Search found 26179 matches

by jackssmirkingrevenge
Tue Dec 26, 2023 11:27 pm
Forum: Pneumatic Cannons
Topic: preloaded pneumatic cartridge
Replies: 338
Views: 200161

Re: preloaded pneumatic cartridge

Image

Some design studies for a 12 gauge air cartridge
by jackssmirkingrevenge
Tue Dec 26, 2023 3:00 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Homemade PCP shotgun
Replies: 5
Views: 9142

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...
by jackssmirkingrevenge
Tue Dec 19, 2023 12:33 pm
Forum: General How-To & Discussion
Topic: Fly-K mortar - "captive piston" variation
Replies: 14
Views: 26525

Re: Fly-K mortar - "captive piston" variation

That's basically what they are, catapults where the power comes from something other than torsion.
by jackssmirkingrevenge
Tue Dec 19, 2023 12:21 pm
Forum: Hybrid Cannons
Topic: Mini Hybrid II
Replies: 11
Views: 28234

Re: Mini Hybrid II

Anatine Duo wrote:
Tue Dec 19, 2023 10:12 am
Hmmmn just when I thought I had no interest in hybrids
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.
by jackssmirkingrevenge
Tue Dec 19, 2023 12:19 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: High Pressure BBMG concept
Replies: 18
Views: 25518

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...
by jackssmirkingrevenge
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: 31384

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 ...
by jackssmirkingrevenge
Sat Dec 16, 2023 11:22 am
Forum: Combustion Cannons
Topic: Potato cannon not igniting
Replies: 3
Views: 6292

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?
by jackssmirkingrevenge
Fri Dec 15, 2023 1:23 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: High Pressure BBMG concept
Replies: 18
Views: 25518

Re: High Pressure BBMG concept

An interesting BBMG project with the pressure ramped up and correspondingly impressive rate of fire:

by jackssmirkingrevenge
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: 31384

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...
by jackssmirkingrevenge
Fri Dec 08, 2023 11:40 am
Forum: Hybrid Cannons
Topic: Hybrid disk burst pressure effect on performance
Replies: 20
Views: 29867

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...
by jackssmirkingrevenge
Thu Dec 07, 2023 10:25 pm
Forum: Miniature Guns
Topic: Dual Camera System to enhance combustion weapons.
Replies: 22
Views: 34355

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 / ...
by jackssmirkingrevenge
Thu Dec 07, 2023 1:05 pm
Forum: Miniature Guns
Topic: Dual Camera System to enhance combustion weapons.
Replies: 22
Views: 34355

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...
by jackssmirkingrevenge
Thu Dec 07, 2023 12:48 am
Forum: Hybrid Cannons
Topic: Hybrid disk burst pressure effect on performance
Replies: 20
Views: 29867

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...
by jackssmirkingrevenge
Wed Dec 06, 2023 12:30 pm
Forum: Hybrid Cannons
Topic: Hybrid disk burst pressure effect on performance
Replies: 20
Views: 29867

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...
by jackssmirkingrevenge
Sun Dec 03, 2023 1:11 pm
Forum: Hybrid Cannons
Topic: Hybrid disk burst pressure effect on performance
Replies: 20
Views: 29867

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...