The RAE chart shows a Spitfire sustained turn advantage across the entire speed range from the Lift limit through to the max 1G sustained speed of around 340mph.
i.e. if the "Angle of straight climb" (Ps=0) for both the Spitfire and BF109 were overlayed on the same chart the Spitfire angle of straight climb would be above the 109 line from the Lift limit through to 1G Vmax. So at any speed in this range the Spit can sustain a higher G according to the RAE .... but not according to the Crumpp plot ...
at any speed.
Both aircraft in this chart having similar values of 1g Vmax at the charted altitude.
There is no mention of prop type in the AVIA report for either the Spitfire or the 109. I take your point on propeller efficiency though ... that is touched on in another AVIA report (AVIA 6/13805) in which the RAE believe the 109 and Spit prop efficiency was essentially the same at 10,000ft with the 109 around 3% better at 15,000ft.... though with caveats.
