Flying between 14000 ft and 20000 ft keeps the temp around 79ºC and 82ºC... I could even reach 28000 ft keeping ATA at 0.8 and setting RPM manually to 2300... This combination kept the oil temp at 86ºC steady and a cruise speed of 190 KIAS !! But like you said, the aircraft was probably not designed to fly in this condition...
But, I have to admit, I'm really confused !!! I never thought that a very powerful FW-190 could not reach higher altitudes.... Several WWII airplanes specs says they can reach even 37000 ft...
I have all the FSX WWII addons possible... And the favorites are A2A P-47, Real Air Spitfire and Both FW-190 from you (Not in this order) and none of them is limited like the FW... P-47 with Accusim can easily reach 30000 ft... even 32000 ft... Even the FW early variants can go higher...
BUT !!!!!! I will not doubt about the accuracy of this project and like I stated before... NOTHING could make me love and appreciate less the incredible CH FW's...
By the way... Since here in my city in Brazil is already 20:00h, over there in Germany you are probably in 2010 !!
Happy new year !!!!!
