Search found 792 matches

by hectmarr
Sun Jun 28, 2020 12:10 pm
Forum: Pneumatic Cannons
Topic: "Sabotless" Semi-Automatic Shotgun Concept
Replies: 19
Views: 3700

Re: "Sabotless" Semi-Automatic Shotgun Concept

Doc j wrote:
Sun Jun 28, 2020 9:28 am
Gettin lost in
What proposed to do.
If drive piston quik.
Would this work.
I don't understand your drawing. Please explain what you mean.
by hectmarr
Mon Jun 22, 2020 9:18 pm
Forum: Pneumatic Cannons
Topic: "Sabotless" Semi-Automatic Shotgun Concept
Replies: 19
Views: 3700

Re: "Sabotless" Semi-Automatic Shotgun Concept

Doc j: you are right. One possible solution is to activate the valve that lets the compressed air pass, with the compressed air generated by moving the piston to the right, in Jack's drawing. The piston does not need to hit the valve. I think a balanced valve is necessary so that it does not have op...
by hectmarr
Sun Jun 21, 2020 2:13 pm
Forum: Pneumatic Cannons
Topic: "Sabotless" Semi-Automatic Shotgun Concept
Replies: 19
Views: 3700

Re: "Sabotless" Semi-Automatic Shotgun Concept

A different application from your idea. The trigger you actually draw is the initiator of the recharge of the repeat hybrid. It is the mechanical locking of the piston, which allows it to move to the right, by the action of the spring, and then, to the left by the action of compressed air. To fire, ...
by hectmarr
Sun Jun 21, 2020 9:51 am
Forum: Pneumatic Cannons
Topic: "Sabotless" Semi-Automatic Shotgun Concept
Replies: 19
Views: 3700

Re: "Sabotless" Semi-Automatic Shotgun Concept

I was having a bit of a think about this idea and it seems it could be greatly simplified and also made more efficient: https://i.imgur.com/Csm81PX.gif The piston itself becomes the hammer that opens an inline balanced valve. It is good simplification. I think that the stem that drives the projecti...
by hectmarr
Mon Jun 15, 2020 5:41 pm
Forum: Hybrid Cannons
Topic: Port size vs performance
Replies: 8
Views: 354

Re: Port size vs performance

Comment deleted
by hectmarr
Mon Jun 15, 2020 10:28 am
Forum: Ammo & Parts
Topic: Ideas for biodegradable cannon-balls
Replies: 15
Views: 2619

Re: Ideas for biodegradable cannon-balls

I recommend the meatballs my mother-in-law makes. :shock: I never consume them and they can be useful for what you are looking for. I always told myself that the woman had the soul of an ammunition manufacturer and not much of a cook :lol: :lol:
 
by hectmarr
Sat Jun 13, 2020 9:57 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

I wonder if the shape of the B version could also have something to do with it. At least you can solve it by making up for it with more fuel and air. The A version is more like a burst disc configuration. I'd like to have two identical cannons, one using a burst disc and the other using a piston, a...
by hectmarr
Sat Jun 13, 2020 8:26 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

Based on the sketches the first thought that comes to mind is that you may not have enough chamber volume to move the piston and also the projectile. Maybe I'm missing something, but if I reduced the chamber volume of my piston cannon to be very tiny, then I'd expect most of the energy to go into m...
by hectmarr
Sat Jun 13, 2020 7:21 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

These are the two cases I was testing. In case "A", the retention corresponds to an o'ring, and the power is much higher than the other case. In "B", the "captive ball valve", when combustion occurs, the 6.35mm mole moves to the left and passes the flow through the transfer into the firing barrel. T...
by hectmarr
Sat Jun 13, 2020 3:48 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

Yes, that's what I was thinking. My interest is to know how much of the total energy is invested in moving the piston, or breaking the disc. I see that it depends exclusively on the specific design, (areas, driving force, stroke), and the chosen method, (such as piston or rupture disc), to let hot a...
by hectmarr
Sat Jun 13, 2020 9:56 am
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

I don't know what the percentage is. I think It depends on the opening pressure of the piston. Since the work is being done with pressurized gas to open the piston, as soon as it opens all of that working gas suddenly goes to work on the projectile and sends it into orbit. So, it may seem as though...
by hectmarr
Fri Jun 12, 2020 4:21 pm
Forum: Hybrid Cannons
Topic: Port size vs performance
Replies: 8
Views: 354

Re: Port size vs performance

Important thought experiment and clarifies in theory the same doubts that Moonbogg has. It must be taken into account that larger diameters generally use larger dead spaces, but it depends on the geometry of the transfer, as mrfoo says. The final gun, in my view, does not exist. The interesting thin...
by hectmarr
Fri Jun 12, 2020 3:29 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1477
Views: 89211

Re: Short question topic

How much energy, (in percentage and approximately), is subtracted from the air powered by the combustion process, in a hybrid with valve to piston, to displace this piston? I mean, I imagine, that of all the energy available to fire the shot, to accelerate the projectile, a good part is "eaten" by h...
by hectmarr
Fri Jun 12, 2020 9:33 am
Forum: Hybrid Cannons
Topic: HA-VI
Replies: 3
Views: 216

Re: HA-VI

If it works well. It is quite difficult to explain, this for me. The dynamics of the gases in the system is like in a two-stroke piston engine, where the mixture intake and the exhaust coexist at the same time inside the cylinder, something similar. Thanks Jack for hanging up the animation.
by hectmarr
Wed Jun 10, 2020 5:17 pm
Forum: Hybrid Cannons
Topic: HA-VI
Replies: 3
Views: 216

Re: HA-VI

I have prepared an animation of the pneumatic system. The explanation is as follows. I hope my explanation is understandable ... :? In the first table: When the valve is opened, the mixture is charged in the combustion chamber and at the same time, the accumulator is charged with pressurized gas. Th...