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[PJS]

I am researching the range (radius of action) capability of the Spitfire.  There is reasonably extensive information on the standard internal and external fuel volumes eg in Morgan and Shacklady's book.  What are rarer are fuel consumption figures, eg for given speeds, altitudes and loads.  Details of the American modifications done to 2 Spitfires at Wright Field to extend their range would also be of great interest.  The reason for the research is to assess the Spitfire's potential as a long range escort fighter.  My initial research suggests that it had considerable potential which was never fulfilled - partly due to pressure on Supermarine to develop new marks in sufficient numbers (leaving little spare resource) and partly due to official disbelief that it would be possible.  Any data sources known to anyone?

[NZTyphoon]

One place to look immediately is http://www.zenoswarbirdvideos.com/Images/spit/SPIT9MANUAL.pdf which gives some baselines for fuel consumption for Merlin 60 series powered Spitfires (page 36)

(iii) Fuel consumptions:
The approximate fuel consumptions (gals./hr.) are as
follows:
Weak mixture (as obtained at +7 lb./sq.in. boost and below):

Boost
lb./sq.in.                              R.p.m.
                        2,650    2,400    2,200    2,000    1,800
+7                      80           __      __          __         __
+4                      71           66      61          54         —
+2                      66           61      57          50         43
0                        60           55      51          45         39
- 2                      53           49      45          40         35
-4                        45          42      38          34         30

Rich mixture (as obtained above -f 7 lb./sq.in. boost):
Boost
Ib./sq.in.             R.p.m.         gals./hr.
+ 15                    3,000             130
+12                     2,850             105
NOTE.—The above approximate consumptions apply for all
Marks of engine. Accurate figures giving the variation
in consumption with height and as between low and
high gear are not available.

I have the Spitfire VII and VIII pilot's notes and the figures are identical

http://www.zenoswarbirdvideos.com/Images/spit/Spit2Manual.pdf

gives some basic consumption figures for early Merlin engined Spitfires while http://www.scribd.com/doc/4599427/Pilots-Notes-Spitfire-V-Seafire-IIIIII will provide some for Merlin 45-55 series engines. Unfortunately there doesn't seem to be much data on given speeds, altitudes and loads immediately available in Pilot's Notes etc; this will take more digging, probably at the likes of the National Archives, Kew for RAE or A&AEE data, or even contacting Roll-Royce archives.

[PJS]

Many thanks for that.  It is a very useful reference and data source.  The warnings on page 7 regarding use of the aft fuselage tanks are interesting - presumably due to longitudinal stability concerns.  Supermarine did seem to take a long time to sort out that problem.  I remain convinced that had there high level pressure to extend the Spit's range from early on, it could have been successfully developed into an effective escort fighter from mid 43. 

[NZTyphoon]

You're welcome; This might also be of some use: http://forum.1cpublishing.eu/attachment.php?attachmentid=9590&stc=1&d=1337143252

[DavidCIsby]

I discussed this in my book THE DECISIVE DUEL: SPITFIRE vs 109, published by Little Brown. 

If you want Wright Field's side of the story, check out my reference to the document, now safely lodged in the US National Archives, that they did postwar to claim they knew all about Spitfire range extension.

But it really deserves a book of its own.  Lots of Anglo-American duels.  Portal vs. Arnold!  Wright Field vs. Boscombe Down!  I was unable to find what the USAAF brass said when Spitfire IXs appeared over places such as Emden in August 1944, a year after they had desperately wanted them, with the same 90 imperial gallon slipper tanks as they had a year before.

[Edgar Brooks]

Initially Portal was very enthusiastic for the Wright Field conversion, but it changed after the airframe was fully inspected. In order to get the wing tanks in, the Americans had removed three ribs from the leading edge "D" box, one of which was of prime importance for manouevering, and this was viewed with misgivings, even though some extra strengthening had been added.
 The fuselage tank entailed removal of some items, in order to make room; this was later achieved, in the XVI, by transferring the oxygen and compressed-air tanks to the wings; however, that could only be done in the "E"wing, and the Air Ministry wouldn't countenance that until 1944, for several years preferring the 4 x .303" to 2 x .5" (but that's another [long] story.)
Another consideration, nearly always missed in these range discussions, is the consequent need for a bigger oil tank, to go with the extra fuel. In order to get Spitfires from carriers to Malta, the island had to accept tropical versions of the Vb & Vc, since they had bigger oil tanks, so complaints about the Vokes filter got a "take it, or leave it" response. It was the end of March, 1943, before the tropical oil tank was fitted, as standard, in the V.
There was also a need for extra oxygen, which, again, the XVI covered by having three bottles, against the usual two.
Edgar

[DavidCIsby]

Boscombe Down ended up calling Wright Field's effort a "lash-up".  This, I suspect, was one reason why they wrote the report that today rests in RG 18 in the US National Archives.  I believe (do not have the document in front of me) Wright Field justified their modification to the structure as still stronger than that of PR Spitfires (Wright had evaluated a PR XI).

[Spits]

Well the longest recorded flight by a Spit is 1800 miles..

http://forum.keypublishing.com/showthread.php?t=36712