The Great Ramjet Challenge!!!

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Eric
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Post by Eric » Tue Jan 16, 2007 1:26 am

You should take most of your paid sick days before then.... dont want to lose them!

Eric
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Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Zippiot
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Post by Zippiot » Tue Jan 16, 2007 5:03 am

good news bad news and my plan:

forgot to crimp the end of the fuel tube, so it spits fire way out the back (maybe 15 feet or so) but my flamehodler works, just need a much much longer cc...
so I am cutting out a 5 inch extension, should have it all set tomorrow

I stuck a big pipe over the back and it roared like a crazy monster!!!!!!
so hopefully the cc lengthening will make it work, and I might try to plug/crimp the fuel line
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redneck
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Post by redneck » Tue Jan 16, 2007 7:30 am

dang zip..... 15 foot flames, what kinda fuel are you using and what kinda blower..... i couldnt make flames that long if i wanted too... i wanna see pics of that!!!!!!!!!!!!!!!!!!!
hooowee that was loud! do it again!

Zippiot
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Post by Zippiot » Tue Jan 16, 2007 7:35 am

gasoline and a 5hp shopvac nozzled down to make 400 mph winds :)
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redneck
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Post by redneck » Tue Jan 16, 2007 8:20 am

ok that explains that...... lol. howecome i dont get 400 mph with my shop vac, i got a 4.5 hp and it only makes 200 mph. what is your exit diameter on your vac nozzel??? also what kinda fuel delivery set up do you have going on???? how do you get a good mist from your liquid fuel... what kinda nozzle are you using???? how are you getting it to your engine, pump or pressurized from something else???? i use a bottle of propane to pressurize my fuel but that dont work so good... hard to throttle.....
hooowee that was loud! do it again!

Zippiot
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Post by Zippiot » Tue Jan 16, 2007 8:26 am

Shop vac nozzled down to 1 inch to fit the ramejts intake

I forgot to plug the fuel injection...so its just shooting a big liquid stream...hence the 15 foot fire

at the moment the fuel delivery is just a squeeze bottle as the hardware store was closed today and I couldnt get the pressure fitting I need to complete my pressurized set-up
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Irvine.J
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The Great Ramjet Challenge

Post by Irvine.J » Tue Jan 16, 2007 8:28 am

Well folks good to see your all doing so well. Redneck I have seen your videos and am very impressed. I too noticed your getting some different coloured flames in the lower area of the exit nozzle. I had the same issue and had problems getting the exhaust plume the same all the way around but was fixed by better setting up the incoming airflow. Also, it did the same if I had ANY tiny obstruction int the exit nozzle. Way to go though redneck, your well on your way. I think you just don't have quite enough airspeed, try what I did and slender out your nozzle using a big sheet of cardboard and lots of the 1.5 or 2 (Can't remember) inch wide 3M scotch tape. It really works quite well. Can't wait to see Zippiots and MR B's entry.

redneck
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Post by redneck » Tue Jan 16, 2007 8:30 am

hmmmm interesting......
hooowee that was loud! do it again!

Jim Berquist
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Ram jet options

Post by Jim Berquist » Wed Jan 17, 2007 2:24 am

Bain Food!


http://www.space-talk.com/ForumE/showth ... eadid=2667



I like Erics approch most!!!!!

What you all think??

Jim
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Post by heada » Wed Jan 17, 2007 3:10 am

H2O2 in concentrations less than 30% are very safe. In order to use it as a mono-prop fuel, you need it at 95% or greater. If you can obtain it and store it safely it is very safe and would work quite well. Most people have to distill it themselves in order to obtain it at higher concentrations and that is where the problems come from. H2O2 can become very unstable and start to decompose into 2(H2O) + O2 with heat and once started, you're in for a world of trouble.

Like they said in the thread, if you can do it safely and can handle all the challenges around it, its a very good idea. Most of the time, it just easier to go another route.

-Aaron

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Post by Zippiot » Wed Jan 17, 2007 4:33 am

70% h2o2 will work in a peroxide rocket, I have heard that 50% works as an oxidizer in a liquid fueled rocket.
Erics approach is very different if you consider this, erics ramjet is a subsonic and the one the other person talked about was a supersonic. But the basic theory works, once up to speed remove the starter and let the rammy operate (might need a few of them in order to provide the thrust to keep the pj onboard).
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Jim Berquist
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H2O2

Post by Jim Berquist » Thu Jan 18, 2007 12:47 am

Zipp:

I think he was talking about the rocket being used to supply the Ram Jet with the required High Speed air.....He stated The craft would not have to be moving.

We know how H2O2 systems are fuel Hogs........I don't know if you would achieve enough thrust from the Ram to Carrie the vehicle and fuel load.

I think the Pulse Jet would be much more fuel efficient!

How much Thrust do you think could be realized from the Ram.....

As I am gearing up to join the ranks of the UNEMPOYEED, I have not completed much on the Can Man Project...

Jim
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Zippiot
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Post by Zippiot » Thu Jan 18, 2007 12:55 am

What I meant is that the h2o2 rocket supplied high speed air to a supersonic ramjet whilst erics pj supplies high speed air to a subsonic ramjet.
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Jim Berquist
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Post by Jim Berquist » Thu Jan 18, 2007 1:15 am

Zipp:

The author was talking about both scenarios! Static and in flight! I just can't see anyone being able to Carrie enough H2O2 to make it work.....

How much thrust do you think a Ram could produce?

I seen a article in pop science about the military thinking of using one to deliver conventional fire on the bad man, within one hour from any place on earth......I need to see if I can find a link.......

Jim
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Zippiot
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Post by Zippiot » Thu Jan 18, 2007 5:25 am

The design of a subsonic is so vastly different from a supersonic!

I drew up a new rammy gonna start construction tonight. It is a bit more complex than any I have made before, but the hardware store around the corner is closing down and everything is one sale!!! Gotta stock up.

This time I will take my time and make sure that stuff fits and is cut properly, cant have any more ugly mess jets sitting in the garage..
Sailing Student- How do I know if my life jacket is tight enough?
Me- Can you breathe?
Sailing Student- Yes
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