Forums: Skydiving: Safety and Training: Re: [DocPop] Question about coming back from a long spot: Edit Log

davelepka  (D 21448)

Dec 8, 2012, 5:15 AM

Views: 3807
Re: [DocPop] Question about coming back from a long spot

What exactly was the context?

What was the context of your statement? You made the reference to swoopers using rears, and that it must be more efficient or they wouldn't be doing it, but I think you're only dealing with half of the story.

Rears can be an asset, but only to a point. When you pull down on the rears, there is a portion of the travel that will flatten out the trim without distoring the canopy. Essentially, the inflated wing pivots downward off the A line attachment points, which effectively flattens out the glide.

However, this only works (well) for a very small portion of the travel. What happens if you pull too hard, is that the B lines will being to slack, and a crease will form in the canopy. At this point, you're no longer simply re-trimming the canopy, now your bending it half and pulling the rear half down into the wind, aka creating drag.

When swooping, that first little bit of travel actually gets bigger becasue of airspeed. When the pressurization is up, like at the tail end of a big turn, your canopy will hold it's shape longer than when pulling the rears in slow flight. On top of that, you have the concept of control effectiveness going up with airspeed, so again, at the bottom of a big turn, a little goes a long way.

So when it comes to ultra-high speed flight, and for minor trim changes to level your canopy for a swoop, the rears are the ticket. Once you're into them for the swoop, it makes the most sense to fly them out to a degree, but as it's commonly known, you don't fly them out to 100% just before the stall before you transition, you need to dump them and go to toggles at about 80% of what they have to give.

When it comes to steady-state flight at slow speeds, the brakes are far more reliable in terms of efficiency, and more forgiving in terms of the jumpers need for accurate inputs (both being good things when trying to cover long distances over 'long' periods of time).

(This post was edited by davelepka on Dec 8, 2012, 5:16 AM)

Edit Log:
Post edited by davelepka () on Dec 8, 2012, 5:16 AM

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