Black 6 Thu 19th Apr update re Spit II

[41Sqn_Banks]

Originally Posted by NZtyphoon

There could be a reason for the difference; read #1219. I know that there is a set of Spitfire II notes on Scribd; these show that there have been no amendments and it is possible that the operational limits for the Merlin XII were originally set at +9 lbs boost, later pushed to +12 1/2 lbs. (Paragraph 4 of the attached document does state that the Merlin XII was cleared for this boost.) It is possible that on operational units an amendment slip specifying +12 1/2 lbs was issued with the notes.

There is a small possibility of printer error, for example on p3 it describes the Spitfire II as being "powered by a Merlin III..."

Now that's a interesting find. The page without amendments only give +12 boost for take-off, but the 1939 documents states +12.5 boost for take-off.

However it's still clear from the June 1940 "List of content" that the page that contains the +12 emergency boost was not contained at that date and was added later and at that date only the page without +12 emergency boost was contained.

IMHO the easiest would be to get the combat reports of the "units concerned" (pun intended ) to find one that proofs the use of +12 in a Spitfire II or search in the National Archives for a similar doc like the one that clears the use of +12 emergency boost for Merlin XX.