already making plans for my very first slingcrossbow (or sling for that matter)

Discussion in 'Slingshot Crossbows' started by SkauneJohan, Jan 7, 2012.

  1. SkauneJohan

    SkauneJohan Member

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    will probably print out some drawings within a few days and make it in cardboard for use as an template for the real thing <img src="http://illiweb.com/fa/i/smiles/icon_cheers.png" alt="cheers" longdesc="28"><br><br>I wanna use theratube for long durability so it will be similar to the medival style in rubber attachment and operation, but i wanna use the type of trigger that the bullpup crossbow is using (is this possible?)<br><br>i think my draw length will be maybe around 45-50cm so my thought is to have a fork about 40cm wide and the bands about 9cm long each<br><br>what do you think?<br><br>any suggestions will be appriciated the draw length cannot be very much more(maybe a little), but fork width can be more <br><br>power is not the most important, if I can break glass bottles at a little distance this is enough <img src="http://illiweb.com/fa/i/smiles/icon_twisted.gif" alt="Twisted Evil" longdesc="13">
     
  2. mr_paradox

    mr_paradox New Member

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    I am fairly new to making slingbows (I am not sure what the technical term is).<br><br>The forks should be as close as physically possible for the maximum power.<br>I would say same distance as a normal slingshot or less.<br>Simple physics, you want the elastic to be as little angle to the projectile as possible.<br><br>I would also say to get more power, get a roller system like Jorge has to compound the elastic.<br>I have not experimented with rollers since I have problems getting basic things where I am, so I am in process of making a small lathe so I can make good rollers.
     

  3. SkauneJohan

    SkauneJohan Member

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    yes I do know forks should be as close as possible for effeciveness, but i have limited gun length and rollers would make it too complex(no fun) and I suspect that rollers do not work as well with theratube like it does with flatband???<br><br><br>Like i wrote in my first comment: the firing mechanim will be like the medival style slingcrossbow, only differs that it is in a smaller scale<br><br>the difference i wanna make is to have the trigger like the bullpup instead of a medival style tiller <br><br>thanks for the input anyways <img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1"><br><br><br>cheers/Johan<br><br>ps. I will show you later why the gun length is limited when i take pictures of my cardboard template
     
  4. JasonP

    JasonP New Member

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    all sounds good, only sugestion is to rethink your band lenths. if i understand your design your bands will be streached about 64cm due to your wide fork not just the 45-50cm of the shaft, for a 9cm band thats a 710% elongation. Idealy a sling bow would use arround 500%-600% elongation
     
  5. SkauneJohan

    SkauneJohan Member

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    draw length in a single plane is no problem for me to calculate, but draw length in dual plane and adding pouch and stuff is beyond my math skills, you must remember that the pouch and the strings to attach the forks with the band will take some room also <br><br>here is one of Jørgs pictures with his tubes and pouch since I will use the same design<br><br><a href="http://img696.imageshack.us/img696/8268/bandsq.jpg" target="_blank" rel="nofollow">http://img696.imageshack.us/img696/8268/bandsq.jpg</a><br><br>I will try to get as much draw length as possible, since I do not know how the balance will be of the finished gun yet, maybe i can get more without it getting too front heavy <img src="http://illiweb.com/fa/i/smiles/bom.png" alt="bom" longdesc="29"><br><br>thanks for the input <br><br>cheers/Johan
     
  6. SkauneJohan

    SkauneJohan Member

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    mock-up finished<br><br><img src="http://i43.tinypic.com/kex27n.jpg" border="0" alt=""><br><br><br>and here is a bad sketch for the plan of the gun<br><br><img src="http://i42.tinypic.com/2qv61xd.jpg" border="0" alt="">
     
  7. mr_paradox

    mr_paradox New Member

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    Nice design, i like the position of the scope
     
  8. SkauneJohan

    SkauneJohan Member

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    thank you Mr paradox, can you see what classic gun is copied? <br><br>after holding the mock-up I know it will be very comfortable to aim, no need to bend the neck to the sights like in normal guns <img src="http://illiweb.com/fa/i/smiles/icon_cheers.png" alt="cheers" longdesc="28"><br><br>have done some measurements, from the fork to the trigger I can have 50cm and if total fork width will be 40cm (20cm per tube) that would give a total "draw" length of almost 54cm per tube. <br><br>Then I will have 10-11cm theratube length for maximum performance,<br><br>does anybody know how much durability and performance difference there is between 550% elongation or 500% when using theratubes?? <br><br>cheers/johan
     
  9. JoergS

    JoergS Administrator

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    Ah, a Tommy Gun... nice. You must use .45 caliber ammo for it <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>Why not adding some rollers, like I did? This will greatly increase the performance. If you want to use tubes, you can take rollers for ropes (hardware store standard stuff).
     
  10. SkauneJohan

    SkauneJohan Member

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    hello Jørg, 10points for the correct gun guess <img src="http://illiweb.com/fa/i/smiles/icon_cheers.png" alt="cheers" longdesc="28"><br><br>can you perhaps show me in a picture or something, what way do you mean rollers? since I don't fully understand<br><br>cheers/J
     
  11. JoergS

    JoergS Administrator

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    <a href="http://slingshotchannel.blogspot.com/2011/09/bullpup-sling-x-bow-front-enhanced.html" class="postlink" target="_blank" rel="nofollow">See some pics in my blog</a>
     
  12. SkauneJohan

    SkauneJohan Member

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    I have thought about rollers, but I think it makes the gun more complex(especially for a beginner in hand craft like me)<br><br>so far your medieval style crossbow is the most inspiring type of fork with the trigger from the bullpup gun<br><br>since this gun is just for fun and not so much power the main aspects will be longevity(theratubes) simplicity and accuracy consistency<br><br>thanks for the input, I may change the design later on anyway<br><br>cheers/J
     
  13. baianatunada

    baianatunada New Member

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    very good questions to discus<br>
     
  14. Camo-sling

    Camo-sling New Member

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