Re: [ATM] Off-Topic: String Theory

[GARY FUCHS <gary@rcn.com>]

Hello Richard,

Suppose your friend George were to arrange things so that each hinge had a string of it's own connected to the hinge on the inside and right in the middle of the hinge. And each of the four strings went through one of four holes in a ring in the center. Each of the holes would be at 90° to the next, and just large enough for the string to pass through.  And within that ring the four strings were tensioned my a single mechanism. If all the strings start out at the correct length would that solve your friend's problem?

Actually, we tried something vaguely similar for a truss scope. Unlike your friend George's idea, we didn't use hinges but instead braces with angled openings for the tubes. And we didn't have any string so used braided wire. The wire ran through the tubes so was mostly hidden. I think if there were a way to incrementally tighten the wire at each junction - like when lacing up shoes - this method might indeed work. Maybe someone has made it work?

Have you suggested that since George will be unemployed (will he be eligible for unemployment, does he support a family, have other expensive hobbies?) he might consider just a sonotube? In any case, I hope he can get some rest. All that tiredness will surely affect his night vision.

Gary Fuchs




---- Original message ----
>Date: Sun, 9 Sep 2007 16:36:04 -0700
>From: "Richard Schwartz" <richard1941@gmail.com>  
>Subject: [ATM] Off-Topic: String Theory  
>To: atm@atmlist.net
>
>My friend George has a problem.   He plans to build a hinged frame
>A-B-C-D with diagonals AC and BD. The sides will be one meter.
>Obviously the frame will be  "floppy" and will not hold its desired
>square shape.   To stabilize the frame, George plans to run a single
>string A-C-B-D, anchored at A and D, and with frictionless slides at B
>and C so that all of the wire is under the same tension.
>
>George thinks this is a great idea because all you have to do to
>stiffen the whole frame is use a single tensioner like a guitar head.
>There is no need to mess with separate tensioners for separate
>strings.
>
>George has grand vision of all kinds of giant self-erecting
>structures: airships, sailboat rigging, bridges,  domed sports
>stadiums, and even giant space colonies, and is about to contact his
>patent attorney.
>
>But he is all bushed, trying to sort out the details, and has axed me
>to have you advise him.  As soon as he works out the details for the
>square frame, his first project using this principle will be a
>telescope truss.   He needs this because he expects to be unemployed
>in the near future.
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