Worlds simplest valveless?

[Bruno Ogorelec]

OK, Michael, I am partly mollified. Your keyboard will NOT turn into blue cheese. I'll think about valve steel, though, ad better concentrate on valveless engines for the time being.

Neighbors may well fart in your elevator; I have little influence over that. Ditto on e-mail. Most of it turns out to be spam anyway.

You can see how little substance my threats actually had. It's pure psychology. You psyche your opponent into surrender and never really have to deliver on your threats.

[Mike Everman]

Toochie, my friend. Hope I haven't scared George off!

[George]

Hy guys !

First, i'm not scared ! i'm just very happy that my documents are interresting all of you.

Since five years, i was searching informations about the valveless PJ and more précisely the SNECMA engines because it's the company who first explore the valveless solutions with ingeniors (good ones i think) and a big structure behind.
I hopefully find a contact at the SNECMA who transmit to me the archives available on these subject, some very interresting things historically but there's pure technical documents who were not found, aniway for the last version of the écrevisse that you sawn (maybe they are in a laboratory as technical archives).

You have to let me time to gather together the notes, parts of books and mémorandums i have, the object for me is to make theses works public.

If Bruno wants to put them on line, its ok, but remember that all of them are in french language and often technical language... and i've no time to traduce them. fortunately there is some plans inside.

To answer to your last questions:

Pieter, i have no dimensions for the écrevisse from SNECMA i shown but i think i would find it in another book about reactors, i 'll tell you soon.
It's probably one of the last versions with a great "bionic" look.
In fact the exhaust come under the combustion chamber to have thrust on one line because this engine was made to test vertical take-off for the "ATAR Volant"

Bruno, you're right, the GS1 had one pulso by wing and a lot of exhaust tubes. All the photos seems have been made near Paris , maybe at Velizy-Villacoublay where SNECMA was testing the engines.

One more photo: GS1 staff around the engine.

[Bruno Ogorelec]

You have to let me time to gather together the notes, parts of books and mémorandums i have, the object for me is to make theses works public.

If Bruno wants to put them on line, its ok, but remember that all of them are in french language and often technical language... and i've no time to traduce them. fortunately there is some plans inside.

George,

Take your time. There is no hurry. The important thing is to preserve those documents. It need not happen in a hurry. I have waited for years. I can wait some more.

In return, here is a somewhat similar concept employing Lockwood engines inside a rotating airfoil.

[George]

Re hy!

Trying to send more photos of the écrevisse:

[Mike Everman]

It's flying! LOL, I love it! by the way, Bruno, are you able to open the pdf I posted of "cool russian" I posted?

[Pieter van Boven]

At the end of the article that can be found here:

http://pj-website.tripod.com/escopette/id6.html

...they are talking about a 0.85m pulsejet making 60kg "pousee". Does somebody know more about this engine? Does it have something to do with the GS1? SNECMA stopped the work because lack of money.

Pieter.

[hinote]

It's flying! LOL, I love it! by the way, Bruno, are you able to open the pdf I posted of "cool russian" I posted?

That Russian concept is probably hooked together for phasing purposes. Does anybody agree with this?

The Ecrevisse (at first look) looks almost like it's mounted on a barstool assembly, minus the seats. Of course, closer perusal shows the "feet' have springs (and shocks?) on them, for a softer landing.

I wish it was in color--it looks like the PJ is really cooking along--the area around the u-bend is running with quite a lot of heat showing.

I'd LOVE to know if the thing was stable in the air. Inflowing concepts like this are supposed to autostable. Also, is that an augmentor on the tailpipe?

Bill H.
Acoustic Propulsion Concepts, Inc.

[Mike Everman]

Also, is that an augmentor on the tailpipe?

Looks like a ring and wire spokes to hold the engine.

[Bruno Ogorelec]

What I find highly unusual is the love Ecrevisse engineers had for unequal length engine ends. Most variations on Ecrevisse have the chamber end of the U much shorter than the exhaust end.

OK, this vertical application may have been built that way to align the two thrust lines, but the arms are usually unequal even on the engines designed to fly horizontally.

In contrast, Lockwood (which is essentially the same engine) is most often bent in the middle and has equal length ends. Baffles me completely.

[Bruno Ogorelec]

Here's an example in which anyone normal would have chosen the sides of the U-bend to be equal. Since the designer made them unequal, he must have had a damned good reason.

[Mike Everman]

Which baflles you? The more I look at the unequal, the more I like it. Perhaps the exhausts are offset just the right amount for thier pulses to be in phase with each other? Wouldn't doubled pressure waves on a single engine make potential for a big augmenter throat?

Or could anti phased reduce pressure waves, of course at the expense of thrust. The pressure waves at least are closely matched and only one period off true wave-form, and roughly sinusoidal. Higher frequencies will not cancel this way, so acoustic noise will still be there.

Faaaaascinating!

[Bruno Ogorelec]

Another thing. Ecrevisse bends at a very unfortunate place -- the bend must have been a real pain to make. A foot further on downstream it would have been a cinch. Nothing to it. So, Either the SNECMA people -- Bertin, Servanty et al. -- were masochists or knew something we don't.

[Bruno Ogorelec]

Which baflles you?

Michael, I am easily baffled.

Perhaps the exhausts are offset just the right amount for thier pulses to be in phase with each other?

Yes, that's the only reason that occurs to me.

Faaaaascinating!

Indeed! I am realyl taken by this. Great fun!

[Bruno Ogorelec]

...they are talking about a 0.85m pulsejet making 60kg "pousee". Does somebody know more about this engine? Does it have something to do with the GS1? SNECMA stopped the work because lack of money.

Do you suppose 0.85 m refers to diameter or the length? The former would mean a very inefficient big pulsejet and the latter a phenomenally efficient one.