Spitfire Combat Radius (range) evolution, limitations?

[wuzak]

No.

It's a photographic airplane and had best not get tangled up with ANY fighter with that much fuel as it would be meat on the table. But, it could go fast and take pictures quite well, which is what it did in real life. With the drop tanks gone, unless approved by the commander, you will be missing the 75-gal rear aux volume and you are down to 122 gallons, which is enough for cruising for maybe 2 hours give or take a bit depending on cruise speed, with a bit of reserve. That is not long-range in anybody's book, likely even yours if you think about 8-hours missions a P-51 flew routinely.

The combination of fuel tanks Pat listed were possible in late production Spitfires. Which had guns and ammo.

VIIIs and XIVs had the 96 gallon main tank, plus 2 x 13.5 gallon tanks in the wing leading edge (inboard of the guns).

Some later aircraft also had rear fuel tanks fitted.

Note that, like the P-51, the Spitfire couldn't fight with the rear tanks full. But could with a partial load.

2 hours cruising is going to be ~500-600 miles. Which is a substantial improvement for combat radius over the standard Spitfire.

Sure it isn't as long as P-51s, but it would have been a useful gain.

 

[GregP]

2 hours cruising is about 360 - 390 miles if you are flying escort since the escorts stayed with the bombers who were on economy cruise at 185 - 190 mph or so. It might be 500 - 600 miles if the mission didn't involve escort but, since we're talking about long-range airplanes, most of the long-range missions WERE escort. Certainly not all. As I understand it, Spitfires were not very often involved in anything close to long-range operations, so what we have here is a bit of wishful retasking that really never amounted to much in actual operations.

You can certainly do it in your invented wish-world, but it didn't happen very often really. Not saying if couldn't have happened. I'm saying it didn't very often in actual WWII, so I'm still having trouble trying to figure out what the end purpose is for retasking one of the world's best fighters to something other than what it was actually used for, taking it away from helping to actually WIN the real war.

Want to win the war sooner? Leaving everything the same except for the bombing targets.

Bomb food production / shipping and the industrial electrical grid and the war ends MUCH sooner, with or without longer-range Spitfires.

 

[wuzak]

2 hours cruising is about 360 - 390 miles if you are flying escort since the escorts stayed with the bombers who were on economy cruise at 185 - 190 mph or so. It might be 500 - 600 miles if the mission didn't involve escort but, since we're talking about long-range airplanes, most of the long-range missions WERE escort.

With the relay system, the fighters did not escort the bombers all the way to target and all the way back.

Even so, 360-390 miles is still an improvement on the Spitfire's combat radius.

As I understand it, Spitfires were not very often involved in anything close to long-range operations, so what we have here is a bit of wishful retasking that really never amounted to much in actual operations.

The RAF did not have the need. The USAAF had the need, but did not know it yet. And when the USAAF did realise their need, they had better options.

Which meant that it wasn't a priority.

The Spitfire would never have had P-51 range, but its range could have been extended allowing for more flexible operation.

 

[Milosh]

Didn't the Spitfires allow more US a/c to escort further? Every Spitfire squadron that did the initial escort freed up a USAAF squadron for the longer escort missions.

 

[GregP]

With the relay system, the fighters did not escort the bombers all the way to target and all the way back.

Even so, 360-390 miles is still an improvement on the Spitfire's combat radius.




The RAF did not have the need. The USAAF had the need, but did not know it yet. And when the USAAF did realise their need, they had better options.

Which meant that it wasn't a priority.

The Spitfire would never have had P-51 range, but its range could have been extended allowing for more flexible operation.

Agree, especially the "could have" part. Makes me wonder if they increased the Merlin or Griffon's oil supply when they added extra fuel .... something to look into anyway.

 

[GregP]

Didn't the Spitfires allow more US a/c to escort further? Every Spitfire squadron that did the initial escort freed up a USAAF squadron for the longer escort missions.

Likely true ... seems very likely, anyway.

 

[wuzak]

Agree, especially the "could have" part. Makes me wonder if they increased the Merlin or Griffon's oil supply when they added extra fuel .... something to look into anyway.

They certainly did for Merlin PR Spitfires,

A Mk IX

https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Supermarine_Spitfire_Mk_IX_%2840929727970%29.jpg/800px-Supermarine_Spitfire_Mk_IX_%2840929727970%29.jpg

A Mk XI

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Spitfire_PRXI_PL893_%2827871192617%29.jpg/800px-Spitfire_PRXI_PL893_%2827871192617%29.jpg

You can see the deeper fuselage just below the spinner where the oil tank was located.

The oil tank was relocated for Griffon Spitfires, so it may not have been visible if the tank volume was increased.

PR Spitfires did a lot longer range than an extended range IX would be able to do, so the exiting tank may be sufficient.

 

[ThomasP]

Merlin_____________ Fuel / Oil
Spitfire Mk I_________ 85 / 5.8 Impgal
Spitfire Mk II_________85 / 5.8 Impgal
Spitfire Mk V________ 85 / 5.8 Impgal
____________________85+90 DT / 8.5 Impgal
____________________85+29+170 DT / 14.5 Impgal
Spitfire Mk VIII______122 / 7.5 Impgal (early)
___________________122 / 8.5 Impgal (late)
Spitfire Mk IX________85 / 8.5 Impgal
Spitfire Mk XVI______ 85 or 95 / 7.5 Impgal

Griffon
Spitfire Mk XII_______ 85 / 6.0 Impgal (early)
____________________85 / 7.0 Impgal (late)
Spitfire Mk XIV_____ 111 / 9.0 Impgal
Spitfire FR Mk XIV__ 142 / 9.0 Impgal
Spitfire PR Mk XIX__ 217 / 9.0 Impgal
Spitfire Mk XVIII____ 173 / 9.0 Impgal

All of the above is from the AM Pilot's Notes.

 

[GregP]

Nice list, ThomasP.

Your post seems simple enough, but we all know it takes awhile to get these things together, especially combing through manuals.

Thanks.

So, we're kind of back to the Spitfire definitely NOT being long range with the above list. The PR XIX had a Griffon. At low cruise, it was 90 Imp gal/hr and, at full rattle, it was 225 Imp gal/hr. So, the 217 Imp gallons shown above would give you about 2 hours at low cruise with a 20 minute reserve. You had a useful radius for pics, but you weren't going all that far.

With the Mk.V, you had 114 Imp gallons without the drop tanks, so you really didn't want to fly more than about 2.5 hours away from friendly territory because, if you dropped the tanks, you wouldn't get back, even at economy cruise. That's with no reserve. To HAVE a reserve, subtract 20 - 30 minutes. With the British weather, you'd NEED reserve. Still, it lets you run a decent patrol about an hour or so from base.

 

[Wild_Bill_Kelso]

Interesting discussion.

To some extent it seems to be a bit US and UK national perspectives talking past each other a bit.

Bomber escort does not just mean strategic bombing, and better range does not just mean bomber escort. Better range means better endurance, which is useful for air defense, and also for all kinds of tactical roles (such as when used as fighter-bombers, which people tend to forget Spitfires actually were).

It seems to me like the P-51 was the best escort fighter in wide use during the war, but it wasn't the only option. The Spitfire had the reputation, fair or not, as the most effective Allied fighter in air combat against German fighters, at least among the Anglo-Americans. It was just limited by it's comparatively short range so it was mainly (though certainly not exclusively) used for defense.

The British did have a lot of Spitfire Mk Vs sitting in the UK at one point during the mid-war which weren't doing much except acting as a deterrent to daylight raids against the home island. When they were released for deployment to Theaters in the Pacific and Mediterranean they were somewhat limited in their tactical role due largely to range.

I believe the Spitfire Mk VIII, which had somewhat enhanced range over the Mk V, seemed to have been more widely used in a broader range of roles, and was generally considered much more effective despite just having moderately better performance. Even in the defensive role, enhanced flight endurance means more time to get up to altitude and form up, more time to find and chase down targets, more time to fight once combat begins. More time to fly back to base after you chased an enemy aircraft.

So it seems to me that improving the range of the Spitfire could have paid substantial dividends even if the P-51 still ended up dominating the strategic escort role. I don't know enough about the technical aspects to say how feasible it was. I know the Spitfire had a pretty slim wing and was generally a fairly small aircraft compared to some of the later war designs, but they certainly improved the range of the Mk VIII over the V. The Bf 109 had the same issues in this regard and the Germans never seem to have really solved the problem either.

Even the longer-legged VIII was still a bit too short ranged for the Pacific. If they could have enhanced it say 50% more it would have been very helpful I think. And if they had something like the Mk VIII just a few months earlier that might have saved lives in the Mediterranean.

 

[GregP]

If you look at ThomasP's fuel tankage list above, they DID improve the Spitfire's range. They didn't make it a long-range fighter, but it got better, which is what I think you were saying.

I'm not too sure why, but very many British airplanes have almost no fuel. The Spitfire started out that way, the Bristol 188 didn't have enough fuel to get to top speed, it needed to throttle back and land before running out. I talked with former English Electric Lightning pilot and asked him if it really was a Mach 2+ fighter. He scratched his beard and said, and I quote, "Toward the fuel you could get going Mach 2 or a bit more. If you ever got going Mach 2 headed away from the fuel, you were never going to get back to the fuel."

His words, not mine.

Try flying a Folland Gnat without extra tanks. You won't get very far!

Likely, the lack of fuel in British planes is exaggerated but, in general, they weren't known for long range unless that was the mission. Then, they flew are far as any other nation's aircraft. You never see the Short Empire or Sunderland being denigrated for short range, do you? The Comet had to have enough fuel to be intercontinental, so likely it's just a few airplanes that give rise to the notion ... Spitfire being one of them.

 

[pbehn]

The need for a top class short ranged interceptor didn't disappear until well after D-Day. Until 1943 when Stalingrad and El Alamein decided the course of the war things could have turned for the worse as viewed at the time. But even after that, the possibility of sneak tip and run raids wreaking havoc on UK and USA assets in UK existed and keeping the D-Day build up secret as far as a landing in Normandy not Calais meant German recon had to be confronted and stopped, which it was.

 

[Wild_Bill_Kelso]

Yeah I think low fuel capacity was part of what made a good interceptor and dogfighter, especially against tactical bombers. In the Philippines and Malaysia etc., during the early war, the Allies sometimes sent up F2As and P-40s with half their fuel in order to perform better against the Japanese fighters.

The Bf 109 and Spitfire were both optimized for combat either right over a battlefield or defending against bombers. They were both quite good at it. The odd thing (to me) is that they never figured out a way to give them substantially longer range. I think Spit VIII had about 40% better range than the Spit V (I'm sure somebody will correct me, but this site says 680 vs. 470, which works out to much less than that in terms of combat radius) but that is about the same range that a lot of other fighters in the war had at the beginning (1940-41) and considerably less than what was considered normal for say, a naval fighter.

The Soviet fighters for the most part stayed short legged and they also, with a couple of one-off exceptions, never really worked out longer ranged versions. But their emphasis was almost entirely on air superiority over the battlefield. And they had a lot of strategic limitations on materials and supplies.

If you are trying to get the ultimate level of performance, the least possible amount of weight is what you want.... but the relatively low fuel capacity is also quite limiting. Like so many design problems in WW2, it's a bit damned if you do, damned if you don't. The trick in threading the needle was making an aircraft which could be configured either 'light' or 'heavy', but that wasn't easy.


I think something like a Spit VIII, had it been more widely available and in greater numbers, could have made quite a difference in the Pacific and Burma, particularly if you could have had something in quantity in say 1942 or early 1943. And in the Med as well.


As for Jets flying Mach 2, i think what you described can be said for a lot of jets, especially in the 60s but even today. I spoke to an F-18 pilot once who told me pretty much the same thing.

 

[GregP]

Yeah, using afterburner / reheat makes even a big fuel tank get small quickly, doesn't it?

 

[Wild_Bill_Kelso]

Getting back to the fighter / fuel capacity thing, I guess the difference is, once you have more than ~1,000 - 1,200 hp engines, you start to have the power to move heavier aircraft around the sky. Then it's time to go back to the drawing board and give yourself a bit more fuel, guns, armor, and other things. The Fw 190 was much heavier than a Bf 109 but by no means less capable. The P-51 was also a heavy aircraft, as was the F4U, F6F, P-47, P-38, Typhoon, Tempest etc.

What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...

And once we have afterburners, it's zoom time but you are getting there by basically sticking a fire hose full of fuel out the back of your aircraft. Hard to carry enough to make that last.

 

[pbehn]

Getting back to the fighter / fuel capacity thing, I guess the difference is, once you have more than ~1,000 - 1,200 hp engines, you start to have the power to move heavier aircraft around the sky. Then it's time to go back to the drawing board and give yourself a bit more fuel, guns, armor, and other things. The Fw 190 was much heavier than a Bf 109 but by no means less capable. The P-51 was also a heavy aircraft, as was the F4U, F6F, P-47, P-38, Typhoon, Tempest etc.

What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...

And once we have afterburners, it's zoom time but you are getting there by basically sticking a fire hose full of fuel out the back of your aircraft. Hard to carry enough to make that last.

Range is great if you have it and you need it. Within days of the Normandy landings airfields were being constructed in Normandy to save the trip of 100 miles across the channel. The guys in combat on the ground would not be impressed to hear that their fighter cover was off to Berlin, because they could.

 

[Wild_Bill_Kelso]

Well if you have the extra range capacity, and have sufficient power to haul your aircraft around the sky in spite of a larger gas tank, (sufficient so that you are still competitive with enemy aircraft) it helps for everything. Including supporting ground troops right over the battlefield. A lot of the problems that the Aussies had defending Darwin was due to the limited flight endurance of the Spit Vs they were flying. If they had Spit VIII, or say, Corsairs, it would have gone a lot better I think.

Similarly, Spitfires were not as heavily engaged as they could have been during battles like El Alamein because they lacked range and flight endurance.

More fuel capacity can mean range to fly to Berlin (or maybe Rotterdam), but it can also mean flight endurance to climb to altitude, form up, fly around and find enemy aircraft, engage them at high boost for longer periods, and still be able to fly back to base if you happened to chase them a bit.

In 1940 or 41, it probably makes sense to build aircraft with very small fuel capacity, since your ~1,000 engine isn't going to be good at hauling 180 gallons of fuel around the sky and the priority is defending the homeland and controlling the sky directly over the battlefield. Once you have a 1,500 hp engine (or a 2,000 hp radial) then it's time to look at carrying more, IMO.

 

[tomo pauk]

Even the longer-legged VIII was still a bit too short ranged for the Pacific. If they could have enhanced it say 50% more it would have been very helpful I think. And if they had something like the Mk VIII just a few months earlier that might have saved lives in the Mediterranean.

They could, and they did. In late 1944, that is, when there was such a thing like rear-fuselage tankage for Spitfire IX for example, by what time Allies were firmly in France.
There was no 'long range escort fighter' doctrine at the RAF, just like at other air forces/services (bar Luftwaffe and what Japanese had). Thus no long range escort fighters.

So it seems to me that improving the range of the Spitfire could have paid substantial dividends even if the P-51 still ended up dominating the strategic escort role. I don't know enough about the technical aspects to say how feasible it was. I know the Spitfire had a pretty slim wing and was generally a fairly small aircraft compared to some of the later war designs, but they certainly improved the range of the Mk VIII over the V. The Bf 109 had the same issues in this regard and the Germans never seem to have really solved the problem either.

Spitfire was one of the biggest 1-engined fighters when introduced. Similar size like the P-40 or P-51. Thus the ability to carry a lot of firepower, fuel and to receive much bigger and more powerful engines as war progressed, without paying the penalty in handling after the upgrades.
Bf 109 was indeed small.

The need for a top class short ranged interceptor didn't disappear until well after D-Day. Until 1943 when Stalingrad and El Alamein decided the course of the war things could have turned for the worse as viewed at the time. But even after that, the possibility of sneak tip and run raids wreaking havoc on UK and USA assets in UK existed and keeping the D-Day build up secret as far as a landing in Normandy not Calais meant German recon had to be confronted and stopped, which it was.

D-Day was 18 months after the German disasters at Stalingrad and in North Africa. Let's not make an elephant out of a mouse, like terror the 'tip and run' attacks were sometimes described.
Hawker Hurricane was not a 'top class short range interceptor', yet it was happily made in more than 2700 copies in 1943, and almost 690 pcs in 1944.
D-Day was made possible via the aerial offensive WAllies mounted through 1943 and 1st half of 1944 (plus the earlier efforts, often futile), it would not have been possible if the WAllies were twiddling their fingers above the UK airspace.

Range is great if you have it and you need it. Within days of the Normandy landings airfields were being constructed in Normandy to save the trip of 100 miles across the channel. The guys in combat on the ground would not be impressed to hear that their fighter cover was off to Berlin, because they could.

The guys on the ground were there because Luftwaffe was trashed by the time the guys were actually there. Air cover was never in question, with RAF and USAAF displaying the many:1 superiority in numbers vs. LW, while also having the qualitative edge.
WAllies not having an all-LR force in the ETO between June of 1943 and July of 1944 at was the thing that supplied some oxygen to the Luftwaffe in 1944, lest they suffocate.

 

[pbehn]

In 1940 or 41, it probably makes sense to build aircraft with very small fuel capacity, since your ~1,000 engine isn't going to be good at hauling 180 gallons of fuel around the sky and the priority is defending the homeland and controlling the sky directly over the battlefield. Once you have a 1,500 hp engine (or a 2,000 hp radial) then it's time to look at carrying more, IMO.

The Spitfire first flew in 1936, with a fixed pitch twin blade prop it had about 660BHP available on take off. The early Bf 109s had Jumo 210 engines that only produced around 600-700 BHP. The British were looking to have more range, that is why they got heavily involved with NAA and the Mustang with its 180 gallons of internal fuel ordered in 1940, it was known as a P-51 when the USA eventually started using it.

 

[tomo pauk]

What everybody wants of course is something like a bearcat, but we didn't see anything that close to the sweet spot until the end of the war, and by then you are in the jet age, with a whole new balance to strike...

Why would everyone want something like a Bearcat, bar as a carrier-vessel bird?