[Gaston]

The possible explanation.


No, none of what these first hand accounts claim violates any basic laws of physics by the way, at least not if you understand the difference between Force and Energy.

The FW-190A, in all its marks, out-turned at low sustained speeds the Spitfire, in all its Marks, obviously because it got the physics right... Nothing in physics prevents the lighter airplane from taxing its wings more than the heavier aircraft: It is not the heavier airplane that is adding, it is the lighter airplane that is substracting more, from a far greater than assumed wing lift tension for both.

The total force on the wings, in sustained horizontal turns, is far greater than the total now assumed to be the truth (could easily be detected if the wing bending on these old things had ever been measured in horizontal turns: It never has: Only in dive pull-outs), because the asymmetry on the loaded prop disc sets up a tumbling of air on the back of the wing: That initial tumbling is sustained in a rotating flow, and "sucks" pressure off the back of the wing, making the wingload total far heavier than what is assumed today for horizontal turns in these types of aircrafts. They all have the strength to absorb this extra load, being all well over 10 Gs airframes.

It doesn't show up in dive pull-outs because the dive unloads the prop, nullifying the tumbling "suction" effect from fighting the frontal leverage of the prop (which wants to stay straight).

That is why the FW-190A performs so poorly on the vertical: Unloaded prop disc = Less "tumbling" suction advantage on the back of the wings, and this makes it match its wingloading "math" more...

The "tumbling" that creates an air "vacuum" pump on the back of the wing is caused by the trajectory being slightly wider than it should be (from fighting the prop leverage to tilt itself): A wider turn means more air is "processed" by the wings, and some of it spills over the top of the wings in a horizontal spiral: This "wingtop pump" spiral sucks more and more air as the turning goes on, bending the wings far beyond the assumed value at the low sustained speed value (3-3.5 Gs). It could be that a "soft" initial turn entry will not set up this "pump".

That is the working theory for now at least. At a well over 48% discrepancy between types, from multiple general statements, it has to be something truly radical, not just "the mouse ate the cat because it was a very big mouse, and the cat was a very small cat..."

G.