"U" shaped valveless pulse-jet

[J.L. Frusha]

This is NOT your typical pulse-jet...
http://s268.photobucket.com/albums/jj5/ ... lsejet.jpg
Does anyone know where I can get plans and design specs?

Thanks,
Jeff

[metiz]

Do you have a bigger picture?

[J.L. Frusha]

Sorry, it's the only one I can find. It's Eric Beck's Avatar, on his forum. Not hearing from him, so I thought I'd ask here.

[metiz]

I see. well if that engine is what I think it is, you can pretty much forget about getting the plans. Even if you did, that engine won't run.

[J.L. Frusha]

To me, it looks like a simplified version of Bruno's design, which has possibilities... If you can point me in the right direction, or make an educated guess, lend a hand. I don't have an unlimited cash resource, but I have time and patience to work with it. It may or may not work, but I'd like to give it a try. If I can figure it out, maybe I can apply it to Bruno's design, for the next version.

[metiz]

Sorry, I can not and wil not help with that.

[Eric]

I dont have any plans to make plans available, and if you build it just as an outer shell with no knowledge of the internals, it will not run.

[J.L. Frusha]

I thought these forums were intended to assist in the development of pulse-jets. This is obviously a pulse-jet. Somewhat different than others, however, it should function like any of the multi-inlet/single chamber pulse-jets. The main difference is going to be the way the combustion flows, compresses and initiates the next cycle and the dual exhaust tubes.

I would be willing to bet that the "U" combustion chamber is reasonably close, in volume, to single-chamber/dual inlet designs. It also would appear that other than using 1 combustion chamber, it should function as 2 pulse-jets, requiring twice the fuel, producing twice the thrust of one "half" of the machine.

What does it hurt, to point me to an article or person? It's not like this is some super-secret, classified project, or I wouldn't have been able to get the image in the first place. The image was placed in the public domain, when Mr. Beck chose to use it as an Avatar, on his web-site.

I'm simply looking for more info. and interested in the design. If it's too difficult to operate, I only have to scrap a bit of steel tubing. The fuel-delivery system can be used on another project.

[J.L. Frusha]

One note: This is obviously intended to be a "Blast Compression" type pulse-jet (Deflagration to Detonation Transition). There are numerous other names to describe the combustion of this type engine, just compare the definitions. In theory, the expanding combustion gases of one side compresses the charge of the other, creating a better combustion process. This means that the energy recoverable as thrust is much higher than the standard "Deflagration" type of low-pressure combustion typical of pulse-jets.

[Mike Everman]

There have been several builds like that, though I'm sure not as considered as Eric's approach must be inside. Obviously if he's not wanting to share, then that needs to be OK. Search here for (I think is was) Vern's work. He made several successful ones of the same basic layout, but little in the way of data, though I see one where he got 10 lb with straight tails.
DDT is a "pipe dream" ha, at least in the classical definition of pulse-jet (which I would say is self sustaining, self aspirating).
So is blast compression, or at least shades of gray there. I've seen some interesting things, but nothing calling itself that and ultimately practical.

[Eric]

One note: This is obviously intended to be a "Blast Compression" type pulse-jet (Deflagration to Detonation Transition). There are numerous other names to describe the combustion of this type engine, just compare the definitions. In theory, the expanding combustion gases of one side compresses the charge of the other, creating a better combustion process. This means that the energy recoverable as thrust is much higher than the standard "Deflagration" type of low-pressure combustion typical of pulse-jets.

No, its not.

Pictures of the B-2 bombers are all over the internet, but you dont see the US government giving out repair manuals online.

The engine works, albeit not as well as I would like. While it isnt something I am currently working on, it is something I would like to get back to eventually.

A picture of an engine as an avatar does not mean the internal workings are in the public domain, because no details of the internals have ever been released, and that's not going to change any time soon.

If you want to build an engine this would be about the worst place to start, since it has what like 13 sections just on the outside. If you are really inspired by the picture, then by all means tinker away and experiment, after all its only a bit of steel.

While I have done experiments with 'high power combustion' as some call, or achieving high compression ratios so that more fuel and air can be packed in the combustion chamber, I have no intention of being anywhere near something that will be producing 200 detonations a second in a thin wall stainless tube. You can still get a tremendous amount of power out of combustion only, and even without detonations there are certain things that are just not safe to be around.

You obviously have done enough reading, and digging around obscure sources like my old forum, find a easier beginner project, get an engine running, then modify it with your ideas and your theories.

[J.L. Frusha]

I've slept on it, my basic theory of operation was wrong. Both sides have to work in parallel to create one large pulse. When the 2 wave-fronts approach each other, inside the bend, the fuel/air mix between them becomes highly compressed and reaches self detonation.

As for how many pieces are welded, I'd say 15 looks about right. Wall thickness? It would have to be around double the thickness of the supposed 'thin-wall' tubing. In other words, roughly the thickness of automotive turbo-diesel exhaust pipe. That's over 4 times as strong as thin-walled tubing, for the curved combustion chamber, which is in the correct range for the secondary(power) impulse, as long as it is seamless tubing... Overall length should be a little less than 3 ft. Inside diameter of the combustion area should be about 1/7th of the length, around the bend, of the 180 degree curve. Inside diameter and combustion chamber length (chamber volume) are determined by the stoichiometric volume of the fuel/air mix necessary for the secondary pulse to be created(call it 3 'normal' chambers worth). For better durability and heat retention, the whole thing should be coated with something like exhaust manifold ceramicoat, internally, and ceramicoat or exhaust manifold paint, externally. The initial spark ignition(both sides) should be about 1/2 the distance between the intakes and where the center-line of the lateral tubes intersect the curve. Did I leave anything out?

[J.L. Frusha]

Yep. sure did! Intakes and fuel nozzles are sized for evenly supporting the triple-sized combustion chamber. In other words, they should each flow 50% more than would normally be required for a single inlet design.

[J.L. Frusha]

Didn't want to get ugly. I just don't like being told one thing, when a little research can point out where the pies in the pasture are. I have never welded, but have 3 people that will teach me. A son, a neighbor and a brother(order of proximity). I can look-up more bunk, than even I can believe. If my theories and facts are so far off as to warrant a serious clamp-down, prove it to me, instead of saying something isn't possible. I'm more than willing to learn, but I'm going to back-up what I'm being taught, with research. I can learn almost anything I put my mind to.

Don't preach at me. Teach me. I'm willing to concede that I only have research, not proof, behind me.

[PyroJoe]

I say put it to steel.
Considerable time with a hammer and welder can show where theory ends and the reality begins. There are many plans of engines on the main page for download, also throughout the forum. The ones Eric mated look like the chinese style.