Post by t***@gmail.comPost by Dudley HenriquesPost by t***@gmail.comLooking at the definitions I have, I can't figure out where air
pressure is taken into account, example, 100kts indicated at 14000
feet will be much faster than sea level, because the air is so thin at
14000.True airpseed takes into account non standard temp, but not
pressure.
Help appreciated.
Think about it for a second. You say "thinner air". Thinner air equals
less what?
Dudley Henriques
Thinner air equals lower density. Yep, I got that. But the definition
says "non standard temperature". Does this mean 15C for all altitudes
or 15-(altitude/1000*2)? i.e. factor in standard lapse rate and
calculate deviation away from standard temp *at the altitude we are
flying at*?
Non standard temperature as relates to TAS means actual temperature at
altitude vs the standard lapse rate. For example, a TAS indicator has
a scale for setting in pressure altitude and a small scale for setting
in your ACTUAL temperature at altitude. The actual temp can be
different than the standard atmosphere, thus non standard. The
combination of pressure altitude and temp gives you the TAS.
Figuring TAS can get to be quite complicated as the need for more
accuracy is desired.
For all practical purposes in light aircraft, a simple calculation is
all that's needed.
DH