I can see how the metal ailerons of the Spit V would help roll rate at high speeds, but at normal speed I dont believe it could roll that much faster than the Spit Mk 1, like our version of the Spit V does.
Supermarine conducted flight trial roll rate tests comparing Spitfires fitted with different types of ailerons. There is some evidence that the fabric ailerons became ineffective above 170 mph while the metal ailerons were most effective at 200 mph and less effective after that.
This is gratuitously stolen from an old ubi.com thread.
From "THE DEVELOPMENT OF THE SPITFIRE AND SEAFIRE", a Dec 1946 address to the Royal Aeronautical Society by J Smith.
---------------Test A-------Test B-------Test C
150 mph-------87-----------87-----------(b)
170mph--------93 (peak)----93-----------65
200 mph-------75----------105 (peak)----73
250 mph-------57-----------93-----------96
300 mph-------40-----------78----------118 (peak)
350 mph-------27-----------60-----------90
375 mph-------20-----------49-----------75
400 mph-------(a)----------40-----------70
Note: values are drawn from a graph by eye, so may differ by a degree or two from actual number.
Test A: Mk V Spitfire w/ fabric-covered Frise type ailerons.
Test B: Mk V Spitfire w/ metal-covered Frise type ailerons.
Test C: Mk 21 Spitfire w/ "plain ailerons w/ tabs".
Between 200 and 250 mph, the metal ailerons are anywhere from 40% to 65% faster in terms of steady-state roll.
