Any ideas? Help wanted!

Discussion in 'New project ideas' started by Sebastian, Aug 11, 2013.

  1. Sebastian

    Sebastian New Member

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    Hello everyone!

    A couple of weeks ago I stumbled over the slingshot channel on youtube.
    Now I am a fan of Jörg and want to build a pump-action slingshot crossbow myself!
    Here are my thoughts on it till now:
    -Is it useful to combine the classic crossbow energy source (bow) with the power of rubber?
    -the twinbow principle would give a huge extension to the draw length and keep the crossbow as compact as possible
    -I'd like to use thera tube (silver?)
    -main material: plywood
    -ammunition: steel/lead balls (size?)
    Since I'm doing a project like this for the first time (actually I built a crossbow some years ago),
    I really would appreciate your constructive tips and advices!

    Keep shooting!

    PS: I have posted this before but forgot to give it a title...
     
  2. moin moin,

    What do you hope, through the combination? Double speed?
    If you want to have the balls faster, better go out and build hand-held spinning. When stretching, you can quickly pull the latex, and release very quickly! Taut rubber speed costs!

    Build yourself or Light Rapid limbs .....

    But a combination of both? How would you like the trigger? Or should the latex bands pull back the limbs yet? Which excerpt weight ....?
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    Nah I do not believe it!
    -
    What speed do you want to achieve? With what weight?
    -
    I'm on build - experiment - a (to me) great ....

    look at youtube....



    oder ich:
    http://www.flickr.com/photos/[email protected]/

    Was erhoffst du dir, durch die Kombination? Geschwindigkeit verdoppeln?
    Wenn du die Kugeln schneller haben möchtest, gehe lieber hin, und baue Handgehaltene Schleudern. Bei dehnen, kannst du das Latex schnell ziehen, und ganz schnell wieder loslassen! Gespanntes Gummi kostet Geschwindigkeit!!!

    Oder Baue dir Leichte Schnelle Wurfarme.....

    Aber eine Kombi aus beidem? Wie möchtest du das Auslösen? Oder sollen die Latexbänder die Wurfarme noch zurückziehen? Bei welchem Auszugsgewicht....?
    -
    Nee ich glaube nicht daran!
    -
    Welche Geschwindigkeit möchtest du erreichen? Mit welchem Gewicht?
    -
    Ich bin am bau - experimentiere - einer (für mich) grossen ....

    schaue in youtube
     

  3. Sebastian

    Sebastian New Member

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    Hello!

    Thanks for the quick reply! it's good to hear someone else's opinions.
    First of all I simply thought, the idea of combining the two energy sources
    was cool... My idea was to have two small limbs left and right of the "barrel" (twinbow-principle)
    which are pulled back by the thera tube.
    What I want the project to result in:
    A powerful slingshot crossbow that is easy and fast to cock.

    Keep shooting!
     
  4. Slagskimmer Mike

    Slagskimmer Mike thinks TBG smells better than roses

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    I've never seen a hybrid like the one you describe.
    You might be onto something exciting here. No one will know for sure until someone tries.

    A robust generic launcher platform would be a great testbed for something like this. Have parts put together with nuts and bolts so you can retrofit the launcher instead of starting over when new ideas hit.

    As far as being easier to draw, I think you always get out a bit less than you put in--period. However, longer draw length can substitute for heavier draw weight.

    Best of luck with your experiments, and let us know what you uncover.
     
  5. Sebastian

    Sebastian New Member

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    Thanks for your encouragement!
     
  6. studer1972

    studer1972 scooter trash

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    Crossbows don't seem as efficient as direct pull latex. The short draw length of a crossbow means you have to have really powerful bowstaves to get an equivalent push to a longbow. The main reason crossbows were popular was the ease of aiming and training compared to conventional bows. On a slingshot, the narrower the forks, the more power you get from the latex, if I understand correctly. You could test this hypothesis on something like Joerg's monster slingshot that he used to break the slingshot FPS record last month. Try it with narrow forks like Joerg used and then mount bow staves as the forks and compare the results.
     
  7. Sebastian

    Sebastian New Member

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    Thanks for your tip! It is a good idea to test this on something like the monster slingshot.
    So you think direct pull would be more efficient?
     
  8. studer1972

    studer1972 scooter trash

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    I haven't tried it myself, but from my research (YouTube videos on longbow vs crossbow draw weight and terminal energy, Joerg's videos, Middleton's "Man Powered Weapons and Ammunition", etc) that seems to be the case. The monster slingshot frame looks pretty simple to build, so it should be a great test bed. Many folks thought it was impossible to fly before the Wright bros went and did it.
     
  9. Sebastian

    Sebastian New Member

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    It is really helpful to get tips from you guys! I enjoy it a lot.