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What You Should Know About Reserve Static Lines (RSLs)
10/8/1996The purpose of an RSL is to provide an automatic link from the cutaway main canopy to the reserve activation. To do this the cutaway canopy must generate a drag force capable of pulling the reserve ripcord.
All means available must be employed to maximize and utilize this drag force. One of the best ways to maximize the drag of a malfunctioned canopy is with a "Cross Connector".
When the "Stevens" system was first incorporated, tests showed that a canopy with one side cutaway doesn't always have enough drag to pull the reserve ripcord (22 lbs.+ 5 lbs. for the seal = 27 lbs.). That's right, you could easily end up with less than a square foot of effective drag surface. Those tests were done with round canopies. There is no reason to believe that a square canopy would do any better - quite to the contrary.
The original "Stevens System" had the cross - connectors at the top of each riser, at the links. That location required two connectors, one front and one rear, to prevent elongation and resultant loss of drag of the main canopy. This configuration is not acceptable on a piggy back as the cross - connectors can and do catch under the reserve container. Presently we are enlightened enough to realize that cross connectors placed at the base of the riser near the attachment point to the harness, will preclude these problems.
The Racer/Elite employs such a cross - connector, with "Quick Releases" on both sides. It's routing takes it from the left riser, under the top half of the exposed ripcord housing, over (outside) the top or yoke flap, then to the right riser. The excess lanyard is concealed under the top "lip" of the pop-top and the respective sides of the yoke flap. Velcro is provided under the edges of the yoke flap to mate with Velcro on the cross - connector itself, thus preventing escape of any critical amount of lanyard in freefall.
After, and only after BOTH risers have separated from the harness does the cross - connector load the reserve ripcord pins, pulling them and activating the reserve.
Other solutions to this problem have no cross - connector, only a direct link or "static line" to the ripcord pin. We call that type "Side Sensitive", that is, it activates the reserve when the side to which it is connected has enough drag to release from the harness and pull the pin.
We trouble shoot the mechanics of parachute equipment operation with the "What if scenario". What if? On a single sided/side sensitive system one riser releases before the other, or that one side hangs up. The canopy goes into streamer and fails to generate enough drag to pull the pin, or the reverse. The other side hangs up instead. the pin is pulled and the reserve pilot chute entangles with the yet unreleased side of the canopy. Both of these scenario's have happened with tragic results on single sided systems
Experience has shown us that all of the single handle cutaway systems in use today release unevenly. Try as we may, (we being the designer and manufacturers) no one has developed a reliable method to perform this feat to date. Additionally, prudence tells us that we MUST assume a possibility of a release hang up. As much as 40 pounds of force has been required to release some poorly maintained riser release systems. This is after the cable has been pulled.
The entanglement scenario is prevented with the two pin, one to each riser, system. However, it retains the, "one side attached without enough drag to pull the pin", problem.
The cross - connector system is "what if'ed" with the accidental reserve activation at exactly the wrong time during the main deployment sequence. Some say, and we acknowledge that this rare occurrence would put the reserve over your head with the main inflated and in tow behind the reserve. Ok! what if that does happen? We have a good canopy over our heads and plenty of time to disconnect either side of the cross - connector and cutaway the main. No panic!
Suppose someone routes the cross - connector improperly under the top reserve flap. No one would do that you say! We did it in a test! No problem, we simply pulled the quick release and separation was complete. Later analysis identified that in that situation all one must do is pull the reserve ripcord. Then we have not only separation; but, a deploying reserve. Additionally, an AAD would provide the ripcord pulling chore.
Cross - connectors have been accused of being at fault by snagging a helmet (namely the motorcycle helmet - which was not designed with skydiving in mind), or other encumbrance. We submit that it is the fault of the helmet design and not the RSL. Helmets and all other pieces of extraneous parachute equipment, shouldn't have edges that snag.
On the Racer/Elite the choice is yours, single sided, or cross - connected, or none (see your owners manual). If you decide to do CRW on the way down and want to disconnect your RSL. Simply release one or both of the snap shackles and go for it.