TSTO

[mikeemmert]

<blockquote><font class="small">In reply to:</font><hr /><p>Since we are not in a hurry, I'd say that tow launch or air drop is a saner alternative.<p><hr /></p></p></blockquote>That does sound a little more workable. Turbines are too heavy to drag along with you into space.<br /><br />Does MAPP gas or psychlopropane "burn" in hydrogen? It's an exothermic reaction. It's important to get a low molecular weight for your fuel and IMHO the fuel needs to be a gas, which requires a preburner. I did some calculations the other day which showed that to boil LH2 and raise it's temperature to 1000 degrees K. takes about half the weight of the hydrogen in oxygen. I was kind of shocked. There's still 87% of the hydogen left, but still...<br /><br />Hydrogen's a great coolant, though.

 

[mlorrey]

Many hydrocarbons work well as coolants (methane, for example), but you are right that hydrogen is a great coolant. It is not clear, however, that such active cooling is entirely necessary. X-43A had minimal active cooling by hydrogen, primarily in the engine throat itself, yet only experienced thermal issues at its max speed of mach 9.8 after descending from its 110kft operating altitude (i.e. hitting denser air). X-43A was not using any SHARP materials, its nose was tungsten, which actually is not that great in air or oxygen (it burns up pretty quick in air or O2 if you use it in a plasma torch, you only use tungsten tips with H2 or Argon gases).<br /><br />SHARP is supposed to be useful at mach 7 at sea level, mach 11 at 100,000 ft. If feasible, this is the material needed for nose cone tips, leading edges, and intakes of airbreathing engines.<br /><br />Thus, without a need for hydrogen for cooling, you don't have to worry about active cooling of a ramjet exhaust or combustion chamber until you reach mach 6 or thereabouts, and even then, you can use your hydrocarbon fuel as coolant, which helps improve its gassification when injected into the airstream. Any additional intake cooling you need can be done with LOX, water, or peroxide.<br /><br />If I can't have cyclopropane or methyacetylene (or MAPP, which is cheap), give me UDMH or propargyl alcohol.<br /><br />That being said, my first experiments with ramjets are going to involve white gas and kerosene. I'll work my way upward from there.

 

[rancamp]

The ability to take off from a stand-still to supersonic speed has several 'solutions' So far, none have proved 'cheap' enough.<br />One 'tantilizing' method is the propriatory 'burner' technology described for use with the Space Access proposal.<br />http://www.spacefuture.com/vehicles/designs.shtml<br /><br />Not much details are known about the design and actual workings of these "Ejectory Ramjets" but from what I seen they use a very impressive adaption of the Gluehoff Pressure jet concept using hydrogen instead of Liquid Propane.<br />http://www.rqriley.com/gluharef.html<br /><br />The expanding hydrogen is allowed to reach supersonic speed, which entrains air from a duct and burns with the hydrogen and is exhausted out the burner as thrust and air. Adding more hydrogen to the exhaust of this creates even more thrust. (Basically 'fooling' the ramjet into thinking it going faster than it is)<br /><br />On another note; Propane gives a bit less payload to orbit than does RP-1/LOx from Dr. Dunns report. But he ALSO listed another report where the Propane fuel was allowed to cool down to just 10 degrees above that of the LOx. He found that this ups the performance of the combination OVER that of RP-1/LOx. (By 10-20 times!)<br /><br />Lastly, you keep using the statement that "None MIPCC ramjets" which doesn't make a lot of sense. NO ramjet has had MIPCC on it that I've been able to find, nor have a found any suggestion that ramjets can actually use the technology. Can you elaborate on where this info came from?<br /><br />Randy

 

[Swampcat]

<font color="yellow">"Can you elaborate on where this info came from?"</font><br /><br />Probably not since he's been banned. <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[space_dreamer]

What! mlorrey has been band!<br />Why? <br />I like its posts, I admit he's provocative, but he does know a lot about ramjets and his F106 ramjet project is really interesting. He worked on the X-plane sim also!<br />

 

[tap_sa]

Apparently some ruckus in Phenomena or something. Dunno the details, I got 11,000+ unread posts in Phenomena and going to let that count go up till Kingdom come. <br /><br />edit: correction, it appears to be on SETI after all. Haven't touched that forum for ages either, too much potential kookiness.

 

[josh_simonson]

Too bad, for all the (oft bitter) debate I actually enjoyed his participation. Dispite his abrasiveness, he certainly isn't a troll.

 

[rancamp]

>>"Can you elaborate on where this info came from?" <br /><br /> />Probably not since he's been banned.<br /><br />Well I suppose I could just email him at the Lorrel Aerospace site.<br /><br />I had meant to note also that there has already been work done on 'backyard/amature' ramjets and a good site with a lot of info:<br />http://www.alt-accel.com/<br /><br />Glen Olsen has done a lot of work AND a lot of study on ramjet technology for space launch as well as airbreathing boosters.<br /><br />Randy