Speed graphs for Spitfire and Hurricane

[BlackSix]

Originally Posted by ATAG_Snapper

Thanks, Black Six. At last we finally know why the Spitfire Ia's top speed at sea level is 240 mph. The slope of the curve was simply applied to the 0 - 3000 m gap in information, so 0 feet = 240 mph. Mystery solved.

More correctly: we didn't have official flight tests for Spits and Hurris between 0 and 3000m for this test.
I don't know how our FM programmer made this planes for game in 2011.