Mike Williams
Senior Airman
- 572
- Oct 19, 2006
The use of 100 Octane Fuel in the RAF pt 2
- Thread starter Glider
- Start date
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NZTyphoon
Airman 1st Class
Another facet of the 100 octane story which has not been touched on is the matter of transporting the fuel across the Atlantic to Britain. Essentially convoys started operating in September 1939; the most important were the HX convoys which sailed from Halifax to (mainly) Liverpool. The first - HX.1 - sailed on 16 September 1939. Arnold Hague Convoy Database
The HX convoys incorporated cargo ships and tankers, many of the latter had sailed from refineries in the West Indies and America. As we have seen elsewhere these supplied 100 octane fuel. The BHX series sailed from Bermuda, starting in May 1940 (BHX.41), and joined the main HX convoys in Halifax. Some of the tankers from the HX convoys diverted to French ports, enough to supply the RAF fighters in France.
From the HX series of convoys alone (HX 11, 13, 31, 33-35, 40, 43, 49, 55, 57-59, 64-68, 70, 73, 76) 44 tankers carrying AVGAS arrived in British or French ports; one tanker was destroyed by a mine in the Bristol channel. This contradicts the assertion in Shacklady and Morgan that
The HX convoys incorporated cargo ships and tankers, many of the latter had sailed from refineries in the West Indies and America. As we have seen elsewhere these supplied 100 octane fuel. The BHX series sailed from Bermuda, starting in May 1940 (BHX.41), and joined the main HX convoys in Halifax. Some of the tankers from the HX convoys diverted to French ports, enough to supply the RAF fighters in France.
From the HX series of convoys alone (HX 11, 13, 31, 33-35, 40, 43, 49, 55, 57-59, 64-68, 70, 73, 76) 44 tankers carrying AVGAS arrived in British or French ports; one tanker was destroyed by a mine in the Bristol channel. This contradicts the assertion in Shacklady and Morgan that
I would say that without a shadow of doubt that 100 octane fuel was in wide spread use during the Battle of Britain from all the proof that this thread, and the other thread, contains. These two threads will be an excellent reference source if the subject ever brought up again.
I would like to thank all who did the research and contributed to the threads.
I would like to thank all who did the research and contributed to the threads.
- Thread starter
- #165
Glider
Captain
The original idea was to look into the 'new theories' about the use of 100 0ctane during the BOB but if you have a question or observation about 1941 feel free to throw it in.
ok, just wanted to be sure before dipping a toe in.... 
The thread made me recall a paragraph i read out of Black Cross/Red Star. It concerned lend lease Hurricanes sent to Russia. An comment made was that the planes engines were quickly worn out over time due to the fact that their engines were designed for 100 octane fuel while the Russians could only pump in 87 octane. This resulted in degraded preformance.
The thread made me recall a paragraph i read out of Black Cross/Red Star. It concerned lend lease Hurricanes sent to Russia. An comment made was that the planes engines were quickly worn out over time due to the fact that their engines were designed for 100 octane fuel while the Russians could only pump in 87 octane. This resulted in degraded preformance.
- Thread starter
- #167
Glider
Captain
I don't know about the life of the engine but using 87 octane would definately hinder performance. I remember reading that the RAF pilots who flew Hurricane when they were forst sent over being very impressed with the Pe 2 as they had a lot of trouble keeping up with them.
pbfoot
1st Lieutenant
The RAF/RCAF fighters were not shot down in droves however they lost more then the Germans by a reasonable margin however this being said the Germans had the advantage because they could opt wh.en and where to fight .
First off, I cleaned up this thread and all the crap in this thread. Mod threats and such are removed as well including my own except this one. This is the last time this thread get's side tracked. It ends. Udet is gone, Kurfurst your next if you step out of line. Ive had it, there is plenty of good info in here and the reason why Ive let this thread live.
Continue on with the discussion please as there is nothing else to see
Continue on with the discussion please as there is nothing else to see
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NZTyphoon
Airman 1st Class
ok, just wanted to be sure before dipping a toe in....
The thread made me recall a paragraph i read out of Black Cross/Red Star. It concerned lend lease Hurricanes sent to Russia. An comment made was that the planes engines were quickly worn out over time due to the fact that their engines were designed for 100 octane fuel while the Russians could only pump in 87 octane. This resulted in degraded preformance.
I doubt whether the Merlins would have worn more quickly on 87 octane; I would suggest that there might have been other factors involved; possibly the fuel wasn't being filtered properly, and the fuel that was used was often contaminated Soviet Lend-Lease Fighter Aces of ... - Google Books Russian pilots were known for their propensity for running engines to the red line well before they were properly warmed.
I did some review, and it appears I recalled in error. Apologies. Another fine example of the quirks of human memory. 
Here's the actual quotation of the memory this Thread triggered:
"Soviet fighter pilots found the British Hurricane to be outdated and cumbersome. Furthermore, the standard Soviet aviation fuel in 1941-42 was the B-70 formulation, with an octane rating between only 70 and 75. Since the Hurricane's Rolls-Royce Merlin engine was designed for a considerably higher octane rating the Soviet fuel wore them down rapidly, decreasing preformance and frequently causing flight accidents."
Source: Black Cross/Red Star Vol II. (p.32)
Here's the actual quotation of the memory this Thread triggered:
"Soviet fighter pilots found the British Hurricane to be outdated and cumbersome. Furthermore, the standard Soviet aviation fuel in 1941-42 was the B-70 formulation, with an octane rating between only 70 and 75. Since the Hurricane's Rolls-Royce Merlin engine was designed for a considerably higher octane rating the Soviet fuel wore them down rapidly, decreasing preformance and frequently causing flight accidents."
Source: Black Cross/Red Star Vol II. (p.32)
Yes Nikademus if the Soviets tried to operate the Merlins at their rated boost pressure using Soviet fuel, then they were abusing the engine, especial with what NZTyphoon posted. It would not take long to destroy an engine using 70-75 octane fuel at 12lb boost.
Shortround6
Major General
It wouldn't take long to to destroy a Merlin on 75 octane fuel at 6lbs of boost. 
Something about this story doesn't ring true.
While "B-70" may have been "a" standard Soviet fuel I doubt very highly that it was the fuel that the Soviets used in 1941-42 in their own fighters.
Anymore than the US used standard "80" octane fuel in their fighters even though it was a standard fuel for primary training planes.
To try to get some handle on the differences between fuels a "performance Number" scale was developed rather than octane because there is actually no such thing as a fuel with an octane rating higher than 100. Also the difference in actual performance is not linear. for instance the difference between 70 octane and 72 octane is actually 1 3/4 performance numbers while the 2 octane difference between 98 and 100 is almost 6 3/4 performance numbers. Adding more and more lead had diminishing returns also. 100 octane + 1ml of lead adds 26 performance numbers while the difference between 100 octane and 5ml of lead and 100 ocatne plus 6ml of lead is 4 performance numbers.
To get back to the Merlins and the Soviet fuel. on the performance scale 100 octane is 100PN. 87 octane fuel is 68.29 PN. 75 octane fuel has a PN of 52.83. This means that the Merlin could operate at about 2lbs of boost at best with such a fuel if I have done the math right. This is assuming that everthing else stays the same which it probably didn't.
Performance numbers are from a chart from a soft cover book called "Aviation Fuels and their effects on Performance" prepared by the Ethyl corperation for the U.S. air forces on a purchase order from the Dept. of the Navy, Bureau of Aeronautics. copyright 1951.
Something about this story doesn't ring true.
While "B-70" may have been "a" standard Soviet fuel I doubt very highly that it was the fuel that the Soviets used in 1941-42 in their own fighters.
Anymore than the US used standard "80" octane fuel in their fighters even though it was a standard fuel for primary training planes.
To try to get some handle on the differences between fuels a "performance Number" scale was developed rather than octane because there is actually no such thing as a fuel with an octane rating higher than 100. Also the difference in actual performance is not linear. for instance the difference between 70 octane and 72 octane is actually 1 3/4 performance numbers while the 2 octane difference between 98 and 100 is almost 6 3/4 performance numbers. Adding more and more lead had diminishing returns also. 100 octane + 1ml of lead adds 26 performance numbers while the difference between 100 octane and 5ml of lead and 100 ocatne plus 6ml of lead is 4 performance numbers.
To get back to the Merlins and the Soviet fuel. on the performance scale 100 octane is 100PN. 87 octane fuel is 68.29 PN. 75 octane fuel has a PN of 52.83. This means that the Merlin could operate at about 2lbs of boost at best with such a fuel if I have done the math right. This is assuming that everthing else stays the same which it probably didn't.
Performance numbers are from a chart from a soft cover book called "Aviation Fuels and their effects on Performance" prepared by the Ethyl corperation for the U.S. air forces on a purchase order from the Dept. of the Navy, Bureau of Aeronautics. copyright 1951.
- Thread starter
- #174
Glider
Captain
Re the second part of the above I can confirm :-
a) - 87 Octane was not deemed to be the primary fuel source by the War Cabinet until further supplies could be delivered
b) - that the conversion of further aircraft to use 100 Octane was not halted by the War Cabinet and that the rest would have to continue with 87 octane.
Indeed the entire topic of 100 octane fuel and the use of it by the RAF was not discussed by the War Cabinet in May 1940. I have spent the day in the National Archives reviewing the War Cabinet minutes and summaries for May 1940 and 100 octane was never mentioned.
Please don't ask me for any copies of the minutes as the Cabinet were meeting almost daily and that is a heck of a lot of paper.
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. Aparently the French almost purchased 12 ex US destroyers but the deal fell through and the RN were asked to consider the taking over of the Swedish Navy, but the First Sea Lord turned this down.
As I said some interesting bits, some unexpected, but nothing on 100 Octane.
On pg 1 Glider you posted:
Stocks of 100 Octane
30th September 1939 153,000 tons(b)
27th February 1940 220,000 tons(b)
31st May 1940 294,000 tons(a)
11th July 1940 343,000 tons(b)
31st August 1940 404,000 tons(a)
10th October 1940 424,000 tons(c)
30th November 1940 440,000 tons(a)
Kurfurst: "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."
How can he say what he said when the stockpile of 100 octane fuel actually increased? In fact, the consumption from June thro Aug (10,000t) was only a fraction of the actually stockpile (1/30th of May 31 and 1/40th of Aug 31).
Stocks of 100 Octane
30th September 1939 153,000 tons(b)
27th February 1940 220,000 tons(b)
31st May 1940 294,000 tons(a)
11th July 1940 343,000 tons(b)
31st August 1940 404,000 tons(a)
10th October 1940 424,000 tons(c)
30th November 1940 440,000 tons(a)
Kurfurst: "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."
How can he say what he said when the stockpile of 100 octane fuel actually increased? In fact, the consumption from June thro Aug (10,000t) was only a fraction of the actually stockpile (1/30th of May 31 and 1/40th of Aug 31).
- Thread starter
- #176
Glider
Captain
I am afraid that I don't know, only Kurfurst can awnser that question.
Frankly, if being rigorous as an historian i won't prise Christer Bergstorm for his technical level, rather low...
Soviet used natural refined fuels with B-59 to B-78 octanes marks, with some 1 to 4 cm cub TEL additives, that makes octane numbers quoted here:
TEL 1 2 3 4
Б-59 73 78 81 82
Б-70 80 85 87 88
Б-74 85 88 90 92
Б-78 87 92 93 95
So 3B-70 makes 87 octane numbers, so for 1.5B-74 or 1B-78.
Your Pe-2's Klimovs 105 worked on 91-95 octanes fuel that ranges (the highest being the best for safe margin) from 3.5 - 4 B-74 to 1.5 - 3.5 B-78.
The mark 75 never existed in soviet standards. (X) B-59 was mainly used in cars or old planes as R-5, Po-2, R-Zet...
Of course, LL deliveries were also massively* used, and some local made B-95 that could gave 96-115 octane numbers at the war's end, using Houdry's cracking methods (Shell patent).
* some sources quote 2 620 thousand tons, aviation fuel and flavours!
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