Help with compressed air thrust

[Danger]

Exactly what I had in mind, but I couldn't find a high enough torque motor that won't be too big. And thanks, but I just need the math is all. Also my line will be steel cord.

Try checking out the "Superheroes" episode of Mythbusters (or maybe the Star Wars one, I forget) if you can find it on U-Tube or the Discovery Channel site. Jamie managed to build a wrist-mounted winch for his grappler that pulled him up fairly smartly, and that dude has got to be well over 200 lbs.