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No Spare Parts; BV launcher

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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No Spare Parts; BV launcher

Unread postAuthor: kydavies » Mon Apr 09, 2012 4:55 pm

This is my throw back BV launcher, i have had the desire to put holes in things. Being unsatisfied with the performance of my previous launchers I gathered my spare parts and threw together a launcher with the plan of attack being simple but effective.

here she is, No Spare Parts (because I like the Rolling Stones and i now have no parts left)

Barrel: 4 feet of 1/2'' SDR 11
Valve: lubbed chrome 1/2'' BV (gives great flow cause the ball is the same size as the id of the barrel :D )
Suppressor: made for my paintball gun (15 year old sl-68ii) so I know its functional,
note about the suppressor: it works for NSP but only to a degree
Typical ammo: 10mm lead balls
Range: 300-350m at 160psi (feel free to doubt but i will stand witness)

damage pics :D

I took it up to comox lake last night and tested the range and had a little fun :D skipping 10mm lead balls on the lake at 200m (reminded me of the ww2 dam busters).

Note: the sound of lead skipping across water and hearing it echo for miles is amazing :D :lol: [/url][/b]
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unsuppressed it stands 5' 6'' :)
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Unread postAuthor: jackssmirkingrevenge » Mon Apr 09, 2012 11:39 pm

Heavy ammunition and a long barrel make up for the ball valve's low opening speed, but I would still fit some sort of detent ;)
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Unread postAuthor: kydavies » Mon Apr 09, 2012 11:59 pm

I was thinking about making a breech for it and adding a barrel support as well because I want to mount it to a canoe (possibly a bad idea) :D a detent would solve the issue of the pb shot rolling out the barrel as well. We'll see when and if i get my epoxy back weather or not theres enough left to make a detent
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Great eyesight.

Unread postAuthor: Technician1002 » Tue Apr 10, 2012 12:26 am

You can see a 1/2 inch projectile hit a lake at 200 Meters.. Wow.. I have trouble seeing golf balls hit the lake at that distance. I can't even hear the splash at that distance. I must be getting old or you have mirror conditions on your lake.
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Unread postAuthor: kydavies » Tue Apr 10, 2012 12:51 am

We were shooting at about 5:30pm to 7pm so there was no wind or waves or nothing, flat calm surface to skip lead shot off of :) I could see and hear the shots landing around 300 meters as well (I was difficult but have good eye sight and excellent hearing). I'll add a picture of the lake for further proof (and because comox lake is beautiful and I want to show off the Canadian landscape)
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Comox Lake, Comox BC.
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 1:55 am

Beautiful, you're lucky to have that to shoot over.

I would be cautious about range estimates though, certainly I would want to film it laterally for a reliable measurement.

The USCG can't estimate the range of something directly in front of their face :roll:

[youtube]http://www.youtube.com/watch?v=ShX7G6dFXLc[/youtube]
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Unread postAuthor: kydavies » Tue Apr 10, 2012 9:52 am

google maps estimates 295m (I had a point of reference) so I was a little off with my upper estimate. possible because I was having to much fun :D
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 1:28 pm

My point was that it's hard to judge the impact point of a splash if you're looking at it down the barrel, I would put an observer with a video camera downrange (a safe distance away of course) looking at the expected impact point from the side.
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Unread postAuthor: kydavies » Tue Apr 10, 2012 1:36 pm

It wasn't very feasable to get down range because of fallen trees, etc...
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mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 1:47 pm

Here's a proposal:

Find some PVC tube with the same OD as your barrel ID. Cut a section 3-5 inches long, and cap and weight one end (epoxy + lead shot for example :D). In the hollow part, put a cork or polystyrene float attached to a length of nylon, the other end of which is attached to the nose.

Cool sig btw ;)
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Unread postAuthor: kydavies » Tue Apr 10, 2012 2:54 pm

Spigot mortar for fishing XD

1" sdr 21 fits nicely over 1/2'' couplings with a little tape and 3/4'' sdr fits over 1/2'' pvc (no fittings) or 1/2'' SDR 21 fits over 1/2'' SDR 11 if I wanted a more aerodynamic projectile. Yeah, I have a lot of PVC under my bed...

I tried* to shoot my lead sinker with 12lbs test line and im pretty sure you could guess what happened..... back to the drawing board...
JSR, with your float idea the cork wont eject, It would have to have a spring epoxied to the inside of the nose. Also I might need a 40lbs test leader to absorb the initial shock of the projectile leaving the spigot and putting a whistle on it would be awesome (trumpets of Jericho).
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mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 3:05 pm

kydavies wrote:..JSR, with your float idea the cork wont eject, It would have to have a spring epoxied to the inside of the nose. Also I might need a 40lbs test leader to absorb the initial shock of the projectile leaving the spigot and putting a whistle on it would be awesome (trumpets of Jericho).


This is roughly what I'm taking about. Not a spigot type projectile, this fits inside the barrel.

Firing would force the cork against the nose, but it shouldn't come out in flight because it's not being exposed to air drag. You could argue that the low pressure area behind the projectile could create a pressure imbalance that would pull the cork out, but I dont think this force would be sufficient.

Once it's in the water, the cork's bouyancy should be sufficient to eject it.
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Unread postAuthor: kydavies » Tue Apr 10, 2012 3:33 pm

Ok, then the projectile need holes behind the epoxy but I front of the cork to let it be pulled out by the corks bouyancy. A 1" sdr 21 barrel (24" long give about a 1:1 ratio excluding the length of the hollow projectile because that would have holes near the end) and corks fit in 3/4" sdr 21 which fits in 1" with a bit of tape.
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mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 3:44 pm

kydavies wrote:Ok, then the projectile need holes behind the epoxy but I front of the cork to let it be pulled out by the corks bouyancy.


Why? If there is air trapped between the cork and the epoxy, it will only help the cork pop out ;) Besides, such holes would allow turbulent air to enter in flight which might pop the cork prematurely.
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Unread postAuthor: kydavies » Tue Apr 10, 2012 3:58 pm

I was working under the assumption that the cork stays in during flight and basing my idea on the difference in density of corks and leaded epoxy.

When fired the cork is going to slam in to the back of the nose leaving Little to no air. Also residual compressed air from firing will have built up in front of the cork, potentially ejecting the cork shortly after leaving the barrel. Here's a compromise between areodynamics and pressures. Check valves between epoxy and the cork.

Edit: I forgot that its going to slam into the water and going to fill with water (not immediately because of super cavitation) so ya scrap the holes and check valves

Edit***: the end of the projectile can not be flat because the fishing line has to be attached to the back... Cut the PVC on a shallow angle?
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mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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