Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!van-bc!cynic!ireta!rob From: rob@ireta.cynic.wimsey.bc.ca (Rob Prior) Newsgroups: rec.skydiving Subject: Re: bungee jump from plane Message-ID: Date: 5 Feb 91 16:31:57 GMT References: <1991Feb13.172511.6896@murdoch.acc.Virginia.EDU> Organization: Federation of Sentient Planets, Burnaby BC Lines: 59 ds4a@dalton.acc.Virginia.EDU (Dale Southard) writes: > >> I can imagine ... not much. (note that the length of cord has no effect > >> on the torque as it is not rigid) > > >Where did you learn physics? Pilot loses one jumper as he leaves, conpensat > >accordingly, and suddenly has to compensate the other way as the cord tighte > >when the lost jumper reaches the end of his line and the torque increases. > > Well, sorry to point it out, but the length of the cord has no effect. > Velocity does. > Effective force constant does. > Distance from CG does. > Length doesn't. I didn't say length had _any_ effect, did I? What I said was that the pilot would compensate for the loss of 1 200lb person and then have to deal with regaining it 3 or more seconds later when he/she gets to the end of the line. Length would affect how long the pilot has to wait for this, though. Another thing, the whole rope isn't bungee. It (if I recall correctly) (someone here did an analysis of it once :) is about 80% rope, 20% rubber (or bungee cord, or whatever). This may have an effect. > 1) Can the jumper really bounce back up and hit the plane? (I think this > violates some enery conversion law somewhere) I don't think so... I would think that (wind resistance+energy loss) would be sufficient to keep the jumper far enough from the plane. Maybe after the jumper cuts away? Could the cord snap back far enough? > 2) Are static lines safe? (It may indeed be that all pilots are just one > student in tow away from tumbling out of the sky) Sure, static lines are safe. BUT... I'm sure that when a student goes out and gets stopped at the end of the line because of something jamming, the pilot gets a _very_ sudden shock that he has to compensate for... I have never jumed SL, and have never seen videos of SL hangups (apart from Wally's :) so I don't know if this is true or not. > 3) Why the hell am I defending an idea that I really don't care all that much > to try? (Couldn't we discuss the best way to do a triple dragplane diamond > instead?) Possibly hoping someone will come up with a completely safe method for implementing the idea? :) I don't know why i'm defending the other side of it either, but debates like this are fun... :) > But at any rate, thanks for the deversions -- I really hate to do productive > work :-) Who doesn't? :) +------------ | rob@ireta.cynic.wimsey.bc.ca | Rob Prior, President, Still Animation Logo Design +------------------------------------------------------------