Battle of Britain Poor RAF A/C Performance

[Squire]

Without getting into a yelling match with anybody, I think the cause of the confusion is probably the references to "early war".

Its true the RAF did use 87 octane grade in 1939, and in the French 1940 campaign, so it was an issue. However, by the spring of 1940 Fighter Command had started converting to 100 octane avgas, as it started becoming available in quantity.

Btw, The Luftwaffe used "B2" fuel in 1940, which was 87 octane, and didnt go to 100 octane C3 untill later in the BoB, with the Bf 109E-4/N and Bf 110C-4/b.

Also, the Soviets, and Japanese, did not use anything better than 87 octane for most of the war, so its hardly just an RAF issue. Just for info. All air forces improved their fuel as the war went on (in most cases not all), even the USAAF.

Regards.

Smiley face to make everybody feel better.

[Angus]

BTW, the 100 oct from 87 and the CS prop from 2-blade gave the biggest performance increase in climb

[MiloMorai]

Look, there was many heated discussions(??) on the availability of 100pn fuel on the board, so when you get the knot out of your silk knickers, go search.

Oh, and I would have supplied links but I have never been able to do a direct link on this board to threads.

Btw, 343,000tons is ~106,000,000 Impgal or enough for 125,000 Spitfires.

[Angus]

Izzy mode on:
"Nein. It was needed for the other aircraft, and these are not correct numbers and 125.000 Spitfires means sorties for those thirsty Merlins and it was all futile anyway "
Izzy mode off:

On the serious side, do you know when they converted? I guess not all at the time, but in the case of the CS screws it happened pretty fast.

[Debonair]

i was taught that higher octane just reduces the temperate of combustion.  
i can see how that could increase performance, but not that it does most of the time...

[Kev367th]

Originally posted by Angus
Izzy mode on:
"Nein. It was needed for the other aircraft, and these are not correct numbers and 125.000 Spitfires means sorties for those thirsty Merlins and it was all futile anyway "
Izzy mode off:

On the serious side, do you know when they converted? I guess not all at the time, but in the case of the CS screws it happened pretty fast.

Started converting to 100 octane May 1940 once Churchill ordered the stocks released to the units.

[mw]

See  HERE for many accounts from the Battle of Britain of the combat use of boost levels only obtainable through the use of 100 octane fuel.

[Angus]

That settles it then

[Neil Stirling1]

See here

http://groups.google.co.uk/group/soc.history.war.misc/browse_thread/thread/9fc48ff4b93f8d4e/c00afbfd81a21765?lnk=st&q=I+kept+no+diary+rod+banks&rnum=2&hl=en#c00afbfd81a21765


I have actually read this book, and Banks is wrong when he states that - "...100 octane became available to Fighter Command ready for the Battle of Britain through Roosevelt's "cash and carry" compromise." In fact Britain had been importing 100-octane from three seperate sources, Shell, Standard Oil and Trinidad Leaseholds, and only Standard Oil importation was affected by the embargoes involved in pre-war Neutrality Acts as the others were not US companies and did not export 100-octane spitit from US terrirtory.  100-octane supply began in 1937 to selected airfields for trials and was then withdrawn to build up a large (400,000 ton) reserve stock.  I'm read the official records and even the damn Air Ministry purchase contracts, something I suspect nobody else commenting on this issue has. When it comes to the BoB, the British imported as much as Fighter Command used in July - October 1940 from BP in Abadan alone.  Banks worked for the British Eythyl Corp, a subsidiary of ICI and Eythyl Export importing tetra-eythyl lead for the Air Ministry, and was clearly not a party to 100-octane supply policy as a whole.  He confuses Standard Oil's 100-octane supply to the Air Ministry with the totality of supply, and is unaware of pre-1939 importation despite the fact that 100-octane had been delivered in barrels by rail to selected RAF bases as early as May 1937. >The question is more of where the fuel came from. I haven't got an >accurate breakdown but I understand 100 octane fuel from several >sources: >1) British refineries >2) Dutch Shell refineries (in the US) handed over to British control >3) US refineries >4) Refineries in the Caribbean (not sure about this?) >Obviously a lot of it came across the Atlantic (possibly in US tankers), >but that doesn't necessarily make it supplied by the US. Here is an extract from a presentation I made on the subject at the Transatlantic Studies Conference, Dundee in July 2002. "It has often been asserted that the supply of high-octane aviation fuel was an operationally-significant factor attributable to American supply in the Battle of Britain [22].  This rests on two largely unsubstantiated foundations - firstly, the operational impact of 100-octane fuel to fighter operations, and secondly the paramount importance of American supply of this fuel. 100-octane fuel allowed aircraft engines to exceed their normal supercharging limits at lower altitudes.  This provided higher power output with a consequent improvement in performance, without the premature detonation that would result from doing this with lower octane value fuel.  However, the constraints involved in this facility are never fully articulated.  In fact, exceeding normal supercharger boost was only permitted for a maximum of five minutes, and the engine power settings involved in most operational sorties were identical to those obtained on lower-octane fuel.  The level of benefit gained from increasing supercharger pressures decreased with height, declining to no additional benefit at or above the full-throttle height of the engine [23].  Nevertheless, the use of this fuel did confer a real, if often overstated, operational advantage in terms of speed and rate of climb at lower altitudes. A larger problem comes with the assertion that high-octane fuel was exclusively attributable to American supply.  100-octane fuel was developed in the mid-30's in the U.S., firstly by Shell and then Standard Oil, in response to a USAAC requirement [24].  However British purchasing of this fuel began in March 1937, from three sources, while the Hartley committee was formed to steer the development of production expansion for the RAF.  100-octane fuel was also produced within Britain [25]. 100-octane fuel was made by blending additives (iso-octanes) with lower-octane feedstock and tetra-ethyl lead.  Iso-octanes were originally manufactured by a process of hydrogenation, pioneered by Shell and copied by Standard Oil in the United States.  Almost all of the British supply of 100-octane fuel in the period up to 1940 was dependent upon this process, but the massive expansion of high-octane fuel production which followed was contingent upon the development of iso-octane production by another process (alkylation).  This was discovered by British Petroleum in Britain in 1937.  BP production of 100-octane fuel using this process began at Abadan in Iraq in 1940, and in that year sufficient 100-octane fuel was delivered from this source alone to replace that issued to Fighter Command during the critical period of the Battle of Britain [26]. The procurement of 100-octane fuel for RAF use involved the use of several sources of supply, and was not contingent upon supply from the United States in isolation, as Table 2 indicates.   Table2.  100 Octane fuel production:  current production estimates exclusive of American domestic production, November 1940.  From PRO AIR 19/254 - 23A Plant   Production (tons per annum) Heysham, UK     150,000 Billingham, UK  15,000 Stanlow, UK     55,000 Abadan  50,000 Trinidad        80,000 Palembang, Dutch East Indies    50,000 Pladejoe, Dutch East Indies     50,000 Aruba, Dutch West Indies        50,000 After early 1941, to economise on tanker shipping tonnage and take advantage of lend-lease supply, a deliberate policy decision was made to favour "short-haul" supply across the Atlantic instead of the longer routes associated with sources of supply in the Dutch East Indies and Persia.  Nevertheless, this indicates a more complex historical picture regarding the supply of 100-octane fuel than is admitted in most accounts.  The availability of 100-octane fuel for the RAF in the Battle of Britain was contingent upon a variety of sources of supply, and the procurement process involved originated in pre-war rearmament policy, not in the emergency measures of 1940[27]." Footnotes: 22      "..a contribution of profound significance to the operational success [of British fighters]", Richard P. Hallion, "The American Perspective", in Paul Addison and Jeremy A. Crang (eds), The Burning Blue.  A New History of the Battle of Britain (Pimlico, London 2000), p. 84.  Hallion's appreciation is derived from Richard Hough and Denis Richards, The Battle of Britain (Hodder & Stoughton, London 1989) Appendix XII, p.387.  Deighton emphasises similarly the performance benefits, Blood Tears and Folly, p.352. 23      Approximately 18,000 feet for the Merlin III engined used in the Spitfire I and Hurricane I in use in the Battle of Britain. 24      For the evolution of 100-octane fuel for the USAAC, Lowell Thomas & Edward Jablonski, Bomber Commander.  The Life of James H. Doolittle (Sidgwick & Jackson, London 1977), p.136-142 and Kendall Beaton, Enterprise in Oil.  A History of Shell in the United States, (New York, 1957), p.535 and p.561-569.  For the evolution of BP production, J. H. Bamberg, The History of the British Petroleum Company, Vol.2.  The Anglo-Iranian Years, 1928-1954 (Cambridge University Press, 1994), p.199-218, and for Shell, George P. Kerr, Time's Forelock.  A Record of Shell's Contribution to Aviation in the Second World War (Shell, London 1948), p.36-59.  An overview is in D. J. Payton-Smith, Oil - A Study of War-time Policy and Administration (HMSO, 1971), p.55 and p.260-279. 25      Air Ministry importation of 100 octane was established in 1937 at 17,000 tons per year from Trinidad Leaseholds, 32,000 tons from Shell and 25,000 tons from Standard Oil (New Jersey).  Payton-Smith, Oil, p.55.  These quantities were doubled after Munich.  Domestic production was in progress at Billingham and Stanlow, with a further plant planned at Heysham. 26      By 11th July 1940 the RAF had 343,000 tons of 100 octane in store, and the rate of importation was such that stocks rose to 424,000 tons by 10th October, 1940 after 22,000 tons had been issued during the Battle.  Derek Wood and Derek Dempster, The Narrow Margin. The Battle of Britain and the Rise of Air Power 1930-1940 (Hutchinson, London 1967.  First published  1961), p.101-102.  Importation from BP at Abadan alone was sufficient to meet this consumption.  Bamberg, The History of the British Petroleum Company, p.244 27      100 octane was delivered to selected airfields and used in trials from 1937, with priority going to those where Spitfires and Hurricanes were to be based.  PRO AIR 2/3424.  A date was set by the Air Ministry in April 1939 for introduction into RAF service in September 1940 after a sufficient stockpile had been accumulated.  In the event this was accelerated due to events in 1940.  PRO AIR 2/3531 - 3A.



Gavin Bailey


Neil.

[Geary420]

Originally posted by Debonair
i was taught that higher octane just reduces the temperate of combustion.  
i can see how that could increase performance, but not that it does most of the time...

Long story short, when you use a supercharger or turbocharger to create boost you run the risk of detonation (the air/fuel mix combusts due to pressure like a diesel, instead of combusting when the sparkplug fires).  Higher octane fuel allows you to run more boost before detonation occurs, so that is where the performace gains come from, the increased boost you are able to run, not the fuel itself.  Yea, I've been up all night and can't see straight so thats not a real great description, but i hope it helps.

[Angus]

Better and cleaner burn right?

[Debonair]

thanks, Geary420.
i've never been trained on turbo piston planes.
now to maybe stick my foot in my mouth again:
cleaner burn is, i think, the result of running at peak mixture....

[Col. Flashman]

Now this is exactly the discussion I was looking foreword to when I 1st posted this & yes I probably should have qualified my statement w/ "the early stages of the BoB", as what was available had been held in reserve w/ coversion being rather slow.

[Scherf]

Neil, I read a thesis online recently re: costs of Bomber Command ops, which made some reference to 150 octane deliveries. The source reference it gave was BP House - have you been able to do any research there?

[Neil Stirling1]

Hi Scherf. BP House? I hadn't considered that, thanks.

Neil.