Pop Sci Ramjet

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cbromano
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Pop Sci Ramjet

Post by cbromano » Tue Jan 13, 2004 10:22 pm

I have a friend who talked about a ramjet design in Popular Science that could run stationary. Anyone have a clue what he was talking about?
thanks CB Romano
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Tom
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Post by Tom » Wed Jan 14, 2004 12:18 am

i have seen one design, i cant remember where, but it was online. it used a leaf blower to simulate air flow. i remember the group insisting that it was a ramjet, and not a motorjet...

Tom
Experience speaks more then hypothesizing ever can. More-so in chemistry.

vhautaka
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Post by vhautaka » Fri Jan 16, 2004 2:07 am

See "estatorreactores" at www.pulsorreactores.com. There's at least one plan that seem to be a pop.sci. or similar article.

The aluminum fuel tank / combustor thing gives me the creeps... It seems dangerous, unstoppable and yet somehow almost as elegant and self-contained as a solid fuel rocket. The same thing applies: if the structure holds, it will just run, unthrottleable, until there's no fuel left.

Should it break up, I wouldn't want to be anywhere near it :)


- ville

Mark
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re: Pop Sci Ramjet

Post by Mark » Sat Sep 03, 2005 2:57 pm

I remember that article in Popular Science too. I liked the copper prototype idea. Sure it melts easily, but it is also easy to shape and work with. Making a pulsejet for very short runs out of copper would be easy enough I think. And you'd get a beautiful green flame.
If you just spray some methanol in an 18 inch long, 1 inch diameter copper tube capped at one end with the flat of your hand and light the tail end, it not only barks quite sharply, but also flashes a brilliant green light. The "burn" goes so fast, you don't even feel any heat. Any you can polish it up to a stunning shine, even though it will quickly tarnish, copper is very pretty stuff. And since it conducts heat so well, maybe you could keep it cool enough to run a pulsejet for a half minute or so using the fuel or a water bath to keep it below the softening point.
Mark
If you scroll toward the bottom you can see a regeneratively cooled combustion chamber with copper liner for a rocket motor.
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Oxidyne.inc
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Re: Pop Sci Ramjet

Post by Oxidyne.inc » Mon Jul 15, 2013 11:07 pm

hey mark i think i have found what you are talking about might this be it

zac
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jetmodelengine.pdf
spent hours trying to track this one down
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Oxidyne.inc
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Re: Pop Sci Ramjet

Post by Oxidyne.inc » Mon Jul 15, 2013 11:11 pm

oh its dead... :( i wanted to see what others had to say...

ace_fedde
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Re: Pop Sci Ramjet

Post by ace_fedde » Wed Jul 24, 2013 9:10 am

Oxidyne.inc wrote:oh its dead... :( i wanted to see what others had to say...
Not completely dead, but very slow lately....
Your scepticism is fuel for my brain.

Mark
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Re: Pop Sci Ramjet

Post by Mark » Fri Oct 04, 2013 12:32 am

One time my brother made a pressure jet of sorts using a small propane tank and perhaps 5 feet of 1/8 inch copper tubing in which the tip of the tubing had been scrunched/mashed down over a needle/pin to form a smooth nozzle. He drilled the valve out in the propane torch head to allow full flow of propane when turning on the torch knob - the head of the torch cut off and copper tubing soldered onto it and by running the fuel line into an open at both ends aerosol can/top and bottom removed, and with a few coils inside the can to preheat the propane he extended the tip of the nozzle on the copper tubing a few feet out in front of this apparatus so that the hot supersonic, fire hot propane shot back into the throat/neck of the aerosol can with entrained air making a spectacle of fire and noise that can only be described as putting the fear of god in you if you stood next to it when running. The noise was immense and deafening. In some way it might have be seen as a primitive linear Gluhareff of sorts. Even for me it seemed as if the propane canister or copper tubing might explode somehow from the back pressure of this super-heated propane in the copper tubing. Again the noise was unbelievable from this little hand-held propane tank.
The little pressure jet you posted Oxidyne seems kind of feeble in the thrust department but it would be a viable way to make a small craft toy move. I've thought about using some of those insulated stainless steel thermos bottles to make a pressurized fuel feed system for my snorkelers. That is, fill the cavity between the double walls up with fuel and have it ejected internally near the top of the thermos for the snorkeler intake to mix and burn it. But calibrating the fuel flow through a wide range of temperatures would be tricky as the thermos would start out relatively cool and heat up quickly.
Presentation is Everything

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