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We can take a look at time the planes were designed.
The Bf-109 was a contemporary of Hurricane, ie. being designed in the era when monoplanes were to replace biplanes in most of the air forces. The blunt LE points us into a thick wing, such a a wing offering the increased structural strength, along with better lift coefficient. The drag coefficient is also greater; the drag of wings was not that great because the wings themselves being comparatively small.
The later designs, be it Allied or Axis, would (some of them should) feature the sharper leading edges. Not many of the fighters were featuring sharp leading edges, to my eyes it was the MC.20x series with sharpest LEs. Spitfire comes close, too. The Fw-190 was using, should we say, a more advanced wing profile (NACA 230 series, same as Grumman Bearcat, for example), not a blunt LE there?
As for the spinners: some AFs were not using them in their radial-engined fighters, mostly because of engine cooling. If we take a look at Bf-109, the outlines of the spinner smoothly blends into engine cowling, that would be impossible to achieve with sharp spinner.
Of course in the late thirties.
It is maybe right with the 109 but not the spitfire regazding the time they have been created.
And what about the Fw 190 and the Grumman fighters? They were later and too late aircraft yet with an (outdated) airfoil?
Can you explain what this means?
Lee Atwood was said to be a keen fisherman and modelled the profile of the P-51's wing on the body of a trout.
IIRC P-51 wing changed from B/C to D adding the bend at wing root, thus slightly increasing wing area. Profile stayed the same though I assume.Fw-190 - yes, once it was decided, in prototype stage, to go with a 'big' wing, the 'small wing' being used on 1st prototypes. The V5 1st received 'big wing' (ie. the same size used until the end)
P-51 - IIRC the -H was using all-new wing.
Schmued was the designer.
where is stated that NAA was provided with unpublished NACA research material.