1. Contra props were probably not considered sufficiently reliable, they were fitted to the last seafire though. It could have used wide track landing gear for sure. 2. ~~ 3. The plane was already sufficiently fast and a higher wingloading would have proven detrimental for future models. 4. Double slotted fowler flaps would have probably added too much complexity to the wing. The time gained by changing from a eliptical wing to a trapezoidal one would be lost when you started trying to fit in fowler flaps. 5. Agreed, something should have been done about the radiators. Seeing as how the jet duct of the P-51 wasn't available at the time I would go for wing leading edge radiators like on the mossie and Tempest I. 6. The Merlin was the only real option IMO. Direct fuel injection could have been used, but at a minimum a neg g carb should have be fitted. A 3 blade constant speed prop should have been fitted from the beginning. Automatic engine controls like those used later in the war should have been used from the beginning as well. 7/8. At best you could put a Hispano through the spinner and a pair of HMG under the engine. But you have to start considering the weight at this stage, the best engine your going to get is probably going to 1,200 HP tops. Moving the wing and pit back and extending the rear fuselage to accomodate a larger tank forward of the pit and add a rear fuselage tank like later models. It was possible to fit 23.5 gallons per wing as it was. Combine a larger fuselage tank, rear tank and wing tanks and it should be able to carry 200-250 gallons HP permitting. 9. Limited HP is a factor here at well. At most you could carry one of a newly designed gun of that caliber and it would have to be through the spinner. Recoil and low rate of fire would be a problem. Yak with 37mm guns had those problems. Instead of starting from scratch, an improved Hispano would be a better gun IMO. Improving the rate of fire to ~800 RPM and giving it a belt feed. You might be able to fit 3 with 120 RPG in the intial variant and possibly moving up to 5 in later versions.

The Yaks with the 37mm cannon also had the problem of the cannons recoil acting as a brake - a salvo of only three shots could significantly reduce airspeed.

shooter please provide evidence that the P39/40 would have performed better in the BOB, as both of these aircraft had poor high altitude performance and the BOB was a high altiude battle I fail to see how they would have done better.

Dear OBNW; The fact that both of those planes had ~twice the range of either the Spitfire or hurricane is what makes them better. While performance was infirior to the Spitfire it was supirior to the Hurricane and adiquate to the task. Remember that Hurricanes shot down the vast majority of BoB victoms. That the increase in range made other tactics available that were to prove very much supirior to those used by the Spit in the BoB. Poor Hi-altitude performance is more than offset by the increase in range. After all poor climb in a plane with enough fuel to spend extra time in climb and then wait untill the target arrived, reduces the effects of that defect dramaticaly. Once up, their long endurance gives them the option of waiting for the targets to arrive or fliing long distances to make the intercepts. When you have fuel you can traid it for speed by using large throttle openings to give you supirior performance. Cielings were more than adiquate for the task at hand as the vast majority of combats took place below 26,000' All in all, if the British government had bought the P-39/40 in numbers that were porportional to the cost of the Spitfire, they would have had many more planes on hand for the BoB and the results would have been much worse for the Germans.

But they still wouldn't have had the pilots to fly them. And the problem with intercepts in the BoB was time to reach altitude, not endurance. Added to the RAF tactics of the time, which was to dogfight, and the Germans would certainly have attempted to dogfight, all at the altitude of the Bomber stream, the P39s/40s would not have fared well.

1. Guising that it might not be reliable enough is hardly a valid objection. 3. That is a strange assertion. Speed is the single most important atribute of fighter planes. It can be shown conclusivly that faster planes are both more effective and harder to shoot down. That the spit had a marginal advantage over the Me-109 because it could use more throttle that it's adversaries and still fly home. 4. See junkers and Sikorski AC from the '30s. The need for extencive flaps is only there if you want to maintain the lower landing speed. Higher speeds were perfectly safe in later planes and only required better trained pilots to exceed slower planes safety records. 5. I had not thought about leading edge radiators. Good idea. 6. Fair enough! But the Allison predated it and had more power sooner. The poor altitude performance could have been remidied with the same insistance on two stage supercharging that both it and the merlin eventualy used, instead of the turbocharger. 7-9. Weapons ideas are as varied as there are people, but anything was better than that origionaly fitted.

to Flamingknives: Actually, the RAF had no tactical doctrine at during the Bob. Dogfighting just happened as Ftr Com. pilots tried to accomplish something, and stay alive. Pre war doctrine was that 'modern' fighters were now so fast that dogfights were impossible. Orders were that enemy fighters should be ignored, because they didn't matter. RAF fighters were for attacking bombers using a set of parade-ground formation attacks. Fortunately, Hurri pilots operating over France had quickly found that bomber formations could avoid the formation style attacks easily by turning thier own formations, and that ignoring Bf109s was suicidal. Note that as late as the spring of '43, RAF Ftr Com was still far behind the Germans in air tactics. They'd finally given up the 3 plane 'vic' in favor of a 4 plane flight, but flights and squadrons were still flying formations that were much too tight.

1. It a logical deduction rather than a guess. The problems of torque were known and it contra-rotating props were feasible they should have appeared on at least one successful pre war fighter. Reliability is IMO a likely cause for them not being used. 3. Seeing as how the spit was already faster than it's primary adversary there is no reason to try and increase the speed at the cost of handling and climb. 4. They were all large aircraft though with room for complex flaps. A few intermidiate settings instead of the UP/DOWN settings would have been good though. 9. With hindsight we can say that, but at the time the armament was decided apon it was considered very heavy, but not long after that choice was made research into changing to cannon armament was already underway.

To AussieEngineer: The Spit may have been slightly faster than the '109, but the Brits expected to be fighting the much faster He113 (actually He100) propaganda fighter. To Shooter: Except for the placement and inadequate protection of the fuel tank, all the other criticisms of the Spitfire were things deliberately accepted as a result of design decisions. Design concept: Smallest, lightest aircraft that could be built around the Merlin engine and 8 rifle caliber mgs, optimized for acrobatics, climb and speed. Bad pilot visibility accepted as price of low pit for streamlining, a problem that got progressively worse as more powerful engines changed the cowling shape. Mitchell wouldn't put blisters on the wings to make room for the hinge for inward retracting gear, or accept the weight penalty of the hard points for attachment, so accepted narrow track, weak landing gear. Note: Supermarine later accepted blisters for installation of cannon, but that was after Mitchell's death. Wide cord wing for low wing loading (climb and acrobatics) with thin shape for drag reduction and single spar construction (for weight) meant complex internal structure greatly limiting wing stowage, resulting in dispersion of initial armament and difficulty installing fuel tankage in wings. The Spitfire was intended as an interceptor, but was really a short range air superiority fighter. Like any good specialist a/c, it was superb at that one job, but there was just no way to build in a real increase in range, which reduced its strategic value greatly after '41. After the BoB (and the propaganda of the period) the Spit was an icon, symbol of the British war effort, and criticism virtually sacrilage. Why else build the Mk XVI to "maximize Spitfire production" when Mustangs were so much more valuable strategically? Why else continue to use a Spitfire dirivative as a carrier a/c after the war, when the far more workable Sea Fury was available?

"Speed is the single most important atribute of fighter planes. " And that is why the US is building 200 SR71s instead of F22s? And that is why F104s are being built instead of F16s? And that is why the F22 has vectored thrust because it makes it faster? And that is why Sea Harriers had a 10 to 1 kill ratio against F15s (in exercises of course)? Nonsense. Speed is but one factor in an air superiority fighter, true an important factor, but only one of many.