But i don't understand http://www.paralog.net/...p;trackid%5B%5D=1201 How the same jumper with same Ws , the same day (only 3 hours between tries) could score: 903m at 151.4km/h AND 1909m at 248.4km/h (same 1000m vertical)
But i don't understand http://www.paralog.net/...p;trackid%5B%5D=1201 How the same jumper with same Ws , the same day (only 3 hours between tries) could score: 903m at 151.4km/h AND 1909m at 248.4km/h (same 1000m vertical)
Mar 14, 2012, 8:48 AM
Post #4 of 10
(1114 views)
Shortcut
Re: [granpasc] Speed with Vampire 4 and Ghost 3
[In reply to]
Can't Post
When looking at any of these figures you should bear in mind that they can be greatly affected by wind, diving/flaring & for base jumps thermals.
The two tracks you posted are in opposite directions (but as drunk pointed out second one looks like profile of tracking jump). It's quite possible that one is down wind and the other upwind. The winds aloft could also have changed in the 3 hours between jumps.
Of course it's possible there was a strong tailwind on the jump in the video, but I'd guess less than 20knts. I suspect there is a strong tailwind on most skydives showing a sustained GR above 2.8:1
For every 10knots of tailwind you can add about 5meters in distance per second of flight. In the Paralog competition the vertical 1000m usually takes 50-90 seconds. 40 knot tailwind for 60 seconds of flight will give you 1.2km extra distance!
(This post was edited by LukeH on Mar 14, 2012, 9:07 AM)
Mar 16, 2012, 12:07 PM
Post #8 of 10
(822 views)
Shortcut
Re: [granpasc] Speed with Vampire 4 and Ghost 3
[In reply to]
Can't Post
That was my videoed V4 performance run. I had a tail wind of 18kts at altitude on that run. I determined the wind from the difference b/t indicated airspeed from the plane and GPS ground speed soon before I left the aircraft. Once I left the aircraft I had a really fun time :)
