I talked with a representative from line maker cousin-trestec, asking for tips on paraglider line care. Here was his response.
- Avoid getting the lines wet. If they do, allow air drying as quickly as possible out of sunlight to the degree possible.
- Avoid high heat. As lines approach 70°C they shrink. One future flights, the loaded A’s and B’s stretch back to normal, leaving the rear lines shorter and thus changing the glider’s shape. Shrunk rear lines slow the glider down and increase likelihood of parachutal stall or spin.
- Never store them wet. As much as heat, allowing lines to stay wet in storage can significantly degrade strength.
- Don’t allow sharp bends. Doing a “daisy chain” like sky divers is considered bad form.
- Avoid excess UV exposure. We fly in sunlight, of course, but when not in use, protect them.
- Avoid excess heat.
I was a bit surprised how much emphasis was placed on avoiding moisture. He made it sound like that was line enemy number one.
Heat is a big one since it only takes one time at high temperature to shrink lines. Leaving the wing in hot car, or laying it out on a hot surface (like a dune) can get be enough to shrink lines and take a glider out if its certified condition.
There are two primary materials used for paragliders: dyneema and aramid (what Kevlar is). They have different properties. For even more details, search “PARAGLIDER LINE MATERIALS, AND WHY THEY MATTER TO YOU” which should bring up a good UP glider’s article on different materials used in paraglider manufacturing.