Spit Mk1 Boost?

[Osprey]

I think most people are able to make up their own minds what you are.

I would like to thank the real contributors to the thread who supplied solid information on the function and specification of the Merlin of 1940 - very informative.

[TomcatViP]

calm down pls

[Kwiatek]

[IvanK]

Whats the title of this Test document Kwaitek or its AVIA Ref No ?

This does not reflect the In service Boost ratings for the Merlin III. Its unusual in that In service MERLIN III climb rating was + 6.25Lbs boost not as +9 shown here. If its genuine then I believe its a 1 off RAE trial report investigating the feasibility of rating the Merlin to +9Lbs climb in preparation for this rating in the Merlin XII. Merlin XII as fitted to Spitfire MKII had +9 Climb

MERLIN III LIMITS from Spit I Pilots notes

[Kwiatek]

I dont know IvanK - i just found these single document some time ago. But it is clearly for MErlin III testing with 100 octan fuel - data is from 28.02.1940.

Document which you posted is of course for Merlin III with 87 octan fuel only - not for 100 Octan fuel.

Here is for Merlin XII for both 87 and 100 Octan fuel used:

[lane]

IvanK: The Inspection and Test Certificate posted by Kwiatek is taken from Aeroplane and Armament Experimental Establishment’s report on Spitfire II P.7280, Merlin XII - Rotol Constant Speed Airscrew, Comparative Performance Trials, First Part of A.&.A.E.E./692,e dated 27th September, 1940. You will note that the rated power listed matches that of a Merlin XII. I always assumed "Mark III" on the Certificate was a typographical error.

[IvanK]

Originally Posted by lane

IvanK: The Inspection and Test Certificate posted by Kwiatek is taken from Aeroplane and Armament Experimental Establishment’s report on Spitfire II P.7280, Merlin XII - Rotol Constant Speed Airscrew, Comparative Performance Trials, First Part of A.&.A.E.E./692,e dated 27th September, 1940. You will note that the rated power listed matches that of a Merlin XII. I always assumed "Mark III" on the Certificate was a typographical error.

Thanks Lane, I have that report in full. All other pages refer to the engine as Merlin XII. The AVIA ref for this report in the UK National Archives is AVIA 18/1574
I am with you Lane, I think it refers to Merlin XII, the Merlin III looks like a typo on that single page

[Kwiatek]

Hmm interesting so you got IvanK linkl for these report?

I got also such documents for 12 lbs limitation of Merlin III:







But i think most know these documents.

[Kurfürst]

Originally Posted by IvanK

Whats the title of this Test document Kwaitek or its AVIA Ref No ?

This does not reflect the In service Boost ratings for the Merlin III. Its unusual in that In service MERLIN III climb rating was + 6.25Lbs boost not as +9 shown here. If its genuine then I believe its a 1 off RAE trial report investigating the feasibility of rating the Merlin to +9Lbs climb in preparation for this rating in the Merlin XII. Merlin XII as fitted to Spitfire MKII had +9 Climb

My take would be that Kwiatek's paper shows an early rating, valid for the first quarter/half of 1940, with +9 lbs being the initial maximum cleared for generic flying, and +12 only for takeoff when necessary. This seems to be quite typical when introducing higher ratings for an engine.