Why Couldn't The Spitfire Be Modified To Be A Long Range Escort?

Yes thanks, a very useful source although it does exclude the cigar-shaped tank often carried on the Continent – unless that more tapered shape in the diagram is meant to include the stubbier one. As I understand it the aft tanks were only introduced near the end of 1944, and were rejected by Fighter Command (ADGB?) because of the stability problems, and their understandable judgement that there was no purpose in flying out further than they could fly back on internal fuel after combat (which is behind my earlier comment that the Mk.VIII would have been better than the Mk.IX – not only more internal fuel but ahead of the aerodynamic centre and thus stabilising). The aft tanks did however prove useful with 2 TAF where the centreline position could be used for a bomb so the aft tanks served the same purpose as a centreline tank – i.e. use first. The real answer was the larger tail and tailplane which was eventually introduced on the Mk.22, by which time any need for long range had disappeared and the use of aft tanks was actually banned on those aircraft fitted with them.

Graham, My fault, I should have realised that it was a typo !

I came across the following:

January 1944, the Air Fighting Development Unit at Wittering, conducted some performance trials between the Mk. X1V, the Tempest V and the Anglo American Mustang 111,the FW 190 and Me 109G.

Comparison with the Mustang 111, showed that the maximum level flight speeds were practically identical. In the climb, the Spitfire was better. In the dive, the Mustang pulls away slightly. Turning; the Spitfire is better. Roll rate; the Spitfire is better.

Fuel system diagram

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Hi Graham – there were various mod standards of Spitfire fuel systems – this should make interesting reading

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Sorry John (and others) you are quite right about the RR estimate. That was finger trouble on my part and it should have said 50mph. I shall go edit it. I have seen it said, with what justification I don’t know, that Boscombe were unable to match claims for the top speed of the P-51B, but that still means it was faster than the Spitfire.

Olde Rigger; The Spitfire Mk.IX only had a 65gall main tank. The Mk.VIII had a 90gall main tank and another 23 gallons in the wing leading edges, but was never fitted with aft tanks. Details which do not affect your main point.

Please everybody – read the whole thread before you comment on the resurrection – all salient points have already been covered

If you were brave enough to fly a Spitfire in this fuel configuration 😉

Spitfire Mk9

96gal (main) +75 gal (rear fuse) + 45gal (drop) = 216 imp gallons

P51 D

180 USG (wing/main) + 85 USG (rear fuse) + 220 USG (drops) = 485 USG = 404 imp Gallons

You really do not need to be a Rocket scientist to work out the A/C with the longer range LOL

It was the P51,s wing NACA numbers that gave the range.Not as manouverable as the Spit though in the turn but great in a straight line..

How many Spitfire threads on the front page ? LOL

Not enough 🙂

Good to see that the ‘Spitfire’ Forum is alive and well 😀
How many Spitfire threads on the front page ? LOL

“In the US, two Mk IXs were experimentally fitted with Mustang 62-gallon underwing drop tanks. These were of metal construction and of teardrop form. The Aircraft & Armament Experimental Establishment (A&AEE) at Boscombe Down tested the jettison properties of this tank from the Spitfire. At 250 mph, the tanks jettisoned cleanly but at 300 mph the tail of the tank rose sharply and struck the underside of the wing heavily enough to dent the skin.”

“….50% faster than the Spitfire…..”

“…..somewhat exaggerated….” That’s an understatement if ever there was one ! So comparing like for like, for example the P-51D and the Griffon Mk.X1V both, operational at more or less the same time, the P-51 would deliver a level flight true speed corrected, of something in excess of 650 mph !! Crikey, who needed jets ?

One other point; from the Mk 1X onwards, the Spitfire was superior to the Anglo American Mustang in the climb.

It was shown by RR aerodynamicists that with the same engine the Mustang would be 50mph faster than the Spitfire. This is described in the RRHT book on the Mustang with a Merlin. That’s a fairly definitive (if possibly somewhat exaggerated) indication that the drag was lower but some time ago modern com[puter modelling work was done on the Mustang, Spitfire and Bf109 which clearly showed that the P-51 was superior in this respect. It was reported in the RAeS Journal, if you want to dig out the report.

The Spitfire could however dive faster than either because the thinner wing gave it a considerably higher critical Mach number.

I’ve just re-read this thread, and no-one has pointed out that one very good reason for not spending effort on pushing the Spitfire to what would have been an extreme state was that the RAF had already ordered large numbers of a long range fighter. Namely, the Mustang. That Merlin Mustang production was largely prioritised to support the 8th AF was one of those decisions that probably was wiser in the overall picture. They were more needed there, than in the RAF.

Thread necromancy, I know, but I came across this –

Also noting that Hawkers had a problem with the Tempest and had to add more fuel tank storage for their high horsepower engines (therefore higher fuel consumption) and they lengthened the fuse in front of the pilot (and may have set the pilot back a little?) and fitted a further 75gal tank behind the oil tank. Adding this extra volume and mass over or close to the COG.

Also noting that this option was not available to them for the Spitfires, “after the event”, as the Tempest was still a prototype or II – Mk1 or so and changes were being added to the production lines as required with the different Marks.

Reading the stats then the Spitfire is in fact faster at the heights that it would engage the enemy…… sea level stats, only being any good for ditching purposes!

Agree with the first while assuming the second is tongue in cheek!

Regards

As I posted previously … a/c performance is complicated…you have to compare like with like – so it would have to be a comparable mark of Merlin,Altitude,MPH/Knots,I.A.S/T.A.S etc etc
Not an easy task !

It was a comment by ‘antoni’ earlier in the thread –

“The Spitfire’s main handicap was drag. It took more horsepower to get the same performance out of it than other contemporary designs. More power means higher fuel consumption which is another important factor that has to be taken into consideration”.

– not sure that it’s anyone else’s contention that the Spit was ‘handicapped’ by this. I for one am waiting for Antoni’s references to back this up – though it has been pointed out that the 109 did manage more speed on less horsepower – Simple power / Speed figures for 109E / Spit I here: http://www.spitfireperformance.com/spit1vrs109e.html From this it looks marginal, and dependent upon use of boost.

Reading the stats then the Spitfire is in fact faster at the heights that it would engage the enemy…… sea level stats, only being any good for ditching purposes!

This is a nice simple and clear diagram of the P51 fuel system…brilliant design from the outset,by comparison some other a/c fuel systems became a bit of a plumbers nightmare ; )

I really don’t understand where this view on the ‘drag’ of the Spitfire airframe came from, it has always been considered to have been the cleanest of designs.

Regards

It was a comment by ‘antoni’ earlier in the thread –

“The Spitfire’s main handicap was drag. It took more horsepower to get the same performance out of it than other contemporary designs. More power means higher fuel consumption which is another important factor that has to be taken into consideration”.

– not sure that it’s anyone else’s contention that the Spit was ‘handicapped’ by this. I for one am waiting for Antoni’s references to back this up – though it has been pointed out that the 109 did manage more speed on less horsepower – Simple power / Speed figures for 109E / Spit I here: http://www.spitfireperformance.com/spit1vrs109e.html From this it looks marginal, and dependent upon use of boost.

=bearoutwest;2077308]
Why would you hamstring your fighter escorts in such a manner? Yes, it does burns more fuel, and they fly slower and are sitting ducks for pinpoint Luftwaffe fighter bounces. They are also slower to react and accelerate to counter the Bf109 and Fw190 incursions through to the bombers.]

That is what the USAAF did !!

The P-51D was also a dog to fly for the first 30-60 minutes with full behind-the-pilot tanks, but the USAAF managed it with rookie pilots within an acceptable loss rate. (Seems horrible to write that, knowing it means a number of pilots wallowed in with full tanks.) It only needs a test pilot to prove it can be done and to establish a set of flying/operating procedures for less experienced/capable pilots to use.

The P51 was not as sensitive in pitch ; ),therefore although it was unstable for the first 30 mins – it would not have been as unstable as a spitfire !Narrow long CofG margins/marginal Longitudinal stability dogged all marks of spitfire !

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Seafire xv probably not the best illustration as it had a griffon engine !

But we could look at the fuel figures vis a vis the JQ flight

Mk9 spitfire fuel system diagram

http://www.spitfireperformance.com/spitfire9-fuelsystem-lr.jpg

So 96gal (main) +75 gal (rear fuse) + 45gal (drop) = 216 imp gallons

P51 D

180 USG (wing/main) + 85 USG (rear fuse) + 220 USG (drops) = 485 USG = 404 imp Gallons

One of my autobios has details of the authors P51 escort missions as an appendix – most were approx 5 hours duration but some were 6.5 hours

and also …

Bud Anderson

The Mustang truly was a remarkable aircraft. Its superiority came from the revolutionary laminar flow airfoil, a drag-reducing radiator cooling system, lots of fuel and a marvelous blend of airframe and powerful engine. It had excellent performance at both high and low altitudes and enough fuel to fly anywhere the bombers were sent in Europe. My average combat mission was about 4 and ½ hours in duration; the longest mission flown on D-Day when I logged 6 hours and 55 minutes. I still had enough fuel in reserve for about another hour. As far as maneuverability, I always felt that I could handle any type of German fighter anywhere I found them.