Spit IIa is now so much more inferior to the 109

[Crumpp]

I just reread the Spitfire and it does make a distinction between the Rotol and DeHavilland propellers on run up. The Operating Notes on a Merlin engine make no such distinction.

The difference in rpm is probably due to lack of airload on run up unless Rotols were not mounted to Merlin III's.

[Crumpp]

Anybody notice you do the run up on a Spitfire at full throttle!!!

Wow, that must have been beast and no wonder the Operating Notes require TWO men holding down the tail!

[Crumpp]

The following publications give 2850 RPM for Merlin II and 3000 RPM for Merlin III:
Notes for Pilot's on Merlin II, III and IV - 1940
Merlin II and III & V Aero Engine, 2nd Edition A.L. 4 - 1940
Spitfire Pilot's Notes - 1940

Well there you go...

In 1940 the Merlin III was given an rpm increase to 3000 rpm.