Burst disk holder with M 12 threads, made out of aluminium.
The back plug is the same red PVC as my piston, and with 2.5 cm. thickness it should hold 1000 psi...
8 mm burst disk to keep things simple and reliable. I just pop the projectile in the front of it.
Maybe I can ask my teacher to buy the materials from the school and put it in the CNC-lathe, to make a nice amount of them.
Just some ideas floating around in my mind....
With a 100 cm 8mm barrel it should give about 180 joules, pretty nice.
Im now designing a gun around it.... I think semi- or full automatic has some power loss because of the cartridge popping out?
Posted: Tue Sep 20, 2011 12:53 pm
by jackssmirkingrevenge
POLAND_SPUD wrote:The only large metal part would probably be a gas engine, as batteries are not as efficient as traditional fuel (think about energy density)..
... and the gun you're trying to smuggle By "stealthy" I mean low visibility and noise, not really referring to radar cross section - it will look like a large bird anyway a cleanly made flying wing will be very hard to spot, and is the most efficient design if you can trim it to fly in a straight line.
I don't think noise will be a problem - AFAIK it's all about the propeller (and in case of gas engines a muffler)
A muffler would definitely be needed, and the engine would drive either a low rpm large diameter propellor or a ducted fan, the latter can be buried in the wing section for a much lower radar echo.
that's why I am surprised... ardupilot pretty much already has all of the features that that guy couldn't do on his own
What's really funny is seeing how this stuff used to be plot material for movies as unobtainable technology:
Labtecpower, looks good will you be making fill rig for it?
Im now designing a gun around it.... I think semi- or full automatic has some power loss because of the cartridge popping out?
Not really, the cartridge is much heavier than the projectile and is being held in place with the bolt recoil spring (which as you can see from previous attempts needs to be substantial) so the projectile would have left the barrel long before any gasses can leak out of the breech.
This will probably be me in a couple of decades
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Posted: Tue Sep 20, 2011 1:03 pm
by Labtecpower
Labtecpower, looks good will you be making fill rig for it?
I don't think so, I will just make a nice pump for it. I don't see the need for a fill rig, except not using a new valve for every cartridge.
Not really, the cartridge is much heavier than the projectile and is being held in place with the bolt recoil spring (which as you can see from previous attempts needs to be substantial) so the projectile would have left the barrel long before any gasses can leak out of the breech.
Good to hear, with the available equipment I should be able to achieve some dakka dakka
A switch between manual, semi auto and full-auto would also be very nice.
This will probably be me in a couple of decades
Or me, but a bit more clean
Posted: Tue Sep 20, 2011 1:08 pm
by jackssmirkingrevenge
Labtecpower wrote:I don't think so, I will just make a nice pump for it. I don't see the need for a fill rig, except not using a new valve for every cartridge.
... so will you thread the rear plug? You need to connect the pump somehow.
A switch between manual, semi auto and full-auto would also be very nice.
Some sort of timing circuit giving one pulse for semi and continuous ignition for full auto will be needed. You would also have to position the contacts carefully in such a manner that on full auto the next cartridge doesn't ignite before being full seated, a cut off switch only pressed when the bolt is fully in place would be ideal.
A breech lock would stop the bolt from recoiling and allow manual single shot operation.
Posted: Tue Sep 20, 2011 1:18 pm
by Labtecpower
... so will you thread the rear plug? You need to connect the pump somehow.
I will just use a Dunlop, Presta or Schrader valve for filling.
Just have to make sure that the valve doesn't keep the cartridge from cycling.
Some sort of timing circuit giving one pulse for semi and continuous ignition for full auto will be needed. You would also have to position the contacts carefully in such a manner that on full auto the next cartridge doesn't ignite before being full seated, a cut off switch only pressed when the bolt is fully in place would be ideal.
A breech lock would stop the bolt from recoiling and allow manual single shot operation.
That shouldn't be a problem. I'm sure me and some friends can design something that will work.
I still have trouble with the time I can spend on a lathe, just got a new school project to finish in order to reach the next year..
If only I was allowed to make a gun for an end project... ლ(ಠ益ಠლ)
Posted: Tue Sep 20, 2011 5:05 pm
by MrCrowley
DYI wrote:Taking a quick look at the Amanda Knox case, I got a good chuckle out of this one. Actually charging the plaintiff with slander strikes me as a fairly elegant approach to drive home the point that you really don't want to deal with these guys, under any circumstances. Surprisingly enough, I've never heard of that being done around here.
Giuliano Mignini is indeed a piece of work. Considering they have already arrested, charged and sentenced the real killer (who admitted to the crime and who has no relation to Knox or her bf), it's ridiculous they are still in jail and that man is probably the main reason. He's obsessed with the satanic ritual motive even though it doesn't even remotely fit in with the real killer's motive or time line of events.
I think Mignini has been charged in relation to the case for some form of abuse, hopefully he's off the case now.
mark.f wrote:What happened to the Dam Buster?
Holy crap, I completely forgot about that cannon. It worked for a bit but there was a leak in the removable end cap and the piston broke not long after, I never got around to fixing it. By the time my interest in it renewed, I wasn't satisfied with the safety of the cannon as me and my granddad had modified some of the fittings to fit over each other by sanding them down so I dismantled it.
I never really got much use out of it, a shame really.
Posted: Tue Sep 20, 2011 5:20 pm
by Zeus
Crna, if you're going down that route, I'd really recommend .308win, it's still cheaper than .22-250, not to mention muzzle energy. Accurate enough for the purposes too.
I presume you aren't too sensitive to recoil, that's (personally) the only reason I'd be looking at a (the rules) rifle under .270. Not to mention if you get a .308 and have access to a lathe you can turn discarding sabots for .223 bullets and get some obscene velocities.
I'll also drop a plug for Savage rifles, the quality is getting really good, not to mention the accutrigger, and they're fairly cheap. Stevens rifles are Savage with the accutrigger.
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Posted: Tue Sep 20, 2011 6:57 pm
by Hotwired
Labtecpower wrote:If only I was allowed to make a gun for an end project... ლ(ಠ益ಠლ)
Did that with my signature cannon.
We were given a rather broad brief for our final project so I retrospectively did the paperwork for the cannon and that was allowed.
Even did a demonstration firing with potatoes on site, outside on a field that had been dug up in preparation for building works.
Posted: Wed Sep 21, 2011 1:44 am
by Crna Legija
Zeus wrote:I presume you aren't too sensitive to recoil, that's (personally) the only reason I'd be looking at a (the rules) rifle under .270. Not to mention if you get a .308 and have access to a lathe you can turn discarding sabots for .223 bullets and get some obscene velocities.
yeah last night i was looking though the second-hand gun sites, ill probably be getting a .308, I'm more worried about weight then recoil.
JSR, I saw tat over on /k/, there's some work being done on an AR lower if I recall, the magazine only goes up to 5 rounds due to plastic not making good springs for the purpose.
(I haven't read the TFB entry on it yet)
Crna, there's a nice .308win, was a No.4 Mk1 Lee Enfield, nice and light, only $650. I had a look at a nice Mauser 98 in .308, 16.5" barrel, iron sights. That was $500 at a gun shop up here (Bendigo) and that shop isn't good value.
Very light too, though I couldn't use it if it had a scope, the pull length was so short my eye would be on the scope.
By "stealthy" I mean low visibility and noise, not really referring to radar cross section - it will look like a large bird anyway 
