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| jackssmirkingrevenge |
 Posted: 01/07/2008 10:02 AM Post subject: valveless launcher patent |
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space monkey
Joined: 15 Mar 2007
Posts: 7087
11414.62 Spud Bux
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An interesting take on the "valveless" design (where the projectile seals the chamber) in this patent.
I believe there had been a similar design made on spudtech. The inconvenience is the need for a perfect seal and a rigid projectile.
I have come up with this (rough) deisgn a few years back on the same principle:
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| Hotwired |
| Posted: 01/07/2008 10:15 AM Post subject: |
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UK Spudgunner
Joined: 13 Oct 2006
Posts: 1808
3912.38 Spud Bux
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Hmm.
I had an idea similar to the patented design for a chain of projectiles fed into that position in semi-auto where the projectile immediately behind is the breech seal.
Too complicated to actually make.
However that design looks fine. As long as you were certain the whole system sealed perfectly.
Otherwise, as there is no safety mechanism at all, once air gets behind the projectile it fires 
Incidentally jack, doesn't your sketch look like an unneccesary complication of a coaxial piston cannon? 
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| _Fnord |
| Posted: 01/07/2008 10:53 AM Post subject: |
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reenigne
Joined: 13 Feb 2007
Posts: 1261
1899.36 Spud Bux
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| I bet you wouldn't even need a piston. You could just use a blowgun to give the projectile a "tap", and full flow would kick in as soon as it started moving forward.
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| jackssmirkingrevenge |
| Posted: 01/07/2008 12:01 PM Post subject: |
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space monkey
Joined: 15 Mar 2007
Posts: 7087
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| It would be the equivalvent of a piston valve with zero opening time and maximum flow, so if it's performance you're after then it's not an unnecessary complication.
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| ALIHISGREAT |
| Posted: 01/08/2008 17:08 PM Post subject: |
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Eternal Noob
Joined: 25 Aug 2007
Posts: 1323
1024.01 Spud Bux
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| so could i shove a projectile down the barrel and over some orings and then use somehting to push it forewards and it would be just like that design or is it a bit more complicated?
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| benstern |
| Posted: 01/08/2008 18:30 PM Post subject: |
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Donating Member
Joined: 21 Sep 2005
Posts: 905
159.02 Spud Bux
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Looks too inconvenient to warrant constructing. Also does not look like any performance increase would be had by this design. A novelty at best. 
Oh and it is a valved design! Note: piston and exhaust valve.
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| jackssmirkingrevenge |
| Posted: 01/08/2008 22:59 PM Post subject: |
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space monkey
Joined: 15 Mar 2007
Posts: 7087
11414.62 Spud Bux
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| benstern wrote: | | Oh and it is a valved design! Note: piston and exhaust valve. |
Ignore my design, the patent shows the projectile simply pushed forward by a lever to expose its base and fire it.
The performance advantages could be tremendous, because unlike a piston valve which is still opening after the projectile has started to move, once the base of the projectile passes the end of the barrel its the equivalent of a piston that has moved back to maximum flow in zero time.
| Quote: | | so could i shove a projectile down the barrel and over some orings and then use somehting to push it forewards and it would be just like that design or is it a bit more complicated? |
Pretty much, but getting it airtight in the first place might be a little tricky.
Have a look at the diagram, the red lever pushes the green pin with moves the purple projecile enough for air to get behind its base et voila, whoomph!
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| ALIHISGREAT |
| Posted: 01/09/2008 1:47 AM Post subject: |
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Eternal Noob
Joined: 25 Aug 2007
Posts: 1323
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| Quote: | The performance advantages could be tremendous, because unlike a piston valve which is still opening after the projectile has started to move, once the base of the projectile passes the end of the barrel its the equivalent of a piston that has moved back to maximum flow in zero time.
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but surely the time it takes for the ammo to move past the brach of the tee is the opening time but i suspect it will be significantly less than a piston's opening time. the one major problem i can think of for us spudders is that regular ammo would be needed, i was thinking about cylindrical air rifle pellets?
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| jackssmirkingrevenge |
| Posted: 01/09/2008 2:18 AM Post subject: |
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space monkey
Joined: 15 Mar 2007
Posts: 7087
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| Quote: | | but surely the time it takes for the ammo to move past the brach of the tee is the opening time |
This is irrelevant, because in a piston launcher this movement doesn't exist - the actual time of firing is when the base of the projectile is in line with the breech, and unlike a piston launcher at this point the valve is already fully open. On the contrary you should get even more power, because the projectile is already moving when in a piston launcher it would be starting from a stop, you would have effectively lengthened the barrel slightly.
With a bit of work it could be made with an ammunition feed to give multiple shots, though there'd be a lot of wasted air:
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