# Found Date

As they say, data is/are where you find it/them. Was flying back from Beijing yesterday (by date, day before by day) and the plane had a
GPS/sensor display. It showed the plane's position on the globe. It showed the speed. Also, from time to time, it showed altitude and temperature. I noticed this on the flight out, so on the flight back, was prepared to take the values down.
FWIW, Here are altitude/temperature data for the Beijing takeoff, and the Newark descent:
TAKEOFF FROM BEIJING Alt (m) TempC =============41 26 462 23 1172 21 1217 19 1228 19 1892 17 2322 15 3009 12 3544 8 4794 3 8534 -27 10058 -38
DESCENT TO NEWARK Alt(m) TempC ===================10363 -36 8229 -24 6553 -12 6400 -11 6248 -10 5943 -7 5469 -5 5213 -4 4930 -3 4865 -2 4849 -2 4771 -1 4665 -1 4500 0 4223 2 3994 3 3841 4 3671 5 3654 5 3505 6 3349 7 3260 8 3106 9 2950 9 2725 10 2567 11 2442 12 2291 13 2146 14 2135 14 1954 15 1836 16 1828 15 1775 16 1566 17 1522 17 1492 17 1361 19 1229 19 1214 19 1192 19 1096 20 974 20 908 20 858 20 747 21 639 22 541 22 449 23 337 24 201 24 113 24 21 24
The relationship is remarkably linear, just as it is in the NOAA Standard atmosphere. A least squares fit intercept should yield the ground temperature as the intercept and the slope should be about the same in both places.
This linear relationship is used to predict pressure and density at various altitudes. It isn't foolproof, though. In spring, for example, the slope is mush steeper.
NOTES: Descents are slower than takeoffs, so there are more descent data..
The display showed data in metric, and sometimes in English with metric XLation. There were more metric values so I used them.
Regards, -Larry Curcio
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Larry Curcio wrote:
<some temp vs alt data>
So, it looks like I can fire the drogue at about 10 degrees and pop the main at 22.
Thanx!
;)
--
Gary Bolles

summum jus, summa injuria est
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Neat. It's kind of surprising how much the temperature changes just a few thousand feet above ground.
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