|
It's much easier to do the upwind-downwind speed runs and
you get the results immediately. First, call weather and get the forecast winds
and temperatures for the altitude(s) you are testing at. Convert the true wind
direction to magnetic. Fly your GPS ground track, not heading, into and with the
wind, recording your groundspeed each way. Average the two of them and and
there's your TAS. Don't worry about forecast wind error unless it's more
than 20k at 90 deg, and even then at TAS greater than 200 mph your error will be
1 mph or less. To get density altitude, use this: dalt = baro altitude +
113.4' x (OATC + 1.88E-3 x altitude - 15C). Then get rho ratio: rr = (1 -
6.88E-6 x dalt)^4.256. Multiply the square root of rr times TAS to get IAS.
'Nuthin' to it!
|