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Old March 5th 13, 03:42 PM posted to rec.aviation.soaring
JohnDeRosa
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Posts: 236
Default Calculating G Forces from IGC file?

I thought it would be an interesting experiment to take an IGC trace
and figure out rates of climb. That much was pretty easy. I took
consecutive IGC file B-records and with just a little math I was able
to determine the ft/min or meters/min climb rates*.

I then thought it would be a good experiment to determine the G forces
as I pull up (decelerate) from cruise to lift or push over
(accelerate) from lift to cruise. Are there any physicists in the
house that can come up with a SIMPLE formula to calculate what a G
meter would have read based on the information I have?

Thanks, John

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* The many individual b-records in an IGC file contains lots of good
information.

B1101355206343N00006198WA0158701558

110135: time tracklog entry was recorded at 11:01:35 i.e. just
after 11am (GMT)
5206343N: latitude i.e. 52 degrees 06.343 minutes North
00006198W: longitude i.e. 000 degrees 06.198 minutes West
A: altitude valid flag confirming this record has a valid
altitude value
01587: altitude in meters from pressure sensor
01558: altitude in meters from GPS

Rate of Climb per minute (m/sec) =
(Altitude #2 - Altitude #1) / (Time-Seconds #2 - Time-
Seconds #1) X 60 seconds

Rate of Climb per minute (ft/sec) = Rate of Climb per minute (m/sec) X
3.28084