Indian Scramjet

[spacelifejunkie]

I just caught wind of this. India is planning its first launch of an hypersonic scramjet demonstrator next year. The long term goal is to build a solar powered satellite infrastructure. <br /><br />http://www.thestatesman.net/page.arcview.php?clid=2&id=188481&usrsess=1<br /><br /><br />SLJ<br /><br />

 

[vulture2]

It will be interesting to see how hypersonic technology develops in India. In the US NASA has abandoned such research and left it to the DOD, which is primarily interested in faster cruise missiles, not access to space. <br /><br />However I do not believe the link to solar power satellites is realistic, and suspect this is just an attempt to justify funding. I love the SPS concept, but realistically, more efficient forms of energy storage and transmission on Earth, such as the hydrogen fuel cell and superconducting power distribution lines have made it difficult to argue that generating solar power in space and transmitting it to earth has a sufficient advantage over even earth-based solar to justify the cost. Moreover the SPS concept was predicated on public rejection of fission-based power, while India's booming nuclear power industry shows no signs of such limits.

 

[spacelifejunkie]

I agree Vulture although I will add that solar cell technology is growing rapidly. Both in performance (> 40% coversion) and reduction in mass and cost. Many of the studies involving SPS do not take current technology into account. If a company like SpaceX can reduce the cost to orbit as planned and Bigelow can provide habitats, how does this affect the cost of an SPS system?<br /><br />But, as you alluded to earlier, I'm not sure it would be enough. HiTemp superconductors or CNT power lines in the near future mixed with next generation fission reactors would quickly make SPS unnecessary. I wish the US would get off their paranoid, green arses and build some modern reactors. Green is good but outdated, cold war era paranoia about nuclear power is another.<br /><br />Good luck India, I hope you are successful. Maybe the US will catch wind of your success and make hypersonics a priority here.<br /><br /><br />SLJ

 

[spaceinquisitor]

Yes, It will really be interesting, further is will save fuel resources. India does not have much of it. It also has much advantages. Lets see how India does this. I would just say ALL THE BEST.

 

[saurc]

Hmm...<br /><br />The article says more or less nothing. Solar energy from space is a ludicrous idea for India, where even thermal and hydro power stations get into scams and muddles.<br /><br />As for scramjet technology, India already has a supersonic ramjet cruise missile<br /><br />http://www.brahmos.com/home.html<br /><br />http://en.wikipedia.org/wiki/Brahmos<br /><br />The article is just a kind of propaganda which newspapers keep putting out from time to time, I would hardly say that is a policy statement. Nevertheless I look forward to development of scramjet technology in India<br />

 

[scottb50]

The problem is everyone focuses on getting up to the speed a Scramjet can work, not down to it. Very good for a maneuverable re-entry weapon. <div class="Discussion_UserSignature"> </div>

 

[propforce]

Someone please explain this to me....<br /><br />Scramjet sucks in air on the front end and blows it out at the back in order to gain thrust, right?<br />:<br />:<br />:<br />So... how can scramjet get to space where there is NO air? <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[spacelifejunkie]

I am not a propulsion engineer so I can offer only the "basic idea." <br /><br />Because the scramjet has such a good T/W ratio (not as good as a rocket) AND specific impulse (better than a rocket) while in the atmosphere much less structure, fuel, mass, etc. is required. Scramjets have Mach 15+ capabilities. Using a scramjet to this speed could be achieved using a much smaller craft due to engine performance and aerodynamic lift. The rest of the delta v must be achieved outside the atmosphere with a second stage rocket.<br /><br />I hope I didn't insult your intelligence on this. I've read a number of your posts and so I don't think I'm telling you anything new. The excitement about scramjets, I believe, comes from it's relative ease at getting to Mach 15 at 150,000 ft compared to a rocket.<br /><br />http://en.wikipedia.org/wiki/Scramjet<br /><br /><br />SLJ

 

[propforce]

Sorry for the late reply, SLJ. I should've add a wink (<img src="/images/icons/wink.gif" />) to my last post. I was speaking in tongue-in-cheek when I made that statement <img src="/images/icons/laugh.gif" /><br /><br />But seriously, sometime we research a project (such as a scramjet) not because of its immediate applications what we're after, but because of in the process of getting there -- the related technologies will advance more so and we'll train more scientists & engineers, both in industry & in universities, as we advance the state-of-art technologies and the underlying fundamental understanding of science. <br /><br />For example, research into scramjet propulsion encounters many area of fundamental phenomena that is perfect to challenge the science & academic communities, from basic fluid dynamics problems (i.e., turbulence modeling) to material technologies (i.e., titantium metal-matrix, carbon-carbon, carbon-ceramic matrix, et. al. composites, etc.) At the end, we may not be successful in reaching our final goal, such as a reusable scramjet as such, but the development of related technologies <i>because of this scramjet research</i> have advanced enough that they benefited other applications (space, commercial, etc.) and we've developed a new generation of young engineers & scientists as a result. At the end, the effort into this scramjet research was not wasted at all.<br /><br />Therefore I have nothing but the best wishes for India's scramjet research program. India produces many more engineers & scientists annually than we do, so they have a vast asset of untapped intellectual properties waiting to be challenged. It sure is better to have these talents to tackle the un-sovled mysteries of physics than it is to have them be employeed as 1-800 tech support for microsoft. Through this scramjet program, I expect they will gain much advances in their computational capabilities, fulid dynamics, heat transfer and material sciences. They <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Scramjet sucks in air on the front end and blows it out at the back in order to gain thrust, right? <p><hr /></p></p></blockquote><br /><br />Not exclusively. It's also blowing burning fuel out the back, like any jet engine. A jet engine, like a rocket engine, is a reaction motor that gets its thrust from combusting two reactants in such a way that the results blast out the back end. The only thing fundamentally different about a jet engine is that it doesn't need to carry its own oxidizer, but sucks that in from the atmosphere. So yes, a scramjet is useless in space. But it *could* make a good first stage booster.... It also has obvious implications for cruise missiles.<br /><br />What you've described is actually a ducted fan, which does just suck in air and blow it out the back. These are useful (and if I recall correctly, the JSF's VTOL variant has a ducted fan to aid in hovering), but are generally slower than jet engines.<br /><br />There are many kinds of jet engines, but in general they have something at the front to compress the air sufficiently to get enough oxygen into the mix when they add the fuel and light it. Airliners have turbofans to do this job. A ramjet, such as the engines on the SR-71 Blackbird, uses the shape of the engine's intake to do it. A scramjet is a variation on a ramjet, except that it doesn't get adequate compression until reaching supersonic speeds (which is why the few scramjets that have flown to date have all had rocket boosters to get them started).<br /><br />One of the weirdest jets I ever saw was an experimental ramjet that *would* have been the first jet to fly if the Nazi's hadn't gone and invaded France before it was completed. The jet flew after the war. It was an insane little thing. The pilot actually sat *in* the ramspike in the middle of the engine! It's at the jam-packed air and space museum in Paris at Le Bourget airport. Well worth a visit if you're ever in Par <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[holmec]

Are scramjets supposed to work at higher altitudes than ducted fan or ram jets? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[CalliArcale]

Not necessarily, but in practice a ducted fan is going to want dense air to operate (for the same reason a helicopter does) and ramjets and scramjets will prefer thinner air simply because they are going very very fast, which presents a whole array of problems at low altitudes. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[spacelifejunkie]

Propforce, I get it now! The sarcasm must be thick for me to see it, unfortunately! <br /><br />Apparently, the Indian President is interested in spaceflight....<br /><br />http://www.space-travel.com/reports/Kalam_Calls_For_Development_Of_Reusable_Space_Transportation_System_For_India_999.html<br /><br /><br />SLJ

 

[jschaef5]

"They may very well inspire us with a better hypersonic vehicle that we could not build before! Wouldn't that be wonderful to see as the U.S. scramble (pun intended) to fund hypersonic research to catch up to India?!"<br /><br />What about the X-51? <div class="Discussion_UserSignature"> </div>

 

[scottb50]

The only use for a scramjet is to go fast to reduce defensive maneuvering of a re-entry vehicle. The idea of going from turbofan to turbojet to ramjet to scramjet and rocket reaches a dead end about half way. <div class="Discussion_UserSignature"> </div>