Weak-links need to be made from calibrated ropes. This often refers to woven fishing line that has been tested to break at certain strengths. Most aero-towing uses "Courtland Greenspot 130lb test", meaning it has been tested to break consistently at 130lbs of pull. Instinct has also purchased their weak-link material from TowMeUp.com as they provide stronger calibrated line that they use for payout towing and we use for our stationary towing. We use 4 different lines from them that are tested to 200#, 250#, 300# and 400#.
You need to know what tow pressures you are being towed at which is specific to your all-up weight (you, harness, glider, etc) and the form of towing you are doing (aerotow, pay-out, stationary winch).
It will be a never-ending debate on how strong the weak-link YOU choose is. The weak-link's job is NOT to prevent you from locking out but to prevent you from breaking your glider or the tow plane in the case of aero-towing.
If your weak-link is too strong, it would not break as it should to HELP avoid you locking-out while on tow. If your weak-link is too weak, a low-altitude weak-link break can be disastrous as well.
As pilot-in-command, the choice is always in YOUR hands.
The fact that weak-link material is tested to break at a certain value means that the second you start using it, there is a chance of it being compromised (weaker than when new). For that reason, it is ideally recommended that you use a new weak-link each flight. That is also your choice if you don't. You should be inspecting the weaklink on your tow system each time you fly.
10 сен 2024