud gives 2100 miles range with 210 gallon fuel.

I wonder why these allegadly hyper-long range Spitfires didn`t blackended out the skies over Berlin, and all over Germany since they were already available in 1943.

There was no need for the Mustang at all, with these really long range Spitfires around.

I am not sure about what the P-51`s milage wa, but wouldn`t that 10 mpg put it into ashame? Since they had the same engine, this really speak about aerodynamics.

You gotta remove that Spitfire burr from under your saddle.  It gets you way too worked up.

Mk. VIII was not used from England as it was tropicalized and used in the Med, Burma and the Pacific.

Standard drop tanks in 43 were the 30 and 45 gallon tanks.  The 90 was available but not used much until later in 44 from what I've seen.

Normal range on the VIII as I have it was 660 without drop tanks.  Do the math from there with the 30, 45 and the 90.

And as I said, I don't see the 90 in regular service until later in 44 where I've seen them on both XIIs and IXs.  The IXs were escorting RAF bombers in daylight in that particular case., and the XIIs were hunting V2 sites. I posted a photo of one of those birds in another thread.

Dan/Slack

[Nashwan]

it`s labeled "a.m.p.g" iirc, in other words, it`s an avarage value.

AMPG stands for AIR miles per gallon, not average.

In fact, AFAIK from him, even 170 gallon tanks were used, and that would mean some 2900 miles, plus there was a rear tank, too, which would raise the Spitfire Mk VIII`s range to well over 3000 miles.

I can't see the 170 gallon tank and the rear tank being used together, and I'd be willing to bet it was never done. It would take you well over the weight limit, I'd have thought.

If this is true, this would change the POV on WW2 air war quite radically, and would set a series of questions, ie. why didn`t the Brits used MkVIII as escort fighter in Europe in place of the Mustangs they also got,

Because they shipped the Spit VIIIs abroad, and because it still didn't have the range of the Mustang.

I mean, even 2100 miles would mean that you can do 1-way sorties not only to Berlin, but Kiev...

Certainly, if you cruise over hostile airspace at 220 mph TAS, without manoevering. It's not a practical range, as Gripen has tried to tell you.

[VO101_Isegrim]

Originally posted by Nashwan

The tests say yes. Isegrim's anecdotal evidence says no.

Actually, I didn`t qouted any 'anecdotal evidence', just a report, a brief summary on MkVIIIs from the australian archieves which say the range is 740 miles on 120 gallons. That`s all.

But if you are right, and indeed the test you are qouting shows 10 mpg, then it appears a revision is needed about fighter ranges. The Spitfire was a very long ranged, if not THE longest ranged fighter of WW2, according to these specs.

That gives 2100 miles range for the Spitfire Mk VIII in common configuration (internal + 90 gallon DT).

That`s as much as the P-51D/K`s range with droptanks and rear tank (2055 miles). BUT, the Spitfire Mk VIII could employ a 170 gallon tank AND a rear fuselage tank in addition, which would mean the range would be at least 1000 miles greater than the Mustang`s.

http://www.mustangsmustangs.net/p-51/p51specs.shtml


So, I am just figuring out what that 10 mpg means.

Originally posted by Guppy  

Mk. VIII was not used from England as it was tropicalized and used in the Med, Burma and the Pacific.

Standard drop tanks in 43 were the 30 and 45 gallon tanks. The 90 was available but not used much until later in 44 from what I've seen.

Normal range on the VIII as I have it was 660 without drop tanks. Do the math from there with the 30, 45 and the 90.

[/b]

Guppy, if the 90 gallon tank was available, why wasn`t it used? It would sure be a good choice for longer  patrol missions over the channel etc. And, since MkVIIIs had more tankage than the others, they could be effectively used in escorting heavies than the others  - why the decision to send them far away in remote places like the Med ?

[VO101_Isegrim]

Originally posted by Nashwan

I can't see the 170 gallon tank and the rear tank being used together, and I'd be willing to bet it was never done. It would take you well over the weight limit, I'd have thought.

But then, probably the 170 gallon tank could and I am quite sure it was used. That would give 290 gallon fuel, in optimal case, enough for 2900 miles on the Spit Mk VIII. I think you said the 170 gallon was quite possible, in fact not uncommon.

Because they shipped the Spit VIIIs abroad, and because it still didn't have the range of the Mustang.

Certainly, if you cruise over hostile airspace at 220 mph TAS, without manoevering. It's not a practical range, as Gripen has tried to tell you. [/B]

Why would they ship Mk VIIIs abroad, and buy US Mustangs instead of them at high price, if they already had a plane capable of reaching Berlin ?

Nashwan, looking at your figures, it did have the range of the Mustang. Let`s ignore the 'non-practical' milage of 10 mpg at 220 mph, and let`s use similiar figures at higher cruising speeds.

The site above says the Mustang`s range was 2055 miles at 280 mph cruise speed at 20k ft.

Your document states 7.2 ampg at 282 mph TAS (2200/+2). This means, with 120+170 gallon fuel, according to your data, the Spitfire outranged the Mustang, ie. 290x7.2 = 2088 miles range at the same cruise speed as the Mustang.

[Nashwan]

But if you are right, and indeed the test you are qouting shows 10 mpg, then it appears a revision is needed about fighter ranges. The Spitfire was a very long ranged, if not THE longest ranged fighter of WW2, according to these specs.

How come? The Mustang carried far more fuel, with the same engine.

Internal fuel for the Spit VIII was 123 gallons, for the Mustang it was 220+, iirc.

The Mustang also carried 180 gallons in a pair of drop tanks, iirc, for a total of 400+ gallons, compared to just over 210 gallons for a Spit VIII with drop tank.

BUT, the Spitfire Mk VIII could employ a 170 gallon tank AND a rear fuselage tank in addition

Says who?

What you are in effect saying is the Spit VIII, with the same engine as the Mustang, and the same fuel load, would have roughly the same range.

Yes, of course it would. More, I'd have thought.

The Mustang certainly had lower parasitic drag, but at 160 IAS, ie very low speed, I'd expect the Spitfire's weight advantage to mean lower induced drag, and lower overall drag.

Of course, the Spit didn't carry the same fuel load as the Mustang. I've no doubt it could have carried a rear tank and drop tank at the same time, and if the USAAF had been building the Spitfire when they found the need for a long range escort, it probably would have.

That would give it around 270 gallons though, which is still nowhere near the fuel load of the Mustang.

[Guppy35]

Originally posted by VO101_Isegrim


Guppy, if the 90 gallon tank was available, why wasn`t it used? It would sure be a good choice for longer  patrol missions over the channel etc. And, since MkVIIIs had more tankage than the others, they could be effectively used in escorting heavies than the others  - why the decision to send them far away in remote places like the Med ?

I don't believe the 90 was produced in large numbers at that point for one thing.  

The Spits were primarily escorting the mediums over France of 2 TAF or the Marauders of the 8th so the 30 and 45 did the job.

You'd have to look at the 8th AF policy on escorts too.  Remember the 8th sent their 38s, which had the range to cover the bombers, to North Africa early on.  Jugs weren't initially equipped to carry drop tanks.  There was a segment of 8th AF leadership that wanted to prove the bombers could do it alone so outside of covering parts of the return trips, the RAF wasn't asked to provide escort in 43.  

The race to get the escorts involved didn't reall get moving til late 43 early 44  and it was still the 8th Fighter Command's job to provide the escort which it finally did with the 51s, 38s and later model Jugs with drop tanks.

Also keep in mind the VIII entered production in mid 443 after the IX and because it was more refined and tropicalized it was sent to the areas where that was more useful, ie; the Med, Burma and the Pacific where it was needed.  This would also be a reason for sending the VIII with the added internal fuel as range was more of an issue while the IXs, Vs, XIIs etc could manage the airwar over France with what they had including the 30 and 45 gallon tanks.

The IX equipped squadrons didn't start getting the tropical nose intakes until problems arose in Normandy from the dust on unfinished airfields.

Image is from the logbook of the late Tom Slack, a Spit XII pilot who was a friend and whose last name I use for my AH name.  It shows a drawing he did in his logbook commenting on "this long range tank business".  Certainly they saw the differences.  This was from January 44.

Dan/Slack

[VO101_Isegrim]

Originally posted by Nashwan
How come? The Mustang carried far more fuel, with the same engine.

Nashwan, the report says 10 miles per gallon is possible. At least, if not anybody else, stand by that.

But that`s only true for the Spit8/Merlin 66 combination, or perhaps the reports is wrong, the other reports give about 6.5 avmpg for the Merlin 61 engined Spit IX.

Put the same engine into a Boing 747, and you will get different milage. Put it into a Mustang, and you get different milage. Possible worser, possibly better.

What I noticed, that if I take your data and compare it to similiar data of the Mustang, they look equal ranged.

But even regardless of the Mustang, your data shows the Spit VIII had no problem reaching Berlin. So why wasn`t they over there, I ask ?

Says who?

What you are in effect saying is the Spit VIII, with the same engine as the Mustang, and the same fuel load, would have roughly the same range.

Yes, of course it would. More, I'd have thought.

The Mustang certainly had lower parasitic drag, but at 160 IAS, ie very low speed, I'd expect the Spitfire's weight advantage to mean lower induced drag, and lower overall drag.
[/B]

Actually I don`t say it, and find it rather hard to believe. But your dataset clearly suggests that. Add the lower drag on the Spitfire than the Mustang as you suggest, and it`s possible in theory, if the dataset, and drag-theory is correct (I wonder if that low speed/lower weight/lower drag theory can be applied to the 109s as well, though).

Naswhan, mounting rear tanks into the MkVIIIs was possible, according to Gripen, who quoted it from Spitfire the History.

I don`t know if using both was possible or not, but there`s nothing that says it was impossible.

[Nashwan]

Nice cartoon.

Under "Isegrim" rules, if this was a 109 it would prove it had the range to reach Japan with a single drop tank.

[phookat]

Isengrim:  as I said in the other thread, that 10 mpg figure is for very slow speeds.

But you should not commit the same mistake Angus was making in the other thread--trying to compare anecdotal information with flight tests , when the conditions of the former are not known.  In this case, cruise speed.

As for why they weren't used over Berlin, probably because if they went that slow the war would be over by the time they got there.

[VO101_Isegrim]

Well actually, there no need to prove that, IIRC there was a number of 109s that didn`t even need droptank to reach Japan.
In any case, 109s would only need to circle over England at best, pick and shoot spitties into the channel, not much fuel is required for that, especially considering the excellent fuel economy of the 109/DB605 combo.

I can prove that with a cartoon, too :



Some WW1 pilot named Udet or something like that did this one.



Now, back to the allegedly 2100 mile ranged Mk VIII that rivaled the Mustang`s range.

[Nashwan]

But then, probably the 170 gallon tank could and I am quite sure it was used. That would give 290 gallon fuel, in optimal case, enough for 2900 miles on the Spit Mk VIII.

The mpg would go down with the extra weight and drag of the 170 gallon tank, and you have to allow about 25 gallons for warming up and climbing to altitude.

Why would they ship Mk VIIIs abroad, and buy US Mustangs instead of them at high price,

Britain wasn't buying Mustangs by this stage of the war, they were getting them free under Lend Lease.

The site above says the Mustang`s range was 2055 miles at 280 mph cruise speed at 20k ft.

Is that IAS or TAS? Does it include an allowance for combat, a safety reserve?

Joe Baugher quotes 950 miles for a P-51D on internal fuel at 395 mph at 25,000ft.

Allowing for about 30 gallons to get to 25,000ft, that's about 5 mpg for the Mustang at 395 mph.

That test shows 5.8 mpg for the Spit at 314 mph, which I think is pretty consistent with Baugher's figures. Certainly the Mustang will have much better economy at high speeds because of it's lower drag.

But even regardless of the Mustang, your data shows the Spit VIII had no problem reaching Berlin. So why wasn`t they over there, I ask ?

It was, as a recce aircraft.

The RAF did not go in for long range daylight bombing. Why would they build a long range escort?

Actually I don`t say it, and find it rather hard to believe.

You find it hard to believe that with the same amount of fuel, the same engine, the Spitfire could have had the same range as the Mustang at low speeds?

Parasitic drag dominates at high speed. No-one is going to argue, the Mustang had lower drag at high speeds.

At low speeds, induced drag is far more important, parasitic drag less so. At low speeds, I'd expect the Spit with it's lower weight and lower wingloading, to have less drag, although I don't think there'd be much in it either way.

I don`t know if using both was possible or not, but there`s nothing that says it was impossible.

170 gallons in a drop tank and 70 in a rear tank equals 240 gallons, which is 1728 lbs of extra fuel alone, without the weight of the tanks. I think we can safely assume it's going to be over 2000 lbs extra.

That's going to push a Spit VIII over 10,000 lbs. It might be possible, but I doubt the RAF would allow it.

Don't forget, the RAF didn't even like the rear tanks on the Mustang, and didn't always allow their use.