Trebuchet Design

Discussion in 'Community Discussion' started by Benjamindaines, Oct 18, 2006.

  1. Benjamindaines macrumors 68030


    Mar 24, 2005
    A religiously oppressed state
    If you were to build a trebuchet with a 36" arm and a fixed counterweight how long would you make each part of the throwing arm (below pivot point [counterweight side] / above pivot point [throwing pin side]) to get the best throw distance / efficiency?
  2. redrider688 macrumors newbie

    Mar 15, 2010
    hey, im building a floating arm trebuchet for my engineering 3 project in highschool. I know basicly what to do, but was wondering if you made a bigger scale version. If so did you have any sugestions, or any major problems you ran into??
  3. ethical macrumors 68000

    Dec 22, 2007
    I never thought I'd find a thread about building medieval weaponry on a Mac computer forum. Let alone one that's resurrected from 2006....
  4. steve2112 macrumors 68040


    Feb 20, 2009
    East of Lyra, Northwest of Pegasus
    MacRumors is like a box of chocolates. You never know what you're gonna get.
  5. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    You should search the xkcd forums. Trebuchets were a popular topic there when I frequented those forums.
  6. richhersey macrumors newbie

    Sep 29, 2010
    About to build my first Trebuchet

    I'm about to build my first Trebuchet and I'm wanting to make a book of tips for everyone to share.
    If you want to build a Trebuchet, what would your biggest question be?
    If you've built a Trebuchet, what was your biggest challenge?

    If you contribute I'll email you a copy for free. The book of tips will be free to anyone else too.

    Can you take a minute to fill out a survey for me so I can collect the answers all in one place? Thanks!

    Trebuchet Survey
  7. Melrose Suspended


    Dec 12, 2007
    Is it accurate enough to take out my neighbour's stereo?
  8. Sydde macrumors 68020


    Aug 17, 2009
    Velvet Green
    Start by asking how much collateral damage is acceptable. Can you afford to take your neighbor out along with the stereo?
  9. Melrose Suspended


    Dec 12, 2007
    That is well within the range of acceptability. :D
  10. Baby Stalin macrumors newbie

    Oct 24, 2010
    First Trebuchet

    I am also doing my first trebuchet for a physics project. I have finished building it i am just tweaking it right now. The long arm is about 63 in. and the short arm is about 15 in. I am using a 7 gallon water jug (~60 lbs) as a counterweight, and i am launching a ~250 ml water balloon as a projectile. I have the correct launching angle for the trebuchet, and the correct size for the sling and pouch. But I am having one problem with the launching. Right when the water balloon releases it pops and i have tried everything. I have reduced the weight of the counter weight but then the balloon barley goes anywhere (20 ft). I have also got brand new water balloons to see if the others were too old and the same effect happens. I have also kept on putting different pouches made of different materials on with no rough seams, but the ending is always the same. When I first built the trebuchet, I was getting good distance and deadly accuracy, but then randomly after wards the balloons started busting as they left the sling. I am aiming for about 100 to 150 ft. Any help would be very much appreciated.
  11. iJohnHenry macrumors P6


    Mar 22, 2008
    On tenterhooks
    The sudden acceleration is causing you grief.

    Try one of the mylar balloons, that you can buy for birthdays, get well, etc.

    Empty the helium, and fill with water. They should give you the tensile strength to withstand launch.
  12. eawmp1 macrumors 601


    Feb 19, 2008
    The sudden acceleration is causing deformational and shear forces on the ballon that exceed it's expansile and tear strength. A smoother, slower acceleration, which would require a longer trebuchet arm to get to an appropriate velocity, or a tougher balloon material is needed.
  13. iJohnHenry macrumors P6


    Mar 22, 2008
    On tenterhooks
    I believe I said the very same thing. :p

    And nice edit on "ballon". I was just waiting in the wings with this, from Wiki. :D


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