Kind of Compound-Slingbow ;)

Discussion in 'Slingbows' started by Silversurfer, Dec 18, 2013.

  1. Silversurfer

    Silversurfer New Member

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    I am totally new in the slingshot business. So I am sorry if I have silly ideas/questions. Just let me know. ;)

    At first I wanted to copy Joergs foldable lightweight slingshot-Crossbow for my first project, but I decided to start with an easyer Slingbowproject.

    I thought about how I can add something new to this topic.

    So what about a kind of Compound-Slingbow to make it stronger?;) (maybe + doubling the tubes)

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    Totally stupid or an idea with potential?
     
    Last edited: Dec 18, 2013
  2. Obl1v1Aus

    Obl1v1Aus Meh!

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    I've been tinkering with a similar concept, just using an old compound bow riser I have and making limbs to suit the rubber like this.

    you need a string stop to emulate the 'snap' of a bowstring, If you reverse where the rubber attaches you can do this on the whisker biscuit guard of your drawing.
    probably a little confusing, so here are a thousand words on the subject
     

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  3. Silversurfer

    Silversurfer New Member

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    Is there any advantage in the changed drawing? I also wanted to use the attachment of the whisker biscuit as a string stop. Doesn't the String hit the stop much more harder and louder every time with your setup and delivers more the feeling of a normal slingshot than a bow? I hope I got your idea right.
     
    Last edited: Dec 18, 2013
  4. Ghosth

    Ghosth Over the hill but still swinging!

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    Interesting ideas.

    I'm not sure if it was me if I'd go with the compound style. Unless you have VERY good bearings you lose a lot of efficiency. Also I remember all too well the pain of trying to maneuver bow's through things like plum thickets.


    However you won't know for sure until you've tried it.

    If it was me, I'd make it less "bow" like, and more linear, more like one of Joerg's creations. If you need more power, go with stronger rubber.

    I suspect Obl1vAus is correct about the string stoppers. From what I've read here they significantly improve accuracy, by giving a clean denock point for the arrow.
     
  5. Obl1v1Aus

    Obl1v1Aus Meh!

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    I found with my setup that the rubber was able to be drawn more consistantly (less up and down shift).
    having the string stop dead where it started from will give a better shot of an arrow, if the stop is too far away the rubber will swing forward and the release at the end of its natural travel which will lose power and accuracy.

    a whisker biscuit itself is not strong enough to be a stop, it needs to be reinforced. ideally the stop should be a couple inches behind the whisker biscuit as there is a risk of the rubber following the arrow through the biscuit and ruining it, although with a good solid stop in place that shouldnt happen.

    I dont see why it would hit the stop harder every time, theres no power increase with each shot if my draw length and anchor point are consistant.

    all of my test shots so far have felt like using a bow, it feels like using a traditional bow more so than a compound. just remember that the rollers in a slingshot bow only extend the draw length, theres no reduced holding weight like a bow.
     
  6. Obl1v1Aus

    Obl1v1Aus Meh!

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    never been in a plum thicket but we have some pretty horrible bushes to content with here in Australia, a full sized bow is a pain.
    my sling bow using a bow riser is a lot more compact at 25" total height still bigger than a slingshot but nowhere near as bulky as the original 38" compound the riser came from
     
  7. JoergS

    JoergS Administrator

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    Of course I tried to go down that road. Failures, failures, failures.

    First off, rollers are not cams. Means, no let off effects. In the best of all worlds, if there would not be any friction and no additional mass, there would be a certain effect of the pre tensed rubber due to the draw length increase.

    But the world isn't perfect.

    Friction and mass do take their toll.

    Turns out that you can't draw out anywhere near the rubber bands you normally use when you go over those rollers. You have to use fairly weak bands instead. So you win a bit, but you lose even more.

    Muscle operated weapons must look at efficiency. There is just not very much energy that goes into the shot. That itsy little bit must be preserved with great care. Straight rubber does a darn good job at that.
     
  8. Silversurfer

    Silversurfer New Member

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    :eek: mmmh that doesn't sound very good. Thanks for your answears. I was thinking about using Skateboard-Speed-bearings for reducing the friction, but you nearly convinced me.;) I think I will build a normal Slingbow first. Might be good for my motivation to have success with a allready proven system for sure. Maybe I make some experiments and some research if I have some plywood left after finishing my first project, just for playing arround.
     
    Last edited: Dec 18, 2013
  9. kohlqez

    kohlqez Accident-Prone

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    I have a less-than-linear compound pulley equipped slingbow in the works, I don't have a program on my kindle that I could draw out the design on so you'll just have to wait... it's my first priority as of 9:45 tomorrow (US Eastern Time) so hopefully I can post some pics by Saturday or Sunday.
    You could also try making a reverse energy bow like these. It would be hard but awesome. Joerg maybe you could make one as part of your branching out into other muscle based weapons?
    Edit: Ok I convinced myself to try it now lol
     

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    Last edited: Dec 19, 2013
  10. Silversurfer

    Silversurfer New Member

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    I canceled my Plans for making a compound Slingbow ;)

    ...I made boring normal one.:D

    Maybe you like it anyhow.

    Thanks Jörg for your inspiration.

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    Last edited: Sep 20, 2014