ProTrack/Neptune/etc. jump downloading/graphing

[peek 21]

ProTrack/Neptune/etc. jump downloading/graphing

Is there anyone who has downloaded and graphed a number of jumps from one or more of these devices?

A lot is said of reading the speed numbers that are displayed after a jump, but I'm not sure many people understand them, and certainly few would understand how they are derived, because the manufacturers are not going to tell you except in a very general way.

I'm not even sure many people even know about true airspeed versus any of the other calculated airspeeds, because I don't think I have EVER heard anyone (without a technical interest in these devices) say exactly which calculation they are refering to when asked how fast they were falling on a jump.

In other words, it appears that most people are treating these speeds as some magic numbers without knowing anything about them.

Ref:
http://www.pcprg.com/baro.htm

[Remster 30]

Quote

In other words, it appears that most people are treating these speeds as some magic numbers without knowing anything about them.

I havent downloaded load of jumps, but a handfull (on my Neptune). Even before that, I woudl not consider any speed value a unit gives (Pro Track, Neptune or other) and an absolute.

Placement of the unit, the unit itself, the type of jump, etc... will all affect the measurments.

The way I see it, these units are a good comparaison tool from jump to jump, if you comapre your own readings each time.

Remster

[Staso 0]

i download from my pro-track every jump i make, since all of them are pretty much speed dives. as long as the same devices is used with the same configuration then it should be pretty accurate for comparing speed. how far away it is from real air speed, nobody knows :)

stan.

--
it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ...
Speed Skydiving Forum

[skytribe 17]

I download the data and most of mine are tandems so one would think that they should be pretty flat graphs what with you hanging under a huge drogue.

But the graphs do vary considerably but fast dives (ie. ones where camera person is in fast sit to stay up) do normally provide a higher airspeed readings on the graph.

I graph them more for interest and to build up data - it also allows me to trace when the drogue was deployed and an approximation of the opening time.