Search found 960 matches

by hectmarr
Wed Dec 01, 2021 8:00 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1331

Re: Designing a inline piston pressure regulator - Fluid statics math model

Include a spring in the low pressure chamber, and a harder spring in the regulation. The piston will move between two greater forces while the high pressure resistance of the o'ring is constant. In this way you can regulate much more pressure. As seen in the drawing above. By the way, your work and ...
by hectmarr
Wed Nov 17, 2021 5:23 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1331

Re: Designing a inline piston pressure regulator - Fluid statics math model

This regulator was designed to be manufactured with inexpensive precast bronze parts, available anywhere. Does not use lathe machining for metal. The two grooves for the two o'rings are made on the domestic bench drilling machine and a small file. It can be put together in a couple of hours ... What...
by hectmarr
Mon Nov 15, 2021 4:14 pm
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1331

Re: Designing a inline piston pressure regulator - Fluid statics math model

It is not so difficult to make the air passage channel. I drilled a hole in the body of the regulator "A" and then made a slot with the Dremel, as the drawing shows, but without breaking the inside of the body, where the piston moves. In this way, there is a conduit through which air can pass betwee...
by hectmarr
Sun Nov 14, 2021 10:17 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1331

Re: Designing a inline piston pressure regulator - Fluid statics math model

Actually the one I show in the photo has only two o'ring, which are 2 mm thick. The inlet hole is very small, 0.75 mm and is polished on the inside, which added to the lubrication, a little silicone, which does not come off, does the job. It works as a shut-off valve for the "HPA" bottle, which I us...
by hectmarr
Sat Nov 13, 2021 10:16 am
Forum: Pneumatic Cannons
Topic: Designing a inline piston pressure regulator - Fluid statics math model
Replies: 19
Views: 1331

Re: Designing a inline piston pressure regulator - Fluid statics math model

This little pressure regulator, I made it. As the areas on the two faces of the piston, (6.3 mm) are equal, the high pressure compressed air, (arrow in dark blue), that enters produces the same force in both directions, and the piston is balanced, without any math. The displacement of the piston is ...
by hectmarr
Wed Aug 25, 2021 9:57 am
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

jackssmirkingrevenge wrote:
Tue Aug 24, 2021 10:45 am
hectmarr wrote:
Thu Aug 19, 2021 6:47 pm
It is not a very neat job, but it works fast and it pays quite little, it is what it is.
Almost like a T-34 tank :)

It's good that you have this resource to better flesh out your ideas!
Oh yeah! Like the Russian T 34, exactly that! 8-)
by hectmarr
Thu Aug 19, 2021 6:47 pm
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

I had the valve and the entire bolt system of the weapon that I am planning built by a turner. I actually drew everything in detail, and measurements, exact, and I passed it to him.
It is not a very neat job, but it works fast and it pays quite little, it is what it is.
by hectmarr
Sat Aug 14, 2021 8:55 pm
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

If you're right. I'm going to try to get a harder o'ring, as a first alternative solution. The second may be, why not? what you propose, make a thread in the place of the o'ring groove, and a small plate with some material to seal the exit of the combustion chamber. For now I have to try another har...
by hectmarr
Sat Aug 14, 2021 10:47 am
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

I understand what you tell me. Actually the small o'ring does not touch anything. It is built as in the drawing. The o'ring fits into a 6.5 mm bronze tube with a conical mouthpiece and all well mirror polished, when moved to the left, (in the drawing), to seal the combustion chamber. When combustion...
by hectmarr
Fri Aug 13, 2021 4:46 pm
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

Here are the photos of how it is inside.
Válvula a pistón 1.JPG
Válvula a pistón 2.JPG
Válvula a pistón 3.JPG
Here are the photos of how it is inside.
by hectmarr
Sat Jul 10, 2021 9:41 am
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

Well, the valve was tested but it has a drawback that makes it almost useless. I am referring to this piston valve design exclusively. The practical problem is that it does not retain the lubrication in the small 6.5 mm piston, and for this reason, the o'ring breaks ... Perhaps the solution is to in...
by hectmarr
Sat Jul 10, 2021 7:14 am
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

I built a new little 16mm piston on the pilot side and 6.5mm on the combustion chamber side. I still have a pressure regulator sandwiched in the air supply going to the pilot area. This is because the piston valve is a bit stiff and that force is in addition to that exerted by the pilot piston. The ...
by hectmarr
Wed Jun 30, 2021 4:56 pm
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

The piston valve is the same one I used here: https://www.spudfiles.com/viewtopic.php?f=28&t=27190 It remains open after firing and closes automatically when compressed air enters the dispenser. Thank you for your input in the calculation. I'm going to make a 16mm pilot side piston, and a 6.5mm comb...
by hectmarr
Mon Jun 28, 2021 8:12 am
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

oh yeah, I like your estimate. An exact approximation is not necessary, but in general terms, 8 mm is very small diameter. Therefore, I am going to remake the valve with a 16mm piston on the pilot side and 6.5mm on the combustion chamber side, to have more power. Thank you very much for your explana...
by hectmarr
Sun Jun 27, 2021 8:22 pm
Forum: Hybrid Cannons
Topic: Hybrid Piston Pilot Air Ratio
Replies: 18
Views: 3465

Re: Hybrid Piston Pilot Air Ratio

Actually the valve is like in the drawing. I did some tests, with the piston ratio 6.5 mm - 8 mm, as it is at present, but, with different pressures in the combustion chamber and the pilot, and compared. In the first case, it is 7 bar for the combustion chamber and 7 bar for the pilot. In the second...