If you mean that their use hev to be accurately rendered as pointless I don't see any reason for devs to loose time on these.

;)

IMHO there is no logic in those curves. I will be cautious giving definitive interpretation only based on this one.

Thank you for that, both of you. I guess most of us would be greatly interested in your findings, as you seem to be honestly curious about the truth behind the matter, just like I am. Frankly people so far only seem to have been interested in putting forward snippets, and curiously their story just 'cuts' after May 1940, which I find somewhat suspicious because of the findings of that Australian reasearcher I already quoted, and the tanker situation that appears to be recorded by most authors (Blair, Morgand and Shacklady etc.).


One can try his luck with Morgan and Shacklady's serial number listings, perhaps somthing turns up. However I was checking into my files, and found a German document of a captured Spitfire II and tests done with it - albeit with a Merlin III which would pretty much make it a Spit I.. though I'd believe that they coulnd't capture this example earlier than 1941. What is interesting though that they make a comparison between the Spit I and II, and list the Spit I with 87 octane and 2 bladed wooden (fixed) propeller, which is indeed true for the initial few dozen, and the Spit II with CSP and 100 octane. I don't think much should be read into it though, given the uncertainities. Whatever its worth, they measured the Spit II/Merlin II to be good for 547 km/h, and then 557 km/h in a later test run, at 5km. Speed at 0 m alt. was 460, which would indicate +6 1/4 lbs.sq.inch boost.

Indeed its true, I have a UK report of Spitfire drag changes during the war, and the effect of serial production on performance. The mirror looks just about right, and its often the most unlikely items that cause the most surprising amunt of drag - cannon stubs, external arm. windcreen and even the internal one for example.

Yes, that's why I don't like to draw guesswork form relative test reports. For example Kwiateks observation about the relative speed difference of 109 and Spit are entirely reasonable, and I tend to believe myself that they probably captured and tested the said Spit with 87 octane in Rechlin. It probably neither had the fuel nor the mods at that time when captured yet.. also when you consider differences in invidual airframes, engines, day temperatures.. the margin of error just becomes too great. For example, manufacturers gave some + or - 5% tolerance on speed. That means we already have an anout 50 km/h margin of error. You can never know if it was a poorly made Spit (109) compared to a exceptionally well made 109 (Spit), how many hours were logged into the motor and so on..

BTW I did a bit of a comparison table of FC's sorties vs. the amount of 100 octane and 'other' (ie. 87 octane) aviation fuel issued during the month. Its interesting.

http://i38.photobucket.com/albums/e1..._duringBoB.png

A few of my own observations:

a, It seems clear that 100 octane has begun replacing 87 octane towards the end of September / start of October. Until then, 87 octane is by far the major fuel consumed.
b, This corresponds with what the Lord Beaverbook memo noted about re-starting the conversion
c, Its also very appearant that issues have a bit of 'delay' built into them. Obviously supply's nature is that they re-supply after the fuel at the airfields has been used and there's reported need for new issues. This takes time.
d, 100 octane issue curves are clearly responding to FC sorties number increase/decrease. Though that's not news, FC used that fuel. But it should be kept in mind that number of Blenheim Sqns also used and were issued 100 octane fuel, and a Blenheim sortie would consume 4-6 times the fuel a fighter sortie would.
e, On the other hand, 87 octane issues ALSO clearly reacts to FC sorties number increase/decrease. It shouldn't, if all frontline Sqns would be using only 100 octane. ;)
f, Obviously the 87 octane curve reaction is less pronounced, as
fa, A good percentage of FC used 100 octane, so they don't their needs 'do not exists' from the 87 octane issues POV
fb, A large number of other aircraft also uses 87 octane, and many of them - bombers, patrol craft etc. - consume much more fuel than small fighters.

In my opinion, the most conclusive evidence that even towards the end of October a number of fighter squadrons were flying on 87 octane is evident by the sudden and perfectly parallel rise of both 87 octane issues and FC sorties curves at the time.

:)

Just a quick note, I have Shacklady and Morgans Spitfire the History.

The only ref to a captured Mk 1 is N3277

234 sqn
Reported shot down over Isle of White 15th April 1940
(Actually forced landing in Cherbourg)
Later had DB engine fitted.

So it probably had The Rotol CS as the De Hav wasn't introduced till July.
Definitley a Merlin III. If it was 100 octane it would have been one of the early conversions.

Poking around the web a bit it would seem that this is the Rechlin MK1.

Just need to find out what it's service history was now!

EDIT: I got the dates wrong! See below.

Cool..

Very interesting..

Just a heads up, the dates are wrong, the 15th April 1940 is the date it was delivered to 234 squadron. According to these links N3277 was shot down on 15th August 1940, this would put this particular Spitfire MkI as an almost definate BoB era 100 Octane variant.

An Image is available here. If you look at the cowling you can see some white stenciling, it should read DTD 100 OCT. It was painted here to remind ground crew what fuel to use.

http://www.flickr.com/photos/8270787@N07/4871667320/

Production details for N3277.

http://www.spitfires.ukf.net/p003.htm

N3277 listed as lost on 15th August 1940.

http://www.the-battle-of-britain.co....Aug-losses.htm

Info on the Pilot, PO Richard Hardy

http://www.thesoutheastecho.co.uk/Pilots/Hardy_R.htm

You are absolutley right.. I hate the way it's laid out in "The History"

As it is in the book..

N3277 485 FF 5-01-40 MU 15-01-40 243s 15-4-40 reported shot down nr IoW, Was dam and f/ld in cherbourg france, 15-8-40 P/O Hardy PoW a/c had daimler benz engine fitted.

So it was converted to 100 oct, thanks.

Just an aside, reading through all the serial numbers is quite sobering..
I usually just find a particular a/c but when you just read line after line of P/O 'Smith' etc kld, FTR and so on for page after page it brings it home to me some how.

Anyway thanks again.

No problem.

So if N3277 was captured on the 15th of August 1940, it couldn't be the one used in the tests Kurfurst quoted, which were carried out on the 10th August 1940.

Just when you think you're getting somewhere..

Was the Rechlin Spit an RAF one?

EDIT : I keep coming across references to Molders 'miserable' spitfire comments being made before the BoB, and also June 1940 seems to be quoted a few times.