What kind of rope is best for a ballista? Answered

+1

I don't know if it's the weave used or what, but in my experience, nylon rope stretches quite a bit under load, (far, far more so than hemp rope) implying that it has a very low spring constant.

So nylon would make a very bad spring as it stretches, which means it isn't a good spring as it wouldn't be able to hold a constant amount of force whereas a hemp or sisal rope would work much better as a spring as it is able to keep its springiness for a longer period of time and hold it better?

Well, that's *my opinion, based on previous experience trying to use nylon rope for both pulling and suspending heavy loads. As I noted, it could be a weave issue, although I'm not sure.

It has been my experience that hemp rope is far less "stretchy", so I would think it would have a higher spring constant. I don't have enough experience trying to support any weight of consequence with sisal. My experience there is pretty much limited to tomato/cucumber cages and bundling sticks.

I was mainly +1-ing the "Do some simple tests by hanging a piece of rope...", since that's probably the best advise of all, short of a ballista expert chiming in.

Well, i made the ballista and tested it... and i couldnt get enough sisal/hemp/manila at a reasonable price to make the second spring, and i found that nylon is actually pretty strong as after a while, it cant stretch and you can just tighten it. A lot.

So which kind of rope do you think worked the best, I'm trying to make a catapult for school and i wasn't sure what rope to use.