dhall_polo
Well Known Member
I have not used the iphone app but I presume it is similar to the widely used NPTS method, ntps.
My understanding is that these methods are more accurate and do not calculate TAS from IAS/CAS corrected for altitude or temp. Instead they use trigonometry/maths (totally beyond me) to calculate TAS and the wind direction and strength.
I am sure someone with more maths intelligence than me could explain it better.
Fin
9A
Yes, the iphone app leverages fellow VAF'er Doug Gray's formulas for GPS->TAS from back in 1998. I believe the NTPS stuff is derived from the same. There are some spreadsheets and java applets available that do the same thing. The iphone version is just more transportable.
Here's a link to Kevin Horton's write-up with a lot more detail:
http://www.kilohotel.com/rv8/rvlinks/ssec.html
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