Valveless section of website now obsolete

[Bruno Ogorelec]

Friends,

I think I can do this without consulting Kenneth. I hereby proclaim the Valveless Pulsejets section of this website officially out-of-date.

(I don't mean the valveless section of the forum. That one is alive and well. I mean the review of valveless pulsejet history and designs.)

I have been writing a new version for about a year and a half now. In fact, I completed two new versions (1.1 and 1.2) since and even sent one to Kenneth for publication. However, just as I would complete a new version, so much new information would start flooding in that the most recent document would be made obsolete. Publishing it made little sense. It would be just as inadequate as version 1.0 which is still on the website.

Two or three months ago I completed version 1.3 and sent it to two or three people for review. It is really different in many respects from 1.0 and I thought I might even publish it in the form of a brochure. But again, as soon as I completed it and started thinking of sending it to Kenneth, events overtook me and I came into possession of new data, pictures and insights. They are important enough to make 1.3 obsolete, too.

Mind you, I am not talking of details, but of major ingredients. By now, much of what I originally published about the Logan, Escopette, Chinese, Thermojet, Ecrevisse and Tharratt is no longer something I can stand by anymore. It needs major revisions.

OK, much of the necessary revision has already been done in the process of writing versions 1.1, 1.2 and 1.3, but there's still major work to be done. I have no idea when I might finish it. A couple of months on the inside; probably more.

I just want to warn you all that anything written in the original documents should now be taken with a large grain of salt.

[Viv]

Ah Bruno you admit your mistakes with a grace and style that leaves me breathless:-)

I am not worthy, I bow down before you:-)

On a more serious note though, this problem is not going to get any easier old buddy, would it be any better if the document was broken up in to smaller sections, it might lighten the load when new information cropped up and caused an update.

Viv

[Bruno Ogorelec]

would it be any better if the document was broken up in to smaller sections, it might lighten the load when new information cropped up and caused an update.

That is not at all a bad idea. I'll think about it. quite a lot of the document is in fact ready and unlikely to see major revision soon. Thanks.

[Dave]

Bruno
From all that I can see, writing about pulse jets is like buying computer equipment. With computers: no matter how long you wait, as soon as you place the order the equipment will be outdated minutes later and you could have bought it somewhere else for less. With pulse jets: no matter when you write the document, there will always be more information and it will come from somewhere else. Your document appears to have become a living needful thing that will never be truly finished. You just have to pick a point in time to publish and then start the process again. Revisions will be consumed by hungry minds with ideas, information and opinions of their own to contribute to the next round. Just keep the revisions coming.
Dave

[dadruid]

Hey, I'm a student at OIT (Oregon Institute of Technology) working on a valveless pulsejet research/experimentation project. Is there any chance of getting ahold of the valveless pulsejet info? At the moment I'm somewhat frustrated with what I'm finding. Also, as this is my first post I'd like to say hi to everyone. I've been an avid (albeit quiet) fan of pulsejets for about three years now, I was immediately fascinated with them after following a link to Bruce Simpson's website. The ultimate goal for this project is to develop and build a working valveless pulsejet, although I might be shooting a little high as I have yet to actually build anything. Anyway, greetings to all!

[Bruno Ogorelec]

At the moment I'm somewhat frustrated with what I'm finding.

Dadruid (or whatever your name may be), why are you frustrated if the aim is to build a workable valveless pulsejet? Grab hold of a plan of a Lockwood with dimensions and build it. Scores of people have done so to their utter satisfaction, getting fire and noise aplenty.

If your aim is to understand valveless pulsejets, however, you should join a monastery first. Namely, you need a course in monastic patience and devotion before you start. Believe me, intelligence and scientific background come very distant third and fourth in importance.

[dadruid]

Just ordered my monk robes, now what? (-: Seriously, maybe I'm looking in the wrong places, but I'm having difficulty finding hard data. The idea is to develop a sound understanding of the theory, then make a small evolutionary improvement, not a rehash of existing design. That's why I've been avoiding the Lockwood, although maybe that's too large a leap for a beginner. A friend of mine attempted a design similiar to your BCVP (san augmenter) last term, but hasn't yet overcome the ignition problem. Would anyone like to see the footage from that? Anyway, the more information I can find the better, regardless of what I end up building, so if you have something prepared I'd be eternally greatful. Speaking of building, has anyone been succesful with a Foa type design? The simplicity is very appealing. Or a Tharrat? And at the risk of getting a bit dreamy, a functional version of either might take my iceboat to a whole new level! Lastly, the real name is Drew.

[sparks]

FOA? Is it KTH´s thermojet you are talking about?
If so, i built one about ten years ago.
Never got it to run properly on propane, just acetylene.
It made my neighbors pretty nervous though, thats for sure ;-)

[Bruno Ogorelec]

Drew, first of all, welcome to Pulsators Anonymous, the club of people abnormally obsessed with pulsating for propulsive purposes, who are not quite sure they want to be cured of their obsession.

maybe I'm looking in the wrong places, but I'm having difficulty finding hard data.

You don't say. Look, 90 percent of pulsejet development history consists of hot air, literally and metaphorically. The chief reason is that pulsejets have been under-researched, comparatively speaking. In comparison to what is known about processes in the combustion chamber of a piston engine, pulsejets are still Terra Incognita.

Early on, these engines were difficult to pin down, chaotic and temperamental and obstinate in some respects. At the same time, turbojets looked far more promising and their output was much easier to predict and tinker with. So, smart researchers chose more promising avenues of research than the frustrating pulsejets. As time went by, there was increasingly little incentive to dig in this blind alley, as all propulsion needs were covered by other engines very nicely. No one really needed a new aircraft powerplant, least of all a noisy and uneconomical one.

The idea is to develop a sound understanding of the theory

Well, that’s easy. Find texts on pulsating combustion written by Joseph G. Foa and Ben T. Zinn. You will hardly need more. For the more obscure pleasures and imagination not quite fettered by practical considerations, read the collective works of Francois H. Reynst. Preferably not just before sleep.

then make a small evolutionary improvement, not a rehash of existing design.

You are of course welcome to try. Hundreds have done so. It looks deceptively easy. I mean, pulsejets are so primitive and have not really been improved upon since the 1960s. Surely, if one added modern electronic ignition and modern electronically controlled fuel injection, the output would soar…. Ha-ha-ha…

A friend of mine attempted a design similar to your BCVP (san augmenter) last term, but hasn't yet overcome the ignition problem. Would anyone like to see the footage from that?

If it will comfort him, no one has overcome any other problem connected to that concept either. He’s in good company. Yes, everyone in the forum would very much like to see pictures, footage, hear stories etc.

has anyone been successful with a Foa type design? The simplicity is very appealing. Or a Tharrat?

We presume Foa and Tharratt, respectively, were successful. That’s what it says in research papers. I am not aware of amateurs building those engines. Yes, they look simple. Tharratt, however, is more complex than it looks at first glance. I am just looking into that design and the more I look, the less I understand. What initially looked like a thing of toy-like simplicity is proving to be much more complex.

And at the risk of getting a bit dreamy, a functional version of either might take my iceboat to a whole new level!

Yes, Drew, you definitely belong here. This last sentence clinched it. Have fun. Learn not to bite your fingernails or tear your hair out. And, by all means, keep your day job.

[Mike Everman]

As (mostly) always, extremely well put, Bruno. I nominate this response as an entry in the upcoming FAQ section! Only what would the title be?

[dadruid]

Aha! Finally some books my library actually has! Thanks!

[cudabean]

Why not post your valveless intro to the Wikipedia?

Here's a Slashdot article that describes the 200,000th Wikipedia entry, which is up from 100,000 entries a year ago:
http://slashdot.org/article.pl?sid=04/0 ... =95&tid=99

(If you decide to post it there, you may have to wait until tomorrow--it's slash-dotted i.e. overwhelmed by slashdot users right now)

cudabean

[Bruno Ogorelec]

Why not post your valveless intro to the Wikipedia?

Um... I don't know. Why should I? Please clarify.

[cudabean]

Um... I don't know. Why should I? Please clarify.

No real reason in particular, but:
1. It contributes to an up-and-coming information resource.
2. It probably wouldn't require too much effort.
3. How many times as a youth have you gone to look up info on pulsejets only to find a lame one or two sentence dismissal? This gives you the power to change that for the next generation.

cudabean

[Bruno Ogorelec]

1. It contributes to an up-and-coming information resource.

Sounds good, but how come I have never used Wikipedia in my life? Over the past 15 years, I have lived off trading in information. I have searched far and wide for information to sell. Wikipedia never even came close to giving me anything. Are you sure it is worth notice?

Mind you, I have nothing agains; I'm not being obstinate; just curious.