[bongodriver]

Annoyingly without going into graphs it seems Crumpp is right, if FTH in standard atmosphere is 17,500ft density altitude, then if ambient temps are ISA + then density altitude is higher than pressure altitude therefore boost drop off should happen lower than 17,500 ft on the altimeter.

There are simpler graphs showing a density altitude conversion from pressure altitude just using ISA deviation temperature, again Crumpp may have a point about dry lapse rates as I think density alt is based on it, relative humidity comes in and complicates matters.

Crumpp, your working out was done with a standard 2 degree lapse rate, I believe a 3 degree lapse rate would work in 'favour' of performance in that case.

19C + 3 degree per 1000 ft lapse rate = 17500/1000 = 17.5*3 = 52.5 = 19C - 52.5C = -33C

using -33C at 17,500ft pressure altitude I find a density alt of 16,000ft so in effect I could go to more than 17,500 pressure alt before boost drop off.

I will look at this again tomorrow.

p.s. I forgot to add....the key to this would be to test and find the in game actual OAT (outside air temp) at 17,500 ft pressure altitude and see what the deviation is from a 3 degree lapse rate.

p.p.s. I think the test is worth doing using standard setting on the altimeter 1013mb, which RAF aircraft use an OAT gauge?, might be worth doing the test as a co op so someone can check temp at various pressure altitudes.

P.p.p.s reverse engineering the games atmosphere model at 1 in the morning is nuts