The use of 100 Octane Fuel in the RAF pt 2

[Milosh]

The following was posted on another board in a thread on the use of 100 octane fuel during the Battle of Britain.

The following Spitfire and Hurricane squadrons are known to have used 100 octane fuel before or during the BoB:
1, 17, 19, 41, 43, 54, 56, 64, 65, 66, 72, 73, 74, 79, 85, 87, 92, 141, 145, 151, 152, 222, 229, 234, 245, 249, 264, 303, 602, 603, 605, 609, 610, 611, 616

These squadrons were stationed at the following airfields (bold text) at sometime during the BoB.

11 Group

RAF Biggin Hill

- RAF West Malling

RAF Debden

- RAF Martlesham Heath

RAF Hornchurch

- RAF Hawkinge
- RAF Gravesend
- RAF Manston, night fighter base
- RAF Rochford

RAF Kenley

- RAF Croydon

RAF Northolt

RAF North Weald

- RAF Martlesham
- RAF Stapleford

RAF Tangmere

- RAF West Malling
- RAF Ford
- RAF Lee on Solent, RN airfield
- RAF Gosport, RN airfield
- RAF Thorney Island
- RAF Westhampnett

Not sure which Sector airfield these were assigned to but as all the sector airfields had 100 octane fuel, these to would need a stock of 100 octane fuel.

RAF Detling

RAF Eastchurch

RAF Hendon

RAF Lympne

In 10 Group, 5 of the 6 airfields had stocks of 100 octane fuel.

In 12 Group, 7 of the 8 airfields had stocks of 100 octane fuel.

In 13 Group, 7 of the 10 airfields had stocks of 100 octane fuel. Of the 3 that possible didn't have stocks of 100 octane fuel, one was based in the Shetland Is. and the other in the Orkney Is.

Despite what the doubters say, I would say 100 octane fuel was in widespread use by Fighter Command if all those airfields had stocks of 100 octane fuel on hand during the battle.

 

[merlin]

I have spent the day in the National Archives reviewing the War Cabinet minutes and summaries for May 1940 ....
Their were some interesting nuggets such as the Cabinet being advised of the performance of the Defiant on the 18th May, the comment wasn't good.

Interesting, can you tell us any more (though I realise this is an old post), especially as the date is before the disaster for the Defiant during the BoB?

 

[Glider]

I had the wrong day, it was the 14th May and the comment as reported to the War Cabinet is as follows

Reference was made to the performance of Defiant aircraft,
which were 2-man fighters equipped with a power-operated turret.
They had had a successful day on the 12th May, but on the
13th May, out of a flight of 6 which had engaged enemy aircraft,
only one had returned to its base. One was known to have been
forced to land in Belgium, and probably a second. The other three
were missing

For those interested All the War Cabinet papers are available online from the National Archives. They are free and quick to download and the May 1940 file starts with CAB 65/7/1.

You will find in the NA that the Defiant had a lot of attention and even Downing had some caution. Check out the wording of item 4 in his memo sent in 1939, which gives me the impression that he thought that any success would be a short lived affair.

PS For those interested, Kurfurst has been made aware of the availability of the War Cabinet Records on line, the link and the file numbers. He was invited to use these to check out his belief in the old Pips posting but as you might expect, he has gone silent.

 

[Ratsel]

The one question that often knocks them off balance is, if C3 was so popular, effective and plentiful why was the DB605 designed for lower octane fuel.

actually, the DB605 was designed to use both B4 C3. but B4 when combined with GM-1 or MW-50 was still one powerhouse of
and engine, let alone with C3. A flip of a switch on the Auto-Mags and the plane can run on the fuel that was on hand.

 

[Glider]

I certainly could be wrong but its my understanding that the DB605 was originally designed for the B4 fuel and later developed for C3, GM1 and MW-50.

I looked at the following amongst other sites
The Luftwaffe page , Daimler-Benz DB 605

 

[Ratsel]

well yes there were different version of the DB605 (A-1, AM, AS, ASM, ASB , ASC, D, D-2, DB, DC) 7.5:1 / 8.5:1 engines etc., but
all were designed to run on different grade fuels. The nature of the beast especially in 1944/45. sorry, didn't mean to take away from
the discussion at hand.

 

[Glider]

No problem, I have been wrong many times before and this could have been another example

 

[Vincenzo]

The following was posted on another board in a thread on the use of 100 octane fuel during the Battle of Britain.

The following Spitfire and Hurricane squadrons are known to have used 100 octane fuel before or during the BoB:
1, 17, 19, 41, 43, 54, 56, 64, 65, 66, 72, 73, 74, 79, 85, 87, 92, 141, 145, 151, 152, 222, 229, 234, 245, 249, 264, 303, 602, 603, 605, 609, 610, 611, 616

These squadrons were stationed at the following airfields (bold text) at sometime during the BoB.

11 Group

RAF Biggin Hill

- RAF West Malling

RAF Debden

- RAF Martlesham Heath

RAF Hornchurch

- RAF Hawkinge
- RAF Gravesend
- RAF Manston, night fighter base
- RAF Rochford

RAF Kenley

- RAF Croydon

RAF Northolt

RAF North Weald

- RAF Martlesham
- RAF Stapleford

RAF Tangmere

- RAF West Malling
- RAF Ford
- RAF Lee on Solent, RN airfield
- RAF Gosport, RN airfield
- RAF Thorney Island
- RAF Westhampnett

Not sure which Sector airfield these were assigned to but as all the sector airfields had 100 octane fuel, these to would need a stock of 100 octane fuel.

RAF Detling

RAF Eastchurch

RAF Hendon

RAF Lympne

In 10 Group, 5 of the 6 airfields had stocks of 100 octane fuel.

In 12 Group, 7 of the 8 airfields had stocks of 100 octane fuel.

In 13 Group, 7 of the 10 airfields had stocks of 100 octane fuel. Of the 3 that possible didn't have stocks of 100 octane fuel, one was based in the Shetland Is. and the other in the Orkney Is.

Despite what the doubters say, I would say 100 octane fuel was in widespread use by Fighter Command if all those airfields had stocks of 100 octane fuel on hand during the battle.

sorry this not prove nothing, we need list alone the airports where the squadrons were stationary at time they used 100 octane fuel

 

[Mustang nut]

sorry this not prove nothing, we need list alone the airports where the squadrons were stationary at time they used 100 octane fuel

Every comparison Me109/hurricane I have read during the BoB quotes performance with 100 octane, pilots wouldnt have chased 109s back to France on 87 Octane. The LW got a bit of a surprise with the Hurricane in the BoB because in France the 109 was clearly faster during the BoB it was faster but not nearly by so much.

I think its fair to say 100 Octane was widely available.

 

[buffnut453]

Do we have any information on availability of 100 octane fuel in other parts of the British Empire or other theatres of the war? If we accept that 100 octane fuel was widely available in the UK in 1940, how long did it take to get 100 octane to North Africa, the Middle East and the Far East?

 

[Glider]

I know that Malta and Gibraltar were using small quantities from the start of the war approx 700 tons a month at the end of 1940. Basically my understanding is that the fuel went with the front line aircraft.

By August 1941 stocks in Gibraltar and Malta were 6,000 tons 100 octane and 2,000 tons 87 octane unfortunately the figures for the rest of the Middle East I don't have. However the July 1941 figures for the Middle East were 27,000 tons of 100 Octane and 34,000 tons of 87 octane

Hope this helps

 

[Shortround6]

Different time lines. With 100 octane widely available, for fighters at least, in the summer of 1940, the availability of 100 octane 18 months later in the Far East shouldn't have been a big problem. While 100 octane might have been a bit lacking in Egypt in the summer of 1940 the question is if was available in the Spring/Summer of 1941. P-40 Tomahawks went into action in the NA in May of 1941 and they required 100 octane fuel unless operated under rpm and boost restrictions. With stories of the these planes soon using higher than factory recommended boost settings for 100 octane fuel (american 100 octane) in service I doubt that they were pulling that trick on 87 octane fuel.

 

[post76]

I think its fair to say 100 Octane was widely available.

Most engine charts note the use of 100 octane fuel.
I think what may have fluctuated was the grade.

Octane is also a number derived from different attributes of the fuel quality.
Its possible to have two fuels that offer different performance and both be graded as 100 octane.
If you read up on octane it goes more into this. I haven't looked at that it some time.

We see the introduction of 130 grade and 150 grade but they're still referred to as 100 octane, no?

 

[Shortround6]

you are right in a sense and that is why it is important to know both date of the reference or chart/manual and the country. In 1939/40 US and British 100 octane was not the same stuff. Octane is actually just one attribute of fuel and was commonly measured, at the time, in a lean condition. Running rich changes the octane rating so it was important to know (and standardize tests) on HOW rich you were going to run/measure. Because of other attributes of the fuel/s US 100 octane could be a little better when run rich or even worse than 100 octane while British fuel varied from around 115-120 to 125 when run rich. Later the British specified 100 octane (or performance number) lean and 130 rich and the Americans soon standardized on the same specification. British fuel would dissolve american gaskets and tank linings in the early years which means it wasn't an easy thing just to switch over. Later ratings included 100/135, 100/140, 108/135, 100/150 and 115/145. The first number could affect cruise performance while the second number affected maximum power.

 

[Ratsel]

Do we have any information on availability of 100 octane fuel in other parts of the British Empire or other theatres of the war? If we accept that 100 octane fuel was widely available in the UK in 1940, how long did it take to get 100 octane to North Africa, the Middle East and the Far East?

Didn't the Americans supply Britan with 100 av-gas in 1939/40? At least I thought I read that. I could be wrong though.

 

[Shortround6]

Again the answer is sort of yes and no. The Fuel came from American refineries but it was contracted by, paid for, and blended to British specifications. It was not US government fuel (or US commercial fuel) in either ownership or characteristics.

 

[fastmongrel]

The 100 octane didnt just come from US refineries a good proportion of it came from British owned or controlled Caribbean and Venezuelan refineries.

Never understood why British blends of petrol dissolved US seals and tanks surely the US werent using unvulcanised rubber.

 

[Shortround6]

Going by memory US fuel at the time could contain NO MORE than 2% aromatic compounds, while British fuel could contain NO LESS than 20% aromatic compounds. This is what made the rich response different and affected the rubber parts. If they filled the tank, flew and burned and then refilled with the proper gas there wasn't much of a problem but a steady diet or parking the plane for days/weeks with the wrong fuel did cause problems.

 

[Jabberwocky]

The 100 octane didnt just come from US refineries a good proportion of it came from British owned or controlled Caribbean and Venezuelan refineries.

About 45% of 100 Octane fuel supplied to the RAF came from US companies or US-owned companies.

The rest is spread around from the Middle East (Iran), Caribbean (Venezuela-Aruba-Curacao), South Africa and Borneo.

 

[Ratsel]

The Trimpell Oil Refinery


"Trimpell" was an amalgamation of Trinidad Leasing, Imperial Chemical Industries (ICI) and Shell (American), and after making aviation fuel for the Air Ministry the refinery was to produce explosives, nitric acid and fertiliser. The main site at Heysham was funded by the Ministry of Aircraft Production. The Ministry of Supply funded a Nitric Acid and Ammonium Nitrate plant for explosive purposes which was also run by Trimpell.

The site was set up in 1939 as the Heysham Aviation Fuel Works to produce aviation fuel for the RAF. Using coke brought in from the Durham coal field together with imported gas oil, ICI produced the base petrol and ammonia while Shell produced iso-octane to boost the base petrol from 87 octane to 100 octane standard. Shell had found that the use of tetraethyl lead and hydrogen as fuel additives made it possible to suppress engine knock and to boost aircraft engine performance.


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.

Going by memory US fuel at the time could contain NO MORE than 2% aromatic compounds, while British fuel could contain NO LESS than 20% aromatic compounds. This is what made the rich response different and affected the rubber parts. If they filled the tank, flew and burned and then refilled with the proper gas there wasn't much of a problem but a steady diet or parking the plane for days/weeks with the wrong fuel did cause problems.

The Luftwaffe used up to 35% aromatic compounds in C3! Geez louis!