Walter Boyd wrote: Doc, great idea. Link didn't work though.
Sorry.. It got trashed.
Try this one:
http://www.ntps.edu/images/stories/documents/gps-pec.XLS
Or just Google
GPS-pec.xls.
And you'll find several of this sort of spreadsheet.... And more-detailed than you need or want explanations of how it works and how to use it.
I like the more app-style version that Don Norris posted below your reply even better than the soreadsheet.
See my comment to Don regarding an input of pressure altitude into the calculation needed, if, as was my intent, what we want for the final number is NOT true air speed TAS but calibrated airspeed CAS....to see if my Air speed indicator ASI is reading out higher or lower than it should be.
The only instance where CAS and TAS woul match would be at a pressure altitude of sea level. Typically the true air speed is 2% higher than CAS for every 1000 feet above MSL.
I guess I COULD wait fior a standard temperature and humidity day and try to fly the three calibration legs skimming over the wave tops at sea level so TAS and CAS would be exactly the same, but for some reason I'd be reluctant to do that. 😉
That 2% correction rule can be a bit off without throwing in an outside air temperature correction, but if iFly used it as a flat 2% with MSL in the final step in the calculation it couldoutput CAS instead of TAS (which would be different than little spreadsheet does.) actually, since it would already know TAS no reason it shoukdn't output BOTH.
That is, iFly itself could actually input a very close to precise final member for CAS using the TAS spreadsheet calculation from the three leg run plus its reading of MSL.
So Walter... Would you be willing to add this to the wishlist stack? It's lower priority than other things, but I suspect it coukd be stunningly easy to implement and add vale disproportionate to the investment.
Alex