Pump Action Pencil Launcher

Discussion in 'Show off your homemades!' started by JoergS, Mar 5, 2012.

  1. JoergS

    JoergS Administrator

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    A pencil can be very dangerous - when The Slingshot Channel builds a weapon around it! <br><br>The "Nerd Revenge 2000" is a homemade pump action slingshot crossbow that can fire 10 razor sharp pencil in under five seconds. The "arrows" travel at an impressive 100 miles per hour, fast enough to go through a <br>apple!<br><br>The compact weapon (24" = 60cm) can also fire a "devilled" version if a pencil, with an achery field tip glued in. Then the once so harmless pencil is turned into a deadly projectile! <br><br>The design was inspired by the Chinese Repeating Crossbow, but the awkward repeating action has been replaced by the far better "pump gun" method. The rubber bands are pre-tensed to 300% and stretched to 500% when you shoot. This means you get good power at a relatively compact size. My experiments with super slomos and the thermal test series laid the <br>ground for this new concept.<br><br>This is probably the most fun slingshot I ever shot!<br><br><embed pluginspage="http://www.macromedia.com/go/getflashplayer" src="http://www.youtube.com/v/PYJ2zj1SB5Y" width="425" height="350" type="application/x-shockwave-flash" wmode="transparent" quality="high" scale="exactfit"></embed>
     
  2. gael

    gael New Member

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    Hi<br>Great ! This seems to be a very fun toy, It makes you want. Is that stop band to 300% could be dangerous on the higher powers?
     

  3. tokSick

    tokSick Senior Member

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    Ha Ha that one is funny.
     
  4. smurfeater25

    smurfeater25 New Member

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  5. CaptainBacon

    CaptainBacon Knowledgeable Man

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    Looks like adding the field tip nearly tripled the effective range. I like how you continue to fire it while ending the video.
     
  6. PDK73

    PDK73 New Member

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    Cool, a little less deadly than usual, but it looks like a lot of fun <img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1">
     
  7. Devoman

    Devoman New Member

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  8. Ryan Wigglesworth

    Ryan Wigglesworth Senior Member

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    Yes! This video was great! All that is left to do is fill the pencils with real lead <img src="http://illiweb.com/fa/i/smiles/icon_razz.gif" alt="Razz" longdesc="9">
     
  9. JoergS

    JoergS Administrator

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    I just had to do it. Against all odds.<br><br>I doubled up the rubber.<br><br>Now we are talking! <br><br>The stronger bandset pushes the weapon into the realm of deadly weapons. The pencils now go through a rubber door mat, which withstands the 20 mm steel ball hits from my strongest slingshots!<br><br>As a matter of coincidence, some better quality pencils arrived (Faber-Castell HB, 1,18 Euros for twelve pieces including tax). Much more solid. Just in time.<br><br>But in order to push the envelope even farther I took a damaged carbon fibre arrow shaft, sawed it into five pieces and glued tip holders in. Then I screwed the field tips in. The arrows now weigh 9,6 gramms (154 gr).<br><br>The impact is absolutely astounding. They go into a massive wooden plank and I need tools to get them out again. They even pierced through a PET water bottle and still stuck in the plank. Distance 8 meters, the flight is absolutely stable. <br><br>I reinforced the string catchers (glued in a steel nail in fact), so the weapon withstands the much harder impact of the 300% pretensed bands (3,5 cm x 2,5 cm x 11 cm relaxed length).<br><br><br><div style="margin:auto;text-align:center;width:100%">
    <a href="http://4.bp.blogspot.com/-f3-Ht4yvT20/T1ZsozP8KxI/AAAAAAAABZ0/4XamAEzMy60/s1600/Newammo.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://4.bp.blogspot.com/-f3-Ht4yvT20/T1ZsozP8KxI/AAAAAAAABZ0/4XamAEzMy60/s320/Newammo.JPG" border="0" alt=""></a><br><br><br><a href="http://2.bp.blogspot.com/-r67Tnx-uv40/T1ZsqDJ9YYI/AAAAAAAABZ8/oR5Zp1PdIn0/s1600/Newammo2.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://2.bp.blogspot.com/-r67Tnx-uv40/T1ZsqDJ9YYI/AAAAAAAABZ8/oR5Zp1PdIn0/s320/Newammo2.JPG" border="0" alt=""></a><br><br><br><a href="http://4.bp.blogspot.com/-VNljqXQ3BNs/T1Zsr9XnrxI/AAAAAAAABaE/gK4ijCsQanE/s1600/Newammo3.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://4.bp.blogspot.com/-VNljqXQ3BNs/T1Zsr9XnrxI/AAAAAAAABaE/gK4ijCsQanE/s320/Newammo3.JPG" border="0" alt=""></a><br><br><br><a href="http://4.bp.blogspot.com/-uQu8dUl_sZw/T1ZstPXED8I/AAAAAAAABaM/J8EGYGqvA0k/s1600/Newammo5.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://4.bp.blogspot.com/-uQu8dUl_sZw/T1ZstPXED8I/AAAAAAAABaM/J8EGYGqvA0k/s320/Newammo5.JPG" border="0" alt=""></a><br><br><br><a href="http://3.bp.blogspot.com/-M4tP3W_TIt0/T1Zsuoscp3I/AAAAAAAABaU/tn8QzcJWi0c/s1600/newammo4.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://3.bp.blogspot.com/-M4tP3W_TIt0/T1Zsuoscp3I/AAAAAAAABaU/tn8QzcJWi0c/s320/newammo4.JPG" border="0" alt=""></a>
    </div>
     
  10. Ryan Wigglesworth

    Ryan Wigglesworth Senior Member

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    <img src="http://illiweb.com/fa/i/smiles/icon_eek.gif" alt="Shocked" longdesc="5"><br><br><br><br>Evil.
     
  11. Sonic

    Sonic New Member

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    daaayuummm , you're gona need body armour to test weapons that kind of lethality <img src="http://illiweb.com/fa/i/smiles/icon_eek.gif" alt="Shocked" longdesc="5">
     
  12. JoergS

    JoergS Administrator

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    I plan to make it bigger. Much. Much. Bigger.<br><br><br>Here is the new "ammo":<br><br><br><div style="margin:auto;text-align:center;width:100%"><a href="http://4.bp.blogspot.com/-yMy1iNF-qcI/T1umcde3vVI/AAAAAAAABbU/_KgOC1FcTjY/s1600/NewArrow.JPG" class="postlink" target="_blank" rel="nofollow"><img src="http://4.bp.blogspot.com/-yMy1iNF-qcI/T1umcde3vVI/AAAAAAAABbU/_KgOC1FcTjY/s320/NewArrow.JPG" style="width: 320;height: 240" border="0"></a></div>
    <br><br><br><br><br>Aluminum shaft, stainless steel tip. 115 gramms.
     
  13. PandaMan

    PandaMan New Member

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    <img src="http://illiweb.com/fa/i/smiles/icon_eek.gif" alt="Shocked" longdesc="5"> You see that's what I like about you Jörg. You take an idea, and just make it twice as bad-ass. If not thrice. <br><br>I look forward to seeing the next step up. <img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1">
     
  14. puidelup

    puidelup New Member

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    Hello Joerg!<br><br><br>Love your Chu-Ko-Nu! Looks like one of your most fun creations yet! <br>Don't want to downplay the awesomeness of your newest toy, but arrows will always penetrate the target further than round balls, just because of their sharp tip. So I am not particularly surprised by their penetration force. But I *am* surprised of how genuinely fun it is! <br><br><br>What I am very curious about are the 300% stretched bands in "relaxed" position. How does that affect the life of the bands? <br><br><br>I know it's slightly off topic, sorry, but I'm going to ask anyway since I am working on a design with prestretched bands myself, and am worried about rapidly ruining the bandsets. How much and for how long at a time can rubber be prestretched without significantly degrading it's elasticity?<br><br><br>Best Regards!
     
  15. e_monster55

    e_monster55 New Member

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    I'm sure this is going to come up often but still, BLUEPRINTS, BLUEPRINTS, BLUEPRINTS!! Pretty please? With sugar on top?<br>
     
  16. JoergS

    JoergS Administrator

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    So far, I could not find any negative effect from the prestretching IF you don't overdo it. If you max out the stretch (leave the weapon cocked at 550% for a loong time), then the elasticity will go down.<br><br>I have recently rebanded a few slingshots I made, like, a year ago, and the rubber bands from the attachment still had their flexibility. But not those that I wrapped around fully stretched. <br><br>My experiments with heat clearly showed that hysteris is related to the cooling of the drawn out bands. Once they reach room temp, they stay at that draw weight for a long time. <br><br>Of course rubber degrades, especially when the sun hits it. Stretched bands have a larger surface and will degrade faster when exposed to light. So keep things in a dark place. <br><br>I don't know why you guys always must have blueprints. I had none. Just take a pencil and make a magazine around it, then make the rest of the weapon. It's not hard. I mean, you can see how the simple mechanism works in my video.
     
  17. Ryan Wigglesworth

    Ryan Wigglesworth Senior Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>JoergS wrote:</b></span></td></tr>
    <tr><td class="quote">
    <br><br>I don't know why you guys always must have blueprints. </td></tr>
    </table>
    <span class="postbody"><br><br>I will give you one hint, it starts with water and ends with forced fluoridation.</span>
     
  18. Droolp1g

    Droolp1g New Member

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    Sonic: daaayuummm , you're gona need body armour to test weapons that kind of lethality <br><br>Actually i think because of jourgs wonderful inspiration all schools are going to have to rethink there dress code with re enforced padding or plating and helmets. <br><br>Haha nice work jourg you bad ass mofo
     
  19. e_monster55

    e_monster55 New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>JoergS wrote:</b></span></td></tr>
    <tr><td class="quote"> I don't know why you guys always must have blueprints. </td></tr>
    </table>
    <span class="postbody"><br><br>I find it easier to have something solid to work from instead of having to draw up my own designs and going back over and over again, making fine adjustments. I've learned from many failed and sloppy projects that poor planning or no planning leads to regret in the design.</span>
     
  20. Droolp1g

    Droolp1g New Member

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    I can see both point of view as jourg must get fed up with seeing the same copies of his original design the whole point in making and creating something from scratch means you could end up with something different entirely. Or better <img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1"><br><br>Where as if you are satisfied with a good model and see no need to make effort or put any thought into making something different then a blue print is the way forward.<br><br>Personally i prefer jourgs point as he has took the time to research and make something new from something old or recent. Making something utterly unique its what all crafts men look forward to.