This is testing a valve design for an upcoming PCP airgun project. The valve operates a bit differently than most airgun valves, it pulls the valve open with a slide hammer instead of pushing it open with a hammer.
A very interesting design. As a PCP shooter for many years, it is always fun to see the interesting designs people can create. I can only imagine similar experiments when some of the 1st modern air bolts were being designed. Thanks for all your great content and sharing your broad range of skills and interests.
NICE!! Reminds me of my own project. The valve opening time is crucial for efficiency so i suggest using PTFE slipper seals for the plunger. Great job! Keep em coming!
It would be interesting to incorporate this into a break barrel pellet rifle, if it is not there already. Have you ever seen a tip man propane paintball marker? The propane ignites, pressing upon a cylinder firing a ball. The astounding thing about it is its efficiency. One standard liter propane bottle can fire 50,000 rounds. A sinilar can of CO2 only last for 400 rounds, it's orders of magnitude more efficient. They even bragged "the gun will wear out before your first tank does" And this propells a ball that does not even fit snug in the barrel at 150 fps. It encountered legal trouble because it could be viewed as a firearm because it uses ignition. A propane pellet rifle would get 10,000 shots per liter, even using 5x the propellant per shot. Another interesting thing that is used often are the propane sound cannons that scare birds away. They can make a shotgun sounding blast every five minutes, for an entire season off one propane tank. Propane guns definitely have an unused niche, that is probably not used only because it is the beuracracy of a "firearm" with the power of an air rifle. Hook up a source of pure nitrous or an oxygen concentrator and you'd be looking at similar fire power to black powder. The US navy actually built a gun to fire on hydrogen and oxygen, it had a further range than the powder shells, but it was less accurate because the ignition varied depending upon how thoroughly the gases were mixed.
When I started watching this video I wasn't sure what your objective was going to be, but as I continued to watch, it became quite apparent it was a Pneumatic pressure gun and it was amazing what you chose for your projectiles. Kind of a comical outcome, but I started getting nervous when I knew you were going to pressurize this thing because of the serious safety risks involved. Nice design, application of simple components in the design, cool targets, and nice analysis in the end to understand the energy departed and the comparison with firearm rounds.
You can kill a moose with that pencil air dart. Damn, that thing has more power than my 3000-dollar Skout Epoch airgun. Insane what a functioning brain can do. Unfortunately, my brain is only good at consuming things not producing things. In other words, I go shopping for things that smart people like you produce. I raced dirt bikes for a living and dropped out of school for that career. I wish i would have stayed in school. Though the money was good I'm still having surgeries and lots of pain from injuries. Oh well, thanks for the entertainment. Your channel deserves more subscribers.
Really elegant and interesting design. From the impact footage I think your velocity readings are accurate, that pencil was super-duper sonic. And can you provide a bit more insight on how you seal the reciprocating valve stem to the end cap? Want to try and build one
Is is practical to put a spring behind the slide/hammer that releases the plunger and build a trigger release for the "sliding hammer" so that it would be a repeating device. I know you would not get the same force as the single full blow, but this design looks so much better than the typical hammer valve. Of course you may need something like a quick-exhaust valve to equalize the pressure.
Yes, you could use a spring and then hit the valve just hard enough to release a burst of air and then shut with out dumping all of the air in the reservoir.
@@kev7777777777 this is possible, however you'd be atificially restricting the power potential of the device. For an inline to work to its full potential the open-close cycle should look as close to a square wave as possible...with the valve fully open untill it's time to close
Ok now I'm starting to sound like an engineer, but what are your safety margins to yield? There is a substantial force in the reservoir acting on the en caps. I hydro test every single gun and reservoir I build just to be safe. Interesting build for sure.
Yes, I did test those end plugs in my shop press. I pushed on an end plug with 4 bolts (because my press is only 20T) and it failed around 16k lbs. I'm using 8 bolts in the end plugs, so I figure it's good for 32k lbs. I also had a polycarb shield between me and the gun at all times there was pressure in it.
@@kev7777777777 You can't simply double the fasteners and expect double the strength. At the same time you drill more holes in line to the reservoir weakening the the line where forces are acting upon. Use threads in the ends. And o rings in the pressure side before the threads.
@@MJPilote Drilling more holes does weaken the tube, HOWEVER, the distance between the holes is .68in, almost triple the diameter of the bolt. The tube is 1/4" wall chromoly, so 8 sections of .68x.25" chromoly is way stronger than the 8 1/4" bolts. If you drilled 16 holes then you would be correct in the fact that it would make it weaker, but not with 8.
Just out of curiosity, has anyone ever tried making piston gun out of a petrol/gasoline piston drove engine. Don't know if that's even plausible but for some reason your video made me think of other ways a piston drove gun might work. Please , if attainable , that would be an interesting concept i'm sure viewers would appreciate. It would be rather interesting to hear someone say, " hold on a min. while i let my gun heat up ". Btw I enjoyed your videos after stumbling across them.
I would love to chat with you about some designs I have. Some completed some theoretical. Pressing a pen through 3 boards is amazing. You ought to shoot stalks of grass. Reminds me of a tornado
Sorry to be skeptical but very often when measuring airguns with the chrony so close to the muzzle you can get readings that are too high as you are in fact measuring the air blast that goes faster than the projectile. Have happened to me and yo many bigbore airgun shooters before, that's why we rely on ballistic radar to get accurate readings before posting velocity readings.
That's possible, but I was getting the velocities that the velocity calculator said I should be getting. Also, my velocities dropped off when I went over 3000lbs pressure, if I was measuring air blast it seems like they would have kept going up with pressure. The reason why I'm getting these velocities is because I'm using a 5-6 foot long barrel. This is a blowgun, not an airgun. Using delrin cones with no rifling is a lot less friction.
A reading beyond the speed of sound for the propellant gas just isn't realistic. Spring driven airguns may push that limit by adiabatic compression of the air.
i would add guide for shaft somewhere closer to the exhaust hole to center it . also question. why not just cone shaped or at least bigger sealing valve?
