[NZtyphoon]

This seems mighty unlikely during the 1940 timeframe given that it seems the two (or three) Blenheim Stations identified earlier [u]were only supposed to be supplied with 100 octane.

If there is no 87 octane in the Station just 100 octane, how they are supposed to tank up from both? This may have been true earlier, but certainly not in these Stations concerned.

Because clearly Blenheim stations were supplied with both grades. Source Warner The Bristol Blenheim: A Complete History (2nd ed) - as definitive a book on the Blenheim as Morgan and Shacklady is on the Spitfire.

P.100 "But the introduction of 100 octane fuel caused further problems for Blenheim pilots...Blenheims were adapted to carry it only in the outer tanks, with 87 octane in the inner tanks.

P.136 (September 1939) "Further difficulties and complications arose as working parties in the hangers of several squadrons were still involved in a hectic programme of bringing up to specification those aircraft that had not been modified to full Mk IV standard, by installing the new outer fuel tanks for 100 octane petrol, plumbing the jettison systems, changing the engines to Mercury XVs....the modifications were all completed by 7 October."

Now, anyone who searches back in this thread will find the actual figures for British / Allied tanker losses in the period, they were quite serious indeed, iirc several hundred thousends of GRT worth. Mines, torpedo planes and bombers, uboots all took their toll. I don't bother to post them again.

Nope, I have checked through all of this thread and nowhere has Barbi, or anyone else, posted figures on tanker losses until AL Schlagater's posting at 8:41 am today. Barbi makes mention of the mysterious "Pip's" paper with some vague stuff about increasing tanker losses, but no other evidence to support his claims...

The Germans were sinking British tankers at an increasing rate, and all 100 octane fuel was coming in those tankers....but this was increasingly uncertain as Uboot took their toll on the tankers, and, during May and June, until the French capitulation, with 25% of their fighters and some of their bombers running on 100 octane the British consumed 12 000 tons of 100 octane and 42 000 tons of other (87) grades, or 54 000 ton of avgas at total - and there was no tanker running in with 100 octane until August 1940.

No "actual figures" and no evidence that there was "no tanker running in with 100 octane until August"

I believe Morgan and Shacklady are quite aware of Payton-Smith's book.

If they are, it isn't listed in their bibliography, nor do M & S refer to it in the text, so how can Barbi make such a leap?

Can you explain to me how Payton-Smith speaks one thing on page 59. - about the 1939 situation, when the British evidently seeked 'absolute certainity 'went on to say' on page 259-260

For example, what is the context "...this problem (supply of 100 Octane aviation fuel) disappeared on pg. 259? Does the second quote it even remotely related to 1939-1940, or you just frankensteined them together?

The book is not entirely about aviation fuel - it deals with all aspects of oil supplies to wartime Britain. The first chapter on Aviation fuel dealt with the pre-war situation when Britain had to plan for the possibility that America would bar fuel supplies to combatant nations.

""By 1939...The prospects of securing sufficient supplies of 100-octane fuel in addition to the 87-octane petrol required for non-operational flying looked doubtful...(he goes on to state on page 57)...It was true that by 1939 it seemed increasingly unlikely that American supplies would be withheld. But to have accepted anything less than absolute certainty, to have depended on the goodwill of foreign suppliers to meet the essential needs of the Royal Air Force, would have been a radical break with traditions that had governed British oil policy since long before the First World War."

Meaning that the pre-war planning papers quoted by KF were being conservative in their estimates, as per a long held tradition."

After this chapter came several others on other issues - civilian oil supplies, shipping etc. Then came another chapter on Aviation fuel which deals with the situation from the declaration of war through to 1942, in which P-S notes that late in 1939...

"...this problem (supply of 100 Octane aviation fuel) disappeared; production of the new fuel in the US, and in other parts of the world, increased more quickly than expected with the adoption of new refining techniques." pp. 259-260