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Zip line cable used to pull supplies up mtn...

  1. Jun 18, 2015 #1
    If even feasible, what minimum type/size cable reqd with trolly attached that would have maximum 1000 lb load suspended from it, that would be pulled up, from atop, by second separate free line for the following location; 1,000 foot elevation change to where base anchor point was, horizontally, 1,800 feet distant, looking straight down over it? Before cable sag and stretch is taken into account, the length of cable appears to need to be about 2,060 feet long. Also, what minimum strength pull rope would be required for 1000 lbs, if trolley was typical, friction-wise? Also, any clue to what minimum size motor or engine would likely be reqd on drum to pull 1000 lbs via that free line? Thank you, in advance, for any insights.
     
  2. jcsd
  3. Jun 18, 2015 #2

    russ_watters

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    Staff: Mentor

    Welcome to PF!

    You should start by drawing a diagram of this. Then we can help you do the calculations. Also, the pull rope needs to be connected below, not above, to avoid rubbing against or tangling with the suspension cable and trolley.
     
  4. Jun 18, 2015 #3
    OK, rough sketch here...
    drawing.jpg
     
  5. Jun 18, 2015 #4

    russ_watters

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    Staff: Mentor

    Great start.

    Now, the minimum strength required by a cable supporting an object comes from when the cable is vertical. Then it only supports their combined weights. The closer to horizontal or straight you try to make the cable (the less it sags), the higher the force. So: how much can it sag without hitting the ground?
     
  6. Jun 18, 2015 #5
    Let's assume as little slack or sag as reasonably achievable, so that the restraining posts at each end are as short as possible, but still high enough to have load off the ground, and not dragging, at either or both ends. When I say 'reasonably achievable', the best I'll be able to do, after top of cable secured, is have a pickup truck winch at bottom end slowly pull and make cable more taut before securing it.

    I won't be able to figure out, yet, just how high those posts will need to be. I've got to take into account the height of load and connecting straps up to the trolley at cable (guessing now about 6-8') and also how much we figure out that whatever chosen cable will likely be sagging below a straight line.
     
    Last edited: Jun 18, 2015
  7. Jun 24, 2015 #6
    I'm also needing to find smallest/cheapest electric or small engine powered winch that'll safely lift, at least, 1000lbs, and has a drum that'll accept 2,000' of 1/4" cable.
     
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