Ballista

I made this Ballista as a school project and thought it would be a cool thing to enter. It uses the elasticity in the rope to launch the dowling forward.

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    12 Discussions

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    fieldhockey4020

    Question 11 months ago on Introduction

    just curious, would this design throw something pumpkin sized and if not could it be adjusted to?

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    I8mAll

    5 years ago on Introduction

    One thing to watch out for: A lot of designs have the arms hitting those supports on the outside, in the end the arm or the vertical fails. The answer is to simply shorten the bow string so it barley holds the arms off the stops. As an extra it assures more energy is transferred to the payload. I've seen working replicas in the UK and the stops were there to hold the arms while tensioning the coils or replacing the string.

    Nice work!

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    jcksparr0w

    7 years ago on Introduction

    would you be willing to post more pics? i am tring to build one and it would be a bit easier with like 5 more pics

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    tylerpienta

    7 years ago on Introduction

    its not the elasticity of the rope its the torsion power when you twist it one way really tight it wants to unwind the opposite way and when you wedge a piece of wood or pipe in between the strands and twist it even more the opposite way when you draw it back it springs forward launching your projectile

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    meburnfire

    8 years ago on Introduction

    How long were the arms on the ballista compared to the size of the frame that held the arms?