While reading an old Flypast publication on the Spitfire, I came across some fascinating info on modifications and flight testing done on a Mk V in 1943.
Replaced ejector exhausts with aft facing fishtail stacks, worth 7 mph.
Removed carb ice guard, worth 8 mph
Fitted a more streamline mirror, worth 3 mph
Made gun link ejectors flush with wing skin, worth 1 mph
Painting and polishing wing leading edges, worth 6 mph
Waxing and polishing entire airframe, worth 3 more mph
All these and a few more minor ones took speed from 357 mph to 385 mph. Quite impressive!
Replaced ejector exhausts with aft facing fishtail stacks, worth 7 mph.
Removed carb ice guard, worth 8 mph
Fitted a more streamline mirror, worth 3 mph
Made gun link ejectors flush with wing skin, worth 1 mph
Painting and polishing wing leading edges, worth 6 mph
Waxing and polishing entire airframe, worth 3 more mph
All these and a few more minor ones took speed from 357 mph to 385 mph. Quite impressive!
