[Seadog]

Yet another RAF force multiplier was high-octane fuel. When the war began, both the Luftwaffe and the RAF were using 87 octane aviation fuel. Beginning in May 1940, the RAF obtained 100 octane fuel from the United States and used it throughout the battle. It boosted the performance of the Merlin engines in the Hurricanes and Spitfires from 1,000 to about 1,300 horsepower.
http://www.airforce-magazine.com/Mag...808battle.aspx


By the summer of 1940,
modiications had improved the
performance of the Spitire and
Hurricane. The Spitire’s original
two-blade wooden propeller was
replaced, irst by variable pitch
three-blade units, and then by a
constant-speed unit. This signiicantly
improved take-of performance and the
vital rate of climb. From May 1940 the
use of 100-octane fuel, as used in the
1931 Schneider Trophy races, increased
the Merlin’s performance from 1,000 to
some 1,300hp.p77
70th Anniversary of the Battle of Britain
Published in association with Royal Air Force Media and
Communications, Headquarters Air Command
www.raf.mod.uk


The most dramatic benefit of the earliest Houdry units was in the production of 100-octane aviation gasoline, just before the outbreak of World War II. The Houdry plants provided a better gasoline for blending with scarce high-octane components, as well as by-products that could be converted by other processes to make more high-octane fractions. The increased performance meant that Allied planes were better than Axis planes by a factor of 15 percent to 30 percent in engine power for take-off and climbing; 25 percent in payload; 10 percent in maximum speed; and 12 percent in operational altitude. In the first six months of 1940, at the time of the Battle of Britain, 1.1 million barrels per month of 100-octane aviation gasoline was shipped to the Allies. Houdry plants produced 90 percent of this catalytically cracked gasoline during the first two years of the war.
http://www.nacatsoc.org/history.asp?HistoryID=30



That process would make a crucial difference in mid-1940, when the Royal Air Force started filling its Spitfires and Hurricanes with 100-octane gasoline imported from the United States instead of the 87 octane it had formerly used. Luftwaffe pilots couldn't believe they were facing the same planes they had fought successfully over France a few months before. The planes were the same, but the fuel wasn't. In his 1943 book The Amazing Petroleum Industry, V. A. Kalichevsky of the Socony-Vacuum Oil Company explained what high-octane gasoline meant to Britain: "It is an established fact that a difference of only 13 points in octane number made possible the defeat of the Luftwaffe by the R.A.F. in the fall of 1940. This difference, slight as it seems, is sufficient to give a plane the vital `edge' in altitude, rate of climb and maneuverability that spells the difference between defeat and victory."
http://www.mindfully.org/Technology/...tane1oct04.htm

The second was the lack of suitable
engines to power a heavy bomber. The
"difficulties experienced by German engine
manufacturers in producing engines that met
comparable performance standards of
American and British industry," limited the
design and performance of their aircraft.38
This was partly due to the late start German
engineers had in designing high-performance
engine types and partly due to the low octane
fuels on hand to operate them. The Germans
entered the war using 87–89 octane fuels.
This octane rating, however, could only be
achieved "by adding 15–18 percent aromatics
with tetraethyl lead to the synthetic fuel."39
In contrast, during the Battle of Britain the
British used 100 octane fuels supplied by the
United States.
http://www.au.af.mil/au/awc/awcgate/ww2/batlbrit.pdf

The plant at Heysham, together with those at Stanlow and Billingham produced iso-octane additives required to raise 87 octane fuel to 100 octane rating. Initially, the limited size of the 100 octane fuel stockpile required strict rationing until supplies could be increased to meet requirements and the 100 octane fuel was dyed green to distinguish it from the 87 octane fuel which was blue.
Bulk supply contracts for higher octane fuel were placed by the Air Ministry and it was put into widespread use in the RAF in March 1940 when Spitfires' Rolls Royce Merlin engines were converted to use the 100 octane fuel.

By May 1940, reconnaissance Spitfires had begun flying combat missions using the 100 octane fuel. By 31 July 1940, there were 384 Spitfires serving in 19 squadrons using the 100 octane fuel.
http://www.heyshamheritage.org.uk/html/trimpell.html

February 16
All the Squadron aircraft [Hurricane 151 squadron] had been modified to enable them to operate on 100 Octane fuel. This gave the capability of operation at +12 boost to meet operational emergencies without damage to the engines.
http://homepage.ntlworld.com/kelsey.family/1940.htm

The Allies have an important advan-
tage over Germany because of their un-
limited access to the highest-grade
aviation fuels.
"Petroleum Press Service," official Journal
of the British oil industry, states that, until
recently, the fuel most widely used, both by
civil and military aircraft, had an octane (or
measure of anti-knock value) rating of around
87, but that there Is now a rapidly growing
tendency to use 100 octane spirit. This enables
the compression ratio of an engine to be
Increased, and, therefore, raises the power.
Spirit of an octane rating of 87 generally
is obtained by the addition of small quantities
of tetra-ethyl lead to good-quality "straight
run" petrol. Germany, it is thought, Is un-
likely to suffer from a shortage of this grade
of fuel.
But if, as Is probable, the Allies eventually
resort to the almost exclusive use of 100
octane fuel, Germany's problem will be more
difficult, for there are definite technical limits
to the use of lead 'c'opa," the only practicable
way of producing 100 octane spirit being to
employ high-qualitv blending agente, such as
"mixed octanes."
Seven or eight plants for the manufacture ol
this vital blending material, with an aggregate
capacity of about 100,000 tons a year, are now in
operation or under construction In Germany.
This quantity would be sufficient for the pro-
duction of about 220,000 tons of 100 octane
aviation petrol-a total which might possibly
be raised to 400,000 tons by the end of 1941
if adequate quantities of other high-octane
blending agents could be spared for the
purpose.
In view of the heavy military consumption
of aircraft fuel by Germanv, however, and
because the total supply of petrol is limited
and big hydrogénation plants are vulnerable
to air attack, her prospects would not appear
to be enviable on the basis of existing
knowledge
The Sydney Morning Herald, April 3 1940

Secrets of the Heinkel
(By Air Mail)
LONDON.
ALTHOUGH the Heinkel III,

which had a "happy landing" to the west of the Maginot Line, after its personnel had found safety in parachutes, revealed no secrets of German aircraft-most of the apparatus had been thrown out by the parachutes-a similar plane shot down later in Scotland proved a veritable mine for the R.A.F. experts.

It is revealed that the Germans use a feed pump regulating the flow through injectors of tiny particles of gasoline direct into each cylinder. The gas ls injected in a fanwise spray and comes into contact with supercharged air heated under pressure.

One advantage is the elimination of freezing which is prolific of air accidents. This is especially important in the operation of air- craft in Arctic zones and at great altitudes.The fuel taken from the Heinkel's tanks proved to be "87 octane," and it is believed that one of Germany's main reasons in employing direct in- jection has been the possibility of using low-grade fuel. Nowadays, for high-performance aircraft, fuel of , "100 octane" is used.
APPEARANCE
The limits to which gasoline injection pump components have to be manufactured are very fine, and it is estimated that the Heinkel's outfit cost not less than £400 to produce. Against this may be set the fact that periods between overhaul are lengthened, al- though surfacing work can be carried out only by specially trained mechanics.

lt is stated that the internal finish or the engine in the shot-down plane is of high order, but the external appearance and detail work do not ap- proach the standard of British planes.
Sunday Times (Perth, WA) Sunday 7 July 1940.

Where Hurricanes Score!
...When Hurricanes return from a patrol special refuelling lorries attend to several machines simultaneously.
These pump in petrol of 100-octane capacity...
Sunday Times (Perth, WA) Sunday 1 September 1940

SPITFIRES FASTEST FIGHTERS.
...It is now possible to reveal one step which has been taken to increase the efficiency of British fighters, namely, the employment of
"100 octane fuel." which, with specially built engines, is able to increase speeds up to 30 miles an hour. Spitfires, using this fuel, are unquestionably still the fastest fighters actually serving un any air force...
The Sydney Morning Herald (NSW) 2 April 1940

Sir Hugh Tett
Sir Hugh Tett, former chairman and managing director of Esso Petroleum, was born on December 28, 1906. He died on January 2 aged 94.
Oil executive who pioneered leaded petrol and concocted the high-octane fuel that made the Spitfire outperform the Messerschmitt
Research by Hugh Tett at the beginning of the Second World War helped the RAF to win the Battle of Britain. Taking over from a colleague who had been called up, he developed a 100-octane fuel for fighter aircraft such as the Hurricane and Spitfire which helped them to outperform the Messerschmitt. He then had the job of persuading the Americans to produce it for beleaguered Britain, as the RAF braced itself to face the Luftwaffe...
The Times (London) January 31, 2001


Higher Performance by Fighters
Change in Fuel
From our aeronautical correspondent

It is now permissible to describe some of the steps that have been taken since the outbreak of war to increase the efficiency of British interceptor fighting aeroplanes.
One measure of importance is the increased aircraft performance secured by the employment of 100 octane fuell. This has long been known to those in touch with the Service, but up to now it has been thought inadvisable that it should be publicly discussed.
The use of 100 octane fuel was always visualized in peace. It allows higher boost pressures to be used with out damage to the engine. Although to obtain the full benefit th engine must be built to use it, it does in practice give an improved performance in speed and climb when used for engines normally taking 87 octane fuel. The speed increase may be anything from five to 20 miles an hour.

It will be recalled that Sir Kingsley Wood, in his speech on the Air Estimates in the House of Commons, said that the Spitfire had undergone a "further"speed increase of 10 per cent. Its previous official speed figures was 367. miles an hour, though whether the Minister meant a 10 per cent increase on that is not quite clear. At any rate, it is positive that the Spitfire, with the aid of 100 octane and some minor improvements, Is still holding its position as the fastest standard fighting aeroplane in any air service
The Times (London, England), Monday, Apr 01, 1940; pg. 5; Issue 48578.