Minimizing friction/additionally propelling projectiles with magnets?

Discussion in 'General Slingshot Discussions' started by Bnethor, Apr 12, 2013.

  1. Bnethor

    Bnethor New Member

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    Hi everyone!<br><br>I just had to register and post because of this idea I came up with after looking at Joerg's videos that have magnets in them.<br><br>First of all, I have no idea how much projectile speed friction eats away on weapons with a barrel or a guided projectile track. I understand that not knowing this info may make this whole thing obsolete.<br><br>Anyhow, what if one used diamagnetic levitation to either lessen or even totally counteract the force of gravity. Basically just having a strong magnetic rail that repulses the projectile, even if it couldn't levitate the projectile it could lessen the friction. The projectile itself should probably be made of something like Bismuth, but then again that is used in projectiles anyhow. Lead could work to some extent too. Another interesting option might be to try to accelerate the projectile with those neodymium magnets embedded into the projectile track at 45 degree angle or so; so that they repulse and thus accelerate the projectile additionally after the rubber has been launched.<br><br>Obviously another possibility that comes to mind is a slingshot-coilgun hybrid where the initial launch would happen with the sling and the coilgun portion would be near the barrel to add acceleration. But that would apparently work best with ferromagnetic projectiles and is a topic for another discussion anyhow.<br><br>I understand that one of the main points of slingshots is simplicity and cost effectiveness, but hopefully that doesn't hinder the search for more power <img src="http://illiweb.com/fa/i/smiles/icon_smile.gif" alt="Smile" longdesc="2"><br><br>P.S. As a new member I can't post a link, but google can help to find more info about the principle.
     
  2. Achso_42

    Achso_42 Senior Member

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    The problem with that is that the magnetic field has to last for just a millisecond, otherwise it will just slow the projectile. Light barriers can work.<br><br>Auditionally, you need high voltage => large capacitors to reach significant acceleration(300V with a 2000n coil do abou 1/2 Joule <img src="http://illiweb.com/fa/i/smiles/sleep.gif" alt="Sleep" longdesc="31">)<br><br>Other idea <img src="http://illiweb.com/fa/i/smiles/icon_scratch.png" alt="scratch" longdesc="33"> accelerating with an electric field(capacitor-style)
     

  3. Hisownself

    Hisownself New Member

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    You guys are talking about making a "railgun" first made in 1918! Search for it on Wikipedia and elsewhere.
     
  4. pelleteer

    pelleteer Middle Aged Delinquent

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    Friction upon a projectile in a gun barrel is significant. In order to get a bullet through a barrel without using gunpowder, you literally have to use a dowel of aluminum or brass rod and hammer the bullet through. This amount of tightness and friction, however, is necessary to seal the expanding gasses behind the bullet. In a slingshot like one of Joerg's that uses wooden rails or a wooden channel in place of a barrel, I don't think velocity loss due to friction is going to amount to very much, as the channels aren't actually constricting the projectile, just keeping it on a set course until it leaves the slingshot. Interesting idea, though. <img src="http://illiweb.com/fa/i/smiles/icon_cool.gif" alt="Cool" longdesc="6"><br><br>P.S. It might be interesting for Joerg to build something like his blunderbuss slingshot, but have some strips of nylon (the plastic-ee kind, not cloth) on the insides of the channel walls and see if there's any difference in velocity with the same projectile, bands, etc. I wouldn't expect a noticeable diff., but you never know. <img src="http://illiweb.com/fa/i/smiles/icon_scratch.png" alt="scratch" longdesc="33">