Inaccurate performance data for BOB fighters in COD comparing to RL data

[Crumpp]

all this paper is doing is estimating consumption for November and December 1940

No it estimates more than consumption, it estimates deliveries of the fuel and increases in strategic stocks.

As I pointed out, the only fact it does relate is:

Crumpp says:
It does establish the fact in October 1940 the United Kingdom had just over half the 800,000tons of 100 Octane in strategic reserve they initially required. There was a shortage of 100 Octane fuel.

Your statement about the squadron log:

NzTyphoon says:
the squadron was operational on 100 Octane fuel in February

1. There was no fuel at the airfields in any quantity. See the Table II consumption document. It is therefore unlikely this is any kind of widespread operational use.

2. Yes, that squadron used the fuel in February but no technical instructions were in widespread dissemination.

3. If the fuel was standard by June 1940, it would have eclipsed the 87 Octane Operating Instructions.

Read AP1590B properly Crumpp; nowhere does this document mention overhauling aircraft, nor does it mention "service inspections". Just to make things especially clear to you:

Paragraph 4 states "Newer engines will already have Mod.No.Merlin/136 embodied" meaning that the conversion was already being undertaken on the production line.

This document refers to older engines being brought up to the same standards:

Paragraph 4 states ...Mod.No.Merlin/77 is already being done as service maintenance

As per usual you have utterly misrepresented what these documents are saying.

Who said anything about overhauling the aircraft? Do you know what a service inspection is NzTyphoon? It is the equivalent of an annual or a FAR 21.183 100 Hour inspection.

There is no misrepresentation and the language is quite similar to Service Bulletins and Airworthiness Directives in use today.

It clearly states the two methods of compliance by part number with the technical order and specifies which one will be incorporated in future production engines. The 900(+) Single Engined fighters using the Merlin already in service will have to be converted along with the maintenance stock of Merlin engines.

It means they have to manufacture quite a few new cylinder heads and rings. That is why the conversion will take place during the cyclic service inspection.

[28_Condor]

Frankly, it is very difficult to follow this discussion ...

For me it is easier to understand articles that have reviewed the literature and where I can draw conclusions:


Palucka, Tim. The Wizard of Octane. American Heritage of Invention & Technology, 20. 3 (Winter 2005): 36-45.
Resume: IF, AS THE DUKE OF WELLINGTON IS SUPPOSED TO HAVE SAID, the Battle of Waterloo was won on the playing fields of Eton, then one can assert with equal justice that the Battle of Britain was won at the Stevens Hotel, in Chicago, on November 18, 1938. It was there, at the annual meeting of the American Petroleum Institute, that Arthur E. Pew, vice president and head of research of the Sun Oil Company, described his company's extraordinary new catalytic refining process. Using it, he said, Sun was turning what was normally considered a waste product into gasoline-and not just ordinary gasoline, but a highoctane product that could fuel the era's most advanced airplanes. 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."

Bailey, Gavin. The Narrow Margin of Criticality: The Question of the Supply of 100-Octane Fuel in the Battle of Britain. English Historical Review; Apr2008, Vol. 123 Issue 501, p395-411, 17p, 3 Charts
Resume: The article focuses on the supply of 100-octane fuel during the battle of Great Britain. Aviation historians have advanced the supply of 100-octane aviation fuel as critical American contribution to the battle. A study of the contemporary Air Ministry records in the Public Record Office shows that this assertion can be challenged. The challenge can be made on the grounds of the aircraft performance benefit involved, as showed by contemporary Royal Air Force (RAF) testing, and on the national origin attributed to 100-octane fuel supplies. The records reveal that contrary to the assertion of aviation history, the supply of 100-octane fuel to RAF in time for use in the battle must be attributed to pre-war British planning and investment on the rearmament period of the late nineteen-thirties.

My only conclusion is that only in this forum I read the statement that 100-octane did not have a role in the Battle of Britain (statement supported by the devs? ) ... and not supported in a peer-reviewed article...

[NZtyphoon]

Originally Posted by Crumpp

Who said anything about overhauling the aircraft?

You did, right here:

Originally Posted by Crumpp

A technical order for conversion of the aircraft had not even been published at that time. It is highly unlikely that the RAF was in the process of widespread conversion to 100 Octane without disseminating the technical knowledge to convert the airplanes in the force.

Originally Posted by Crumpp

There is no misrepresentation and the language is quite similar to Service Bulletins and Airworthiness Directives in use today.

It clearly states the two methods of compliance by part number with the technical order and specifies which one will be incorporated in future production engines. The 900(+) Single Engined fighters using the Merlin already in service will have to be converted along with the maintenance stock of Merlin engines.

It means they have to manufacture quite a few new cylinder heads and rings. That is why the conversion will take place during the cyclic service inspection.

You have no idea what technical service documents were published between November 1939 and February 1940, so claiming that none had been published is completely wrong.

The designation AP1590B J.2-W indicates that there were documents before this one

Read AP1590B J.2-W properly Crumpp - it refers to older production Merlins

Paragraph 4 states[B]

1) .Mod.No.Merlin/77 is already being done as service maintenance "is already being done" means that the parts and the information needed was available before March 1940.

2)"Newer engines will already have Mod.No.Merlin/136 embodied" "Will already" means that production engines built before March 1940 incorporated the modifications.

Originally Posted by Crumpp

7. In October of 1940, the United Kingdom as just half the Strategic Reserve required of 800,000 tons. In other words, there is a shortage of 100 Octane fuel in the United Kingdom.

Once again utter nonsense. You are still obsessed with a pre-war document to decide what happened in wartime when a country was under attack. Reserves of 100 Octane never reached 800,000 tons - in 1941, when all services had converted to the fuel, reserves reached a peak of 527,000 tons in February before steadily declining.

Originally Posted by Crumpp

Not at the required consumption to stock ratios....

Strategic reserves of "Other Grades", including 87 Octane fuel, got far lower than 100 Octane in August 1940; 230,000 tons cf 404,000 tons of 100 Octane. Your "required consumption to stock ratio..." is completely erroneous

August 1940

Consumption of "Other Grades" = 26,000 tons plus reserves of 230,000 tons = 256,000 tons of other grades. Heavy bombers, flying boats etc were still consuming 87 Octane fuel considering that big aircraft with big fuel tanks were using the fuel the difference in consumption is a little easier to understand.

Consumption of 100 Octane
10,000 tons plus 404,000 tons in reserves = 414,000 tons of 100 Octane

Get it clear in your mind Crumpp - only 15,000 tons of fuel was needed to cover all operational defensive sorties flown by Merlin powered aircraft of Fighter Command right through the battle. You have never explained what happened to the remaining 36,000 tons of 100 Octane fuel consumed, and you never will. Instead, as per usual, you continue to evade some very basic questions.

[41Sqn_Banks]

Originally Posted by NZtyphoon

You have no idea what technical service documents were published between November 1939 and February 1940, so claiming that none had been published is completely wrong.

Exactly. For example Operational Notes for Pilots on Merlin II and III. 2nd Edition January 1939. It doesn't mention +12 boost, it mentions that a unspecific higher boost than +6 1/4 can be used for take-off by operating the boost-control cut-out.
It doesn't mention any modification, only that 100 octane fuel must be used. (Note that the 4th Edition from April 1940 mentions that "sparking plugs approved to withstand this high boost must be used", so if there was any modification required in January 1939 it would have been mentioned.)
It does however state that this higher boost setting has to be determined on the ground before it is used by listening if there is detonation.

The 4th Edition from April 1940 now gives +12 boost and as already said mentions that specific sparking plugs must be used and that the boost-control cut-out has to be modified to limit boost to +12 boost.
Looks like in April the cylinder head modification was no longer required (maybe because all engines had been modified).

[lane]

Originally Posted by 41Sqn_Banks

Exactly. For example Operational Notes for Pilots on Merlin II and III. 2nd Edition January 1939. It doesn't mention +12 boost, it mentions that a unspecific higher boost than +6 1/4 can be used for take-off by operating the boost-control cut-out.
It doesn't mention any modification, only that 100 octane fuel must be used. (Note that the 4th Edition from April 1940 mentions that "sparking plugs approved to withstand this high boost must be used", so if there was any modification required in January 1939 it would have been mentioned.)
It does however state that this higher boost setting has to be determined on the ground before it is used by listening if there is detonation.

The 4th Edition from April 1940 now gives +12 boost and as already said mentions that specific sparking plugs must be used and that the boost-control cut-out has to be modified to limit boost to +12 boost.
Looks like in April the cylinder head modification was no longer required (maybe because all engines had been modified).

My copy confirms your statement:

Emergency +12 lbs./sq. in. Boost Operation: Pilot's Notes, Merlin II, III and IV, 4th Edition, April 1940, page 6.