il-2 Compare for 4.09m

[AndyJWest]

I hadn't realised you'd deleted your last post, Buzpilot. I've edited mine to avoid confusion.

The percentage figure is only an approximation - the relationship isn't totally linear, and in any case only holds under standard atmospheric conditions. None of the stock maps reproduce this, though I believe that Smolensk is the closest.

There is more to high altitude performance than just the IAS/TAS relationship in any case, and I don't think there is a systematic error in IL-2 due to any miscalculation.