Spiteful

[delcyros]

The Meteor issue is an interesting one and certainly there is potential for a more rapid introduction, but I doubt that it could have been avaiable that early. One should not forget that the US provided the tooling tech necessary to mass produce jet engines to the UK in early 44.
The 490 mp/h are also somehow optimistic. I can recall in between 768 and 770 Km/h at 3000m (477-478 mp/h) in clean configuration after tail modifications in late 44. Below or above this altitude, the speed curve drops off significantly.

[delcyros]

The theoretical estimates of speed should be taken with a serious grain of salt. This is true for all ww2 nations estimates which achieved higher speeds than Mach 0.75. In Germany, f.e. (I could examplify the US or Britain as well but I am particularely more familar with the RLM issues) every company used it´s own mathematical system, which tends to produce contradicting estimates. The full problematic of transsonic speed calculations were solved in late february 45 by the DVL and any earlier design proposal was prone for to high estimates.

[Hop]

Talking of spit development. Wasn't their an atempt to significantly improve the the Spits range for bomber secort which ended in failure?

There were quite a few methods used to improve the Spitfire's range.

The first was to fit drop tanks, of 30, 45 or 90 gallons. A 170 gallon tank was used on some ferry flights and for recce Spitfires.

Second was increasing the lower forward fuel tank by 10 gallons. This was standard on Griffon Spitfires and Spitfire VIIIs, and common on other late production Spitfires.

Third was fitting tanks in the wing leading edge, of up to about 18 gallons each.

Fourth was fitting a rear fuselage tank. This was first done on Spitfire Vs for ferry to Malta, when a 30 gallon tank was fitted. In 1944 and 1945 some Spitfires were fitted with rear tanks of up to 75 gallons.

The most fuel a Spitfire could reasonably fly with would be a Spitfire VIII with 95 gallons in the main tanks, 28 in the wing tanks, 90 in a drop tank, and up to 60 in a rear tank, for a total of 273 gallons. The first Spitfires had started out with 85 gallons.

Such long ranges were rarely required of Spitfires, though. The recce aircraft, which did need long range, were equipped with lots of extra fuel, for example the PR XIX carried up to 257 gallons internally.

The only "attempt" I know of to equip the Spitfire as an escort was by the USAAF. Two Spitfires were modified in the US, having tanks put in to their leading edge, and wing drop tanks added. The modifications to the wing for the leading edge tanks were thought to have weakened it (although slightly larger tanks were routinely fitted to Spitfires in production). The aircraft were flown back across the Atlantic to Britain.

There was no reason for the Spitfire not to have greater range. The British didn't really require it in most cases, and when they did Spitfires were equipped with extra tanks. The US seriously considered using the Spitfire as an escort, but by the time they would be available with long range tanks the Mustang was entering service as an escort fighter, and Spitfire production wasn't high enough to fulfil all the demands placed on it.

Here's the consumption figures achieved under Australian testing of the Spitfire VIII with Merlin 66:

This aircraft had 123 gallons internally, and a 90 gallon drop tank. The drop tank remained attached at all times, hence the "ferry" designation.

[davparlr]

Originally Posted by Civettone

Davparl, wouldn't you consider the Spiteful aerodynamically more refined and lighter in weight than the P-51D?

Since the P-51D that set that particular record is tail number N5410V, which is Dago Red, a rather famous and highly modifed racer, the answer is, no, until all the things that was modified on Dago Red was applied to Spiteful.

And the tandem engine configuration of the Do 335 was aerodynamically inefficient, as acknowledged by the Dornier guys themselves.

Kris

I don't know, you may be right. The overall design concept is aerodynamically sound with a puller and a pusher prop and the aircraft looks clean. The detail execution of it may be inefficient. It does seem strange that the Do 335V-1, with 3500 hp available was only capable of reaching 455 mph. Also, tandem engines always seem to pose cooling problems, which may have been a problem here, too.

[davparlr]

Originally Posted by Smokey

The Supermarine Spiteful

That site usually has flight test or manufacture data to support its statements. In this case it does not provide that. I would like to see that before I would conclude this data is accurate.

[pbfoot]

Every pound added whether its fuel, oxygen, weapons etc or even the weight of the paint affects the useful load an aircraft its coming up with a balance that makes or breaks the aircraft . The spit could never be a long range fighter without sacrificing one of its other attributes

[Civettone]

Davparlr,
I didn't notice the P-51 was modified that way.

As to the Do 335, the problem was that the front prop couldn't achieve its maximum efficiency because the air flow interrupted that of the other engine ... or something like that

But it's obvious when you look at the next Do 335 designs: they abandoned the tandem engine layout in the P 247 and P 252.

Kris

[davparlr]

Originally Posted by Civettone

Davparlr,
I didn't notice the P-51 was modified that way.

What you can see is the small flaired-in canopy, the high gloss reflection in the wing which indicates a highly polished finish, and the advanced, and modern, wing-tip flairings. What you can't see is the efforts that was spent to lighten the airframe and the detail that went into eliminating any source of drag such as gaps, uneven alignments, etc. in order to achieve the cleanest airframe. Also, the I believe the wings had been clipped. As it was, the baseline P-51D in military trim was one of the cleanest fighters of the war as indicated by the hp required to generate speed at sea level (1640 hp, 375 mph), with only the Fw-190D coming close (1750 hp, 380 mph).

As to the Do 335, the problem was that the front prop couldn't achieve its maximum efficiency because the air flow interrupted that of the other engine ... or something like that

But it's obvious when you look at the next Do 335 designs: they abandoned the tandem engine layout in the P 247 and P 252.

Kris

Good information, and reasonable.

[Kurfürst]

Originally Posted by Hop

Here's the consumption figures achieved under Australian testing of the Spitfire VIII with Merlin 66:

This aircraft had 123 gallons internally, and a 90 gallon drop tank. The drop tank remained attached at all times, hence the "ferry" designation.

It should be noted that Hop usually waves about this leaflet from an Australian archives, which is claiming 10 miles per gallon achievable. That of course, is by far the highest mileage you`d find for any Spitfire test - it appears to be a single abberant test result, with dozens of other fuel consumption trials showing around 6-6.5 mpg being realistically achieavable. Hop knows those very well.

Here`s for the Mk IX. Mk IX and VIII had the same engine :




These full endurance trials showed 6.76 mpg being achievable at 20000 feet, 1800 rpm.

If you`d add up the claimed mileage in Hop`s paper with the fuel tankage, ie. 10 mpg and 120 gallons available, this would give you something like 1200 miles (!!!) of range for the Spitfire. If this would be true, there would be never any need for the Mustang as Spitfires would easily reach out to Berlin and back. Nonsense, of course, and all MkVIII data sheets give only 740 miles or so range, which points to the 10 mpg data is simply result of an abberant test, perhaps, but agrees well with the ~ 6.5 mpg given everywhere else.


The original comment on the Spitfire`s lack of penetrative range is quite correct. Despite many attempts, the Spitfire, as the war progressed, become increasingly a defensive fighter, lacking the range for any serious escort job.

Simply adding fuel droptanks did not solve the problem, since your penetrative range in any case is determined how much internal fuel you`re left with after you dropped the fuel tank. In other word, you can`t use practically a 90 gallon droptank to bring you over to enemy territory, if all you have is 85 gallons (some of which you`ll use up quickly during combat, where fuel consumption skyrockets at max power) to return on.

The rear tanks, fitted irregularly to some planes at the very end of the war were similiar to droptanks, as they could be used for ferry (one-way) missions only, like Malta. The reason was that with the rear aux. tanks the Center of Gravity shifted so far back that the plane was outright difficult and dangerous to fly, not to speak air combat. Therefore the rear tank, like a droptank, had to be emptied first, and then return on the normal internal tankage, again 85 gallons on the vast majority of Spits.

The third factor was that the rapidly increasing fuel consumption of the Merlin made the Spitfire shorter and shorter ranged. The confidental document titled 'Development of the Spitfire Fighter' from the Australian archives gives some idea :

The Spitfire I, while cruising very slowly - hardly an option over enemy territory - could go as far as 575 miles at 188 mph, but only 350 miles if it travels at 250 mph.

The Spitfire V was shorter ranged, at slow economic cruise it would manage 480 miles at 185 mph, and 335 miles at 310 mph cruising speed.

The Spit IX was even thirstier, at economic cruise it would manage 450 miles on slow economic cruise, as seen above.

The Spit VIII was the only variant which had some range at least, with the internal fuel being increased by 50% to 120 gallons with 740 miles being possible at slow economic cruise, and much less if any reasonable speed was maintained. However few were build and most of those went either to the PTO or MTO, where with the large overseas missions the short range of the Mk V or IX would simply not do.

Enter the MkXIV and the Griffon engined fuel hogs.. range was down again, fuel tankage was 120 gallon, as in the MkVIII, but the Griffon engine was not any shy using it up... at enourmous rates. The range at an economic, slow cruising range was down again to about ca 450 miles. That is, with 50% more fuel carried than the Mk I, and having 100 miles less range. That of course would refer to the luxury of cruising at slow speed over enemy territory, asking to be bounced by an enemy fighter.

Of course this is on interal fuel, but for escort or any two-way mission, it makes sense to look at the droptank range. The absolute maximum range of a mission was defined by the range of what you could get back on your limited internal tankage, ie. after dropping your external tank when engaged and using up considerable amounts of fuel at high power during air combat. A % of allowance had to be also given for navigational etc. errors, or just circling above your own airfield and wait for your turn to land.

There`s a good reason why US escort fighters were introduced, and while they featured very large internal fuel tankage.

[Hop]

What Kurfurst knows well is that the page he posted is for a test on a Spitfire IX with Merlin 61. The Merlin 61 was rather different to the Merlin 66, the engine which powered most Spitfire VIIIs/IXs/XVIs.

The Merlin 61 had a slightly different supercharger, but more importantly it had an SU float carburettor. The Merlin 66 had a Bendix Stromberg injection carburettor.

The Australian test is for a Spitfire VIII with Merlin 66.

If you`d add up the claimed mileage in Hop`s paper with the fuel tankage, ie. 10 mpg and 120 gallons available, this would give you something like 1200 miles (!!!) of range for the Spitfire. If this would be true, there would be never any need for the Mustang as Spitfires would easily reach out to Berlin and back.

The problem is escort range is typically one third of maximum range, which means you need about 1800 mile range to escort bombers to Berlin and back. And you don't want to cruise at 160 IAS, either, because you'll be a sitting duck over Germany at that speed.

The rear tanks, fitted irregularly to some planes at the very end of the war

From the Spitfire IX/XVI manual:

Later production Mk IX and all Mk XVI aircraft mount two additional fuel tanks with a capacity of 75 gallons (66 gallons in aircraft with "rear view" fuselages), they are fitted in the rear fuselage.

1,054 Spitfire XVIs were made.

The rear tanks were also fitted to the Spitfire XIV, possibly other models as well.

were similiar to droptanks, as they could be used for ferry (one-way) missions only, like Malta.

Wrong. Source for this claim?

The reason was that with the rear aux. tanks the Center of Gravity shifted so far back that the plane was outright difficult and dangerous to fly, not to speak air combat. Therefore the rear tank, like a droptank, had to be emptied first,

In other words, exactly like the Mustang. Both had to use most of the fuel in the rear tank first. The RAF Spitfire IX manual notes:

"When the rear fuselage tanks are full there is a very marked reduction in longitudinal stability, the aircraft tightens in turns at all altitudes and, in this condition, is restricted to straight flying, and only gentle manoeuvres; accurate trimming is not possible and instrument flying should be avoided whenever possible."

The RAF Mustang III (P-51B) manual notes:

"Stability.—Except when earning full fuselage tank, the aircraft is stable longitudinally, laterally, and dircc-tionally. When the fuselage tank is full, the aircraft is longitudinally unstable in all conditions of flight, and tends to tighten up in turns; until at least 40 Imp. gallons (48 U.S. gallons} have been consumed from the fuselage tank, no manoeuvres other than very gentle turns should be attempted."

Regarding aerobatics, the Spitfire manual:

"Acrobatics are not permitted when carrying any external stores (except the 30-gallon " blister " drop tank) nor when the rear fuselage tanks contain more than 30 gallons of fuel, and are not recommended when the rear fuselage tanks contain any fuel."

Mustang manual:

"Flick manoeuvres arc not permitted. When carrying bombs or drop tanks, or with fuel in fuselage tank, aerobatics are prohibited."

As you can see, the restrictions on the Spitfire with rear fuel tank are not quite as bad as for the Mustang, the Mustang is prohibited from any aerobatics with any fuel in the rear tank, the Spitfire with more than 30 gallons in the rear tank.

and then return on the normal internal tankage, again 85 gallons on the vast majority of Spits.

Depends on the Spitfire. Most Spitfires had only 85 gallons internal because that's all they needed. Those that needed more fuel, like the Spitfire VIII, the Spitfire XIV, the recce Spits, got more tankage.

[Kurfürst]

Originally Posted by Hop

What Kurfurst knows well is that the page he posted is for a test on a Spitfire IX with Merlin 61. The Merlin 61 was rather different to the Merlin 66, the engine which powered most Spitfire VIIIs/IXs/XVIs.

The Merlin 61 had a slightly different supercharger, but more importantly it had an SU float carburettor. The Merlin 66 had a Bendix Stromberg injection carburettor.

The Australian test is for a Spitfire VIII with Merlin 66.

Smokescreen.

What Kurfürst knows is that Hop likes the Spitfire very much, thus Hop would like to to attribute it with properties that are beyond the actual capabilities of the aircraft, and therefore Hop waves around a single test that contradicts all others, and would like to dismiss all those others, via making up that the test is with Merlin 61, a claim Hop repeats over and over again and fail to back up over and over again.

In any case, it doesn`t matter. The range of the Spitfire IX is given in the paper is 450 miles. The range of 'rather different Merlin 66' is given as 434 miles. Hardly a difference. Smokescreen.

http://www.spitfireperformance.com/s...e-lfix-ads.jpg

The problem is escort range is typically one third of maximum range, which means you need about 1800 mile range to escort bombers to Berlin and back. And you don't want to cruise at 160 IAS, either, because you'll be a sitting duck over Germany at that speed.

That would mean that realistically, the Spitfire, when fitted with the biggest practical, 90 gallon slipper tank, would be good about for a (low speed sitting duck) escort of ca. 300 miles at economical cruise, more realistcally 520/3= 175 miles escort radius. That`s barely reaching into France. Oh sorry, you can`t even reach out that far because then you`ll have obvious problems returning on your 85 gallon internal tangage, draing further by air combat, after getting their on your 90 gallon droptank.

Short ranged indeed. Wasn`t that the point all the way?

From the Spitfire IX/XVI manual:

Later production Mk IX and all Mk XVI aircraft mount two additional fuel tanks with a capacity of 75 gallons (66 gallons in aircraft with "rear view" fuselages), they are fitted in the rear fuselage.

1,054 Spitfire XVIs were made.

The rear tanks were also fitted to the Spitfire XIV, possibly other models as well.

Well, the Mk XVI was in production only from September 1944, and as far as it went, only about 6-7 Squadrons were being operational with the 2nd TAF.

Too late, too few in other words, carrying fuel in an aux tank that made the aircraft a pregnant pig and was useful for 1-way ferry missions only.

Wrong. Source for this claim?

The RAF Spitfire IX manual notes:

"When the rear fuselage tanks are full there is a very marked reduction in longitudinal stability, the aircraft tightens in turns at all altitudes and, in this condition, is restricted to straight flying, and only gentle manoeuvres; accurate trimming is not possible and instrument flying should be avoided whenever possible."

In other words, exactly like the Mustang. Both had to use most of the fuel in the rear tank first.

Except of course the Mustang had plenty of range internal tankage and plenty of range after using up it`s internal fuel tank.

The Spitfire didn`t.

As you can see, the restrictions on the Spitfire with rear fuel tank are not quite as bad as for the Mustang, the Mustang is prohibited from any aerobatics with any fuel in the rear tank, the Spitfire with more than 30 gallons in the rear tank.

Except again of course, that after emptying the rear tank as instructed, the Mustang will have plenty of internal fuel to perform and return from an escort mission, and the Spitfire don`t.

That`s why the Mustang was so important during the war, and why the post-war Spitfires tried to catch up with that.

Depends on the Spitfire. Most Spitfires had only 85 gallons internal because that's all they needed.

And they had thus the shortest radius of action any WW2 fighter I can think of. A bit of a luxury if the target is so far away., isn`t it?

Those that needed more fuel, like the Spitfire VIII, the Spitfire XIV, the recce Spits, got more tankage.

The Spitfire VIII`s use was extremely limited in Europe, and it`s operations largely confined to the PTO, where it`s relatively longer range, compared to the other very short ranged Spitfires, was still laughably inaduquate for the theatre.

As for the Spitfire XIV, even less were around than VIII, appeared even later, and all the extra tankage was used to make up for increased fuel consumption. Having 50% more tankage than the Mk IX, the XIV could just have the same very short range.

[Morai_Milo]

So Kurfurst, if that Aussie Spit range test is an abberant test, then so must that supposed document text (no document scan ever posted) Pips posted about availability of 100PN fuel you like to wave so much about since there is reams of documentation of there being large quanities of 100PN fuel available for BoB, using your logic process.

[Morai_Milo]

And they had thus the shortest radius of action any WW2 fighter I can think of. A bit of a luxury if the target is so far away., isn`t it?

Is that shorter than the 135 mile tactical radius of the 109?

[Kurfürst]

Originally Posted by Morai_Milo

Is that shorter than the 135 mile tactical radius of the 109?

Well these figures are without droptanks; the Spitfire figures are with droptanks.
Of course, the 109 had droptanks as well, this would extend the range.

As noted, the practical 2-way range is dependant on range on internal fuel; the 109 with the exception of the 109E, had more range on internal fuel than the Spitfire, except the Mk VIII which was comparable.

The document you posted seems to stipulate the range of an enemy fighter-bombr on hit-and-run attacks on southern England, without droptank, using high power all the time and plenty of room for errors and combat added.

Perhaps this would give you comparable figures :



In any case, this thread is about the Spitfire, not it`s relative merits compared to the Bf 109.

[Udet]

Excellent information Kurfurst.

And by the way what´s all this thing about drop tanks used in Spitfires? It´d seem it was a comodity rarely used as i am unable to recall any mention of drop tanks used in operations in virtually all books i have.

Finally, has anyone seen a single photo of Spitfires flying with drop tanks fitted? I have not, and my Spitfire photo collection ain´t small.

Possibly because the Spitfire variants which used it saw very limited combat action if any.

Although no date is specified on the document, point (II) reads: "it is asummed that the tanks will be jettisoned when approaching the combat or target area..."

Assumed? Does not sound the guys who made the paper were very convinced regarding this particular issue.