Another Trebuchet-related question: Is there a ratio of arm to sling for a trebuchet?

Answer 1

I'll take a stab at this. I would think you want the sling to begin moving as soon as the arm starts to move. You DON'T want to shock load the sling as the first answer might indicate. Why? You lose power and control. Shock loading is an instantaneous acceleration. Extremely rigid bodies aren't as susceptible to shock loads as a rope would be.

A shock load will stretch the rope, which will then rebound, stretch, rebound...you get the point. Some of your energy is now tied up in the yo-yoing of the sling. I'm guessing on this one, but I think a sling length of 1/2 to 3/4 the length of the arm would be a good starting point. And seriously, I think there is some trial and error involved.

Answer 2

There would be a few things to consider, you want to provide the maximum force, with that you would want the sling long enough so that it doesn't start to move until the arm is at it's maximum velocity, but if the sling isn't strong enough to take the stress, or the payload isn't, then you would need to start motion at a different time.