Posted: 06/12/2008 13:09 PM Post subject: Video added: Time to make some NOISE! + diagram
Corporal
Joined: 16 May 2008 Posts: 65 205.82 Spud Bux
Independence Day is coming soon so I made a barrel attachment that uses a tennis ball as a burst disk without actually shooting the tennis ball. I have too many houses around me to actually fire anything in my neighborhood.
Once the tennis ball passes the two exhaust ports, it is stopped with an end cap. a ramrod is permanently attached to the tennis ball and is guided out of a hole in the end of the cap.
This should make for rapid reloading and firing. The pressure created by the tennis ball should make a nice loud BANG! Hmm...wonder what my C:B ratio is on this thing.
After I fire it tonight, I'll assess whether the exhaust ports need deflecting.
Jeff
UPDATE: Two more exhaust ports were added for a total of 4. Much louder now.
Good deal! I'm in the process of finishing my noise makers, 3 of them, in time for my 4th gigs. I'm using burst disk'd barrel stumps with huge effect.
Have you thought about 4 or even 6 exhaust ports? at least portage equal to the square area of your chamber breech? My thought is you'll be unnecessarily choking off your flow and thus your db's...
I'll be curious your impression of the noise level of this. It's hard to compare non-instrument measured noise levels over a written media, very subjective.
Hope you plan on firing it remotely the first couple times, then inspect it after each Boom.
Looks like the ball, rod could smack into the end pretty hard, putting stress on it. (at the threads and chamber)
Also the pressure itself could really build up before hitting the noise chamber.
I'm sure you've already considered that probably.
Hope to see the updates on it.
I just fired it. DAMN, this thing is much louder that the 1.5" potato barrel!
I made the port area equal to about the area of a 1.5" barrel. I love it! The tennis ball capture was perfect, also.
The rod doesn't hit the end cap. The tennis ball takes the blow. Since the tennis ball has only 1" to gain speed, it barely reaches the end cap.
Jeff
How is the poor tennis ball fairing? If it had any fuzz on it, it doesn't now.. ..taking the full direct high temp flame front and not being able to cool down through flight.
I'm using a ball that has been launched many time and had crusty fuzz. I'll let you know how long the ball can take the abuse as I use it over time.
The part that screws on is 2". Adapter to 2.5" barrel for tennis ball.
I could make the ports bigger or make more of them to equal the breech size but after firing it my ears were ringing for a while. Good enough for me. I'll use ear plugs next time.
Jeff
EDIT: Video coming soon.
Last edited by xpitxbullx on 06/12/2008 16:16 PM; edited 1 time in total
I'm using a ball that has been launched many time and had crusty fuzz. I'll let you know how long the ball can take the abuse as I use it over time.
The part that screws on is 2". Adapter to 2.5" barrel for tennis ball.
I could make the ports bigger or make more of them to equal the breech size but after firing it my ears were ringing for a while. Good enough for me. I'll use ear plugs next time.
Jeff
Yeah I thought later I should have told you to wear plugs, the holder and anyone within 10 ft of the thing. My left ear tends to get the ring because of the way I hold the gun...tending toward the left.
This looks like a great idea! I'm going to put one together and see if there's any difference from the burst disk boom.
After comparing the loudness of the noise barrel to the potato barrel, turns out they were the same loudness. I'm going to remake this with a 2.5" tee.
I have a video of 2 flames shooting out of the sides but it was recorded too far away so I'll wait tip I make the single port barrel using a tee for one bigger flame out the front.
The tennis ball took about 20 shots and looked like it was taking it fine.
I added 2 more ports for about 4" square area of holes. I'll do a bang comparison later tonight. I decided not to to with the tee for asthetic reasons.
I'll try for a good video at night of it.
Jeff
EDIT: Those extra ports were exactly what it needed. The tennis ball clears the ports and hasn't even hit the end cap. The "boom" is obviously louder. It's a different sound but its very loud. This works great, now.
Im glad to hear the extra ports worked
Try to optimize the flow and get thus the largest vent hole possible for the loudest bang. The pressure has to escape as fast as possible.
Do you think if I added 4 more exhaust ports that it would be even louder? It's pretty damn loud as it is. It may destroy the integrity of the barrel. All the ports are measured to the exact same level.
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..taking the full direct high temp flame front and not being able to cool down through flight.
