Slingbow not shooting straight

Discussion in 'General Slingshot Discussions' started by Tonto, Nov 24, 2013.

  1. Tonto

    Tonto New Member

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    Hi all, I built this bow and when shooting, the arrow goes straight for a few feet and then flies upward. I'm using Thera-Band black tubing. I'm using Carbon Express fiberglass arrows 26" and 28". These arrows are too heavy for some bows but shouldn't be a problem with this slingbow. I've also used a very lightweight dowel arrow with the same results. Does anyone know what the problem might be? I later even added a whisker biscuit (not pictured) as an arrow guide, but the result was the same. [​IMG][​IMG]
     
  2. beaverIII73

    beaverIII73 Junior Member

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    Hi Tonto,
    First thing I see is your string for the arrow nock is right in the middle of you grip the arrow rest should be directly behind and parellel to the string. You can off set the hand rest lower on bottom arm and that should put the arrow nock right behind the arrow rest. Good luck, oh and the bow look great other than that.
     

  3. beaverIII73

    beaverIII73 Junior Member

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    Here is a pic of my bow that shows what I ment in my last post, I hope it helps.
     

    Attached Files:

  4. Obl1v1Aus

    Obl1v1Aus Meh!

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    Can't say I've ever experienced that before.
    Could be that you nock point is too low. It could also have something to do with the bands as each side are different lengths from the picture, the shorter side will contract faster as its stretched further than the bottom bands ( so I understand anyway)
     
  5. Tonto

    Tonto New Member

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    This is actually about the 4th version of the center string nock point. Paracord stretches like crazy and I assumed this string should be as short as possible so I finally just used leather at that point. I cut the two bands exactly the same length (about 13 inches) and took great pains to make them the same. But again, because the paracord stretches so much, I can see in the pic that one paracord loop is longer than the other at the ends of the bow, which could throw it out of sync. I was going to make the handle off center like Joerg's, but I found drawing it off center was beyond my capabilities at the time. But in earlier versions of the string configuration, the string was longer and I did shoot it from the dead center of the bow and at other positions higher than dead center and still had the problem.
     
  6. Ravensbull

    Ravensbull New Member

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    If it's not an imbalance of tube length/power and it's center shot as far as knock point, maybe try increasing the weight of the arrow point and/or raise the knock point..?
     
  7. Deejay22

    Deejay22 New Member

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    Whisker biscuit.. they can be pricey but totally worth it. they give the arrows stability when firing and can be used as a targeting device...
     
  8. Ghosth

    Ghosth Over the hill but still swinging!

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    Tonto in your first picture according to my ruler your right set of rubber is shorter than the left set.

    My solution, swap ends with the bands, probably want to lower your handrest as much as possible.

    If in doubt, use a square (probably looks like a big L out of metal) align one side with your bands/string, put the corner at your nock point and see where it contacts the frame. Do it both ways, split the difference. If that is not where your arrow rest is you either need to move the arrow rest, or nock point.

    Sometimes "close" is just not quite close enough.

    Also you should have a knot in your string where your "nock point" is so the arrow nocks above that and slides down to that point, so it is the same every time.

    Hope this helps you out.

    [​IMG]
     
    Last edited: Nov 24, 2013
  9. JoergS

    JoergS Administrator

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    I see you haven't added a string stopper. This means that the nocked arrow will be released in a very unclean way probably. I added the string stoppers for a reason to that design and recommend that you employ them!
     
  10. kohlqez

    kohlqez Accident-Prone

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    Like I always say I'm no expert, but...
    I've experienced similar problems with bows the solution does lie in the nock or at least it did for me. I recommend purchasing some archery nocks (they're little metal things that go around the string and lock there so yo know where to nock your arrows) find the best nock-ing point on the slingbow, then mark that spot and put the archery mocks on either side of that point with a little room to spare. That should make it easier to nock properly
     
  11. Tonto

    Tonto New Member

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    Yes, I recall in your video that you said you put them there for wrist or hand slap. Without them, was a lack of them also causing shooting problems?
     
  12. Tonto

    Tonto New Member

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    Ok, Ghost, thanks for the tips. I'll work on it and see if I can get it working better.
     
  13. Tonto

    Tonto New Member

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    I did actually add a whisker biscuit to help keep the arrow straight but it didn't help. It had no whiskers in it and was just a round circle cut out of plywood but if that was the problem, it should have helped but didn't. I like the homemade whisker biscuits like Jorg and others have made with rubber tubing, toothbrushes etc. Yesterday I was looking at arrow rests with whisker biscuits at Walmart and the bristles were extremely stiff. I'm sure they were made for very powerful compound bows.
     
  14. JoergS

    JoergS Administrator

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    Without the stoppers you get hand slaps as well, but also the arrow will pull the bands forward a long distance. The bands are nowhere near as tense as a bowstring is, so I suspect that the arrow will stay nocked until the bands have passed the handle and your hand has stopped the bands. Since your hand will have stopped the bands just from below, the arrow flies into a strange angle.

    Just do it man. Make these stoppers and things will be fine.
     
  15. Tonto

    Tonto New Member

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    Thanks, Joerg, I'm going to just cut another bow and include the stoppers as part of the bow this time. It should work out much better.
     
  16. Tonto

    Tonto New Member

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    Joerg or someone, can you tell me what lengths you cut the Thera-Band black tubes to get the draw weight of about 50# that was mentioned in the video for these tubes? The band calculator is not applicable for this application. I originally cut mine about 12 inches total length for each band then doubled them, but I think this may have been a bit too short.