Cliffs of Dover is the Best. (A few screenshots).

[senseispcc]

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With the new patch RC2 and a Spitfire MKIa 100oct I have tried and did get to 28100 feet of altitude without any difficulties, without exploding my engine by fiddling with the rudder trim and the pitch, mixture, radiator opening, here is a picture to attest it (add 1000 mb );
http://s13.postimage.org/4zdxiq547/s...012_223612.png
http://postimage.org/image/vx7ukgpr7/
It took me 43 minutes from take of at Upavon to landing at Manston.