Spitfire Combat Radius (range) evolution, limitations? (2 Viewers)

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

Monogram's vintage 1/48 Spitfire IX features a belly mounted drop tank. When I read WingCo J E Johnson's book, "Wing Leader" he mentioned the "Slipper tanks" and I assumed it to be the ones Monogram depicted. In reality the Slipper tanks looked rather like slippers. The Monogram kit was depicting the 90 gallon cylindrical tank that did not appear until 1944.

View attachment 891711
View attachment 891714
Seafire MkIII's were fitted with 89G P40 drop tanks to increase loiter time, one added benefit was the Pilots found the tanks made landings easier because the added drag made the Seafire less likely to ''float" over the deck, a leading cause of accidents.
 
This is from a book by Dr. Alfred Price, "The Spitfire Into Combat" and I recommend it although I think a more accurate title would be something like "Neat Info About the Spitfire That You Probably Have Not Heard About."

This is the second worst example of screwing up a beautiful airplane, the first extra fuel added to the Spitfire. This resulted in a small production run so Spitfires could be made available for longer range missions across the Channel

First a 30 gal non-jettisonable tank was added.
View attachment 891709
Then a 40 Gal tank was added for the definitive production version.

View attachment 891708
1787277161352.png

They could have just extended the leading edge tanks to rib 4 and have 40G on the COG and no handling issue's, you shake your head at their thinking.
 
They could have just extended the leading edge tanks to rib 4 and have 40G on the COG and no handling issue's, you shake your head at their thinking.
Interesting. That worked on the P-47N, but you think the Seafire's MLG would still fit in there? Given that it was a carrier aircraft, that area had to be pretty beefed up, I would think.
 
Not saying that it could not have been done earlier (I have suggested the wing LE fuel tanks being implemented earlier in other threads covering this subject) but the LE fuel tanks installed in the Seafire Mk III were of the Mareng self-sealing type type (I think), and in order to fit and service them (ie repair/replace them reasonably easily) they had to remove one of the LE structure ribs. The reason they did not extend the FT in size toward the #4 rib in the diagram above is that the #5 rib is part of the strength girder of the inner wing, and the wing in that area could fail at unacceptably low G loads if the additional LE bit of #5 was removed from the existing wing structure. The wing could have been reworked to allow tha larger tank, but it would have required serious redesign work and/or testing, and entail some added weight (beyond the tank and fuel).

NOTE that the same basic arrangement as used in the Seafire Mk III was used in the Spitfire Mk VIII, although I do not know if the first batches had them?.

Also, FWIW there were at least 2 different capacities for the LE tanks used (12.75 & 14 Impgal). I do not know which came into service first.

The Spit Mk VIII arrangement as of Dec'43.
Spit Mk VIII LE 14 Impgal tanks.jpg
 
Last edited:
You can do a lot of things, if you have enough money and time.

British have had more than enough time and money to outfit the Spitfire with greater internal tankage. What was not there was doctrine that will favor the fighter with big footprint; a good dose of institutional inertia and myopia was present when the benefits of such fighters became obvious.
 
Last edited:
British have had more than enough time and money to outfit the Spitfire with greater internal tankage.
Bill Gunston pointed out that in the postwar discussions over RAF fighter design it was even argued that British fighters traditionally had short range. As if that was a feature to be jealously defended!

I note that the P-36C had a range of 820 miles without a drop tank. The P-40B had a maximum range of 945 miles while the P-40E with one drop tank had a max range of 850 miles.. The Brewster F2A-3 had a range of 1680 miles. The P-51A had a range of 1000 miles without drop tanks.

If the USAAF had been equipped with fighters with typical RAF ranges they would have had trouble making it out of Texas without stopping to refuel.
South Carolina is the smallest Southern state and yet it is about 2/3 the size of England, Wales and Scotland put together.
 
I will note that AHT says that the British got over 1800 Merlin powered Mustangs of the B, C, D. K models. I don't know when they started or stopped. Or when they had been first promised. Need for long range Spitfires may have gone up and down depending on promises/deliveries of Merlin Mustangs. Actual need for another 1000-1500 Spitfire VIIIs with rear fuselage tanks may not have been great.
 
View attachment 891737
Is this the first worst example?.
Purely intended for long range ferry flights, not for use 'in anger'. Placed restrictions on the handling and required the adoption of special techniques during take off and landing for retraction and extension of the undercarriage due to the impacts of the airflow around those large underwing tanks. In practice, adoption of the larger of the standard tanks fitted to the underwing hardpoints provided just as good a result without the penalties of these ferry tanks.
 
Not saying that it could not have been done earlier (I have suggested the wing LE fuel tanks being implemented earlier in other threads covering this subject) but the LE fuel tanks installed in the Seafire Mk III were of the Mareng self-sealing type type (I think), and in order to fit and service them (ie repair/replace them reasonably easily) they had to remove one of the LE structure ribs. The reason they did not extend the FT in size toward the #4 rib in the diagram above is that the #5 rib is part of the strength girder of the inner wing, and the wing in that area could fail at unacceptably low G loads if the additional LE bit of #5 was removed from the existing wing structure. The wing could have been reworked to allow tha larger tank, but it would have required serious redesign work and/or testing, and entail some added weight (beyond the tank and fuel).

NOTE that the same basic arrangement as used in the Seafire Mk III was used in the Spitfire Mk VIII, although I do not know if the first batches had them?.

Also, FWIW there were at least 2 different capacities for the LE tanks used (12.75 & 14 Impgal). I do not know which came into service first.

The Spit Mk VIII arrangement as of Dec'43.
View attachment 891827
It doesn't have to be a tank, the same leading edge was used as a wet wing on the PR variants, or split the tank so it saddles the rib.
 
You can do a lot of things, if you have enough money and time.
IF You don't want to screw up production too much and don't want to spend a lot of money of tooling and designing/testing/certifying you have few options.
There's no negative's to adding internal/external fuel capacity to fighters which is why every frontline fighter ended the war with more capacity than it started with for benifits more than just an increase in range, the MkV as an example when they fitted slippers used the extra fuel to fly at increased cruising speeds over France making them harder to bounce. I like the saying, 'The only time a plane has too much fuel onboard is when it's on fire'.
 
British have had more than enough time and money to outfit the Spitfire with greater internal tankage. What was not there was doctrine that will favor the fighter with big footprint; a good dose of institutional inertia and myopia was present when the benefits of such fighters became obvious.
It must have been humbling watching American fighters taking off from English fields on their way to Germany.
 
I will note that AHT says that the British got over 1800 Merlin powered Mustangs of the B, C, D. K models. I don't know when they started or stopped. Or when they had been first promised. Need for long range Spitfires may have gone up and down depending on promises/deliveries of Merlin Mustangs. Actual need for another 1000-1500 Spitfire VIIIs with rear fuselage tanks may not have been great.
The RAAF could have used every one of those MkVIII's.
 
Just though I should post this drawing of the 170 & 29 Impgal ferry tank arrangement. Unfortunately, I have not been able to find a weight and balance sheet with the weights and moments arms.
View attachment 891869
From this drawing it seems clear that there was no pressurization for high altitude capability which is another limitation when comparing to 1944 US escort fighters. Similar handicap with the Republic 200-gal ferry tank.
 
The RAAF could have used every one of those MkVIII's.
The 1,658 Spitfire VIII were all built by Supermarine at its dispersed production sites across southern England so numbers were never going to match what a single dedicated factory like CBAF could churn out in terms of Mk.V & IX. Final assembly took place at four different sites from components produced elsewhere.

Mk.VIII production ran from late Nov 1942 to mid-Jan 1945.

But from Oct 1943 those same facilities began turning out the first of 956 production Griffon engined Spitfire XIV, that version being based on the Mk.VIII airframe. Production of that variant ran through to mid-1945 and was followed by 300 Mk.XVIII from May 1945 to mid-1946. Low volume production of the F.21 was also undertaken from mid-1944 but development problems prevented that version reaching the first squadron until April 1945 (Only 2 squadrons operated that version before the end of the war in Europe).

So if you want more Mk.VIII you would have to sacrifice Mk.XIV production. Retooling CBAF to built Mk.VIII would be even more costly in terms of overall Spitfire production.

Initial deliveries of the Mk.VIII was to squadrons in the Med, often to be operated alongside Mk.V or IX.

Mk.VIII began arriving in Australia in Oct 1943, reaching the squadrons of the Churchill Wing at Darwin in early 1944. The last of 410 ordered by the RAAF arrived May / June 1945. The first squadrons in SEAC to get the Mk.VIII were 81 & 152 which re-equipped with the type in Egypt and flew them to India in Nov / Dec 1943.
 
When you look at the ranges of the Gauntlet, Gladiator, Hurricane and Spitfire they settle on around 523 (Gladiator) to 626 miles (Gauntlet) or about the maximum distance between any two points of Great Britain mainland.

Firstly to get extra range into the Spitfire II and later requires extra fuel just to get back to where you started from given you are bolting on more powerful engines while tare weight went from 4,341 pounds in the mark I to 5,805 in the mark VIII.

The proposed Merlin powered mark III fighter enlarged the fuselage tanks to 99.5 gallons, up from 84. The Hurricane I range on 87 octane is put at 600 miles, the IIa with 100 octane at 524 miles, Spitfire I with 87 octane 575 miles, so as a crude approximation, (524/600)*575*(99.5/84) = 595 miles.

The proposed Griffon powered mark IV fighter had 101.5 gallons in the fuselage and a pair of 17.25 gallon wing tanks, total 135 gallons. The engine was rated at 1,445 HP, the Spitfire XII had either 1,720 or 1,735 HP, range 329 miles, another crude approximation (135/84)*329 = 529 miles, then deduct for the more powerful engine.

Spitfire Va range 480 miles, to get back to the 575 miles of the Spitfire I with 84 requires around 96 gallons.

The extra 30 gallons of the mark VIII (96 gallon fuselage and a pair of 14 gallon wing tanks) upped range to 660 miles compared to 434 miles of the mark IX, or 7.5 miles per extra gallon at economic cruise, meaning to maintain the range of the Spitfire I with 84 gallons of 87 octane the Merlin 60 series Spitfires needed around 113 gallons, Spitfire I economic cruise 8.9 miles per gallon.

Using the yardstick ranges from Francis Dean the Allison Mustangs came in at about 1,000 miles on 180 gallons, the Merlin types 1,250 to 1,300 miles with 269 gallons, 50% more fuel, 25% more range. Allison P-51 empty weight 6,433 to 6,550 pounds, P-51B/C 6,988 pounds then add another 250 pounds for the rear fuselage tank. (As an idea about fuel tank weights, Lancaster 580 gallon tank 702 pounds, 383 gallon 550 pounds, 114 gallon pounds or 0.83, 0.7 and 0.57 pounds per imperial gallon)

From mid 1940 onwards the British economy became highly stressed, to get something meant not getting something else. The British assumed the enemy would be coming for them "soon" to at least mid 1941 then assumed Barbarossa gave them under a year's reprieve from an even bigger air assault than in 1940. Range is not a big issue when you are on the defensive, getting quality aircraft is more important and in 1941 and 1942 that meant the Spitfire, which from say mid 1941 to mid 1942 had generally inferior performance than the fighters it was encountering but was better than the Hurricane, anything available from the US or anything Sabre powered, more so given the expected increase in average combat heights. So the Spitfire III was cancelled, and Fighter Command became close to an all Spitfire force during 1941, Hurricanes retained for ground attack and bomber destruction away from enemy fighters. All anticipating major air attacks in mid 1941 then mid 1942.

Adding weights to a lower performance aircraft is not a good thing even though a case can be made extra range would help as it gave a wider area to attack or alternatively allowed longer time in combat.

The Spitfire PR.IV wing tank was between ribs 4 and 21 and apparently non self sealing, essentially a sealed wing leading edge, the size and shape meant the pilots had to regularly switch from using one wing tank to the other while cruising

From 1940 to 1942 the RAF was in the position the axis powers ended up in 1944/45 it needed numbers and quality but had to trade off between the two. Odd question how far from where you live do you need maps to get around? Numbers and quality also apply to pilots, short range fighters means little need for pilot navigation training or extra wight/cost/complexity of navigation aids.

Yes the RAF ideas of long range were what the USAAF would consider medium range, even in 1943 and that played a part in fighter ranges, the war situation coupled with the engine upgrades played a much bigger part in Spitfire ranges. Also consider the industrial costs of bulk numbers of metal drop tanks, and how paper tanks changed the economics.

If the USAAF in Britain was determined to bomb Germany in 1943 nothing you could do to the Spitfire would enable escort to target, and until mid 1943 the USAAF was generally prosecuting an unescorted heavy bomber war and a separate fighter then fighter and medium bomber war. By interrupting supply of the one fighter every front from Britain to Australia was asking for in numbers with emphasis on the latest version you could put together and maintain a Spitfire escort force in Britain that could cross the northern German border to around the Ruhr, assuming relevant escort tactics. Or you could put together a similar sized longer ranged Mustang force in about the same time frame if delivery schedules could be kept. Would require additional pilot training and also a bomber force with acceptable numbers willing to stick to escort range. Even then you can make the case the Luftwaffe could concentrate more interceptors in Germany than the escort numbers needed to keep bomber losses down, plus not rebuild the twin engine day fighter force which required unescorted bombers to work, instead upping the single engine fighter force.

Of course the allied air situation swung from not enough to too many in 1944/45, the RAAF received 656 Spitfires, as of September 1946, 92 of them were still in their shipping crates.

Castle Bromwich produce its first Spitfire 21 in April 1944, then production July 1944 to January 1946, mark 22 from February 1945 to February 1946, the factory finished mark IX production with a final 1 in August 1945, mark XVI with a final pair in September. Supermarine series production of mark XIV finished in October 1945 (plus 1 more each in December 1945 and February 1946), mark XVIII production May 1945 to March 1946, mark XIX finished in November 1945 apart from 7 laggards January to May 1946, mark 24 production was at Supermarine, starting in February 1946.

Vickers produced Seafire 45 from February to December 1945, Supermarine mark 46 from January 1946 to March 1947.

British P-51 Allocations 1943, monthly, 10, 15, 25, 50, 50, 50, 50, 50, 60, 65, 85, total 600 (probably not including 50 P-51A in May)
1944, January to May, 90, 100, 100, 50, 50, 50, total 350

Merlin Mustang arrivals to RAF in Britain, Italy and India,
September to December 1943, 3, 74, 90, 105, total 272
1944 by month, 90, 105, 53, 60, 14, 70, 70, 81, 38, 109, 88, 80, 107, 41, total 811
1945, January to September, 53, 53, 211, 112, 86, 15, 90, 22, 46, total 688, grand total 1,771, from 1,781 delivered for RAF in US.

The 1943 difference is a combination of production delays, travel times and the USAAF changing its priorities. Through 1942 and into 1943 the British knew the USAAF was nowhere near as interested in the P-51 as they were, things like the A-36 order in August 1942. That started to change with the two big orders from Inglewood and Dallas in August and January 1943 respectively. It would be the second half of 1943 before the P-51 effectively displaced the Spitfire as "the" in demand fighter.

The RAF issued 947 Mustang III and 876 IV serials, total 1,823 remembering 35 RAF allocated aircraft were transferred to the USAAF in Britain in 1943 and 37 USAAF aircraft in Britain were transferred to the RAF in 1944.
 

Users who are viewing this thread

Back