## Search found 1743 matches

Wed May 09, 2012 7:57 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

My concern on that one is it may re ingest a significant quantity of spent gas.

Some of the stuff I haven't tested looks like this. With a partial cone or just a portion of pipe placed over some holes between the intake and the augmentor pipe.
Wed May 09, 2012 4:19 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

In looking at overpressure there is probably some useful information in the "Pressure drop in a pipe" math. The math basically describes: pressure drop = (pipe friction coefficient)x(Length/Diameter)x(Density/2)x(Flow Velocity squared) as we look at this, pipe friction can probably be set, and also ...
Wed May 09, 2012 1:36 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

I think the problem is in the pop itself. There is a very big difference between pop that has an overpressure near 5 psi and a overpressure that is near 0.10 psi. If you could place a augmented fraction engine (near double length) producing a very low overpressure into a Meredith shroud, things woul...
Tue May 08, 2012 7:09 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

The trick for me is to use up as much inside noise as possible, so that when it reaches the outside there is less to suppress. Engine size, versus thrust production, versus noise production have typically been opposing characteristics. Its typically been a struggle of: here are 3 positive characteri...
Tue May 08, 2012 6:32 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

Well I stand by that using pressure to cancel pressure requires a energy loss somewhere. As far as being able to cancel some noise with what you have illustrated and constructed, I have no problem in believing the noise can be reduced that way. Hell, if you were able to suppress 1 psi of the overpre...
Tue May 08, 2012 6:05 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

Ok luc, I see where your coming from, not necessarily to agree, but i see it.
Tue May 08, 2012 5:29 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

Mike, Yes, sound and pressure synonymous. To this I ask, what drives mass acceleration? Why would we see peak +pressures near 30 psi in the CC and only +5 psi peak at the tail openings, dumping out as an overpressure? what happened to that other +25 psi? luc, Ok, got it i think. What would we like t...
Tue May 08, 2012 4:58 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

Ok, I have flipped it around, now where is the contact to be?
Tue May 08, 2012 4:48 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

We probably have our wires crossed so lets look at the example to clarify. I think this is what you had proposed a 1" pipe within a 2" pipe, each at 24" length and each with a closed end? Are the capped ends in the correct configuration?
Tue May 08, 2012 3:44 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

I have seen better results in not cancelling sound with sound. That would reduce the pressure somewhere, pressure that was developed at the cost of fuel. It is better in my opinion to convert as much pressure possible directly to mass flow before it is released. Not fancy, and not new, but it works.
Tue May 08, 2012 2:34 pm
Forum: Rocket forum
Topic: Mobacken Racing - Rocket build - NOX and Methanol
Replies: 3
Views: 2909

### Re: Mobacken Racing - Rocket build - NOX and Methanol

Tue May 08, 2012 2:32 pm
Forum: Rocket forum
Topic: Finally back, building PVC Rocket!
Replies: 1
Views: 1607

### Re: Finally back, building PVC Rocket!

Any progress/videos?
Tue May 08, 2012 1:32 pm
Forum: Tools and Construction
Topic: Cutting noise
Replies: 37
Views: 11583

### Re: Cutting noise

Naw, sound energy isn't needed for the function of the engines. You basically have a pressure source, and the pressure drops with distance from the source. The closer the pressure is released to the source, the higher the over pressure release will be. If most of the pressure is converted to mass fl...
Wed May 02, 2012 3:43 pm
Forum: Tools and Construction
Topic: Fueling ridiculously big engines
Replies: 6
Views: 3442

### Re: Fueling ridiculously big engines

I have been looking at this picture Mark provided earlier, the one thing that has my attention at the moment is the step down that the holes are near. Notice the step is closest to the venturi opening side. On the Bailey the are positioned right near the step. I wonder if the holes in lucs design co...
Thu Apr 26, 2012 3:19 pm
Forum: Off topic forum