Hey, I realize I'm coming to this game waaaay late, but this thread popped up in a search I was doing and caught my eye so thought I might
shed some light on all this. When I am speccing any aerial rigging I START at a 2000# attachment
point for the apparatus for a single person. This covers most situations, though sometimes you need to look a
bit closer as to what's going on on the other side of the
point and run the numbers. I saw the comment about
Hall Associates hanging a flying rig from the linesets - please understand that a theatrical flying rig is very different than a circus rig, especially in function. It's very difficult to create a
shock load with a harness performed on a glorified curtain
track (no offense to Peter Foy, I wouldn't be doing what I do without him), whereas circus performers seem to get paid based on the amount of
shock loading they do in a routine. When you run the calculations with the right numbers on a silk, you wind up with a 220# guy hitting a hard 6'
drop generating just under 8kN of force, which sortofkinof translates to 1750#. A 110# beginner who is MAYBE doing three
foot drops might hit around 700-800#. The big mitigating factor here is the stretch of the material itself as stopping distance is a massive modifier in
shock load equations. Pros tend to use a 'medium' stretch fabric which can have up to 50% stretch, making the stopping distance quite a
bit more than the 1" used by the OP. Ultimately, though, the right answer to all of this popped up a few times in this thread - if you're get asked fly someone, hire an aerial rigger. We're a lot cheaper on our day rates than the liability claim that's lurking around the corner, and way more fun!
Aaron -
www.otvaerial.com