Ramjet tidbits

[Mark]

"An amateur ramjet experimenter interviewed stated that he started his rotor-tipped ramjets by stuffing a gasoline-soaked rag in the exhaust, lighting it, giving the rotor a swing with his hand, and letting it accelerate on its own. Interestingly, his test stand was a long rotor on a stand in the middle of a pasture."

http://www.alt-accel.com/ramjet2.htm
http://www.air-and-space.com/20031001%2 ... de%20l.jpg
http://airpower.callihan.cc/HTML/PoWArc ... 4-4-05.htm
http://www.boeing.com/history/mdc/BigHenry.htm

[Zippiot]

i see many rockets with rams on them, how plausible wud it be to fit a ram onto a model rocket? if so wud a ram small enough to light under the accel of a model rocket engine make any lift? or woud the rocket jsut scream down trowards earth at a higher speed with a flaming tail?

[Zippiot]

oh, and is it possible to make a ramjet out of graphite to save weight? the stuff wont melt or anyhting, but can it stand the pressures? that wud make a super lightweight ram

[Najm]

Isnt graphite flammable?

[Zippiot]

graphite is unwoven carbon fiber, graphite is used as a brake pad and clutch in race cars to prevent brake fade from excessive heat, graphit/ceramic lines the bottom of the space shuttle to protect it during re-entry. graphite is what most rocket nozzles were made of for a long time. i doubt its flammable

[Bruno Ogorelec]

graphite is unwoven carbon fiber, graphite is used as a brake pad and clutch in race cars to prevent brake fade from excessive heat, graphit/ceramic lines the bottom of the space shuttle to protect it during re-entry. graphite is what most rocket nozzles were made of for a long time. i doubt its flammable

If I may quibble, graphite is not fiber. It is an amorphous form of carbon. Another amorphous form of carbon is soot, but here the situation is less clear, as soot is actually only part amorphous. The other part is composed of buckyballs, which are a truly curious form of crystals. Maybe there are even nanotubes in soot, but I'm not certain that those occur naturally. The purely crystalline form of carbon is the diamond.

[Zippiot]

carbon fiber is made from graphite, graphite strands are woven, then the fibers are woven into a mat, making a sheet of carbon fiber. i also found out that while diamonds wont melt under creatable circumstances, they will shatter around 4000 degrees (cant rememebr celsius or farenheit, and i cant spell either). the element with the highest melting point is tungsten, anyone make a jet or a piece of a jet out of tungsten? cud u tig weld it (lol)?

at the hardware store i asked them for some kind of clay or molding that will sustaing high temps, the two thigns they showed me not only said avoid direct contact with heat but burn once exposed to flame...

[Mark]

Carbon has a higher melting point than tungsten.
Mark

[Zippiot]

carbon wut? carbon fiber burns quite readily givin that it needs epoxy to shape, soot cant burn there is nuthing left for it to burn. graphite is incredible at dissipating heat but it is quite fragile.

[Mark]

http://www.webelements.com/webelements/ ... W/key.html
Note the one below tungsten.
http://www.lenntech.com/Periodic-chart- ... -point.htm
http://www.aeroconsystems.com/graphite/

[leo]

diamond burns, soot to because its carbon.


http://www.science.edu.sg/ssc/detailed. ... t=5&cat=53

[Mark]

They sell a cylinder of tungsten and a cylinder of magnesium together to compare the lightness of magnesium to the weightiness of tungsten. It seems a good example of why tungsten isn't a favorite of jet engines.
Mark

[Dang911]

Did you know carbon conducts electricity......

Learned that the hard way.......

[Zippiot]

did anybody see the article in popular science where they showed a possible us plan to have big tungsten rods in space. at a moments notice they shoot them out and the rods (shaped like rockets or missles) come hurdling towards earth. i believe that there is no explosive in them, just a guided piece of ridiculously heavy metal that is moving beyond fast.

soot burns because it isnt pure carbon. things that burn are part hydrogen, hydrocarbons burn. if you remove the hydro part there is nothing flammable left. think about the best things to burn: gasoline (hydrocarbon) alcohol (hydrocarbon). now think about things that burn "pure": hydrogen. carbon is the unburnable part that is left behind after a reaction, if there isnt anything except hydrogen all that comes out of the reaction is water.

[Zippiot]

how well does salt crystals disipate heat? i noticed it holds heat well but wut is the melting point?