SO SMALL

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Steve Wallington
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SO SMALL

Post by Steve Wallington » Sat Jan 28, 2006 4:07 pm

Hi all
I just had to try the next size down
So Small is 270mm long, CC is 37mm dia, exhaust is 20mm dia, inlets are 10mm dia.
She runs on propane and she screems.
I hope pics and vid are attched,
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hagent
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re: SO SMALL

Post by hagent » Sat Jan 28, 2006 4:28 pm

Steve that's awsome!

Great Job.

Do the intakes protrude into the CC ?
Hagen Tannberg

Steve Wallington
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re: SO SMALL

Post by Steve Wallington » Sat Jan 28, 2006 4:33 pm

Thanks Hagent

The intakes do not go into the CC.

Mark
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re: SO SMALL

Post by Mark » Sat Jan 28, 2006 4:52 pm

Not bad. You could use the spark plug for a mount though. Very nice work, but a smaller spark plug would look more natural. The metal and mounting are very pleasing to the eye. Good presentation. If you could find some tubing to match the spark plug thread you could try some variations with your jet, add another port of some sort or length, just to experiment. If your fuel feed line isn't touching the jet, you might could get a spark to arc inside one of the side ports with a tiny bit of angling.
Mark
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Mark
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re: SO SMALL

Post by Mark » Sat Jan 28, 2006 5:08 pm

If you fill it with water, and then pour the water into a measuring cup, you can see what the total volume of your jet is. Again, that's a pretty engine you have made.
Mark
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Eric
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re: SO SMALL

Post by Eric » Sat Jan 28, 2006 5:18 pm

Very nice! Can I put that in your gallery page?

Do you have any Mapp gas you could try to run it on? The video clip seemed to be only a second or two long, was it just my computer?

If you go much smaller you are probably going to have to make fuel injector tubes with venturi's to premix the propane with some air before it gets injected in order to speed up the timing, either that or maybe use mapp gas.

This is about the smallest I have made, I think Steve B.'s was a little smaller, I scaled the image to show up about actual size on most monitors. To get it to really run I need to use mapp gas.

Do you have any plans to go smaller?

Eric
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Zippiot
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re: SO SMALL

Post by Zippiot » Sat Jan 28, 2006 7:55 pm

wuts it made of? im sure its stainless but wut grade, my mahcine shop teacher tells me that ss grades have completely different properties ranging from bronze all the way to hardened steel quality.

very sweet man, but instead of mapp gas run it off of hydrogen. that stuff isnt very expensive (if u have a welding supply store nearby) lights quite easily and burns very quickly, so an even smaller v-pj is possible i guess
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Mike Everman
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re: SO SMALL

Post by Mike Everman » Sat Jan 28, 2006 8:44 pm

Steve, that is a virtuoso performance with propane. You've shattered all my pre-concieved notions of how short a time propane can cycle. My deepest respect, man. Incredible! 545 Hz is amazing. Any appreciable thrust, or just noisy?
Mike
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Rambo
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re: SO SMALL

Post by Rambo » Sat Jan 28, 2006 9:30 pm

I was tring to make a pulse jet long time ago.But the engine just dont want to go boom and start :? , the fuel burnes too slow.I suppeuse if I use H2 for fuel it will work but it is getting too complicated.Can someone tell me an easy way to make mini engine? :)

Bruno Ogorelec
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Re: re: SO SMALL

Post by Bruno Ogorelec » Sun Jan 29, 2006 4:58 am

Steve, your engine is amazing, apart from being beautifully built. You have undoubtedly entered the pulsejet world with a bang.
Rambo wrote:I was tring to make a pulse jet long time ago.But the engine just dont want to go boom and start :? , the fuel burnes too slow.I suppeuse if I use H2 for fuel it will work but it is getting too complicated.Can someone tell me an easy way to make mini engine? :)
Rambo, starting in pulsejets with a very small engine is not a very good idea. The smaller an engine is, the greater the art. My sincere recommendation is to go for a bigger engine first.

Rambo
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re: SO SMALL

Post by Rambo » Sun Jan 29, 2006 7:31 am

Do you think that an engine with 150ml chamber and 20ml alkohol in it will start just by lighting the mach if it have some O2 in it.Ill try to make PVC one to see can I ignite it with spark in the chamber.All be happy if it runs more than 15s.

Bruno Ogorelec
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Re: re: SO SMALL

Post by Bruno Ogorelec » Sun Jan 29, 2006 11:59 am

Rambo wrote:Do you think that an engine with 150ml chamber and 20ml alkohol in it will start just by lighting the mach if it have some O2 in it.Ill try to make PVC one to see can I ignite it with spark in the chamber.All be happy if it runs more than 15s.
It depends on the geometry. Pulsejets are acoustical devices, like musical instruments. They have to be tuned to work.

skyfrog
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Re: re: SO SMALL

Post by skyfrog » Tue Jan 31, 2006 11:00 am

Zippiot wrote:very sweet man, but instead of mapp gas run it off of hydrogen. that stuff isnt very expensive (if u have a welding supply store nearby) lights quite easily and burns very quickly, so an even smaller v-pj is possible i guess
I recall I've read an article somewhere stating that hydrogen is not a good fuel for pulsejet, simply because it will burn at any ratio of air mixture, rich or poor. In short, no pulsation we will get using hydrogen.
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Zippiot
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re: SO SMALL

Post by Zippiot » Tue Jan 31, 2006 2:23 pm

my experience with hydrogen is that it goes boom if slightly enclosed, that will make 1 pulse, then hopefully it creates a vacume to suck in air for another boom. if you can see the flame then it isnt pure hydrogen and that is why it will cumbust at any ratio. u may be right, but im pretty sure it needs at least sum air in order to cumbust instead of just burn

the nasa scramjet ran off of hydrogen right?
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larry cottrill
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Re: re: SO SMALL

Post by larry cottrill » Tue Jan 31, 2006 2:37 pm

skyfrog wrote:I recall I've read an article somewhere stating that hydrogen is not a good fuel for pulsejet, simply because it will burn at any ratio of air mixture, rich or poor. In short, no pulsation we will get using hydrogen.
I don't think the wide range for hydrogen would make it totally unworkable - it will explode in air, after all. I think your main problem would be throttleability.
Zippiot wrote:my experience with hydrogen is that it goes boom if slightly enclosed, that will make 1 pulse, then hopefully it creates a vacume to suck in air for another boom. if you can see the flame then it isnt pure hydrogen and that is why it will cumbust at any ratio. u may be right, but im pretty sure it needs at least sum air in order to cumbust instead of just burn.
Hydrogen does burn with visible light, you just need it dark enough to see it. I used to use hydrogen and oxygen in my underwater cuttring torch (Victor Model 3900) - you could see the flame underwater where the light was limited. It was a beautiful pink flame, with BLACK feathers coming out of the six ports in the cutting tip!!!

Underwater, that torch roared like a blast furnace. I wore my favorite full-face Scubapro mask, and when I had the torch tip down on a piece of steel to make the cut, the vibration reflected back at me through the water was so great that I had to clear the mask of water every four or five seconds. What fun!

L Cottrill

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