fit a ramjet to a model rocket?

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Zippiot
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fit a ramjet to a model rocket?

Post by Zippiot » Sat Jan 21, 2006 4:44 am

how difficult would it be using standard estes engine? sized c, maybe 2 c's if needed but the size d's r too big of a hassle and expensive!! well maybe a d if it would work
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re: fit a ramjet to a model rocket?

Post by Zippiot » Sat Jan 21, 2006 4:51 am

cops already got me on record for blowing a hole thru a few fences, i guess adding missles to that wudnt be a smart idea huh?
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re: fit a ramjet to a model rocket?

Post by Zippiot » Sat Jan 21, 2006 5:50 am

http://www.onera.fr/conferences/ramjet-scramjet-pde/

they have many designs for rockets with rams mounted on them...
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re: fit a ramjet to a model rocket?

Post by airrocket » Mon Feb 27, 2006 7:07 pm

It can be done at the smaller scale only you would have to make your own solid fuel ram jet rocket motor. It would use just enough solid oxidizer (concentrated around the propellant core) to get it up and moving then the when the oxidizer at the foreward end burns through it would allow atmospheric air inlet through remaining burn cycle. This part of the burn cycle would not require as much solid oxider. So you could extend the performance of C size solid motor. This would negate an ejection charge which would then require tumble recovery or electronic ejection . Or better yet boost glider. If you want help design the glider contact me at RetroFlight.com.

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re: fit a ramjet to a model rocket?

Post by Zippiot » Mon Feb 27, 2006 10:59 pm

actually i just decided to cancel my plans to make an rc edf...my stuff is just too heavy. a glider might work, b/c i can use the small batt pack instead of the giant one...

i have made some rocket motors large enough to support a liquid fueled ramjet, but off of the c sized motor the physics dont add up...

i just cant make a ramjet that size that will produce useable thrust...

i know they are done all the time, just not for me right now. i live between 2 international airports, a small airport really closeby, and even closer is a military airforce base... and nasa...
making a high altitude rocket launch near my house is a nono, gotta stay under 1500 feet.
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re: fit a ramjet to a model rocket?

Post by Hank » Tue Feb 28, 2006 12:54 am

Zip- For added efficiency to your C Class rocket dream without the complexity, try adding an augmentor (ejector). I've done so with four pieces of 16 gage wire and the tube from a roll of toilet paper. It flew with stability, though not attaining the altitude gotten by adding a 1/4" by 20" Balsawood Stick. Attached are images of an augmentor designed for a Pulsejet and an image of a Hale rocket.
Attachments
Hale 24-Pounder Rocket.jpg
Hale 24-Pounder Rocket.jpg (18.79 KiB) Viewed 7836 times
Flow Ejector IV.JPG
Flow Ejector IV.JPG (25.79 KiB) Viewed 7839 times

Greg O'Bryant
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re: fit a ramjet to a model rocket?

Post by Greg O'Bryant » Tue Feb 28, 2006 3:02 am

Zipiot;
What if you made a ram jet rocket hybrid like this. Take a pipe and fill it with parafin and have a core of rocket candy going through the parafin. Make a really small nozle for the pipe so when the rocket candy burns it melts, vaporizes and ejects the parafin at high speed through a diffuser that collects ambient air and into a ram jet combuster. It may be a little rich compared to other ram jets, do you think it would work? You may not even need to have it at speed like other ram jets to get it to run.

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re: fit a ramjet to a model rocket?

Post by Zippiot » Tue Feb 28, 2006 6:04 am

one i was going to try was a rocket motor, pretty basic but with a few mods. first off use really large diameter pipe for its lenght, fill it with parrafin wax or other so,lid fuel. drill it out so that you can fill the core with rcandy. make some ducted holes at the top of the rocket, and fill them with solder (low temp) or even hot glue..

once the rocket reaches high enough temp the solder/glue melts off, revealing the holes shooting air down the center of the rocket tube. hopefully i measured it out correctly so by the time i run outt of rocket fuel the holes are open and im moving fast enough. so i just turned a regular solid fuel rocket into an air breathing ram/rocket. it uses the solid fuel ramjet theory, which i know from testing to work. the only problem is, i need some sort of breakaway nozzle... the ramjet needs a much wider nozzle than the rocket, so i must solder in the rocket nozzle onto the ramjet nozzle. once again i gotta do some math so everything melts off at the correct time...


sound good? i might actually do this soon, i was gonna devote a lot of time towards turbines but this sound slike fun
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