Looking at the drawings I can see where something like this could work but question the feasibility. The above drawings show the chamber as open, I question that. I would expect to see some form of pressure relief valve or poppet valve. The idea being you fill the chamber with an explosive gas mixture be it oxygen and propane, oxygen acetylene or other mixture. Then ignite it which will cause a rapid, very rapid, increase in chamber pressure. Once the pressure achieves the relief pressure it escapes with a bang. All of this takes place in a small fraction of a second.

Just as an example a typical rifle shot, I use "typical" so as not to get into cartridge or chamber specifics, takes place in about 2 mSec (0.002 Second). That means from ignition (primer ignites powder charge) to when the bullet exits an average barrel including bullet travel down the barrel. So we can safely say pretty darn quick. Now to get things in perspective a typical M16 or M4 has a cyclic rate of fire of about 800 rounds per min or about 13.3 bangs per second. The mechanics (gas system) of the rifle seem to do just fine at that speed. The cartridge develops about 50,000 (a little less) PSI of chamber pressure. This using US methods and procedures to measure the chamber pressure. Incidentally as mentioned, that is a cyclic rate of fire not a sustained rate. Things get hot real quick so at some point things need a pause for the cause, in this case heat.


I really do not see where any new technology is developed here. You ignite an explosive gas mixture in a chamber and get an explosion. The work is in the design. While I can explain the operation I haven't a clue what the real world numbers actually are and it will take some calculations and experiments to refine the process. I can tell you it will be a far from inexpensive project at a glance and only suggest how I might go about it. The initial setup would need some serious test, measurement and diagnostic equipment.

Ron

What I can tell you is that acetylene is one gas that can explode with a bang just in a paper cup sitting on a flat surface, with nothing except the inertia of the air above as resistance. Adding any obstruction will make it rather dangerous. And as for that 800 rounds per minute rate, 13+ openings per second is a real stretch for most solenoid valves. Possibly solenoid fuel injection valves, but I am not sure that they would have enough flow at the pressures that they use. So a start would be to copy some of the injector driver circuits.

What is certain is that such a device could also be used as an effective firearm, needing only a mechanical system to load in a projectile to make it work. Sort of like the Vulcan gattling gun, except with gas power.

 

And as for that 800 rounds per minute rate,

The 800 rounds per min was merely a reference to the cyclic rate of fire of a few automatic rifles. I agree it would be fast for any off the shelf solenoid. Keep in mind though that is the actual cyclic rate of fire and mechanically happens in a real automatic rifle. If I were to attempt such a project I would likely use a pop off valve and I am not sure how I would feed my gas into the chamber. Also not sure how I would meter the gas.

Ron

 

The A-10 Warthog twin turbo-fan airplane was used in the Vietnam war and now it is back to fight ISIS. Its pilot sits in a titanium bathtub for protection and its huge gatling gun shoots at 3900 rounds per minute (65Hz).

 

The A-10 Warthog twin turbo-fan airplane was used in the Vietnam war and now it is back to fight ISIS. Its pilot sits in a titanium bathtub for protection and its huge gatling gun shoots at 3900 rounds per minute (65Hz).

What's not to love about a General Electric GAU-8/A Avenger 30 mm hydraulically driven seven-barrel Gatling-style auto cannon? It's more fun then the 6 barrel 20 mm Vulcan. All guns are fun but really big fast guns are also interesting.

Ron

 

The 30mm projectile weighs almost 1 pound! It is not just a big bullet, it has an explosive charge like a missile.
I wonder what it sounds like if it flies past you. Sonic boom?

 

The 30mm projectile weighs almost 1 pound! It is not just a big bullet, it has an explosive charge like a missile.
I wonder what it sounds like if it flies past you. Sonic boom?

Each round has a US Dollar cost of about $100. They come in a few flavors (projectiles). Everything that ever flew past me made a crack sound and the bigger the projectile the louder the crack. Something else interesting is having heard aircraft fire both 20mm and 30mm cannons it's a strange sound, like a brrrrrrp and not like typical small arms automatic fire. I read somewhere that the US Army runs through almost 500,000 of 30 mm rounds a year, most fired from the Apache helicopters. Somewhere around here I have an inert 20mm round which is pretty cool as you can unscrew the tip and see where the explosive charge goes.

Ron

 

Each round has a US Dollar cost of about $100. They come in a few flavors (projectiles). Everything that ever flew past me made a crack sound and the bigger the projectile the louder the crack. Something else interesting is having heard aircraft fire both 20mm and 30mm cannons it's a strange sound, like a brrrrrrp and not like typical small arms automatic fire. I read somewhere that the US Army runs through almost 500,000 of 30 mm rounds a year, most fired from the Apache helicopters. Somewhere around here I have an inert 20mm round which is pretty cool as you can unscrew the tip and see where the explosive charge goes.

Ron

The reason for that "crack" sound is that it is a sonic boom. Many military rounds are faster than sound. And if you ever get a chance to see and hear a fly-by demonstration you will understand. It sounds a bit more like a chain saw at red-line. And after it is done and you get to see the targets and see all of the holes it is impressive indeed. And that was a demo using the very cheapest rounds.

 

Actually, if it would not blow it apart, they could supply the Airsoft guns with a propane-acetylene mix and just add a spark plug. It would add a kick and a real muzzle flash. And it would not need any extra solenoid valves. How about that for an idea??

 

The reason for that "crack" sound is that it is a sonic boom. Many military rounds are faster than sound. And if you ever get a chance to see and hear a fly-by demonstration you will understand. It sounds a bit more like a chain saw at red-line. And after it is done and you get to see the targets and see all of the holes it is impressive indeed. And that was a demo using the very cheapest rounds.

I was aware of that. I am still active in the shooting sports. This is pretty cool. As a young Marine on the rifle range you take turns "pulling butts". Pulling butts is working in the target area below the targets so the rounds are zipping over your head and yes, you hear the sonic crack. What is cool is on the firing lines (200, 300 and 500 yards or meters) we have phone talkers and in the butts we have phone talkers. I have been a phone talker. We used the M14 at the time so figure we were shooting basic 147 grain GI M80 ammunition (Standard NATO). The average muzzle velocity is about 2800 FPS. A shooter at the 500 yard or meter line is in the prone position. So at 500 yards we have 1500 feet and allowing for bullet deceleration it takes the bullet just a little over 1/2 second muzzle to target. What was cool is I could hear the shooters rifle go Bang over the phone line and then about 1/2 second later hear the sonic crack as it went over my head the through the target. You pull the target down and mark the hit and put a black or white pastie over the holes and run the target back up. We also use a score pin to mark the targets. Shooting GI match and competition is something I always enjoyed and being up here I am not too far from the nationals held here at Camp Perry which is a big annual event.

I can still manage to get into the sitting and kneeling positions, granted not as tight as younger days but at 70 I still bend a little. The 7.62 NATO M80 decelerates to sub sonic at about 800 to 850 yards and the bullet goes through some destabilization at that point impacting accuracy.

June of 1969 The Edson Range Camp Pendleton CA that's me sprawled out in the prone position on target #29. Some notice and yes, I shoot left handed. That was qualification day and I came away sharpshooter missing expert by a few points but well above Marksman score. The guys standing over us were either Drill Instructors or Preliminary Marksmanship Instructors. Hard to believe over 50 years ago.

I also got a real good demonstration and feel for bullets in flight in Vietnam.

Ron

 

they could supply the Airsoft guns with a propane-acetylene mix

What good would that do? Two fuels and no air or oxygen to make them burn? The do have propane powered air soft, or did. I have an air soft M1911 the works by propane, to cycle the slide.

 

What good would that do? Two fuels and no air or oxygen to make them burn? The do have propane powered air soft, or did. I have an air soft M1911 the works by propane, to cycle the slide.

It is simple to add an air inlet check valve so that the hot gasses expanding out will draw in fresh air.And I hac\ve never come across a situation where acetylene would not explode.

 

I hac\ve never come across a situation where acetylene would not explode.

And I have never came across one where it did. One place I worked at was next door to a welding gas supplier, not welding shop but place that stored and distributed gases. It caught on fire and burned to the ground without even one of the gas bottles of any kind exploding.

What I can tell you is that acetylene is one gas that can explode with a bang just in a paper cup sitting on a flat surface, with nothing except the inertia of the air above as resistance.

Give a reference to that ever happening. Not an anecdote but a real reference. I've played around with acetylene and the carbide that makes it in my misspent youth and have never had an explosion that wasn't planed in advance.

 

I know this is an old threat, but I came across this: https://www.popularairsoft.com/news/x9000-gun-sound-simulator-airsoft except that I can't find any info on this either. But thought I'd share it anyways.

 

Welcome Rens Tillmann to AAC.

Usually threads this old have either found the solution to their problem OR they've given up. But thanks for your input.

 

And I have never came across one where it did. One place I worked at was next door to a welding gas supplier, not welding shop but place that stored and distributed gases. It caught on fire and burned to the ground without even one of the gas bottles of any kind exploding.



Give a reference to that ever happening. Not an anecdote but a real reference. I've played around with acetylene and the carbide that makes it in my misspent youth and have never had an explosion that wasn't planed in advance.

I have seen it in person, from about 20 feet away. Gas from a welding torch carefully put into a paper cup. A shrt string fuse, lit by the welder who backed off. Quite a flash-bang in a dark shop.

 

I have seen it in person, from about 20 feet away. Gas from a welding torch carefully put into a paper cup. A shrt string fuse, lit by the welder who backed off. Quite a flash-bang in a dark shop.

You just set up an Oxygen Acetylene torch about 45 PSIG Oxygen and 10 PSIG Acetylene. We did it with a balloon. Fuse it and run, run real fast. Not really a good topic for discussion.

Back around 2000 an AmeriGas plant maybe a mile from the plant I worked in had a major propane explosion. Bottles and large tanks just kept exploding. Felt like a major earthquake and miraculously only one person was inured. They ended up evacuating the entire industrial area. This was also beside Interstate 90shutting the interstate highway down for evening rush hour. It's like the Cleveland, Ohio area is a magnet for industrial gas explosions.

As to back on topic I have not seen anything at a decent price point that would simulate machine gun fire.

Ron

 

NECRO-POST

This thread is almost a year and a half old between last post and the new guy posting. Hey! We've all made that mistake. As for what the TS wants (or wanted) either he's gotten it - or has given up long time ago.

 

NECRO-POST

This thread is almost a year and a half old between last post and the new guy posting. Hey! We've all made that mistake. As for what the TS wants (or wanted) either he's gotten it - or has given up long time ago.

Yes, but it's always fun to discuss things that explode or go bang.

Ron

 

Stacey David's "Gearz" TV show had propane-powered replica machine guns mounted on a truck:
https://web.archive.org/web/20141029113143/http://www.iracinc.com:80/
http://www.highgateco.com/brands/irac-llc/
https://www.youtube.com/channel/UCvrclg_bvRCdu3HZ76ByLdQ

 

You just set up an Oxygen Acetylene torch about 45 PSIG Oxygen and 10 PSIG Acetylene. We did it with a balloon. Fuse it and run, run real fast. Not really a good topic for discussion.

Back around 2000 an AmeriGas plant maybe a mile from the plant I worked in had a major propane explosion. Bottles and large tanks just kept exploding. Felt like a major earthquake and miraculously only one person was inured. They ended up evacuating the entire industrial area. This was also beside Interstate 90shutting the interstate highway down for evening rush hour. It's like the Cleveland, Ohio area is a magnet for industrial gas explosions.

As to back on topic I have not seen anything at a decent price point that would simulate machine gun fire.

Ron

If your ears are not ringing the simulation is a poor one. I was exposed to .50 Caliber Machine Gun fire once without hearing protection beyond my hands while working on antennas near the bridge. The was beyond loud and well into painful but way too much fun with proper hearing protection.

https://asa.scitation.org/doi/pdf/10.1121/1.5134069