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It cannot be like you said Shortround. If all Rolls Royce did was sort through bins of parts, they would have had a huge mountain of scrap parts that didn't exist. And they didn't have that when Merlin production ended. Not all their parts fit other required parts, and they DID had fit and had file. They just tried to start with a part closer to what was needed to reduce the hand-fitting process. That's why they call it hand fitting. If the production process produced parts as loose as you contend, then they HAD no process.
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Note that the original 100 octane that the RAF used to replace 87 octane really was only 100 octane ie more like 100/100 and purchased or "free" lend lease supplied from American refineries. It did not have as significant rich mixture response. The latter 100/130 came from the addition of synthetic alkylate produced from acid alkylation. Hence the RAF can thank Major Jimmie Doolittle for winning the BoB because it was he who apart from BeeGee racing, and heading the Tokyo air raid from the Aircraft carrier Hornet was responsible for aviation fuels development at shell in the 1930s and make sure there was refinery capacity to produce 100 octane. The process of catalytic cracking with regenerative catalysts was used. The rich mixture techniques developed and tested in Schneider floatplane trophy racing must have come into use well after BoB.
Without the 100 octane fuel Merlin power was around 1030 rather than 1280.
The Germans struggled as their investment was directed at coal to oil technology. They used a different way of producing octane from syngas to upgrade their fuel but latter also added alkylation.
It cannot be like you said Shortround. If all Rolls Royce did was sort through bins of parts, they would have had a huge mountain of scrap parts that didn't exist. And they didn't have that when Merlin production ended. Not all their parts fit other required parts, and they DID had fit and had file. They just tried to start with a part closer to what was needed to reduce the hand-fitting process. That's why they call it hand fitting. If the production process produced parts as loose as you contend, then they HAD no process.
purchased or "free" lend lease supplied from American refineries.
I would note that there was a short lived American specification for 100/125 fuel.
The Americans and British agreed to a "common" 100/130 fuel specification shortly after that.
However they went through at least 3 different specifications for 100/130 fuel that differed in the amount of allowable lead per gallon and perhaps other things. There may have been either later specifications or combined changes for allowable amounts of certain aromatic compounds along with the last change in allowable lead. I don't know, most accounts are not clear. However each change allowed for increase production of 100/130 from the available base stocks (more gallons of aviation fuel from the same number of tons of crude).
I do know that post war there was one specification for military 100/130 fuel and another for civilian or commercial 100/130 fuel. The Commercial/Civilian fuel was allowed less lead per gallon. More expensive (needed more costly base stock) but saved on spark plugs and plug changes.
The History of aviation fuel is not well documented and has to be drawn from various places.
Roy Fedden of Bristol was another Englishman who pushed for 100 octane fuel during the late 30s. His company had nothing to do with fuel except wanting the greater performance such fuel would bring.
Rolls-Royce had announced power levels for the Merlin at the 1938 Paris AIr show/exhibition using "100" octane fuel but I don't know if the 100 octane they were testing in 1938 was the same as the British government was buying and stockpiling in the fall of 1939.
Note that the original 100 octane that the RAF used to replace 87 octane really was only 100 octane ie more like 100/100 and purchased or "free" lend lease supplied from American refineries. It did not have as significant rich mixture response. The latter 100/130 came from the addition of synthetic alkylate produced from acid alkylation. Hence the RAF can thank Major Jimmie Doolittle for winning the BoB because it was he who apart from BeeGee racing, and heading the Tokyo air raid from the Aircraft carrier Hornet was responsible for aviation fuels development at shell in the 1930s and make sure there was refinery capacity to produce 100 octane. The process of catalytic cracking with regenerative catalysts was used. The rich mixture techniques developed and tested in Schneider floatplane trophy racing must have come into use well after BoB.
It cannot be like you said Shortround. If all Rolls Royce did was sort through bins of parts, they would have had a huge mountain of scrap parts that didn't exist.
On the subject of 100 octane for the BoB, this link is interesting
100-Octane
AFAIK the two opinions are mostly correct and together give a fairly complete picture.
I have a feeling that once a lot of American engines were in Britain in 1941, there was a move to co-ordinate Octane numbers. Probably after the problems with P-38's.
Thanks for the link.
'Problems' with P-38 were related to many things, fuel not being high on the list, if even it was on the list.
By the time P-38J was in problems (winter of 1943/44), the Allies have long accepted the 100/130 fuel as standard.
One of the best sources of information on the developmental and production problems of the Merlin is The Merlin in Perspective:The Combat Years, by Alec Harvey-Bailey (Rolls-Royce Heritage Trust, Historical Series No 2)
View: https://www.amazon.com/Merlin-Perspective-Combat-Years-Historical/dp/1872922066