Looked up the speed of sound at altitude data. With a max permissible Mach of 0.89, the highest an a/c could do 640 mph TAS would be 15K. The a/c would still be in compressibiltiy, with the controls locked, and without recovery flaps recovery couldn't begin until the a/c dived into even denser air at lower altitude. Unless the a/c was could be slowed enough by sharply reduced throttle, no recovery above 10K, maybe lower. Chances of successful recovery look questionable to me. The '38s structure was very strong (in the manual you sent me to, the max allowed NEGATIVE Gs was 3.5!!!) and they still started recovery much higher using the flaps. Probably never went much, if any, above 540mph. The chances of a Spitfire, or any prop. a/c seriously approaching 700 mph and serviving the dive doesn't look very likely to me.

Maybe some of you who are deeper into engineering than I am (my bag is history, and what little engineering I had was long ago) could explain the significance of this from Green's WAR PLANES OF THE SECOND WORLD WAR, Vol II. Subject is the developement of the Mk21 Spitfire: "With the constant increase in operational speeds the effect of torsional stiffness of the wings on aileron effectiveness assumed major importance, and whereas a theoretical reversal speed of 580 mph had been catered for by the wings of earlier Spitfires, that of the Mark 21 featured a forty-seven per cent increase in stiffness which catered for a theoretical reversal speed of no less than 825 mph."

-Firstly, why are you using 81gal/hr as cruise fuel consumption. For maximum cruise, the fuel consumptions are 68gal/hr for rich mixture and 49gal/hr for weak mixture. I believe if you use the correct cruise fuel consumption you'll find that the reduction in radius is only about 20% of the most economical settings radius. -Secondly, I think your overestimating the amount of time spent on the ground with the engine running before takeoff and after landing. Typically, the time from a scramble call to takeoff was only a minute and a half. The aircraft were parked very close to the runway so very little fuel would be used in taxi. -You'll notice I included a 20 MPH headwind, both ways(which is highly unlikely). That is a legitimate reason for the reserve only being 30 minutes on arrival at the aerodrome. -Furthermore, I was conservative and didn't include any time at reduced power for the decent.

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Finally I'd like to point out that a radius of 50-100 miles is more than sufficient to cover all of southern England and out into the channel. Look at the map of the airfields I posted previously. An extra 100 miles radius would be superfluous.

The Spitfire wing was very thin, thinner than even the Mustang (i'll dig out the chord ratio later and post it, as well as the mach tests ... Xmas ... too many things to do). It was very strong along the main spar (+12G if I remember correctly), but tended to warp at very high speeds on the trailing wing. This could cause aileron uplift due to the distortion in the wing shape and hence airflow. This was major factor in the aileron stiffness at high speeds (but I also found a document that I think stated - after unpicking the maths - that the gap in front of the aileron was also a factor). Strengthening the rest of the wing came with a penelty - weight. After doing this the weight of Spit was much closer to the Mustang, but engines were so much more powerfull by then that this was not seen as a limiting factor. A far cry from the days when only 900hp was available when the Spit was originally designed!

A weapon with twice the range, will be 41% more effective than one with less range. It will make 41% more intercepts, RTB 41% more offen and thus reduce the Non combat, "Opperational" losses and in general do a better job than a weapon system with less range. Care to provide proof for this statement. As far as I can tell you are pulling these numbers out of you know where. You could possibly elaborate on your vague reference to game theory. Maybe you could produce the "equation" that gave these numbers. As I've pointed out before, despite having a far longer range than the Bf-109 the Bf-110 was cut to shreads over Britain. It's extra range didn't make it any more effective did it.

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That the Hurry was certyainly adequate to the task is beyond dought! The after all did shoot down twice as many Germans as the Spit did. If the number of Hurries that could have been built in leu of the more complex Spitfires would have made a significant differance to the BoB! The BoB fighter composition was 38% Spitfire, 62% Hurricane. Yet the Spitfire made up 43% of total kills despite being tasked with the harder targets. From July to August 1940, it shot down 49% of all Bf-109s in September they shot down 54%. The Hurricane had a loss rate 50% higher than the Spit. These statistics speak for themselves, the advantages in performance of the spitfire made them far more effective on a plane for plane basis. Seeing as how demand never outstripped spitfire production, a plane to plane comparison is the only one that matters.

January - May 1944 with 2 Spit XI, photo recon conversions from mark IX, Merlin 63 and 70 engines. Special measuring equipment was added. Profile: Reach max speed at 40,000 feet, then dive at 45 degrees The Spitfire reached a maximum of 0.89 mach at 29,000 feet diving from 40,000 feet. The trials were repeated many times with a few accidents, including blowing an engine when the propeller constant speed mechanism failed and over revved it. The Mustang reached 0.8 (an Allison engined one), the p-47 trials wre aborted after going out of control and having to pop the dive recovery flaps. Apparently there was no flow seperation on the Spit up until mach 0.85. Closterman wrote of combat at 40,000 feet in a Spit VII in his book 'The Big Circus' ... hairy stuff, he must have been in this sort of speed region chasing a Me 109.

You are clearly dilusional! The fixes you want to make are not possable with the early spit! The PR types had to remove the guns and ammo to increase range due to less weight "INDUCING" less drag. That you seem to be ignorant that drag has two components, first by the form and skin friction and secondly as a condition of making lift. It is called "INDUCED DRAG" because it is that portion of the total drag that is because of weight. That the Spit's wing was totaly unsuited to adding fule is also ignored in your post. The CG of the guns and ammo were located exactly where the fule tanks would have to go! Where would you put the guns and how much ammo would you remove to make room and weight available for fule? RIGHT!!! I'm talking about an extra 30 gallons in a rear fuselage tank and a 13.5 gallon tank in each wing. Both of which could have been easily included in the initial design, unlike some of your ideas. The extra 57 gallons would have given the spitfire I a range similar to the P-40. Both of those fuel tanks were put in fighter spitfires with full armament.An extra 550 pounds of fuel and fuel tanks would only add an extra 18% induced drag to the aircraft. The spitfire already had minimal induced drag due to it's elliptical wing.

To AussieEngineer: The wing tanks were introduced in the MkVIII after some redesign to make it possible -- wouldn't go in the MkI airframe (including the MkV and MkIX). The fuselage tank would have been a serious risk where hostile ftrs might be encountered over your own field. Until it was burned empty, the Spit would have been unable to fly combat maneuvers due to the cg shift. Should the original design have allowed for wing fuel tanks?? I would say yes. The RAF just didn't believe long range fighters were possible and actively resisted any attempt to develope them pre war. Also, even the MkVIII (the longest range Spitfire) would still be about 150 miles short of the P40s range without the fuselage tank that was only suitable for ferry flights, and so wasn't even made self sealing.

To MustangFlyer. thanx. I do notice that from my sources the Mk21 was only 300 lbs heavier empty than the MkXIV in spite of the armament being upped to 4x20mm from 2x20s and 2x.50s. The wing had been totally redesigned and had a planform much more like a P47, and was just very slightly greater in area than the standard Spit wing.

I should added that this was the main factor why the roll rate of the Mustang was faster above 250mph. Its stiffer wing meant less wing twist at high speeds and meant that its ailerons, although smaller than the Spit's, remained more effective at high speeds. The price paid was weight and a lower mach limit due to its thickness, also because it it was a trapezoidal design with a high wing loading, it was prone to high speed stalls. Still a superb wing, one of the very best of the war, though the laminar flow claim was really a myth. Similarly the Tempest's eliptical wing, although comparably thin to the Spit, was also stronger (and heavier) and it meant that its roll rate was better than the Spit's above 350 mph, though the Spit was all over it at slower (and more common) speeds. The Tempest was designed specifically for mach resistance and control at high speeds, with all the knowledge gained over the years. Just shows that nothing is perfect, just different compromises, which is still the case today. Which one was better? Depends on the circumstances and the pilot. Still it was pretty impressive work by Supermarine when you consider that the Spit's wing was designed in 1935, with virtually no knowledge of compession and mach effects.