lml@lancaironline.net Mailing List Archive

Computing True Airspeed

The spreadsheet AirspeedFromThreeTracks.xls Computes the actual true airspeed of a plane given three GPS tracks taken at the same airspeed. Given three GPS tracks at the same airspeed you can compute a complete solution for the heading on each track and the TAS. The spreadsheet contains actual data taken at low altitude in Lancair IV-P N776CM. Additional data will be added to the spreadsheet as it is collected for other altitudes.

On Tue, Dec 10, 2013 at 4:07 PM, Craig Jimenez <cj@awlbiz.com> wrote:

Chris & Hamid,

Using similar ideas to take wind out of the picture, Ed Williams
(references below) derived the equations for an easy to fly method. Hold
3 headings separated by 120-deg, measure GPS ground-speed -> true
airspeed:

http://williams.best.vwh.net/avform.html#3gs

He also converts IAS to TAS even when Mach is not negligible (good for
finding calibration issues with OAT & airspeed):

http://williams.best.vwh.net/avform.htm#Mach

I put both into a spreadsheet that works on computers and iPads:

http://www.beechtalk.com/forums/viewtopic.php?f=3&t=49840&start=400

--
Craig

--
For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html