Yet another annular -- the Quasi-Argus

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Bruno Ogorelec
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Yet another annular -- the Quasi-Argus

Post by Bruno Ogorelec » Sun Feb 26, 2006 7:29 pm

I've been looking at the almost forgotten Argus valveless engine, whose development was scuttled by the order of the German War Ministry. The Ministry wanted Argus to develop a valve-equipped large size engine based on Schmidt’s ideas, to power a flying bomb. We all know the result. With the end of the war, the Argus company ceased to exist, as far as I know, and no one else has ever attempted to take its valveless design any further.

The Argus worked well with forced intake – after all, the company apparently wanted to power a turbine with this combustor – but I see no real reason why it shouldn’t work with normal aspiration. It looks like Argus thought so, too, as their engineers also toyed with a compressor-less version. I think it merits another look.

Here’s the look I have given to it. It is no longer quite the design the Argus engineers had in mind, I guess. Maybe I can even claim it as mine, but the Argus background is quite obviously there.

The functioning of the intake vortex chamber should be obvious. It offers a completely different impedance to incoming and outgoing flows. The direction of the vortex fights against the outgoing flow but aids incoming flow.

The interesting detail is that the direction of rotation remains the same during both intake and exhaust parts of the cycle. What has occurred to me is a bit weird – If the direction remains constant, well, perhaps a constant, ‘trapped’ vortex might actually be possible in the intake cavity. One that is set in motion by the first expansion, aided by the suction that follows it, maintained by the next expansion etc. etc.

OK, the vortex would inevitably pulsate, as its temperature would change during the cycle, but the momentum of rotation should be preserved. I find the idea fascinating.

The tube on the left, sticking from the bottom of the chamber, is another of my conceits – a fueling device that is also a starting device and a tool to purge the chamber of the products of combustion. Purging is very difficult with such dead-end chambers and I think this device might help.

It is just a Bunsen burner. Crack the propane valve open, slide the masking ring off the air holes and the device will pump pre-mixed fuel-air mixture into the combustion chamber. When the chamber is full of mixture, ignite it with a spark plug. If I’m right, the engine starts. When it does, the masking ring on the fueling tube is pushed to cover the air holes and the tube starts delivering pure propane.

The masking ring can be used in conjunction with a needle valve regulating the propane flow into the jet. That way, the initial mixture prepared by the Bunsen can be very rich, so that the inflow of air through the intake proper does not make it too lean for combustion. As you snap the air holes shut, the amount of propane decreases, so that it suits the available air. (For simplicity, I have not drawn the needle valve on the sketches.) Given that propane has a fairly broad flammability range, I feel confident that this transition can be done well.

As the air sucked from the intake proper billows into the chamber in the form of a toroidal vortex, the propane shot into the center of the vortex is ideally placed to mix with the whirling air. Some fiddling with the exact relation between the Bunsen tube length and the intake path length will obviously be required to get the timing right. Ditto for the exact positioning of the inner end of the fueling tube.

Liquid fuel injection should also be possible, but without the Bunsen tube – instead, a much shorter tube with connection to a compressed air source should be used.
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pezman
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re: Yet another annular -- the Quasi-Argus

Post by pezman » Sun Feb 26, 2006 7:47 pm

Hey, that's a mongo burner on the intake!

I might need to scour the kitchen and bathroom sections as Wal Mart and Target to see if I can find the requisite parts for the rest of the beast ...

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re: Yet another annular -- the Quasi-Argus

Post by Bruno Ogorelec » Mon Feb 27, 2006 12:48 am

Well, it might be called 'mongo burner' in the US, but it's a Bunsen burner in the rest of the world. named after Robert Wilhelm Bunsen. (1811-1899), a German chemist who invented it (and a host of other useful lab devices).

Also, it is not, properly speaking, the intake. It is just a starting and fueling tube. Once the engine catches on, it is supposed to use the intake proper, on the right of the sketch -- the one with the vortex chamber.

If I were to build ot, I'd be tempted to use the dimensions (sections) off a proven engine wherever possible, to minimize the number of unknowns.

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re: Yet another annular -- the Quasi-Argus

Post by pezman » Mon Feb 27, 2006 1:45 am

The "mongo burner" is just a set of venturi burner designs published by Ron Reil and intended for use by amateur metalworkers -- worldwide; hence no national price embodied in the designation. In fact, it is a humorous appelation -- "Mongo" was a character in the Mel Brooks classic, "Blazing Saddles".

The mongo is a bunsen-like variation on the original EZ Burner (the EZ burner, had a bell-like venturi rather than little holes on the side of a pipe). The chief virtue of these burners is that they can be built easily out of standard plumbing parts and they perform well in comparison to forced-draft burners of similar size.

If anyone is curious about building something like this, here's a link: http://www.abana.org/ronreil/Minimongo.jpg

I have managed to build smaller versions using 1/2" copper pipe for the burner and TIG welding tips for the nozzles. You can easily cut threads on the TIG tips and screw them onto standard 1/8# tubes (e.g. put a coupler on the end of a 1/8# pipe and screw the threaded TIG tip in the other end).

Even a small torch puts out a stunning amount of heat. Note that you'll need a small flare on the end of the burner if you want to burn it in the open. A 1/2" to 3/4" adapter slipped on the end of the burner will do.

Yes, I picked up the little detail in your write-up that the bunsen-burner-like-thing-a-ma-bobo gets its ports sealed when everything is under-way.

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Re: re: Yet another annular -- the Quasi-Argus

Post by Bruno Ogorelec » Mon Feb 27, 2006 1:51 am

Thanks for the story on the burners, Pezman.

Do you think the transition from the starter feed to the intake would be manageable? I hope it can be made to work. It would solve some of the pesky problems of engines whose ports are on ine side of the combustion chamber.

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re: Yet another annular -- the Quasi-Argus

Post by pezman » Mon Feb 27, 2006 4:36 pm

I suppose that anything can be made to work, once you figure out what the system wants to do.

The only problem I forsee with the design as drawn is that if the burner is designed to make a stoichometric mixture, then the CC will tend to burn steady state. It might be tricky to load up the chamber, fire off a pulse than then transition smoothly from front aspiration to rear aspiration.

Maybe a design where the annular intake is a big venturi would be a little simpler (e.g. put a ring around the intake with tiny holes driled into it to, pointing into the CC). This seems a little more in line w/ the original concept, except that it's using a venturi rather than a turbine for induction.

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Re: re: Yet another annular -- the Quasi-Argus

Post by larry cottrill » Mon Feb 27, 2006 5:03 pm

pezman wrote:The only problem I forsee with the design as drawn is that if the burner is designed to make a stoichometric mixture, then the CC will tend to burn steady state. It might be tricky to load up the chamber, fire off a pulse than then transition smoothly from front aspiration to rear aspiration.
pez -

I don't think that's what you'd do. I think you would start out with a very rich mixture, running like a burner with a yellow flame. You'd up the ante of fuel until you get the Rossco "growling mode", and then add a light gust of air somewhere through the annular gap to kick it up into the stoichiometric range. After that, you'd be running. Or, maybe beyond a certain point, it would just self start, like a lot of the bigger engines tend to do. This would be because of air drafted in through the annular gap as the burner flame induces flow out the main pipe stack.

The burner appendage is nothing more than a fancy form of the Rosscojector, in my opinion. It's only really different in that it has its own little air intake to work from.

I'll bet that any reasonable sized valveless could be started using a cheap lab Bunsen burner in lieu of the Rosscojector, but in basically the same manner. Just attach some kind of long handle so you could get it in where you need it. Flame-proof fuel tubing, too, of course!

L Cottrill

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re: Yet another annular -- the Quasi-Argus

Post by Bruno Ogorelec » Mon Feb 27, 2006 10:28 pm

Larry,

Essentially that's how I imagine it. A very rich mixture -- probably over-rich -- is blown into the chamber. It mixes with the air that's already there and gets diluted to the point of flammability. The first bang creates enough of the overexpansion for fresh air to be drawn in through the intake. This again mixes with the over-rich mixture coming from the 'bunsen' etc.

The fuel jet is adjustable by means of a needle valve, so that you can play with mixture strengths. Stoichiometric certainly wouldn't be good except for the purpose of purging the chamber of burnt gases.

Mixing should be prettry good, as the 'bunsen' is shooting into the center of the vortex, which is the right place for fuel to come in.

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re: Yet another annular -- the Quasi-Argus

Post by Dave » Thu Mar 02, 2006 2:55 am

Pezman, or anyone else who is seriously thinking about building one of these. Check out this source on ebay for exhaust donuts:

http://cgi.ebay.com/ebaymotors/1-1-2-Mi ... 1838QQrdZ1

By clicking on the "Store View" you will see that they have sizes ranging from 1 1/2 inch to 4 inch in both mild steel and stainless.

By splitting it around the outer circumference (the inter seam is not welded shut) you will end up with two nicely shaped pieces to form the bottom of the combustion chambers on a set of engines…

They also sell U bends in both mild and stainless, along with Chrome-Moly Tubing and other neat stuff. Kind of expensive, but interesting things I have not found elsewhere...

Dave

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re: Yet another annular -- the Quasi-Argus

Post by Anders Troberg » Thu Mar 02, 2006 5:36 am

It's a neat construction in several ways.

I'm thinking that the fairly large volume of the "burner tube" could be beneficial, as it provides a springyness in the fuel flow that will push back the fuel mixture during the expansion phase, perhaps even compressing it slightly, building up a larger charge that will get sucked into the CC in the low pressure phase. It could provide better fuel efficiency. It's like the normal self regulation that has been observed in pulse jets, but on steroids.

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Re: re: Yet another annular -- the Quasi-Argus

Post by Bruno Ogorelec » Thu Mar 02, 2006 6:16 am

Dave wrote:Pezman, or anyone else who is seriously thinking about building one of these. Check out this source on ebay for exhaust donuts
Wow! Great find! I've had I don't know how many ideas that involved donut-shaped parts. Thanks!

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re: Yet another annular -- the Quasi-Argus

Post by Dave » Thu Mar 02, 2006 12:27 pm

Bruno

The Stainless Donuts first popped to mind again when I saw your SP-22 Constant Flow engine. Unfortunately, it took a while to track down the manufacturer again, even though they are located in my own back yard (Buffalo, NY). Apparently they had shut down for vacation and, even though an ebay search would still find them, all their listings became inaccessible… But they are now back and willing to take cash from all who want to exchange it for specialized parts.

Dave

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Re: re: Yet another annular -- the Quasi-Argus

Post by Viv » Thu Mar 02, 2006 2:54 pm

Dave wrote:Bruno

The Stainless Donuts first popped to mind again when I saw your SP-22 Constant Flow engine. Unfortunately, it took a while to track down the manufacturer again, even though they are located in my own back yard (Buffalo, NY). Apparently they had shut down for vacation and, even though an ebay search would still find them, all their listings became inaccessible… But they are now back and willing to take cash from all who want to exchange it for specialized parts.

Dave
Well you may have to bring a couple of those with you when you come to visit next mate:-)

Viv

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re: Yet another annular -- the Quasi-Argus

Post by Dave » Thu Mar 02, 2006 11:33 pm

Viv
No problemo. Just tell me what sizes you are interested in and I will do my best to scare them up before my next trip north. And, am I correct in assuming that you are only interested in the stainless ones?
Dave

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re: Yet another annular -- the Quasi-Argus

Post by larry cottrill » Fri Mar 03, 2006 1:50 pm

Dave -

It occurs to me that they probably make these by welding together two half-shells. Try to find out if that's the case, and if you can get them to sell those to us in pairs!

Why should we let them weld them together so we can saw them apart?

It never hurts to ask ...

L Cottrill

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