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Old 06-06-2012, 10:34 PM
IvanK IvanK is offline
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Join Date: Oct 2007
Location: Australia
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Crumpp you said "Try the dry adiabatic lapse rate of 3 degree C / 1000 feet.... "

Why ?

The International Standard Atmosphere (ISA) lapse rate is 1.98 deg C per 1000 feet !

Its going to give a TAS even lower than what the IAS to TAS conversion above gives.
e.g. Based on the assumption Surface Temp is 19C then using the DALR at 3C/1000ft gives an OAT at 16,000ft of -29C so the 231MPH IAS I got would result in TAS of 289MPH versus the 298MPH TAS value I got using the ISA lapse rate.

Last edited by IvanK; 06-06-2012 at 11:00 PM.