dirka
16th May 2007, 13:58
Can someone, help me with an easy way to remember what the relationship between TAS, Mach, and Temp is. For example; if you are cruising at a constant mach number and the temperature increases, what happens to the TAS - and vica verca.
Thanks in advance:ok:
Old Smokey
17th May 2007, 01:44
Rainboe, Interesting linear formula for the normally expected temperature range, it seems reasonably accurate for day to day purposes:ok:
The exact formula, dirka, which is not linera, is -
TAS = 38.975 X SQR SAT X Mach Number,
Where, TAS is in Knots, and SAT (Static Air Temperature) is Degrees Absolute in Kelvin, i.e. °C + 273.15
The constant of 38.975 does suffer from a bit of Rounding Up/Down, depending upon the source of information, NASA's formulae work for me:ok:
If you look at both of the posts following your question, dirka, Hotter = Faster; Colder = Slower.
Regards,
Old Smokey
Kanga767
17th May 2007, 06:41
I've probably misread the last post, but for interest sake kelvin is not expressed as degrees kelvin, it is simply kelvin.
(ie water boils at 373 kelvin, not water boils at 373 degrees kelvin)
K
PS - and it is not spelt with a capital K