Quote:
Originally Posted by IvanK
In short during BOB all operational fighters were running 100 octane fuel.
Seek and ye shall find.
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Frankly this was discussed a zillion times, but despite years of research, there's still no positive evidence that 'all operational fighters' were running on 100 octane. It simply appears to be wishful thinking from a few fanatic fans of the aircraft. WWII aircraft performance.com does list a large number of papers,
unfortunately none of them state that all fighters are to or currently using 100 octane fuel. There's no doubt that a signficant number of Spitfires and Hurricanes were running on this fuel, this has been known since the 1960s, so nothing new here, but as to how many, or what percentage, nobody so far can tell for a fact.
The issue is further clouded by the fact that fighter stations (around 50 or so were used during the Battle), and not fighter units were supplied physically with fuel drums.. and the fighter units tended to change their bases every now and then, to be replaced by an another unit. If say, Squadron A, flying from Station X (which had 100 octane present), transferred to Station Z (which did not have 100 octane present but regular 87 octane) and its place was taken by Squadron B in mid-August which until then was flying from Station Z, then you would have Combat Reports from both Squadron A and B using 100 octane, but the reality was that one of them used it in the first half of the month, and the other during the second half of the month..
The closest evidence is a 18th May meeting record, which is still far off from that, as it states farily clearly that the changeover effected select units.
The paper - Co-ordination of Oil Policy Committee, 7th meeting memo - says (direct quote):
"... satisfaction was expressed at the fact that the Units concerned had now been stocked with the necessary 100 octane fuel"
There's a reason why the articles you refer to tend to be dismissed - there seem to be always a case of subtle manipulation of the original papers. Take example the reference to this same meeting mentioned above at the wwiiaircraftperformance.org site, which interprets it as the following:
The Co-ordination of Oil Policy Committee noted in the conclusions of their 18 May 1940 meeting with regard to the "Supply of 100 Octane fuel to Blenheim and Fighter Squadrons" that Spitfire and Hurricane units "had now been stocked with the necessary 100 octane fuel".
Note how this reference to
"the Units concerned" suddenly becomes
"Spitfire and Hurricane units" in the text of the article; the original suggest that an unknown number (perhaps few, perhaps many), but definietely not all (otherwise why the distinction,
if ALL units would be concerned?)
Unfortunately, the wwiiaircraftperformance.org article suddenly goes silent after what has happened after 18 May 1940. That's is unfortunate, because I saw the authors of said article discussing the same subject with an Australian researcher, who has informed them of the following at butch2k's board:
Quote:
The first bulk shipment of 100 octane fuel had arrived in Britain in June 1939 from the Esso refinery in Aruba. This and subsequent tanker shipments from Aruba, Curacao and the USA were stockpiled while the RAF continued to operate on 87 octane petrol. Having secured what were considered reasonably sufficient quantities of 100 octane, Fighter Command began converting its engines to this standard in March 1940, allowing boost (manifold) pressures to be raised without the risk of detonation in the cylinders. This initial increase in maximum boost from 6 lb to 9 lb delivered a useful power growth of around 130hp at the rated altitude.
By the time of the invasion of the Low Countries by Germany in May 1940 the RAF had converted approximately 25 % of it's total fighter force to 100 octane fuel use. The subsequent escalation in air activity and demands placed upon Fighter Command over the next two months put great strain on both the 100 octane fuel stockpiles and aircraft modified to use the fuel. Against the backdrop of total war the RAF found that it's reserves of 100 octane fuel was well below the level considered necessary for widespread use, for any sustained length of time.
Two actions were immediately undertaken by the British War Cabinet in May to resolve the looming crisis. Firstly 87 octane fuel was deemed the primary fuel source to be used until further supplies could be discovered and delivered in sufficient quantities to allow the Merlin conversions to again take place. Those existing fighters already so converted (approximately 125) would continue to use what supplies of 100 octane were available, but all other fighters that had not been modified to continue with the use of 87 octane (of which there was more than adequate supply). The second action was for the British Government to contract the Shell Oil Refining Company to assist the British-controlled Iraqi Petroleum Company at Kirkuk to produce 100 octane fuel. This arrangement proved quite successful as production was quickly converted to 100 octane fuel.
The first Middle East shipment of 100 octane fuel arrived in Portsmouth on 12th August, with a further two deliveries in September and four in October. Although too late to allow widespread conversion for the use of the fuel the deliveries did ensure that from this point on Britain would not be lacking in 100 octane fuel levels. With the newfound supply RAF Fighter Command again embarked upon a Merlin II and III conversion to 100 octane use from late September, finally achieving 100% conversion of it's fighter force by the end of November in 1940.
Given that large quantities were not available until late August, the volume of usage/week of 87 Octane must be far higher than that quoted for 100 Octane. So to put things into perspective that why I asked for a comparison.
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