Search found 26179 matches
- Tue Dec 26, 2023 11:27 pm
- Forum: Pneumatic Cannons
- Topic: preloaded pneumatic cartridge
- Replies: 338
- Views: 208578
Re: preloaded pneumatic cartridge
Some design studies for a 12 gauge air cartridge
- Tue Dec 26, 2023 3:00 pm
- Forum: BB, Airsoft, and Pellet Guns
- Topic: Homemade PCP shotgun
- Replies: 5
- Views: 11118
Re: Homemade PCP shotgun
Welcome to the forum! It's a little hard to picture your project without images, and can you link to the valve you intend to use? To my knowledge the "Z" type valves are intended for AirForce Talon/Condor type rifles that have a hammer coaxial with the barrel. If the dimensions you described are wal...
- Tue Dec 19, 2023 12:33 pm
- Forum: General How-To & Discussion
- Topic: Fly-K mortar - "captive piston" variation
- Replies: 14
- Views: 28968
Re: Fly-K mortar - "captive piston" variation
That's basically what they are, catapults where the power comes from something other than torsion.
- Tue Dec 19, 2023 12:21 pm
- Forum: Hybrid Cannons
- Topic: Mini Hybrid II
- Replies: 11
- Views: 33305
Re: Mini Hybrid II
For sheer power there really is no comparison with pneumatics, even with thousands of psi of air and fast valves you will struggle to get the same results.
- Tue Dec 19, 2023 12:19 pm
- Forum: BB, Airsoft, and Pellet Guns
- Topic: High Pressure BBMG concept
- Replies: 18
- Views: 27988
Re: High Pressure BBMG concept
would love to get a look inside It seems no details are forthcoming from the builder but I'm willing to bet it's a cloud/vortex variation with no moving parts, the performance comes from the fact that he's feeding it with 3000 psi when these things are normally run on shop compressors with 20 times...
- Sat Dec 16, 2023 11:28 am
- Forum: Pneumatic Cannons
- Topic: fl(air) gun - mechanically locked pneumatic cartridge for a 26.5mm flare gun
- Replies: 13
- Views: 35401
Re: fl(air) gun - mechanically locked pneumatic cartridge for a 26.5mm flare gun
Here are some details of the valve, first with o-ring in place and then slide down to show the groove: http://i.imgur.com/Zx2I8Hyh.jpg http://i.imgur.com/17IwsIWh.jpg Also interesting to note the about of wear happening the two areas where the locking balls contact, on the firing pin as well as the ...
- Sat Dec 16, 2023 11:22 am
- Forum: Combustion Cannons
- Topic: Potato cannon not igniting
- Replies: 3
- Views: 7542
Re: Potato cannon not igniting
For a simple combustion you need a decent spark gap, in my experience around 6mm when using piezo igniters. How are you metering your fuel? Are you using a syringe for the butane?
What are you using as an igniter?
What are you using as an igniter?
- Fri Dec 15, 2023 1:23 pm
- Forum: BB, Airsoft, and Pellet Guns
- Topic: High Pressure BBMG concept
- Replies: 18
- Views: 27988
Re: High Pressure BBMG concept
An interesting BBMG project with the pressure ramped up and correspondingly impressive rate of fire:
- Thu Dec 14, 2023 11:54 am
- Forum: Pneumatic Cannons
- Topic: fl(air) gun - mechanically locked pneumatic cartridge for a 26.5mm flare gun
- Replies: 13
- Views: 35401
Re: fl(air) gun - mechanically locked pneumatic cartridge for a 26.5mm flare gun
While using a single o-ring as both a seat seal and a check valve for filling functioned as a concept, I noticed that sometimes while purging the air line it would not reseal immediately, resulting in lower pressure in the cartridge and inconsistent performance, so I've modified the design with a se...
- Fri Dec 08, 2023 11:40 am
- Forum: Hybrid Cannons
- Topic: Hybrid disk burst pressure effect on performance
- Replies: 23
- Views: 34897
Re: Hybrid disk burst pressure effect on performance
If my gut is right, making the baffle shorter (increasing volume of the chamber that has the spark gap in it), will decrease performance (decrease the step function effect). According to the study that inspired hectmarr's other thread, peak pressure should increase, but for a smaller effective volu...
- Thu Dec 07, 2023 10:25 pm
- Forum: Miniature Guns
- Topic: Dual Camera System to enhance combustion weapons.
- Replies: 22
- Views: 38081
Re: Dual Camera System to enhance combustion weapons.
I made a second baffle that was both shorter and with a 1/8" orifice that looks something like this to scale: baffling2.png I then did some more testing again at 16x and using photo paper disks and 0.25g airsoft BBs as projectiles: 1) 1 disk no baffle - 1136 fps / 21 J 2) 1 disk baffle - 1851 fps / ...
- Thu Dec 07, 2023 1:05 pm
- Forum: Miniature Guns
- Topic: Dual Camera System to enhance combustion weapons.
- Replies: 22
- Views: 38081
Re: Dual Camera System to enhance combustion weapons.
pressurepiling.png Looking at this in more detail, the paper describes what is happening in a closed system, with a significant pressure peak happening in the secondary chamber much higher than what occurs in the first one. In our case the dynamic is a little different as we want the second chamber...
- Thu Dec 07, 2023 12:48 am
- Forum: Hybrid Cannons
- Topic: Hybrid disk burst pressure effect on performance
- Replies: 23
- Views: 34897
Re: Hybrid disk burst pressure effect on performance
You need something to induce turbulence! Some experimentation was definitely in order, so I machined a Delrin cup to fit the chamber with a 1/4" orifice through the base: 20231206_213324.jpg baffling.png I fired a series of shots and the results were quite interesting. The first thing I did was rep...
- Wed Dec 06, 2023 12:30 pm
- Forum: Hybrid Cannons
- Topic: Hybrid disk burst pressure effect on performance
- Replies: 23
- Views: 34897
Re: Hybrid disk burst pressure effect on performance
This effect would be affected by the chamber's interior, however. The more bends, rough surfaces, and such, the faster the gases would go turbulet. With that said, VERA has a fair amount of equipment mounted internally and the construction (steel pipe) means a less-than-glass-smooth surface. By con...
- Sun Dec 03, 2023 1:11 pm
- Forum: Hybrid Cannons
- Topic: Hybrid disk burst pressure effect on performance
- Replies: 23
- Views: 34897
Re: Hybrid disk burst pressure effect on performance
Late to the thread here (and I've only read the first post) but one of the things I've seen with VERA is that the burst pressure doesn't really make much difference (at least, not on her). Why? Simple, really... Once the disk bursts and the gases start to move, everything becomes very turbulent. Wi...