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

[Kurfürst]

Well its always refreshing to hear some mature arguments gentlemen. Please do carry on.

Dear Condor,

I will look into the papers you have provided, though in my opinion not much new is surfacing in the thread, some people just like to repeat themselves. As others have correctly observed, this thread long took a demented course ever since some people graced us with their enduring presence. Most of us, and I dare to say correctly, already drawn the conclusion that the amount of Stations/Squadrons operating on 100 octane fuel cannot be ascertained - although its well known and undoubted for 70 years that it was used - we lack sufficient evidence to form an educated opinion about its extent.

[Glider]

Well that is a slight change on your position. On another forum you believed that it was a Pips posting ie approx 145 fighters, which was enough for about 7 squadrons with a few in reserve

[Kurfürst]

Originally Posted by Glider

Well that is a slight change on your position. On another forum you believed that it was a Pips posting ie approx 145 fighters, which was enough for about 7 squadrons with a few in reserve

I fear that you have not yet quite understood my position.

Pips noted that in May 1940 the British decided to stop the roll out of 100 octane and limit it to apprx. 25% of the force.

We of course know from the papers in AVIA 282 that in May 1940 the British indeed noted that they have supplied 100 octane to select fighter stations and a number of bomber stations.

Pips also noted that later when the supply situation eased they decided to continue with the changeover. Pips noted that the changeover was completed by the late autumn.

We also know from the same AVIA papers that it was not until early August 1940 the British finally decided to authorize 100 octane use for all operational aircraft. Of course it was just that, an authorization. The actual steps took some time.

From the fuel consumption and issue papers we know that 87 octane was the primary fuel, and 100 octane issues only increased towards late September 1940.

[Al Schlageter]

Originally Posted by Kurfürst

Pips noted that in May 1940 the British decided to stop the roll out of 100 octane and limit it to apprx. 25% of the force.

From the fuel consumption and issue papers we know that 87 octane was the primary fuel, and 100 octane issues only increased towards late September 1940.

LOL, he we go again with the Pips paper while ignoring the number of squadron over and above the 16 +2 that used 100 octane fuel.

You continually fail to supply a breakdown of which RAF Commands received what fuel.

A single bomber in BC carried enough fuel to fuel an entire squadron of Spitfires or Hurricanes.

[Al Schlageter]

Originally Posted by Kurfürst

We also know from the same AVIA papers that it was not until early August 1940 the British finally decided to authorize 100 octane use for all operational aircraft. Of course it was just that, an authorization. The actual steps took some time.

Can I quote this line when 1C does late war with the 109K-4 and 1.98ata?

[NZtyphoon]

Same old same old; Adam-Barbi doesn't have a single scrap of evidence to prove anything he claims, so he'll just go over the same old ground again, with the same old arguments.

[Crumpp]

Let’s look at some of the facts being supplied.

First we have this document:



Estimates...estimates for consumption and estimates future stocks two months ahead of 29 Oct 1939.

Estimates = best educated guess. An estimate is not a fact. While interesting, it means nothing for establishing the extent of use of 100 grade. 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.

We have evidence that some 100 Octane was used as early as 16 February 1940. This squadron log definitively states the aircraft are converted and using the fuel.



It is a fact; this unit was using 100 grade. However, that does not mean the RAF had adopted the fuel or it was in widespread use.

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.

Technical Order dated March 1940:



The technical order tells us the major work required to convert an engine by replacing the cylinder heads, in some cases piston rings, and altering the fuel metering system. It also gives us the plan to make the conversions. Airplanes were to be converted when their service inspections where due. In order to make this conversion, there must be an adequate supply of the new cylinder heads and parts in the inventory to replace the old ones. Somebody has to make the parts required and distribute them.

These squadron log entries prove that the conversion was taking place. It does not show that they were using 100 octane fuel. The only fact it shows is that the planes were converted according to the plan laid out in the technical order.





Looking at this document, we know for a fact nobody in the United Kingdom was using any sizable quantity of 100 Octane fuel before June of 1940.



That would make sense given the other facts we have at hand.

1. There was no technical order or instructions to convert until March 1940.
2. Conversion required major work and a supply of cylinder heads to be in the manufactured and distributed to the inventory.
3. Conversion was done on the periodical major inspection schedule of the aircraft when it was down for service anyway.
4. None of the POH's list +12lbs as authorized before June 1940. If it was the major fuel, those instructions would eclipse the instructions for 87 Octane.
5. There were no stocks in any quantity of 100 Octane fuel at any airfields prior to June 1940.
6. 100 Octane fuel does not become the major fuel on hand at any airfields until October 1940.
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.

Even after June 1940, 100 Octane does not come anywhere close to eclipsing 87 Octane use. It represents on 27% of the fuel on the airfields during July thru August.

In September, 100 Octane represents 37% of the fuel on hand at the airfields. In October the increase is significant with 47% of the total fuel at the airfields being 100 Octane. The other 53% in October is still 87 Octane.

That concludes the facts at hand. All of this points to the biggest fact of all, we don't know for sure at this point.

Lastly lets address why I believe the 16 squadrons over simplistic calculations.

Now the 16 squadrons is found in two sources. First Morgen and Shacklady list RAF Fighter Command as having 16 squadrons for Fighter Command and 2 Squadrons for Bomber Command by September of 1940. The Trimpell Oil Company also confirms this plan. They list 19 squadrons and 384 Spitfires using the fuel by 31 July 1940. If we count squadrons listed in both sources:

16 squadrons in Fighter Command + 2 Squadrons in Bomber Command + 1 PRU unit in Coastal Command = 19 Squadrons.

16 Spitfire squadrons in Fighter Command = 352 A/C at the establishment of 22 A/C per squadron enacted in July 1940.

That leaves 32 Aircraft for Coastal Commands PRU unit.

Both sources seem to agree and their conclusions are close enough on the 16 squadrons. Those conclusions are backed by the Aircraft Operating Instructions and the airfield stocks as listed in the United Kingdom’s Table II - Consumption report and Strategic Reserve situation.

That 16 squadrons using 100 Octane fuel during the Battle of Britain puts the reserve to consumption ratio at a much more believable rate and the accounts for the inventory lag of replacing cylinder heads. In short, from a logistical standpoint, it is much more credible and is agrees with the evidence found in the aircraft operating instructions.

Now several second hand sources make the statement that 100 Octane was the predominate fuel for Fighter Command during the Battle of Britain. This is true depending on the dates you choose to end the battle. On 15 September, I would say it was unlikely that 100 Octane was the predominate fuel. However by December 1940 it did become the predominate fuel and by the German date for the end of the battle, May 1941 when the bombers were transferred to the east, 100% of the RAF was using 100 Octane fuel.

[Crumpp]

wikipedia

Is a joke in academic circles. Including it as a source at the college I graduated from was an automatic failure.

Read Wikpedia's own General Disclaimer:

http://en.wikipedia.org/wiki/Wikiped...ral_disclaimer

[NZtyphoon]

Originally Posted by Crumpp

Let’s look at some of the facts being supplied.

First we have this document:



Estimates...estimates for consumption and estimates future stocks two months ahead of 29 Oct 1939.

Estimates = best educated guess. An estimate is not a fact. While interesting, it means nothing for establishing the extent of use of 100 grade. 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.

We have evidence that some 100 Octane was used as early as 16 February 1940. This squadron log definitively states the aircraft are converted and using the fuel.



It is a fact; this unit was using 100 grade. However, that does not mean the RAF had adopted the fuel or it was in widespread use.

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.

Technical Order dated March 1940:



The technical order tells us the major work required to convert an engine by replacing the cylinder heads, in some cases piston rings, and altering the fuel metering system. It also gives us the plan to make the conversions. Airplanes were to be converted when their service inspections where due. In order to make this conversion, there must be an adequate supply of the new cylinder heads and parts in the inventory to replace the old ones. Somebody has to make the parts required and distribute them.

Read the first paper dated October 29 properly Crumpp: Deduct Estimated Consumption Nov/Dec - all this paper is doing is estimating consumption for November and December 1940 - it has absolutely nothing to do with actual fuel consumed July- October 1940.

As for the second document correct - the squadron was operational on 100 Octane fuel in February, meaning that the modifications to Merlins was well in hand before March...as for AP1590B March 1940;

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.

[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.