Sling-x-bow with Pulley and Bands (no Tubes!)

Discussion in 'General Slingshot Discussions' started by otta88sun, Nov 19, 2012.

  1. otta88sun

    otta88sun New Member

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    Hi,<br>i'm gonna build a sling-x-bow with thera band gold.<br>I'ld like to check 2 things before.<br>1- can i use bands instead tubes for making it? (i mean, bands on pulley work good like tubes?)<br>2- my "barrel" will be 100cm lenght, but the total stretched band lenght will be 200 cm... yeah 100cm up and 100 cm down (under the barrel), so i can get more acceleration power. starting band lenght: 47cm , stretched band-> 200cm..... what do u thing bout it? Using 2 bands per side with 12mm steel bullets how much speed (theory) could i have?<br><br>Thank u<br>ottavio
     
  2. theraband gold will work fine, check out Joerg's slingshot xbows he uses band not tube on a lot of them, maybe all. As for the speed you will get from your design I do not know, I'm still too new to this myself to give you any info on that. But that seems about near a couple of Joerg's designs, it should be quite powerful.
     

  3. CEZ

    CEZ New Member

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    I think TBG doesn't go faster than 70 meters/s so there's your answer, if power(Joules) is what you want than use heavier ammo and more draw weight.<br>I think a 200% pre-stretch will tire the rubber and make it less elastic.<br>Also a 200cm stretch of a 47cm band is something about 4.25 ratio, you will get most power out of rubber that has a 5.5 ratio.
     
  4. otta88sun

    otta88sun New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>CEZ wrote:</b></span></td></tr>
    <tr><td class="quote">I think TBG doesn't go faster than 70 meters/s so there's your answer, if power(Joules) is what you want than use heavier ammo and more draw weight.<br>I think a 200% pre-stretch will tire the rubber and make it less elastic.<br>Also a 200cm stretch of a 47cm band is something about 4.25 ratio, you will get most power out of rubber that has a 5.5 ratio.</td></tr>
    </table>
    <span class="postbody"><br><br>Yeah, i red bot that 70/80 is max speed, so if i want the max speed for bullet what kind of band should i use?</span>
     
  5. CEZ

    CEZ New Member

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    Well there is thera band black, it's faster but you have to use about 2.3 times as much as TBG. Also taper-cutting bands will go faster than straight but don't last as much.<br>You can also try a pulley system like in the Raptor slingshot <a href="http://www.youtube.com/watch?v=kHxS2eiEZ3M" target="_blank" rel="nofollow">http://www.youtube.com/watch?v=kHxS2eiEZ3M</a>
     
  6. otta88sun

    otta88sun New Member

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    Black, are u sure? I saw blue too...<br>check this <a href="http://www.youtube.com/watch?v=I2pwSdt7zgA" target="_blank" rel="nofollow">http://www.youtube.com/watch?v=I2pwSdt7zgA</a><br>and he used only 1 band per side!<br><br>isn't a table of color/speed/weight?
     
  7. The tapering used on the slingshot in that video would make bands life quite short.
     
  8. otta88sun

    otta88sun New Member

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    so, using gold band is hard to get more than 100mps?<br>Black seems to be a good solution but i think i've to get more bands per side... sigh <img src="http://illiweb.com/fa/i/smiles/icon_sad.gif" alt="Sad" longdesc="3"><br>if gold is right solution i think is better to launch 20mm steel balls instead 12mm one.
     
  9. The heavier the ammo the more energy imparted to the target. If you plan to use this to hunt you want pretty good sized steel or lead balls to shoot. 12mm won't do it for hunting but will suffice for target shooting. But either way with that much rubber a 20mm will be more powerful than a 12mm. Not sure how much it will slow down with the heavier shot but the power increase is worth it.
     
  10. otta88sun

    otta88sun New Member

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    Ok. I'ld like to use it for hunting, or better for do "big damage" (no worry no people no animals <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"> ). 20mm seems to be quite good.<br>Yeah the problem is speed, i usually pratice targeting at 50m (yeah 50m <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15">). And balls need about 1sec to hit my target. My actually slingshot shoots 12mm stell balls at 61mps. I'ld like to shoot 20mm steel balls from 50m and hear the target hit in 0,5s... seems like i've to shoot at more than 100mps... but i fell it a little difficult with thera-band-gold if their max speed is 70/80..
     
  11. You'll probably have to use theraband blue, from what I have seen it is the fastest.
     
  12. otta88sun

    otta88sun New Member

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    I'll try to use them, i think i'll ve to do 5 or more bands per side!<br>I did a little calc... shoot my favourte 20mm steel balls (33g) at 140mps (my target speed) means 323 JOULE... Wonderfull... really hope to get it!<br>I'll order blue and black thera bands.... i'll keep u upgraded if u want <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"><br><br>PS: joerg, i'll really like (i think all really like) if u can make a calc for other bands color... and add the speed too! <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"><br><br>thank guys,<br>Ottavio
     
  13. CEZ

    CEZ New Member

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    <a href="http://www.youtube.com/watch?v=vKSPJt93M9A" target="_blank" rel="nofollow">http://www.youtube.com/watch?v=vKSPJt93M9A</a> Here Tobias proves that TBG can go really fast with 20mm steel, but those were probably very tapered bands.
     
  14. otta88sun

    otta88sun New Member

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    yeah chrony showed 120 mps but he say at end of video that it could be a error for over heating.<br>However i don't find nothing more powerfull 100j is "normal" enery for 20mm steel ball.<br>He shoot with albatros style too, it is the more powerfull but it's not really good for precision... my favourite style is "butterfly" i can hit 40x40cm wood flat pannel at 50m of distance <img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1">
     
  15. onnod

    onnod Im from Holland, isnt that weird?

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    isn't albatross and butterfly the same?
     
  16. CEZ

    CEZ New Member

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    Well there is always TBBlack, it's faster because it's thinner. I wouldn't go with Blue for 20mm, you would have to use a ridiculous amount of it compared to TBG.
     
  17. otta88sun

    otta88sun New Member

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    i think albatross i total extended arms while butterfly is 90° curve hand with non total extended arms..
     
  18. onnod

    onnod Im from Holland, isnt that weird?

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    Just checked, albatross and butterfly are the same <img src="http://illiweb.com/fa/i/smiles/icon_surprised.gif" alt="Surprised" longdesc="4"> . Both are with totally stretched arms
     
  19. FIAAO

    FIAAO Failureisalwaysanoption

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>otta88sun wrote:</b></span></td></tr>
    <tr><td class="quote">i think albatross i total extended arms while butterfly is 90° curve hand with non total extended arms..</td></tr>
    </table>
    <span class="postbody"><br><br>That style is called "Half Butterfly".</span>
     
  20. otta88sun

    otta88sun New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>Failureisalwaysanoption wrote:</b></span></td></tr>
    <tr><td class="quote">
    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>otta88sun wrote:</b></span></td></tr>
    <tr><td class="quote">i think albatross i total extended arms while butterfly is 90° curve hand with non total extended arms..</td></tr>
    </table>
    <span class="postbody"><br><br>That style is called "Half Butterfly".</span>
    </td></tr>
    </table>
    <span class="postbody"><br><br>U're on right man. My mistake! <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"><br>Sure, i prefer "half butterfly" <img src="http://illiweb.com/fa/i/smiles/icon_wink.gif" alt="Wink" longdesc="15"></span>