Bullpup Slingshot Crossbow integrated w/ Sling-X-Bow?

Discussion in 'Slingshot Crossbows' started by nolan, Sep 22, 2011.

  1. nolan

    nolan New Member

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    After watching Joerg's Bullpup Slingshot Crossbow and Sling-X-Bow video I got thinking. <br><br>In my mind I see the Bullpup being an excellent platform for the sling-X-bow's arrow firing capabilities. I think combining the two shouldn't be to hard. However before I break out the wood and tools, I was wondering what you guys think. Any thoughts or suggestions on how to integrate the two into the perfect slingshot cross bow?<br><br>Thanks for the help.<br>Once I am done I will post my weapon on here.
     
  2. Ryan Wigglesworth

    Ryan Wigglesworth Senior Member

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    No thoughts other than its a good idea <img src="http://illiweb.com/fa/i/smiles/icon_razz.gif" alt="Razz" longdesc="9"> Can't wait to see it!
     

  3. Ivo

    Ivo New Member

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    Ivo checking in to the slingshot portal.<br><br>Had no internet for a <br>few days and decided to go play with this design a bit...not yet ready <br>to build off of, but certainly a dreamer. <img src="http://illiweb.com/fa/i/smiles/drunken_smilie.png" alt="drunken" longdesc="30"><br><br><a href="http://www.servimg.com/image_preview.php?i=510&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb12.jpg" border="0" alt=""></a><br><br>Tried incorporating a spanning lever similar to the one on <a href="http://thearbalistguild.forumotion.com/t26-levers-cranks-and-other-spanning-devices#84" class="postlink" target="_blank" rel="nofollow">AK-48 Crossbow</a>.<br><br><table class="spoiler" width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <span class="postbody"><br><br><a href="http://www.servimg.com/image_preview.php?i=511&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb13.jpg" border="0" alt=""></a><br><br><a href="http://www.servimg.com/image_preview.php?i=512&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb14.jpg" border="0" alt=""></a><br><br>And<br> to do that had to reposition the riser so that it mount upside-down <br>compared to the way it was done on the original. Also I figured it could<br> be made a bit more compact with the addition of two more rollers. <br><br><a href="http://www.servimg.com/image_preview.php?i=513&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb15.jpg" border="0" alt=""></a><br><br>I<br> am of two minds on this design. There are issues that may follow due to<br> friction and inertia, but that's something that will only be known if <br>built. <img src="http://illiweb.com/fa/i/smiles/icon_tongue.png" alt="tongue" longdesc="24"><br><br><font color="blue"><strong>Ivo</strong></font></span>
     
  4. nolan

    nolan New Member

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    After looking at that Ivo all I got to say is wow... I'v got to start from scratch on my model. <br>What you have there is a work of art and must be built!<br><br>I have a question for you though. Any chance you can explain the firing mechanism and mechanics of it? I am great at wood working, I craft furniture as a hobby. However I am no mechanical engineer. A diagram of the firing mechanism would be a blessing. That is the one spot where I am having trouble with on this build. I want to do it right so I don't get and arrow in the foot. <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"><br><br>Thanks for the help,
     
  5. nolan

    nolan New Member

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    <a href="http://www.servimg.com/image_preview.php?i=2&u=16905701" class="postlink" target="_blank" rel="nofollow"><img src="http://i40.servimg.com/u/f40/16/90/57/01/image_11.png" border="0" alt=""></a><br><br>Consider this in your design.
     
  6. Ivo

    Ivo New Member

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    Haha, I'm far from an engineer myself mate....did have some help along the way from around the globe over the years - gotta love forums.<br><br>The so called firing mech isn't really a "firing" one. Just saying, because that could get you in trouble since folks are a bit touchy when it comes to correct terminology...ever hear firearm guys go off when someone calls a mag - clip? Hehe, same here...just call it "trigger" and instead of "firing" just say "shoots" and off the bat you're one of the boys.<br><br>Now the build. There's lots to this one and since you mentioned the draw length...well I'm a pretty laid back guy and not too much of a speed demon when it comes to these things (other things...maybe, haha). I like the slightly shorter draw since now there is room for a cheek rest. It's not in the model yet (still the foam insulation from when I was talking to Joerg about it), but will be added soon. Also with longer draw you'll have to swing that lever farther, and that's already going past the butt of the stock...which is not going to be too comfy since in order to cock this thing you'll be resting the butt against your leg...I mean...I guess it could be done, just I chose the path of least resistance. <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>The trigger mech is kinda cool, been thinking about it for a while now. I'll draw it up and post it. Also I've been tooling up and working on a low cost trigger thats good for up to 100lb for folks. Will be sending out a few prototypes to some friends for testing soon, so that's another thing I'll let everyone know about when ready. <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>Ivo
     
  7. JoergS

    JoergS Administrator

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    Ivo, that is a great sketch for sure. Many enhancements at once.<br><br>However, my experience is to attack one issue after the other, and not enhance too many things at once. Each improvement will probably nned substantial tweaking.<br><br>I am currently thinking about a repeating mechanism. In order to use one of the most important advantages of rubber over other energy storage/conversion materials (the much lighter draw you need for serious energy), I am looking at a pump action repeating mechanism. <br><br>Many issues come up. How do you keep the rubber from twisting? How do you transport a ball in front of the pouch? <br><br>I think I have pretty much sorted out the pulley/roller side, it will soon be time for the next step.
     
  8. Ivo

    Ivo New Member

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    Hey Joerg, I'm no pro, but I do like to throw the plank higher than the one I can reach...keeps me occupied.<br><br>I like the pump version you're working on...way to go on the auto-loader. <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>I hate your triggers though *no offense* <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"> (except the double jaw...that's my favorite of your triggers...and can be further improved to auto-engage...really looking forward to drawing it up) ... I've been messing with triggers for several years now and really excited to be able to share what I've learned, so I'll share what ever I can. <img src="http://r28.imgfast.net/users/2811/10/40/86/smiles/524936.gif" border="0" alt=""><br><br>As for this build...as promised...I finished sketching the concept I have in mind.<br><br>It has a very cool automatic safety that makes this action very unique.<br><br><a href="http://www.servimg.com/image_preview.php?i=530&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb16.jpg" border="0" alt=""></a><br><br>The latch is simply cut from square pipe and is spring loaded by two torsion springs working in opposite directions in such a way that it comes back up to be engages by the string while spanning.<br><br><a href="http://www.servimg.com/image_preview.php?i=531&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb17.jpg" border="0" alt=""></a><br><br>It's a modular assembly similar to upper/lower receivers on firearms. The two modules are attached to different parts of the crossbow...the latch that retains the string is the upper receiver(orange) permanently attached to the the crossbow body and the release is the lower receiver(green) and a permanent part of the spanning lever. These two modules come apart during spanning and once the latch engages the string and is in the locked position, the sear also becomes locked by a safety mechanism...*the ghostly component in the next picture*.<br><br><a href="http://www.servimg.com/image_preview.php?i=533&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb19.jpg" border="0" alt=""></a><br><br>Since the mechanism's safety is engaged as soon as the string is latched...it prevents accidental releases when you snap the lever back in place to bring the two modules back together. Weapon remains in safe mode at all times except the moment the string is latched(since the sear needs to be unblocked for this) and when you grip the weapon to pull the trigger.<br><br><a href="http://www.servimg.com/image_preview.php?i=534&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb20.jpg" border="0" alt=""></a><br><br>So yes, to shoot this thing you basically grip the pistol grip of the weapon - pressing the orange lever which disengages the safety and then pull the trigger. Otherwise it's always in safe mode.<img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>EDIT: The parts are located on different planes, so they don't bump into each other...just thought I'd mention it. May need to be spread apart a bit more though. <img src="http://illiweb.com/fa/i/smiles/icon_pirat.png" alt="pirat" longdesc="23"><br><br>Top View.<br><br><a href="http://www.servimg.com/image_preview.php?i=535&u=14665618" class="postlink" target="_blank" rel="nofollow"><img src="http://i46.servimg.com/u/f46/14/66/56/18/slingb21.jpg" border="0" alt=""></a><br><br><font color="blue"><strong>Ivo<br><br></strong></font>PS: It's still a concept, not a blue print...don't hate...I'm still working on it. <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7">
     
  9. JoergS

    JoergS Administrator

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    Cool design, seems a bit hard to do without CNC gear though. Small parts that need precision machining.<br><br>And it is not really useable for bullets, right?<br><br>One big advantage of rubber based crossbows is the low draw weight, in comparison with steel or compound prods. Low draw weight allows very simple triggers.<br><br>And I still like the good old medieval style rolling nut and tickler!
     
  10. Ivo

    Ivo New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <tr><td class="quote">Cool design, seems a bit hard to do without CNC gear though. Small parts that need precision machining.</td></tr>
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    <span class="postbody"><br><br>It might look that way on the computer model, but I actually tried to simplify the parts as much as possible to allow the use of common wood/metal working tools and widely available hardware store material stock. Of course it's a bit of a pain to do everything by hand, but it has it's rewards <img src="http://illiweb.com/fa/i/smiles/icon_pirat.png" alt="pirat" longdesc="23"> ...<br><br>I'll try to get some time out this weekend and pull out some of the similar parts I've already made for my other crossbow.<br><br></span><table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <tr><td class="quote">And it is not really useable for bullets, right?</td></tr>
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    <span class="postbody"><br><br>That's an interesting topic. I really like modular systems that allow upgrades/adjustments and/or use of different projectiles...but like with everything there is always a handful of compromises to make.<br><br>This bullpup slingshot you built actually fell right in the middle of my workshop as I've been thinking about a compact lever action reverse draw bullet crossbow on a similar stock/platform for a long time now and even had a discussion with the guys about barrel and bullet design, as well as different mechanisms to improve the ballistics. <a href="http://thearbalistguild.forumotion.com/t270-bullet-bow-with-a-rifled-barrel-discussion-project-planing?highlight=bullet" class="postlink" target="_blank" rel="nofollow">Link</a><br><br>Barrel design that I stopped at is a removable smooth bore barrel + adjustable hop-up module mounted a few inches back from the muzzle. The barrel has slits cut on each side to allow the string to travel....very much like on your recent pump-action slingshot. <br><br>As much as I would like the weapon to accept different size ammo, the hop-up might just be worth the sacrifice of that bit of freedom for the luxury of adjustable trajectory...plus it's easier to just take an aluminum tube barrel for a specific round than build an adjustable one (I wouldn't even know where to begin).<img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"> This bullet bow is my next project...right now I'm still working on my little bow here as well as a few other little projects...<br><br><table class="spoiler" width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <tr><td class="quote">One big advantage of rubber based crossbows is the low draw weight, in <br>comparison with steel or compound prods. Low draw weight allows very <br>simple triggers.</td></tr>
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    <span class="postbody"><br><br>Yeh, I really like that bit. I'm no big fan of long draw length, so we'll probably still land in some heavier draw weights, but it's still going to be low enough (#100-120) to use softer steel/aluminum for parts that would normally be overbuilt or made from high strength carbon steel or alloys to handle heavy draw wight.<br><br></span><table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <tr><td class="quote">And I still like the good old medieval style rolling nut and tickler!</td></tr>
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    <span class="postbody"><br><br>...for a long time I was under the impression that Germans *liked* to over complicate things...not saying that it wasn't done in the <strong>most awesome and unique way though</strong>...<br><br><table class="spoiler" width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
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    <span class="postbody"><br><br>Then one day I read Albert Einstein's famous quote: <strong>"Build as simple as possible, but not simpler."</strong> which made everything so clear and engineering once and for all became an addicting topic. Trigger design and fabrication being one of my favorite departments...so I can understand both love of simplicity and complexity, as they are two parts of one whole. What took me a while is to understand your building style...and it seems I'm just the one who reaaaaally likes to over complicate things...a hopeless dreamer of sort. <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><br><br><font color="blue"><strong>Ivo</strong></font></span></span></span>
     
  11. DesertMonitor

    DesertMonitor New Member

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    personally i preferred the "bonecrushing Sling-X-Bow" pouch holding mechanism.<br><br>for<br> my opinion it is better whan you need to improvise in the field, you <br>can load pebbles much more easily once your out of ammo, while in the <br>"Ultra Compact Bullpup Slingshot crossbow" or UCBSC <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"> seems to be restricted for objects with very fine anatomy like metal balls.<br><br>maybe<br> there is a possibility to combine the compact body of the UCBSC and its<br> roller system with the Sling-X-Bow pouch holding mec'?<br><br>i say, if one day I'll have the time to built it maybe I'll tray to do it combined.<br><br><br>tnx Joerg for your inventions and the inspiration it gives all <img src="http://illiweb.com/fa/i/smiles/icon_razz.gif" alt="Razz" longdesc="9"><br><br>by the way Ivo, amazing sketch work!!!
     
  12. DesertMonitor

    DesertMonitor New Member

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    something like this<br><br><a href="http://www.servimg.com/image_preview.php?i=3&u=16946338" class="postlink" target="_blank" rel="nofollow"><img src="http://i44.servimg.com/u/f44/16/94/63/38/112.png" border="0" alt=""></a><br><br>sorry for the rough drawing, its my first time.<br><br>nothing like yours Ivo <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7">
     
  13. Ivo

    Ivo New Member

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    There is always a first time for all of us. <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"> I'll upload the model to 3D Warehouse once I bring it up to more or less usable condition (lots of tweaking needs to be done...if not a complete rebuild)...<br><br>3D Warehouse...meaning you'll be able to download it and mess with it further. <img src="http://illiweb.com/fa/i/smiles/icon_pirat.png" alt="pirat" longdesc="23"><br><br>I like that double jaw release too. I'm planning on starting a topic here discussing it's improvement...it's just screaming..."make me auto-engage!" <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><br><br>What that double jaw *isn't* very good for is shooting arrows, while a regular latch release can be good for both. I'd just drop the bullet shooting feature, but designing it to accept both types of ammo is a challenge I can not turn down.<br><br>Weekend is coming up, I'll be in my shop filming stuff (it's been a while <img src="http://illiweb.com/fa/i/smiles/icon_razz.gif" alt="Razz" longdesc="9"> ).<br><br><font color="blue"><strong>Ivo</strong></font>
     
  14. JoergS

    JoergS Administrator

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    The "double jaws" trigger has one big disadvantage.<br><br>You can not safely load it when the bands are under stress. <br><br>Therefore, the "bone crushing" crossbow has a sliding fork - you cock it AFTER you have put ball+pouch between the jaws. Both winch operated weapons (tripod and cannon) will pull out the entire trigger/lock assembly out AFTER the ball+pouch are loaded.<br><br>Slinding forks/triggers do not work so well for a bullpup.
     
  15. DesertMonitor

    DesertMonitor New Member

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    indeed, i'm aware to the safty problems, yet it has so much advantages:D
     
  16. DesertMonitor

    DesertMonitor New Member

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    i Think that the new "pump slingshot" is much safer - do you intend to make an "how do" video? <img src="http://illiweb.com/fa/i/smiles/icon_razz.gif" alt="Razz" longdesc="9"> it will be awesome <img src="http://illiweb.com/fa/i/smiles/icon_cheers.png" alt="cheers" longdesc="28">
     
  17. JoergS

    JoergS Administrator

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    Again, I don't recommend the double jaws lock for the bullpup. But the rolling nut lock (modified for balls, as I did for my medieval style crossbow) would work fine.
     
  18. onnod

    onnod Im from Holland, isnt that weird?

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    cool drawings, cool idea
     
  19. baianatunada

    baianatunada New Member

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    amazing, i hope your jobs keep good
     
  20. zenoah

    zenoah New Member

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    really nice design man! <br><br>Could you elaborate on how the trigger assembly will behave during cocking? <br><br>If you don't mind I'd like to toy with the basics of this design, I'm trying to figure out a way to make a slingbow/gun for pellets with a pump/break action like cocking mechanism and I really like the bullpup style, so your design is the best I've come across so far!<br><br>Jb