Kazoo engine

[Bruno Ogorelec]

supercomputers are "super" because of their relative speed, nothing more: the "back of the envelope calculation" remains my trusted friend.

Yes, certainly. All computers are 'super' because of their speed. I am not aware of any function of the computer that people cannot do on their own, given unlimited time. The fact, however, that the pulsating combustion models I was talking about require _hours_ on supercomputers means that slower computers will have difficulty handling the problem and people without computer will have to do without – or will have to invent another way of going about it. You seem to have found another way of going about it.

My late father always claimed that the only computer he ever really needed for his computational needs in the field of electrical conductivity phenomena in amorphous semiconductors was a Sinclair Spectrum. Everything else that came afterwards, he would say, only did things a bit faster. To him, speed did not matter, as long as it was in the electronic processor realm, rather than pen-and-paper. He simply scheduled the workday so that computing started as he was going home. He would pick up the results next morning, whether they took fifteen minutes or fifteen hours. But, he always wrote all his software himself; never used commercial products.

I have previously offered, and I still offer, to provide assistance in modeling prospective pulsejet layouts.

That is very generous of you. I may take you up on this yet. Not now; it would be a waste of your time, as all my concepts are 'paper engines' at this point. If I take any of them to the stage where prototyping is the logical next step, I will probably drop you a polite line.

When I can finish writing up the results, I will post some new information (fresh from the oven, err... model) relating to the Ecrevisse.

Good news! I am waiting with bated breath.

[Viv]

Aw, Chris, isn't she cute! See attached for another size challenged engine. Most of the guys here will say we're MAD, MAD I TELL YOU! I'm just having fun bending stuff. I learned I've got to make a fixture to do this right, no matter what size I do.

I hope you are proud of that:-) It does look the business and yes I know its a bit small but it does look ready to run!

Go on pour some meths in and see what happens, you know you want oto:-)

Viv

[resosys]

Aw, Chris, isn't she cute! See attached for another size challenged engine. Most of the guys here will say we're MAD, MAD I TELL YOU! I'm just having fun bending stuff. I learned I've got to make a fixture to do this right, no matter what size I do.

Wow, that is tiny. They may say we're mad, and that's quite alright. We're doing it and that's what matters to me.

How do you plan to supply fuel to you little tube engine? How are you going to start it?

I'm cutting the parts for the triangle pulsejet tonight!


Chris

[Mark]

the collars worked great, but the jury is still out. this mat'l is .049" wall, 1" od. You can see on the top picture how it buckles in the middle, bound to be worse when mat'l is thinner. I'll squish some 2" tomorrow, and Graham, I'll get some 3" collars ordered tomorrow too.

Where did you find those collar type clamps? They seem kind of neat for some future application somehow.
Mark

[Mark]

Last night I did some layout work on a straight through triangle engine design. I printed three copies onto paper, cut them out, and taped them together to make sure my math and eyes weren't too far off. It looks pretty good, if not a bit odd. I'm really looking forward to welding one up this weekend.

I cut down an image of my baby lockwood combustion chamber and intake tube as it sits right now (see attached).

If anyone has any thoughts on special requirements a triangle engine may need in terms of ratio changes, fuel inlet placement, etc... please post them. It would be nice to go into this thing with some ideas to try during the test phase.

Thanks,

Chris

And even that size will be plenty loud. It is a nice looking approach, it looks embyronic, a newborn pup on its way.
Mark

[Mike Everman]

Where did you find those collar type clamps? They seem kind of neat for some future application somehow.
Mark

www.mcmaster.com under "two piece clamp collars" or somesuch. this company has everything, I use them all the time. Oh, look for butt-weld stainless pipe fittings, they have some nice reducers and standard stuff in Schedule 10. Kind of spendy, but not too bad for building an engine.

[Mike Everman]

Two questions.

(1) Off topic. Do your robots have anything to do with biotechnology. biochemistry, pharmaceuticals etc? My daughter is writing a paper on robots in those industries and is looking for some interesting background info. She's majoring in biotechnology. One day, she will be growing pulsejet plants hydroponically in our basement. Kirney can tell you all about it.

(2) Closer to the pulsating topics. I am mad enough to go back to valves. And not even the lightweight reeds but old-fashioned heavy-duty steel poppet valves you normally find in piston engines. I think I have a good reason to go that way with a pulsejet. Would you consider a design of such a pulsejet and evaluate it for practicality of manufacture?

1. I will post something to the off-topic tonight with regard to my robotics and their uses in biotech, in case anyone else is interested, and it's my pleasure to help.

2. I am certainly interested in manufacturing any engine that makes sense, with full royalty to the designer, unless he's the customer. I also have connections for higher volume manufacture in China, but that of course would need quantities that this market may never bring to bear. There is nothing we cannot build, but I think the price will be problematic in the low quantities.

I fear that the manufacturers to date have not been truly business oriented, so correct me if I'm wrong. Seems to be guys in garages making to order, not needing to make X dollars per actual hour. Dynafog most likely finally realized that hobbyists will only pay so much for a Dynajet, and it's just not profitable.

All that being said, I may not care if it is profitable because it is fun, and if it funds a reasonable amount of over-head, we're a GO.

[Bruno Ogorelec]

I am certainly interested in manufacturing any engine that makes sense, with full royalty to the designer, unless he's the customer. I also have connections for higher volume manufacture in China, but that of course would need quantities that this market may never bring to bear. There is nothing we cannot build, but I think the price will be problematic in the low quantities.

Oh, I didn't mean that. I meant evaluation from the point of view of manufacture. You are closer to manufacturing than most of us and can probably evaluate whether something would be easy, simple and cheap to build or not. I want eventually to build an engine that will be strapped to you back and cary you aloft with some kind of a lifting surface – a wing or a propeller or something – at acceptable cost and with acceptable noise. Even if a design is ingenuous, it need not be easy to manufacture. Look at Wankel.

I fear that the manufacturers to date have not been truly business oriented, so correct me if I'm wrong.

Um… Mike, there was no business to speak of. There were the modelers, and even they have not been terribly numerous. I would certainly have been loath to start manufacturing pulsejets in the 1970s even in small batches. Dynafog was lucky to be able to do something marketable with their design.

All that being said, I may not care if it is profitable because it is fun, and if it funds a reasonable amount of over-head, we're a GO.

I like the spirit. I also think that the market might be there at last. One should develop a good-looking, well performing engine with acceptable SFC and tolerable NVH (noise-vibration-harshness) parameters and it will be eagerly evaluated and tested by UAV and ultralight aircraft manufacturers. At the lower end of that market, there is nothing that does the job really well.

[marksteamnz]

Snip.

(2) Closer to the pulsating topics. I am mad enough to go back to valves. And not even the lightweight reeds but old-fashioned heavy-duty steel poppet valves you normally find in piston engines. I think I have a good reason to go that way with a pulsejet. Would you consider a design of such a pulsejet and evaluate it for practicality of manufacture?

Bruno if you want a one of made I'd interested in having a shot at it.
Prototypes are what we are trying to do.

[Mike Everman]

I meant evaluation from the point of view of manufacture.

Oh, sure, of course! Day in, day out, eeez my yob.

[Bruno Ogorelec]

Bruno if you want a one of made I'd interested in having a shot at it. Prototypes are what we are trying to do.

Mark, thanks! I'll certainly ask you for a quote if/when I'm close enough to contemplating building a serious one. Before that, however, I will have to build a rough and ready one to test the concept. If teh concept is faulty, why waste time and money on fancy prototypes?

[Mark]

Where did you find those collar type clamps? They seem kind of neat for some future application somehow.
Mark

www.mcmaster.com under "two piece clamp collars" or somesuch. this company has everything, I use them all the time. Oh, look for butt-weld stainless pipe fittings, they have some nice reducers and standard stuff in Schedule 10. Kind of spendy, but not too bad for building an engine.

Thanks for the link. I tried for a catalog, but alas, they are expensive to produce I guess, and they politely delined my request for one of their catalogs. Had I been a business, I might have gotten one. MSC is another good company and they did send me one of their catalogs. It was jumbo thick and hard covered and had little taps to find the section you were looking for. They sell tools and raw materials such as spring steel and bar stock.
Mark