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hop-up

This area is for the discussion of BB or airsoft sub machine guns, and or other small arms such as pellets.
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Unread postAuthor: ALIHISGREAT » Sat Oct 20, 2007 4:51 am

ok, ill just use a tissue sabot to stop spin completely, i agree the tweaking could be quite hard.
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Unread postAuthor: ALIHISGREAT » Sat Oct 20, 2007 5:37 pm

ahhh

"So, in hop up, the bb is given backspin. This causes the air pressure above the bb to drop, hence allowing the greater air pressure below the bb to cause an upward thrust to the bb. This can be seen if you turn the hop on your weapon too high, and the bb will fly upwards."

thats why hop-up works so if i made a cut or drilled holes in the top of the barrel then do you think that it would casue the bb to have backspin?
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Unread postAuthor: Hubb » Sat Oct 20, 2007 6:12 pm

Backspin generates the Magnus Effect. So, in essence, you are right about what backspin does. However, I don't think you are going to be able to create this simply with holes in the top of your barrel. It will lower the pressure on the top of the round, but it is not going to be enough to generate backspin with a bb.

Granted, the holes will not hurt it, but you will need further assistance if you want to create backspin.
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Unread postAuthor: ALIHISGREAT » Sat Oct 20, 2007 6:32 pm

maybe the air speed would be lower on top and higher on the bottom which would cause backspin?
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Unread postAuthor: MrCrowley » Sat Oct 20, 2007 7:19 pm

What about horizontal (to the barrel) slits instead of holes?
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Unread postAuthor: ALIHISGREAT » Sun Oct 21, 2007 4:26 am

MrCrowley wrote:What about horizontal (to the barrel) slits instead of holes?


already thought of that
if i made a cut
, so is that a slit along the top of the barrel?
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Unread postAuthor: Hubb » Sun Oct 21, 2007 4:32 am

I think he was talking about more than one. Sort of like this:

-----------------------------------------------
--- --- --- --- --- --- --- --- ---
-----------------------------------------------

Edit: Yes, along the top part, in the same place you was wanting to put the holes.
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Unread postAuthor: MrCrowley » Sun Oct 21, 2007 4:57 am

I meant slits like:


-----------------------------------------------
| | | | |
-----------------------------------------------


But as the above poster said, it's be thought of already.
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Unread postAuthor: ALIHISGREAT » Sun Oct 21, 2007 5:00 am

hmm could work, probably better than one long slit along the barrel or holes along the top.
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Unread postAuthor: Novacastrian » Sun Oct 21, 2007 5:46 am

Comment deleted. (cuz it was dumb)
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Last edited by Novacastrian on Mon Oct 22, 2007 4:04 am, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Sun Oct 21, 2007 5:57 am

Hop-up is for airsoft guns firing light BBs at relatively low velocities - you'll have denser BBs and higher velocity, i don't think it's worth bothering about.
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Unread postAuthor: ALIHISGREAT » Sun Oct 21, 2007 6:59 am

Novacastrian wrote:I think it would work if it were on the bottom of the barrel.


i would have thought that would give topspin which would make the bb dip.
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Unread postAuthor: battlemonkey » Sun Oct 21, 2007 2:19 pm

yeah it would. :?: :!:
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Unread postAuthor: ALIHISGREAT » Sun Oct 21, 2007 3:22 pm

who needs hop up when you can have these http://cgi.ebay.co.uk/RAP4-Airsoft-Airfin-6mm-bb-Target-Ammo-Bag-of-500_W0QQitemZ200128563577QQcmdZViewItem?hash=item200128563577 looks like i have no need for hop-up now, the only thing is that the airfins are .19g instead of .20 oh nooo a .01g loss :cry:
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Unread postAuthor: jackssmirkingrevenge » Sun Oct 21, 2007 3:48 pm

Now you'd talking - they're even a better ballistic shape than a sphere so will lose less velocity to drag as they fly along, I think that 0.1g loss is worthwhile :)
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