109 e3b against spitfire II

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Merlin XX would be 1485hp at 14lb/3000rpm @ 6000ft and 1490hp at 16lb/3000rpm @ 12500 ft and 1280hp at 3000rpm/12lb @ TO

The document compares the operational engines at the time it was prepared. At 17500 feet, the document is correct in the power output of a Merlin XX at it's approved Emergency Power rating of +9lbs at the time the engine were compared. It is also correct in its assessment of the DB601N series.

It is not correct in its math of the power to weight ratio of the engines. The Merlin XX is the same as the DB601N.

You need to look at the DB605 series to compare those other ratings. Also ensure you are looking at the correct power, ie...indicated, static or RAM, Brake or Thrust, and if it takes into account exhaust thrust...