Forums: Skydiving: Safety and Training: Re: [Martini] Opening High for Bad Spots: Edit Log


Hooknswoop  (D License)

Feb 18, 2004, 6:42 AM

Views: 2409
Re: [Martini] Opening High for Bad Spots

Quote:
Derek, I have to disagree with you on the separation/groundspeed thing. The aircraft and the jumpers aren't influenced by the ground or it's relative speed, the ground doesn't even exist for them (unless ya get too close). Aircraft and it's spawn, that's you and me, only know the air.

Airspeed for a particular jump ship tends to be constant for each jump run. If the jump ship always flies into the upper winds for jump run, then as the upper wind speed increases, the jump ship’s ground speed decreases and more time must be left between exits in order to achieve the same amount of separation. The pilot could increase the aircraft’s jump run speed equal to the upper winds (if the aircraft had the performance to do so) and the amount of time between exits could remain constant, but this isn’t done. Therefore, exit separation is a function of the aircraft’s ground speed on jump run. In order to ensure separation between groups the following groups must look at the ground and allow sufficient ground distance to be covered before exiting. This is why the 45-degree rule for exit separation does not work.

So, as a jump ship’s ground speed decreases, more time must be left between exits to ensure the same amount of separation. This is why I said that separation is a function of ground speed. Ground speed (for a particular jump ship) is the variable, since airspeed is constant. Ground speed is used to adjust the length of time between groups.

Derek


(This post was edited by Hooknswoop on Feb 18, 2004, 6:45 AM)


Edit Log:
Post edited by Hooknswoop () on Feb 18, 2004, 6:45 AM


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