Ronaldo 0 #26 August 11, 2006 I do agree that line stows create bag whip, specially because they are not all placed in the same plane as the bridle but IMO bag inertia and pilot chute speed play a very important role in not giving the bag much chance to rotate. I think that it would take hundreds of jumps with controlled packing and deployment to show at least a measurable difference in line twists with or without stows. Besides that, any advantages of free stowing might be overcome by the potential for packing error (tension knots, for example). I also would expect free stows to be more effective on smaller (lighter) canopies as they would be more sensitive to bag whip. IMHO line twists are caused by the way the bag leaves the container (caught by a flap or a corner or having the last stow too close to the links). I’m only considering bag twists, not twists during inflation, which are usually caused by body position. BTW, I don't have much skydiving experience so please take all this as an engineer's opinionEngineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted Quote Share this post Link to post Share on other sites
Martini 0 #27 August 11, 2006 I'm inclined to agree with you regarding inertia and "bag whip" although bag whip isn't the same as a spinning bag. My experience with relatively small canopies also doesn't bear out the assumption that lighter /smaller d-bags are more likely to spin. My Xaos has twisted up a few times but mostly during canopy inflation not at deployment. Most of my jumps are wingsuit throwing in full flight. No doubt about it, the bag spinning as it leaves the container is the main culprit since I rarely have problems in normal freefall. I might take some exception to "not twists during inflation, which are usually caused by body position. " Ever jumped Stilettos? Well known for: I got it, I got it....ZOOOOM.! But generally I would agree that uneven risers can cause twists (and spins ) during inflation. Right now my spin is caused by the empty bottle of wine next to me. The obvious remedy is to open another.Sometimes you eat the bear.............. Quote Share this post Link to post Share on other sites
mjosparky 4 #28 August 11, 2006 Quotetension knots, for example). Tension knots are more likely with line stows. There is more chance you will have uneven release of the line groups. It’s the slack in one line group that causes tension knots. But by far the biggest cause is body position at line stretch. If one shoulder is low the line groups on that side will take tension first while the other side is slack. This is when tension knots happen. jmo QuoteI also would expect free stows to be more effective on smaller (lighter) canopies as they would be more sensitive to bag whip. The bag I pictured is jumped with a 245 Sharpchuter. Pretty heavy canopy. It is my feeling, no proof, that line length has more effect then canopy size. Again jmo BTW, I have a lot of skydiving experience so please take all this as a retired test jumper’s opinion. (I couldn't resist)My idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
