Spit Mk1 Boost?

[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.