New Bullpup Slingxpistol design

Discussion in 'General Slingshot Discussions' started by baz550, Feb 6, 2012.

  1. baz550

    baz550 New Member

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    <font color="black"><font face="'Times New Roman'">As you may have seen I have made a slingxpistol, greatly influenced by Joerg&rsquo;s design. I have also seen his new bull pup slingxbow design and love it. However I don&rsquo;t really shoot steel balls and especially not of that diameter so I would like to use the same release as the slingxpistol, I also wanted to have a sliding cocking mechanism so the trigger could be loaded and left ready to fire at a moment&rsquo;s notice. It needed to be compact as well. My problem defined, I set about designing a concept. I came up with this;</font></font><br><br><font color="black"><font face="'Times New Roman'">I haven&rsquo;t started building yet, and am in the process of designing another one, that I will post pictures of soon.<font color="black"><font face="'Times New Roman'"><img src="http://s19.postimage.org/5i6w0dvn7/slingxbow_design_Copy.png" border="0" alt=""></font></font></font></font><br><br><font color="black"><font face="'Times New Roman'"><font color="black"><font face="'Times New Roman'"><img src="http://s19.postimage.org/zbdw8zkab/slingxbow_design_with_arrows.png" border="0" alt=""></font></font></font></font><br><br><font color="black"><font face="'Times New Roman'"><font color="black"><font face="'Times New Roman'"><img src="http://s19.postimage.org/yadnjv3ar/slingxbow_design2.png" border="0" alt=""></font></font></font></font><br><br><font color="black"><font face="'Times New Roman'">I would appreciate any help, advice or constructive criticism.</font></font><br><br><font color="black"><font face="'Times New Roman'">Many thanks</font></font>
     
  2. CaptainBacon

    CaptainBacon Knowledgeable Man

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    I would opt to make the clamp and roller frames a bit less bulky. The bars going across the tops of those structures will make loading a bit more cumbersome
     

  3. JoergS

    JoergS Administrator

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    Yes, you won't need all that bulk. The rollers will work fine without the top bars. So will the clamps.<br><br>The "fork" looks too high, pushing the fork part forwards won't be easy.<br><br>Also, keep the rubber draw ratio in mind. <br><br>If you want the rubber slack for loading and STILL have a 1:5 draw ratio, then you have to use a lot longer "barrel". <br><br>Your sketch looks like you have a "barrel" length from lock rollers to front rollers of about 30cm, plus 20 cm from the fromt rollers to the attachments. This means that the slack bands are only 10 cm long. <br><br>Other than that, this will work!
     
  4. baz550

    baz550 New Member

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    Thanks for the tips Joerg, I will redesign it to include your advice. I have also designed one with horizontal rollers, I will also modify this so it includes your tips. I cant wait to get this thing built!!<br><br>Many thanks again.
     
  5. baz550

    baz550 New Member

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    Thanks for the advice Bacon, I am redesigning it at the moment to incorporate both yours and Joergs tips.
     
  6. baz550

    baz550 New Member

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    Here is the new updated version, incorporating the advice I was given.<br><br><img src="http://s19.postimage.org/uhyqhvd6b/slingxbow_design_mk_II.png" border="0" alt=""><br><br><br><br><img src="http://s19.postimage.org/utblgw48j/slingxbow_design_mk_II_2.png" border="0" alt="">
     
  7. JoergS

    JoergS Administrator

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    Make sure the rollers are more narrow than the attachments, so the band does not touch itself!<br><br>Also, keep the roller diameter large enough. The larger the dia, the less important is the friction of the axis. The clearance between the fork rollers does not have to be greater than maybe 4 cm, tops.
     
  8. baz550

    baz550 New Member

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    Thanks again for your advice Joerg, I have taken it into consideration. I have also come up with another design, however i dont think it would work that well.<br><br><img src="http://s19.postimage.org/6nsig7qer/slingxbow_design_mk_III.png" border="0" alt="">
     
  9. JoergS

    JoergS Administrator

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    That design won't work. It hurls the ammo in unpredictable ways.
     
  10. mr_paradox

    mr_paradox New Member

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    I do not like the moving fork design at all, it was the first one I made.<br><br>The next design I made was with the "bull pup" style trigger release.<br>Problem with that one is, the stronger the bands, the more force is required on the trigger. As you put more force on the trigger, the upper velocity component on the ball will change, depending on trigger pull.<br><br>The most recent design I made, has a ball release similar to Jorge's "crossbow" design. It was just a small pistol for my kid.<br>At the time, I never saw Jorge's crossbow, then I noticed it is the same as mine <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>The "wheel release" is very smooth if done properly.<br>Also since the ball is always in the exact same position, it will have better accuracy.
     
  11. mr_paradox

    mr_paradox 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">That design won't work. It hurls the ammo in unpredictable ways.</td></tr>
    </table>
    <span class="postbody"><br><br>The rollers hurl the ammo in unpredictable ways, because the "ball" will never be in the exact same place when you reload ?</span>
     
  12. JoergS

    JoergS Administrator

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    I think it is the impact of the roller, the bands don't move in a straight way. They throw the ball in an arch instead.
     
  13. Beginner

    Beginner New Member

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    Witch programm did you use to make the Picture?
     
  14. FIAAO

    FIAAO Failureisalwaysanoption

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    Cool design!