There were a number of questions regarding the engineering for this project that needed to be addressed before starting. Here are a few that immediately came to mind:
- If I string a cable between two trees, how much tension should be on the cable? Too much and it might pull the trees together, especially when a weight is hanging on the cable. Too little and the cable will sag – maybe to the point that a rider would stop in the middle.
- How steep should the cable slope be? Too steep and the rider may gain too much speed to land safely. Too shallow and the rider may not make it to the end.
- How much weight will the cable hold?
- What is involved in stopping the rider safely? If the rider is going too fast and there’s nothing to safely stop him / her, then he / she will smack into the tree and sustain injury. And any system that safely slows a forty pound rider may not work with a hundred sixty pound adult, since the adult will have quadruple the momentum that needs to be stopped.
- Based on the answers to some of these questions, how much tension will be on the cable, and what size cable should be needed to withstand the tension?
My general approach was to use experimentation and trial-and-error to figure out the answers to these questions. Then, based on the results of these experiments, I would be able to come up with a design that should work and provide a reasonable margin of safety.