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

[NZtyphoon]

Originally Posted by Crumpp

Spitfire Mk I Pilots Operating Notes, dated June 1940:



This is an Inspection and Test Certificate for a specific aircraft with a Merlin Mk III engine. Inspection and Test Certificate is probably the same as an FAA Form 337 allowing major modification for research or testing purposes. Note the document clears a single aircraft by serial number on 28 February 1940. The July of 1940 Spitfire Mk II manual clears the Merlin III engine for use of 100 Octane fuel and notes +12lbs may be used.

That is not the Spitfire Mk I but rather the Spitfire Mk II. There is nothing authorizing the Spitfire Mk I to use +12lbs in any of the Operating Notes.

And? All that it means is that the Pilot's notes, which you say were printed in June 1940, did not show 100 Octane fuel.

The problem is that any changes to the notes, before the next issue was printed, were altered through sets of amendments which were noted in the inner front cover of the book, and by gummed slips which amended the text in the appropriate locations. All this shows is that this particular set of notes was not amended. Look in the front cover of the notes and you will see this.

Better still how about showing all of us the front covers, including the inner fly leaf and index pages which show the date these notes were printed?

Attachment 3 shows that Merlins in Hurricanes of 151 Sqn had been converted to 100 Octane in February 1940.

The certificate, printed in February 1940, specifically discusses one aircraft, for sure, however, there are TWO problems:

1) There were no Mk II Spitfires in production in February 1940, and the engine is described as a Merlin III, although the power ratings suggest a Merlin XII which, as attach 1 shows, had been cleared to use +12.5 lbs boost.

2)Clearly this was a Spitfire I being used to either type test a Merlin XII or test a Merlin III at higher boost pressures. All it proves is that this particular certificate belonged to a test aircraft. How does this prove that this aircraft was the only Spitfire using 100 Octane fuel, and how did this lone Spitfire manage to chew through 52,000 tons of the stuff?

You have not explained why it is that there is a great deal of evidence showing that Merlin IIIs were modified and rated to use +12lbs boost and there are combat reports showing this. And why did Dowding feel compelled on 1 August 1940 to issue a general notice to all squadrons warning them against excessive use of +12 boost when only 16 Squadrons were using the fuel? http://www.spitfireperformance.com/dowding.pdf