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.

Comments

[fieldhockey4020]

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

[I8mAll]

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!

[jcksparr0w]

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

[ethiran]

nice one,but can u make a popsicle ballista?

[tylerpienta]

oh and how far does it shoot?

[tylerpienta]

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

[mdaly3]

How many times did wrap the rope

[meburnfire]

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

[lynx66]

could you post how you made it

[rimar2000]

Good work, Brandon!

[brandon.horrell]

Thanks

[mr.incredible]

You'll put your eye out kid...