[nzwilliam]

Also from pilot to pilot top airspeed will differ widely depending on personal experience and skill. Whats the likelyhood the test pilot for each particular aircraft tested was an expert in that particular plane? I'm guessing they probably would be if it were a prototype but for production models I'd take the word of a veteran with years in the same aircraft over a test pilot with a few hundred hours in that same aircraft...how often have you considered your level flight speed to be as fast as you can go at the verge of overheating - only to be overtaken by someone in exactly the same model or a much earlier one (and I'm pretty sure production abnormalities aren't modeled in IL2). I'm not saying the test pilots at the time weren't experts in their field but I don't think I'd be considering their top speeds as gospel.