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

[Crumpp]

Unless you can provide a print run history for the manual it's all guess work.

Winny, it is not guesswork. It is what the Operating Notes say for every edition until we get to January 1942.

Could have a look at this as well, won't be for a month or so though.

That would be nice if you could do that and let us know what you find.

Crumpp your theory require that in January 1942 at least one operational squadron used at least one Spitfire I aircraft.
Otherwise the restriction for operational units to 100 octane noted in the Pilot's Notes would be obsolete and by your theory would have been instantly removed and changed to "all units 87 octane fuel".
Please name at least one operational Squadron that used at least a one Spitfire I aircraft at that time.

Why does that matter?

It is a fact the manual was reprinted in January 1942 and it is a fact the fuel changeover to "All Operational Units" is important enough to be added to Paragraph 1, Operating Limitations.

The 100 Octane fuel changeover is important enough to make it into every Operating Notes, Paragraph 1, Operating limitations when it occurred.

For example, the Hurricane II Operating Notes dated September 1943 clearly list 100 Octane as the ONLY fuel to be used:



It will note in paragraph 1 the fuel options when 100 Octane becomes common and it will note when all operational units will use the fuel, and when it is the only choice.

It is the operational documentation and not logistical!!

Now, it might not be the exact month because there is some lag time and technical orders will cover that short time period.

you will not see technical orders that are applicable to operational units that do not make it into the new edition.

It is really simple. We have a 1939 edition and we have a June 1940 edition with no changes to paragraph 1, Operating Limitations. That fact tells you 100 Octane was not in common use. It was in use but it was not the most common operational fuel in the RAF at that time.

In between that time we have a technical order to AP1590 which is the engine series and not the airframe series. It makes a difference in aviation and there are plenty of engines that modifications are not approved in specific airframes. There will be an order approving that engine modification for the specific airframe.

For example:

Why isn't the Mooney M-20-C (or Piper Comanche) approved?


A. The Mooney and Comanche both experienced vapor lock problems when they were tested. We solved the vapor lock problem, but could not overcome pneumatic lock. Pneumatic lock takes place when the fuel boils as it enters the carb. The engine then dies due to an overrich mixture. This is just the opposite of a vapor lock where the engine quits or runs poorly due to a lean mixture. The better an airplane performs, the more difficult it is to get it through the flight test program.

Q.If the Apache with 150 or 160 hp engines is approved, then why isn't the Apache with the 0-540 235 hp "B" model engines approved? These engines are listed as approved in your website.


A. The 235 Apache was flight tested and failed the flight test due to vapor lock. At that time if an airframe failed the flight test it was washed out and we went on to the next airplane. There are numerous examples of airframe/engine combinations which would appear to be approved since they have STC's individually, but may not be approved in conjunction with each other either because they failed the flight test or were not tested at all.

http://www.autofuelstc.com/autofuels...Mogas_FAQ.html

I don't know the specific explaination in the case of 100 Octane as too why the large lag time between the engine approval and the airframe operating limitations but I do know that is a flag to anyone knowledgeable in airplane maintenance for claims of widespread general use.

I would get the editions to the Operating Notes and throw away any squadron logs that do not specifically state "100 Octane Fuel in use".

You will have good factual picture on the timeline for the fuels operational use if you do that.

[Crumpp]

For the purposes of CloD, does it matter if ALL operational RAF units were using 100?

No, It was claimed in this thread that all operational units were using the fuel by June 1940 and that is not correct.

[Osprey]

It is correct, only a total fool would argue against such a weight of evidence.

[pstyle]

Originally Posted by Crumpp

No, It was claimed in this thread that all operational units were using the fuel by June 1940 and that is not correct.

Ok fine, that's certainly debatable, but not strictly relevant to the game.... Not unless they model the whole UK and every RAF unit.

[winny]

Originally Posted by Crumpp

Winny, it is not guesswork. It is what the Operating Notes say for every edition until we get to January 1942.
.

How many editions are there and what dates were they printed?
And what about the vol.II's?

As I've mentioned unfortunately the notes are not 'gospel'

FC's total fighter strength during BoB (operational) peaked at around 750 aircraft, Spitfires, hurricanes and all other types. And was around 350 at the start.
We are talking less than a 3rd of the whole RAF. At around the same time they had 220,000 tons of 100 octane.
It makes no sense for them not to use it. Morgan and shacklady say the conversion started in march, there was a team of rolls-Royce engineers running around the airfields showing the mechanics how to do the conversion, in the field. Geoff Wellum says he was using 100 octane "just before" the battle of britain, tim viggors was putting it in his car in June 1940. All Deere says it was in use "just in time for the BoB". Peter brothers also says that they converted in the spring of 1940. All these pilot's, and more...


I contacted Dilip Sarkar, and asked the question. He said it was done in the spring of 1940. Bungay and Holland say the same thing. Then there's you...

[Crumpp]

As I've mentioned unfortunately the notes are not 'gospel'

The notes are gospel Winny. For a short period of time a technical order will override them until the next edition of the Operating Notes is published.

We have a 1939 edition and we have a June 1940 edition with no changes to paragraph 1, Operating Limitations. That fact tells you 100 Octane was not in common use. It was in use but it was not the most common operational fuel in the RAF at that time.

Morgan and shacklady say the conversion started in march

Yes.....with a total of 16 squadrons converted to 100 Octane sometime in September.

That is exactly what I said I believed happenend. Both the Operating Notes and Table II showing fuel at the airfields point to that same conclusion.

For the last 20 pages I have been called every name in the book for stating that!!

[Crumpp]

Ok fine, that's certainly debatable, but not strictly relevant to the game

No, you guys pay for your game and the developers should give you what you want to enjoy it.

Honestly, a "simulation" would not be very much fun of this stuff. Ask the survivors how much fun they had in it.

[winny]

Originally Posted by Crumpp

The notes are gospel Winny. For a short period of time a technical order will override them until the next edition of the Operating Notes is published.





Yes.....with a total of 16 squadrons converted to 100 Octane sometime in September.

That is exactly what I said I believed happenend. Both the Operating Notes and Table II showing fuel at the airfields point to that same conclusion.

For the last 20 pages I have been called every name in the book for stating that!!

Firstly the meeting was held before the war started at a point when nobody, not even Hitler thought the war would start until 41 at the earliest, the British were looking at '42 as the probable start. This meeting was followed by other meetings that are again documented here that superseded the original meeting due to the minor inconvienience of Hitler deciding to risk war and invade Poland.
There were meetings held in '39 that were specifically held to secure and produce 100 octane without having to rely on the USA. In 1939 the government spent the most amount of money on any single production facility for the entire war when they contracted TRIMPELL to build the Heysham iso-octane plant, who's specific purpose was to convert 87 into 100. Why would they do this if they were expecting the total consumption to be 10,000 tons per annum, as Morgan and shacklady say, when they already had 100,000 tons in stock.. 10 years supply according to that meeting. See next point.

Morgan and shacklady states that the same meeting decided that the change over would result in "consumption of 10,000 tons per annum" the reserve of 800,000 tons was, if you look at the relevant documents already posted in this thread, for the entire RAF as projected for 1943.

I noticed you gloss over the fact that Deere, Wellum, Brothers, Hillary, Lane, Viggors, Page, Malan and a few others mention in their memoirs that the changeover happened in the Spring of 1940.

At the end of the day I don't give a shit what you think. I value people who were there, and who were writing diaries at the time over your desperate clinging to a meeting that was held when Britain was in the process of re arming for a war they were expecting in 2 or 3 years. I mean.. Who exactly are you? Actually don't answer that, I don't care.

[camber]

Dear Crumpp,

I just can't find these arguements compelling where you compare current peacetime FAA (US) procedures and definitions to the RAF in 1940, then state conclusions that are held and argued no-matter how they are contradicted by the rest of the evidence. I understand you have some background in (today's) civil aviation, it may be a good place to start but it is not producing very compelling arguments.

Plus there a lot of assumptions being put into your mix. Your current argument rests on implying new cylinder heads are needed (with consequent large requirements for time and materials), where AP1590/J.2-W (which you posted) refers to a rather more mundane "cylinder head spigot depth modification" (elsewhere referred to as a "top joint modification") which has aleady been done in routine maintainance or at the factory for new engines as Glider and others have said (document from March 40). It would be nice to see some more info on what exactly Merlin Mods 64,77 and 136 entailed (these are the cylinder head mods), but there are a lot of posted documents detailing that the airfield conversions were done very quickly.

The nature of the boost control modification itself rather argues against the relevance of comparing today's civil aviation standards with the 1940 RAF. Drilling extra air channels to convert an existing boost control cutout into a boost pressure setpoint control? Brilliant, ingenious, very seat of the pants. I have a little background in civil aviation too (Australia) and I can't see it happening today

I am not saying the devil's advocate role is not useful. I loved it when you totally offended the Spitfire purists by saying that according to a college course you did, the Spitfire fails control stability design standards developed in the US at the end of the war. There was an interesting point there that the pre 1940s belief that instability was necessary for manouverability was wrong...US engineers figured out that you can have both. This (correct) technical detail about changes in standards does miss the point though that pilots of the time (and today) found the Spitfire a delightful aircraft to fly.

There was also the time when you offended an ex-RAAF fast jet pilot (who also flew Yak 50s) by contradicting him repeatedly on flying in the "buffet", when you stated (correctly) that flight in the buffet regime is wrong because it represents a loss of aerodynamic efficiency and hence turn efficiency. But this (correct) technical detail misses the point that military or aerobatic pilots have often used the first point they can detect the onset of buffet (i.e flying in the "buzz") to stay in proximity to their maximum AoA...any slight deterioration in performance is offset by the ability to detect the point of departure and stay near it.

Bolding text and making statements that "this is a FACT" and "anyone that knows about aeroplanes would know this" I (and I suspect others) find very unconvincing. Generally you have used them to make statements that are correct within a narrow technical context or definition but then become misleading in the historical application to which they have been put.

Cheers, camber

[Crumpp]

I just can't find these arguements compelling where you compare current peacetime FAA (US) procedures and definitions to the RAF in 1940

Convention Relating to the Regulation of Aerial Navigation Signed at Paris, October 13, 1919
(Paris Convention)
THE UNITED STATES OF AMERICA, BELGIUM, BOLIVIA, BRAZIL, THE BRITISH EMPIRE, CHINA, CUBA, ECUADOR, FRANCE, GREECE, GUATEMALA, HAITI, THE HEDJAZ, HONDURAS, ITALY, JAPAN, LIBERIA, NICARAGUA, PANAMA, PERU, POLAND, PORTUGAL, ROUMANIA, THE SERB-CROAT-SLOVENE STATE, SIAM, CZECHOSLOVAKIA AND URUGUAY,
Recognising the progress of aerial navigation, and that the establishment of regulations of universal application will be to the interest of all;

There have been other conventions since but 1919 was the first. Aviation is the same around the world for the most part.

Yes, the Air Ministry of the United Kingdom follows the same rules and concepts as the FAA. Those principles are exactly the same. Once more, the instructions found in every Air Ministry Operating Notes reflect this practice.

Crumpp says:

you will not see technical orders that are applicable to operational units that do not make it into the new edition.

"cylinder head spigot depth modification"

Do you know what a cylinder head spigot is on an engine?

routine maintainance

It is not routine maintenance; it is done at Service Inspection. Do you know the difference?

There was also the time when you offended an ex-RAAF fast jet pilot (who also flew Yak 50s) by contradicting him repeatedly on flying in the "buffet", when you stated (correctly) that flight in the buffet regime is wrong because it represents a loss of aerodynamic efficiency and hence turn efficiency.

You misrepresent this completely. The statement was not using the buffet to find maximum turn performance. He flat stated that maximum turn performance occurs in the buffet. That is not correct and once he clarified that we had no issue.

This (correct) technical detail about changes in standards does miss the point though that pilots of the time (and today) found the Spitfire a delightful aircraft to fly.

Up until the moment they died from it! What the engineer likes and what the pilot likes are not always the same thing. Why let a pilot take a plane someplace it cannot fly?

Generally you have used them to make statements that are correct within a narrow technical context or definition but then become misleading in the historical application to which they have been put.

How can it be technically correct and then wrong in some imagined historical application? Sounds like horse-puckey to me. What I have passed on is true and how it works. There is no point in arguing the same information over and over. Problem is that most aviation historians have no practical aviation experience. In fact, the vast majority of books on aviation history are written by interested amatures who don't have a background in either history or aviation.

What I have said about the Operating Notes is technically, historically, and whatever else you want to attach to the word, "CORRECT". I don't care if you believe it, hate it, or love it.

Cheers,

Crumpp