I've just been looking at a cutaway drawing of a Mk.V to figure out what would have to change to fit wing tanks. I think the main issue would have been structural strength. There is nothing in the wing leading edge back to the main spar up to the 20mm cannon and then after that it is only the space taken up by the barrels of the 20mm and the .303s. The guns and cannon are entirely (barrels excluded) behind the the main spar. Removing the outer guns would also add a lot of space for fuel as well.

PR spits flew all the way to stettin, thats a 5 1/2 hour round trip.

They just picked very small pilots or those with very hard ends (I suppose you'd build up callouses over time. Happy New Year guys.

Yes: If the eight .303s were replaced by four .50s, you can use the system from the P47 with the guns side by side, one set back far enough that its ammo feed ran behind the other. With the barrels together, just outside the propeller arc, the entire leading edge beyond the guns becomes usable. Maybe get 30 gal. or so instead of the 17.5 in the MkVIII. They got 110 in the leading edge tanks of the P38J, but a longer wing, and no guns at all in the way. Could try cannons in place of two fifties, but the matter of weight would be entering in, and the 20s weren't ready at the time of the MkII anyway.

Even more crazy when you think that they got 1,600 miles@300mph (1,000 without external tanks) for the PR Mk 1 in October 1939, no guns but armoured. Perhaps another way of looking at it would be to ask "how to fit guns to an existing long range Spitfire" as an exercise in lateral thinking. Nose mounted, external gun packs, new gun designs (like the later Mk V Hispano 20mm? Even if the operational radius dropped to 500 miles with reasonable armament, it still would have been a tremendous improvement. You are confusing the terms range and radius! Range refers to the distance that the plane could fly in a straight line with maximum fule on board. This is typicaly flown at the most ecomomical speed unless noted otherwise. This is one of the biggest deffects in arguments about ranges. In the US it was customary to quote range at the maximum continious cruising speed, which if it was reduced to the most ecomomical speed would add fifty to sixty percent to the range as listed in the books. While in the rest of the world, prity much without fail, they used the econo speed for the plackard range. Radius is the distance that the planes could reach and return to base. It might not include combat for Photo Recon planes and usualy did include reserves for weather and alternate field landings. In high altitude, long range bombers it might be as much as 45% of range. In shorter ranged bombers like the Mosqueto, it would typicaly be 30-40% of range. In fighters it might be as little as 15-25% of range depending on the flight plan and operational requirements. I know that this will rub some fur the wrong way, but that is just how it is!

Two replies with one post? >>If you could let me know where the PR Spit carried all the extra fuel, we could discuss how usable the various locations would be for a fighter. I have fewer ref.s for PR types than fighters. Nose armament could have been installed, but it would have meant jumping thru a lot of hoops to deal with the cg changes, and increased size of the cowling to enclose say, a 20mm hub gun and a pair of syncronized .50s would have done nothing to improve the pilots forward visiblity -- which wasn't a strong point in the Spit anyway. Also, gearing the Merlin to allow for a hub gun would have included some mechanical as well as aerodynamic problems -- change in the thrust line, etc.<< It would have been entirly possable to make the nose gun mods without altering the extirior shape of the Spifire one milimeter! If you have ever seen the plane with the cowl off, you would know this. there is litteraly many inches between the engine oil pan and the bottom of the cowl. Changing the gearing would have lowered the engine but not the thrust line enough to mount any gun. Changing the CG was a much worse problem though and may not have had a solution short of moving the wing forward closer to the fire wall. Something not impossable, but easy at the design stage. As to the fuel requirements, the tankage could have been installed in the wing, if the guns were any place else! Fuselage tanks behind the pilot in any plane were not a good idea and even worse in the Spit when the 'pit was so far back in the fuse. Remember that the main tank was between the 'pit and engine OVER the CG! This is one of the things that gave the spit it's "delightfull" handeling, mass centralization. Wing tanks require powerfull alerons if the rate of roll is not to be serriously degraded and the spit already had the worst rate of role in europe. >> One Spitfire was modified with enough range to fly the Atlantic to the US. Was used for 'war bond' tours. Trouble was they not only had to take out all the weapons and ammo, but gut the internal structure of the wing to make space for fuel tanks. Reduced structural strength well below what was needed for combat. << Two things about this second post; 1. Range to fly the "Atlantic" means from Ireland or Scottland to Iceland to Greenland, to Nova Scotia to Main or upstate New York. 2. Brit standards of structial strength were about 45-50% of US standards and when we built the "Lite weight" prototype Mustangs to 50% OVER Brit standards, we were not happy with them since we enjoyed a standard of toughness well in excess of continental standards. Note that the P-51H was more than twice as strong as the Spit and still removed from inventory early durring Korea because they were not as strong as the D models and could not "take a licking and keep on ticking"!

>> You'd only be 150 miles short of berlin with that much fuel. That would have made the sweeps over France more effective at the very least << Why on earth would you think this combo could go that far? Weight removed even without more fuel extends range. If the ratio between empty and laden weight was increased range goes up by the LOG of the differance. See DeMairs formula? SP? The guns and ammo would degrade range just by their weight. Secondly, The farthest range that I've ever seen posted for any Spit was 1600 miles. That was undoughtedly at econo cruise speed and not usable in a combat senario where substantialy larger throttle and less efficiant mixture settings would be required! In real terms that 1600 mile range would equate to no more than 4-500 miles of RADIUS! Hardly enough to get any where near Berlin from the British Isles!

>>I don't think a 500 mile radius is possible especially on internal fuel unless you want to really start redesigning things, like moving the wing back and using tricycle gear. I reckon you could get about 300 miles combat radius on internal fuel and retain the full armament from an early Mk Spit with appropriate modifications. Later spits might be able to get close to 400 because of the availability of more HP. << The engine power has very little to do with range. Since none of the things we discuss here would be nearly as drastic as the things the Ruskis did on single engine record flights of over 7000 miles. The Spits problems can be traced to two things the wing shape/profile precluded large shifts in the CG and the shape had a large surface area and skin friction component with a resultantly smaller aspect ratio. I note that someone posted a list of planes and their aspect ratios as if it was not a big deal. I did not respond at that time because I thought that others would point out the folly of that possition. IE, there was 10-15% differance in the ARs of the planes mentioned, even though there was less than ONE didget of differance. 10% differance in AR is huge! and means that the plane with the lower AR will fly substantialy less distance and at a substantialy slower speed than the plane with the longer AR! To get a handle on this in practical terms, think of the Allison engined Mustang 1, it was much faster(390MPH to 355MPH) than the Spit, on less power, while fliing at a much larger gross weight and at a lower altitude! All things that should have made it much slower, but the 'stangs AR was much better and it showed! Not that the AR was the only thing that gave it the edge, as the Radiator instalation helped too and the laminar flow wing, IF IT WAS CLEAN, did not hurt either. But the single biggest factor was the increased AR!

>>I've just been looking at a cutaway drawing of a Mk.V to figure out what would have to change to fit wing tanks. I think the main issue would have been structural strength. << The issue is not strength, but location. Putting any large amount of fule or any other disposable load ahead of the spar was almost but not quite impossable due to CG location restrictions. Again the "thin" wing profile gave "touchy" caracteristics. The fuel if there was to be any substantial increase, had to go were the ammo and feeds were located. In order to do this, the easiest solution would be to relocate the guns to the nose beside and below the engine. If you have ever seen the plane with the cowls off, you would know that four 20MMs would fit there easily! The BIG trouble would be relocating the wing forward to make the CG right and the reduction of the main fuse tank cappasity. Eliminating the fuse tank between the 'pit and firewall would give the pilot beter vision and if the wing had to be moved to accomodate the CG shift due to relocating the guns, makes it all possable. You also get the big bost in effective fire power from the shift too! A wet wing could cary more than enough fule to fly any practicle mission in Europe and would not automaticaly cook the pilot with a hit.

shooter your talking balls again the 20mm will not fit inthe nose of a spit without major redesign as they are TO LONG! remember the spit was designed as short range interceptor it was war neccessaty that kept it in production, that and niether the UK or the US ever produced a fighter that was superior. yes the P51 was longer ranged but the range was not the issue that you imply if it were fighter production in the Uk would have been mustangs not spits the fact is that the spit did the job it was required to do from 38 till the end of the war, yes more range would have been nice in the later years but as the role of the spit changed to ground support in the later war years (least for the majority mk9s) this was not the problem you make out. the only role for a long range fighter was bomber escort and only the US used long range bomber during the day so only they had the operation need.