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    Semi Ballista

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    hullutiedemies
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    Semi Ballista

    Post by hullutiedemies on Wed Dec 05, 2012 10:07 am

    Here is an easy and economical way to build a torsion engine




    Just tie two short skeins of cable
    Stick one end of a frame bar and throwing arm through the loop of the skein.
    Twist both arms one turn and string

    This thing pulls about 40#/7"
    It puts an airsof pellet into a card board box
    and a .17 BB through the box.


    Torsion spring here is manilla rope.
    1 gram of manilla can take 2 Joule load before failing - about as good as rubber band.
    About as goot as biomaterial goes.

    Other cable materials can of course be used.
    I have tested this system eg. with old woolen socks.
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    Re: Semi Ballista

    Post by Ivo on Wed Dec 05, 2012 1:54 pm

    I have tested this system eg. with old woolen socks.



    Not sure if you were going for laughs there, but you certainly succeeded and then some...

    This little ballista is actually really cool...three sticks, two socks, a shoe lace or the like for the string....damn, that's good stuff, haha!

    I've been flooded with *want* with similar ideas...I really like seeing shapes in things created by nature...and one thing the comes to mind is using a trunk of a tree with two branches serving as riser ends to mount limbs/levers on for a reverse draw crossbow (call it ~ Log Bow maybe jocolor)....and this little engine fits so well with the concept.



    Do you plan on taking it a bit further or is this more of a research type of build for information and inspiration? cyclops

    Ivo




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    Re: Semi Ballista

    Post by hullutiedemies on Sat Dec 08, 2012 10:55 am

    Ivo wrote:Do you plan on taking it a bit further or is this more of a research type of build for information and inspiration?

    This was originally intented just for proving the concept and testing materials.
    But it worked so well that I need to re-build it. With properly shaped riser and trigger. This should make a fun pistol type pellet bow for backyard plinking.
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    Re: Semi Ballista

    Post by Ivo on Sat Dec 08, 2012 6:30 pm

    Good to hear! drunken Definitely looking forward to seeing it, would make my day!

    Ivo

    PS: Cool avatar...did you encounter any examples of that kind of chukonu in reality?




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    Re: Semi Ballista

    Post by hullutiedemies on Mon Dec 10, 2012 10:06 am

    Ivo wrote:PS: Cool avatar...did you encounter any examples of that kind of chukonu in reality?

    Thanks ,
    I have made one.
    I have not published any pictures yet, as it is still undergoing field testing and has mildly put "somewhat unfinished" appearance.

    My own primi-compound system with chuko-action and magazine spring, so it can be shot sideways.

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