Slashdot Mirror
HyShot Scramjet Test Declared a Success
An anonymous reader writes: "ABC news is reporting
that analysis of the flight data from the recent
HyShot scramjet test (covered by Slashdot
previously) suggests that the test was successful and that the engine achieved combustion in flight after reaching Mach 7.6. The University of Queensland is also reporting the news."
One step closer to being able to fly farther, cheaper, faster?
That is, other then getting drunk on jet fuel and then lighting my own farts.
The ultimate network admin tool needs HELP!
BBC story
For fsck sake. If I have to read about this 1 more time, I'm gonna screamjet.
"I used to have that really cool,funny sig
Wow!
This must be twice better than Gillete Mach3 system !!
They are using it for reaching the secret extra terrestrial base on the other side of the moon with great speed on short notice.
I know that if I go on vacation, I would rather not have to strap myself to an MK 70 Rocket before the preflight movie. They have a lot of work before this is practical for almost anything than spyplanes. Also, was this flight manned, they said that the previous attempt was not, and there was no mention of what a flight like this would do to a living organism.
Xaotik Designs
"A speed of Mach 7.6 would allow airliners to travel from London to Sydney in two hours, compared to more than 20 now."
There's a ton of photos at http://photos.cc.uq.edu.au/HYSHOT/ and also at http://www.mech.uq.edu.au/hyper/hyshot/HyShot_phot os.html. The former link has some friggin huge jpegs.
There is also a page about the HyShot program itself at http://www.mech.uq.edu.au/hyper/hyshot/
Consider the artilce we saw on here the other day. What would a Scramjet's exhaust do to raise the global tempature?
Brought to you by Team SPAM! where we believe: "Information in the noise!"
The thing I don't like about Mach numbers is it's not consistent. Reason being, the speed of sound changes based on your altitude. Higher, where the air is thinner, sound travels slower. So Mach 7.6 at 50,000 feet is a lot slower than Mach 7.6 at sea level. Sure, it's a cool sounding number, but I wish we'd see these numbers represented in miles or kilometers per hour as well as a Mach speed. When the author of the article gave the comparison of a London-Sydney flight, (2 hours vs. 20), was he/she figuring that based on Mach 7.6 at sea level or at 75,000 feet? (not to metion it'll be decades before, if ever, we see passenger planes anywhere near this speed)
While scramjets raise the possibility of Sydney to London flights in two hours, they are set to revolutionise the launch of small space payloads, such as communications satellites, by substantially lowering costs. They have the added benefit that they do not even have to carry most of their propellant as they use oxygen from the atmosphere.
Just wondering, but wouldn't travelling at Mach 7.6 be a little tough on a human? I'm no physisct, but it seems like the G's would be something really painful for a human. Of course, maybe the two hour flight from London to Sydney wouldn't require Mach 7.6 speeds.
314 km straight up, followed by a plunge straight into the ground?
I sure as hell hope it was unmanned!
I choose to remain celibate, like my father and his father before him.
What's the difference between a normal jet engine and a scramjet?
Everybody has a purpose in life, maybe mine is to lurk in slashdot.
I'm just wondering at what a speed would these planes land and how long must a slope be to allow a non catastrofic landing.
If I'm not wrong shuttles land on slopes of 15 km, but they're much faster than mach 7
Even if you did find a few willing souls, would it be enough to make any kind of profit? If I am not mistaken, it costs about $8,000 USD to fly on the Concord and they still have problems making money.
Seriously, read the damn article! It says that it cuts the travel time from London to Sydney from 20 hours to 2! Obviously you are not getting there the moment you take off. The Earth is a huge huge place and even at Mach 7.6, it will take you a while to get somewhere.
--Won't that be grand? Computers and the programs will start thinking and the people will stop. - Dr. Walter Gibbs
Mach 7.6 is right around 2,260 m/s (7,414 ft/s) or about 5,055 mph. It would still take you 5 hours to circumnavigate the globe. Plus you have to consider acceleration time - the rocket doesn't have to worry about killing people.
Realistically, we probably won't hit Mach 7 in commercial flights for some time, and there will probably be "low-speed" versions for shorter distances. As the article notes (emphasis mine):
--
Warning! Error reporting system failu
That what was all this school was for... to teach us how to solve our own problems. -- janeowit
Me too, but it is an expiremental craft, and there were problems launching the first one.
hmmm...
Add a warhead and you have one hell of a fast ICBM...
Xaotik Designs
It's not how fast, but how did they fly that fast.
The Scramjet theory has to have occurred. Which is basically an engine with no moving parts. The intake air has to hit the fuel so fast, and at such high density that some sort of "Critical Mass" combustion takes place that produces more thrust that drag of the air molecules hitting the craft at about 10kph.
When you're on a shoe-string budget, it's hard to figure out if that really happened. It'll take a much more expensive project to figure this out for sure, hence, NASA's much more expensive project.
Who needs this anyway, with
Sydney's Mardi-Gras going bankrupt!
Hello Frisco!
Acceleration, on the other hand, is a problem. Ever been in a jet? I don't think it'll be worse than that.
Big difference between speed and acceleration. What's Earth's orbital velocity again?
You were right, though, you're no physicist.
It's only a high rate of acceleration that causes passengers to experience excessive G force. Once you've reached Mach 7, so long as you remain at a constant velocity nobody should notice how fast you're going.
The 2nd article points out that the engine is for use with space payloads, you dont have to carry your oxidizer while in the atmosphere, reducing vehicle weight and increasing payload.
Now, getting to Mach 7.6 to light one of these off may take a railgun, something that rules out living payloads, but good for launching cheap infrastructure into LEO.
Starman97@Gmail.com (bring it on spammers)
Special suits are made for high G's. Once you reach high G's, the special suit squeezes the blood from your feet back up to your brain so you won't pass out. The human body (while wearing this suit) can handle around 9 G's. So I don't think this is feasable for passenger travel, as it takes special training with the suit and it costs a lot of money for the equipment.
G-force is created by acceleration, not speed. Otherwise the speed of Earth's orbit around the sun would crush us all.
Nonetheless, I'd rather be in Sydney in 2 hours with a bloody nose and bruised ribs than endure a 20 hour flight with a bunch of Englishmen...
I've been wondering that myself, and have been trying to find info on the limits of the human body (with no luck yet).
At best, it would probably be uncomfortable, and that would make it unsuitable for commercial flights.
It's the same reason we don't have flying wings for commercial flights - many of the passengers would be made uncomfortable during turns.
Dark Nexus
"Sanity is calming, but madness is more interesting."
So when do we get to seek out new life?
use constant PERL_IS_BROKEN => $] >= 5.006;
Don't forget the two hour airsickness puking recovery time before the troops would be ready for action.
There should be a moratorium on the use of the apostrophe.
Max V.
NeXTMail/MIME Mail welcome
Something like that would be impressive, and also would have definite mind bending impact on the popation below, just due to the sonic boom.
"It is a greater offense to steal men's labor, than their clothes"
Assuming you weren't trolling:
Mach 7.6 is a speed, not an acceleration. A hypersonic passenger vehicle will presumably travel with moderate acceleration until reaching high speed.
At 1/2-earth-gravity acceleration, you get one sea-level Mach number per minute, more or less, so you'll be at Mach 7.6 a few minutes after launch.
2*3*3*3*3*11*251
"We received data for the full length of the 10-minute flight. All indications are that supersonic combustion occurred." :-)h tml
Read: After ten minutes it exploded.
No seriously this is cool.
Although it leaves me with one fear of how it will be used.
http://www.darwinawards.com/darwin/darwin1995-04.
doh
"It is a greater offense to steal men's labor, than their clothes"
at least for the near future.
all this is is a proof of concept. I mean, you are still wasting tons of fuel getting the enguine up to a speed at which the scoop and compression will work.
True capitalism = lots of similar companies = jobs for everyone who wants one.
Note that the figures at
fas.org indicate that the speed of the Minuteman III at burnout is approx. Mach 23.
What you do have the potential for (given significant further progress) is very fast cruise missiles, not ICBM's.
John_Chalisque
Ever hit a speedbump at low speeds?
Not that bad.
Ever hit one at a higher speed? Say, at least twice it's rating (hitting a 15km/h bump at 30km/h, for example)?
It's not the most pleasant things.
Now, you're saying that "Planes don't have to worry about speed bumps!", and you're right.
But what about turbulence?
You can hit turbulence at Mach 0.76 that's pretty rough. What would that same turbulence to do a large plane at Mach 7.6?
Dark Nexus
"Sanity is calming, but madness is more interesting."
"We do believe we achieved supersonic flight for the first time," Mr Paull said.
Hmmmm. Musta never met Chuck.
Cool, that was my next question too. Thanks for the info. I slept through most of my physics classes in college.. (although I remembered speed vs. acceleration after a few minutes of posting).
Mach is a measure of speed relative to the speed of sound at a given elevation, it is not a measure of acceleration. So, at sea level, Mach 7.6 is roughly 5800mph (~2600m/s), but at 25000ft, where the air is thinner, Mach 7.6 is about 5000mph (~2250m/s).
The gravitation of earth (ie, the amount of force we feel from gravity) is 9.8m/s^2. So, a constant 1G force (which the body won't find too uncomfortable) would accellerate a body to 2250m/s in about four minutes... If a genter push is desired, say .5G, that level of acceleration would need to be maintained for a bit over seven and a half minutes...
Unless, of course, my physics is rusty.. :^)
attach this engine to the flying robot three atricles down, he would be able to lift himself. Good stuff for Terminator III though.
IANAL, but imagine a beowulf cluster of in Soviet Russia all your belong are base to us welcoming the new SCO overlords.
there will probably be "low-speed" versions for shorter distances
Probably not. To understand why requires some knowledge of how a scramjet differs from a normal turbofan engine. There are no spinning parts in a scramjet or ramjet engine. The (sc)ram engine requires a strong standing shock to me maintained in the intake. This standing shock replaces the compressor section of a normal turbo fan. There is a minimum speed which will produce a sufficiently strong, stable shock that will allow this to work.
The SC part is for supersonic combustion which makes that standing shock also replace the combustor portion of the turbo fan. Chemical reactions and transonic fluid dynamics can interact in very complicated ways. This can make this supersonic combustion unstable. The best way to stabilize it is to go faster and increase the strength of the shock.
So, to sum up, operating scramjets at lower speeds is more difficult, so if anything, we will probably see them operating at the highest possible speeds that the airframe and aerodynamics will allow.
Scientists were hoping the engine would work under its own power on its descent to Earth - reaching a target speed of Mach 7.6 just before hitting the ground.
Nice landing speed for a passenget jet.
IANAL, but imagine a beowulf cluster of in Soviet Russia all your belong are base to us welcoming the new SCO overlords.
When you're on a shoe-string budget, it's hard to figure out if that really happened. It'll take a much more expensive project to figure this out for sure, hence, NASA's much more expensive project.
Not really, a pressure distribution along the combustion chamber was measured. You need to check two things. Is the gas supersonic, and was combustion achieved. Supersonic can be checked by comparing the pressure in the combustion chamber with that predicted due to wedge compression.
Combustion is shown by comparing the signal in one chamber with no fuel, with the signal in the second chamber with fuel.
In addition, supersonic combustion in a parallel combustion chamber gives a pressure profile which rises along the chamber, whereas subsonic combustion gives a pressure profile which drops along the combustion chamber.
The real trick is to check that nothing else could simulate these signals.
This is very interesting, but don't get too excited. This was basically a firework, and it is a loooong way from here to a flyable payload-carrying plane. The first objective, as they say, is probably cheap satellite launches - essentailly another firework. probably a good vehicle for Amsat-type launches.
Consciousness is an illusion caused by an excess of self consciousness.
At a constant 1G acceleration, you'd hit Mach 7.6 in about 4 minutes and travel about 260 KM. The Space Shuttle goes supersonic within 75 seconds of liftoff, so it really doesn't take too long. I think by the time the boosters drop off (2-1/2 minutes) it's doing Mach 3 or better.
The X-15 hit Mach 6.72, and its maximum burn time was under 5 minutes (it was a rocket plane though), so it makes sense for something like a hypersonic engine to be used for real flights, even NY-LA would be practical...under 1 hour door-to-door, no need for a crappy airline meal! The SR-71 has already done NY-LA in about 1 hour at Mach 3.5.
A man's reach must exceed his grasp, or what's an erection for?
Mach 7.6 would be a bit too much for your average passenger. Fighter jet pilots train for hours on how to keep concious, they are also in excellent physical shape and have a lot of equipment to help them.
here's a little lesson from Einstein k?
if I am going nearly the speed of light in one direction and you are going nearly the speed of light in the other direction, who dies because their body can't handle the speed?? NEITHER OF US DIPSHIT!! it's the accel that fscks up the body... and not the velocity... so as long as you aren't pulling more than a G or two in the acceleration process, you're golden...
Oh god, that woman is John Romero!
This is a really cool idea and I'm glad it's beginning to pan out. If the global scientific community wants to continue to move forward during this century as rapidly as it did during the last, it needs to tackle problems with innovations like these instead of simply trying to ameliorate other people's ideas.
For instance, a friend of mine thinks that the future of the computer industry lies in abandonning the binary basis that has been established and beginning to work with, perhaps, a 4-state diode... Granted, it's not exactly the best idea, but a good example to illustrate my point: it's only a matter of time before old ideas get stale. How many of us have even considered Base n != 2 computing?
...Whether my Maker is prepared for the great ordeal of meeting me is another matter.
Churchill
Well that depends on how turbulance works when you that supersonic
thank God the internet isn't a human right.
True, except that the heat loads on a vehicle at this speed, at atmospheric pressure, are enormous, as is the drag. That's why they fly at altitude. I guess a simpler way of thinking about it is: if you can only shed your nose cone at 25km altitude (to prevent excessive heat load on the engine), how fast would the rail gun have to launch you at sea level to be going Mach 7 at 25km altitude?
I haven't done the Maths on it, but I suspect that a rocket launcher would actually be cheaper.
Quoting the article... "We do believe we achieved supersonic flight for the first time," Mr Paull said. Chuck Yeager didn't do that in the fifties did he? Naaaaw! That is just an urban legend, like the concorde.
How ya like dat?
1. Then use a normal plane, dumbass. Trust me, no one will force you to use this.
2. Crazies in various countries? This is being developed in Australia, not the US. So it's already in one "various" country.
"A terrorist is someone who has a bomb but doesn't have an air force." -William Blum
I would reckon these things would be easier for a Star Wars system to defend against than true ICBMs. They have to come through the upper atmosphere, which gives you a releatively thin slice of directions it must be coming from (say 50,000 ft vertically) compared to the wide angle (bauically, anywher up) an ICBM is coming from. And an ICBM will come in faster: plummetting from 100 miles up should beat even Mach 7.6, and the heat sahileds have to last for only the last minute or two of the flight rather than the whole flight.
Actually, defence wise, I seee these as increasing the techno-advantage of the high-tech states. High tech states could build very fast bombers, cabable of responding from (say) the US to (taking a radom example) Iraq in 45 minites or so. Which means that a surprise attack has to be launced in an even narrower window than before if it is to get away before vengeance arrives.
Consciousness is an illusion caused by an excess of self consciousness.
Old joke. Sorry.
Wow! You know about the base. I am glad the real news is finally getting out.
The Uncoveror: It's the real news.
Um, just as a point of reference, ICBMs travel much faster than Mach 7. On suborbital trajectories from the other side of the globe, you might see a time of flight of 30 minutes or less. Think 20,000 km/hour.
Scramjets are not really interesting as strategic weapons. Extra-atmospheric vehicles (MVRs) are faster and proven 30-year-old tech. Scramjets are going to be useless for cruise missiles, because a Mach-7 shock cone will standout rather nicely even if the missile itself were stealthy. Depending on the altitude, it could also cause ionization of the atmosphere which would show up on radar!
Military applications here are going to be reactive in nature...fighter-bombers that can reach any corner of the globe in two-hours is a big selling point, as is the (literally) stratospheric flight ceilings such crafts would have. But I don't know what form a scramjet-based weapons system might need to take or what niche it might fill.
As I read the article, I see that they ignited the fuel, but I have yet to see anyone claim that the burning fuel produced any thrust. Can someone point to more info?
This is very interesting, but don't get too excited. This was basically a firework, and it is a loooong way from here to a flyable payload-carrying plane.
My sentiments exactly. And how far past Mach 1 must it go before it can actually work? Does it have to go all the way to Mach 7 first?
Very fast ramjet cruise missiles were under development in the 1950's, but they fell out of favor because ICBMs are even faster and just about impossible to shoot down. However, they did look way cooler than today's boring ICBMs.
There will be no "low-speed" version of this! Scramjets only work at hypersonic speeds, the whole need for the rocket was to get the scramjet up to speed so that it could operate. There are theoretical designs for an engine that would work as a normal jet engine to get the vehicle up to speed and then reconfigure itself to a mode that would allow for scramjet operation, but they are mechanically complex, more failure prone and almost surely more expensive to make, so what will probably happen will be multi-engine systems where you will have say 4 engines, 2 traditional jet engines and 2 scramjets, you take off and land with the traditional engines and cruise with the scramjets.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Opinions vary. Estimates of starting Mach numbers range between Mach 4 and Mach 6.
They didn't just bring it up to high speed and turn the engine on. They shot the thing up to an altitude of 314 km, pointed it to the ground, and let it fall, all the way (it is unclear to me if it was a powered dive (before the scramjet)). Only as it got near the ground did the engine activate, and then only for a few seconds before it heated up from re-entry. Then it cratered into the desert.
Don't Bogart the fish sticks
I dig the tech ... but from preceding comments I believe that a somewhat false impression has been made on a few people: There is indeed this fantastic engine which can reasonably efficiently propel you around the globe at speeds exceeding that of sound by a factor greater than the number of finger most people have on one hand - but: it has to be accelerated to more than twice the speed of the fastest jet aircraft built to date for it even to ignite.
I once had this motorbike I always had to push start. It was quite annoying.
yes, we have no bananas
I read about 'the base' back in ~1995 or possibly earlier in documents allegedly written by one 'Milton Cooper' , supposedly ex-USAF personnel.
Remember that everybody made a big deal about breaking the sound barrier? That's because going mach 1.1 is much more than 20% harder than going mach 0.9. Likewise going mach 5.1 is MUCH harder than going mach 4.9.
Once you have gotten hypersonic though, you are theoreticly OK until the friction of the air you are traveling through melts your plane. Which of course has to do with the selection of materials, not the ability of the propulsion system.
___ I don't respond to Anonymous Cowards, and I Never Mod them UP.
While we are on the subject of gravity, the effective gravity you would feel while in flight at mach 7.6 at 250000 ft is about 90% g. This happens because of two effects, the reduced gravity from the height (about 25% of the effect int his case) and the centripital forces due to your rotating reference frame (the other 75%).
Considering the Concorde is banned from most airports due to polution and especially noise problems, I doubt you will be seeing this thing on a runway near you, anytime soon.
I'm not even sure if a G-suit would keep you from blacking out.
Generally speaking, g-suits are designed to protect you from g's that press you down into your seat, in a turn for instance, not g's that press you into the back of your seat. G's from lateral acceleration, as would be experienced on this scramjet, would be unlikely to cause unconsciousness because blood is not being drained from the heads of the passengers. It would still be mighty uncomfortable, though.
Evil is the money of root.
if I am going nearly the speed of light in one direction and you are going nearly the speed of light in the other direction, who dies because their body can't handle the speed?? NEITHER OF US DIPSHIT!!
EEENH!!! Wrong Answer, thanks for trying. If you're going nearly the speed of light, and you're friend is going nearly the speend of light, you both die.
As you approach the speed of light, a finite mass will actually weigh more, by many, mnay orders of magnitude. The forces your own molecules would be exerting on themselves would cause your body to implode itself.
If your body no longer exists in the form it currently is, instead being either a) a group of atoms violently moving apart or b) a superdense chunk of matter, I don't think you'll be alive...
As I read the comments, it seems that some people don't get the implications. In a normal jet engine the flow has to be slowed to less than Mach 1 for compustion to occur. Faster, and it goes out. This limits the range of velocity that can be attained. So, there is a range of velocity that can only be attained with rockets. With a working Scramjet it becomes possible to fly most of the way to orbit. From an energy consideration, once you are in low earth orbit you are half way to anywhere in the solar system and can use low acceleration, high efficency engines to get anywhere.
Scramjets are the realistic key to space exploration.
Eschew Obfuscation
Also, for the trivia-minded, Lincoln was also near the top of the list to be nuked by the Commies during the cold war, as that particular runway could serve as a base for B-52s, etc.
But wouldn't the scramjet work at lower speeds in denser atmosphere, or not?
So what would it be like to hit turbulence at Mach 7.6? Or for that matter if a rivet was not quite flush? I'll bet you'd get a lot of Gs then, maybe too many to notice.
Mach 4 at 1 bar doesn't have the same heat load as Mach 7 at 0.02 bar. And you need to be going faster than your cruising speed anyway if you want to launch from a rail gun.
I'm very impressed that this was headed by a University (versus, say, Lockheed-Martin or Nasa). The article says there were collaborators from around the globe, but who picked up the tab?
Our monkey brains can't really appreciate the size of this Earth. Circumference = 24,000 miles. Mach 7.6 = 5000 mph. So it'd take about 5 hours to circumnavigate the globe -- or about 2.5 hours to reach the opposite point on the other side of the world.
Depending on lift ability, this could have fascinating implications for rapid-response troops.
But more importantly, it's potentially an excellent way to lower costs to get things into orbit. And air travel is all well and nice, but the future is in space travel, at least to LEO.
The Mongrel Dogs Who Teach
Don't take this the wrong way, but nobody gives a damn what your vacation preferences are. It'd be used for extremely urgent deliveries; rapid-deployment troops; or -- and this is the payoff -- launch assit to low earth orbit. Air travel is so, well, 20th century.
The Mongrel Dogs Who Teach
Yet... the average distance the molecules must mobe -- their mean free path -- moves inversely with the density: the lower the density, the greater the separation of molecules. At larger distances with a given speed, the rate of energy transfer would of course be lower. So shouldn't density matter?
Well, as I pointed out elsewhere, the crux of the matter is that pressure and density do matter. But for an ideal gas, their effect cancels out, and indeed, yields the temperature dependance everyone is so worked up over.
The Mongrel Dogs Who Teach
The problem with scram jets is you have to be moving very fast before they start working at all. That speed just happens to be about mach 7. These types of engines might be able to get up to about mach 15 before you run out of air. To escape velocity is about mach 33. If you could keep the thing in the high atmosphere at the point were you have enough air to keep accelerating but not too much that you burn up. The idea of these is to gain enough speed to put something in orbit whithout hauling around all that O2. When you consider that the upper atmosphere isn't all that well understood as thundersorms can double the air density 200,000 ft above the storms and that would be like hitting a wall at mach 15.
"It'll take a much more expensive project to figure this out for sure, hence, NASA's much more expensive project"
Don't you mean much more expensive failures? Or could this be the dawn of a new NASA era. Low-cost failures, followed by high cost successes.
fair enough
scramjet payload and impacted some 370km downrange of the launch site
please note the word impacted, not the way I'd want them to send the heart I need for my transplant.
There is a lot of work to be done here before it can be used for anything other than a missile right now, and unfortunately, they don't have the funding for another launch.
Xaotik Designs
Now is the proper time for me to reveal my patented SPAM-JET - delivering accrate and timely spam to email users at the speed junk!
Bzzzt. But thank you for playing. Since forces are dependent on acceleration, moving at constant speed is indistinguishable from being at rest. That's not even Einstein -- that's Galileo.
Bzzzt again. This just isn't your day. First, modern physicists don't even talk about mass increasing as velocity increases. Mass is mass is mass; ie., what used to be called "rest mass". The observed kinetic energy increased with velocity, of course. But we don't use relativist mass because it implies things like, "Oh, Newton's laws are OK if you just put a factor of gamma in", which is not true. It can be shown that in fact, there would be two relativistic masses, a "parallel component" one and a "transverse component" one. This complicates the idea of mass and force so much it's of no use whatsoever.
Second, even if your mass seems to increase as measured by an observer, it wouldn't for you... All of your molecules will be traveling at the same speed, so each sees the others at rest and therefore, by the first principle of relativity, can see no mass effect.
Third -- and now I'm just being obnoxious -- you seem to confuse "mass" and "weight".
The Mongrel Dogs Who Teach
"After everyone had gone home, the researchers faced a nail-biting wait for the telemetry officers to come in from the dust with their precious data, before analysis could occur."
Don't they have some form of high speed network they can just FTP the data over? Why did they have to wait for these guys to come back from remote tracking stations? Anyone know?
--P
Even more practically, according to the article at New Scientist you have to be travelling Mach 5 to even get the engine to ignite. Perhaps this is why they had to launch it on a rocket and then attempt ignition as it re-entered the earth's atmosphere.
I talked with a buddy of mine who is really into aviation, and to the best of his knowledge, even our (i.e. the US) best and newest fighter jets top out around Mach 4. While this jet engine certainly seems amazing (I mean, c'mon, it's Mach 7.6!), it doesn't seem like there are really any practical uses for it on Earth at this time.
This is not the greatest sig in the world, no. This is just a tribute.
Passenger traffic will probably be the last application.
But there are tons of military possibilities: Bomber/ spyplane that not only gets to the target extremely fast, but can outrun all antiaircraft weapons (including missiles).
-Tor
starman97 writes:
"Now, getting to Mach 7.6 to light one of these off may take a railgun, something that rules out living payloads, but good for launching cheap infrastructure into LEO."
Apologies in advance for splitting hairs (because that's more or less what I'm doing), but it needn't be cheap nor LEO, but it would help if it was hardened if you're going to railgun it up. =)
My
Limekiller
It isn't too often you hear the word "success" in the same article as until it began to burn up
So when the terrorists hijack one of these after the 10 years of flight school or whatever they would have to take to be able to handle one...
This will revolutionize worldwide air transport.
--Blair
Bzzzt again. This just isn't your day. First, modern physicists don't even talk about mass increasing as velocity increases. Mass is mass is mass;
No shit, which is why I said a finite mass weighs more, that that the finite mass gains more mass.
IIRC a person weighs less on the moon, with respect to the moon, because the gravitational forces (cause by the mass of the moon) are smaller.
As you approach the speed of light, you weigh more, not in respect to eh earth, but in resepct to yourself.
Your molecules, having the same mass as they did at rest, have a much stronger force of attraction between them.
I said nothing about mass increasing, that is both physically and theoretically impossible, without actually adding mass of course.
Third -- and now I'm just being obnoxious -- you seem to confuse "mass" and "weight". Now I can be obnoxious... Everyone always complains about people not reading the articles and posting a reply to a front-page story, but it seems you have not even read the comment you are replying to... or your 5th grade english skills make it impossible for you to comprehend.
Either way, I'm not the one at fault.
Stupid Humans.....
Part of that can be easily arranged.
=brian
... is mysteriously close to Paul Allen! Come on, who spells there name with all those extra L's
Live web cams
..about low speed scram jets. I had always been told that the shock was totally impossible bellow Mach 4. They should eventually get the speed down if its only a stability issue. AEs seem to be good at designing arround stability problems. Perhaps they could even lower it further by including compressed oxygen on the plane? The oxygen could be used to help with the standing shock.
Perhaps something like this: Normal jet engines from take off to mach n (n 4), compressed oxygen "rocket mode" version of the scram jet enginee up to mach m, real scram jet mode on up. You would get three diffrent types of engine for the cost of two.
The Christian religion has been and still is the principal enemy of moral progress in the world. -- Bertrand Russell
What? Why is that article saying this is the first supersonic flight? Didnt that happen in like 1960 (roughly??)?
Whale
I won't comment about hypersonic dynamics because I have no experience in the field, but lifting bodies have such high aerodynamic loading anyway, turbulence has little relative effect.
So, let's drop it down to an over-ambitious 600 mph, since scramjet-powered craft will be flying considerably higher than 20,000 feet. Multiply by 7.6 and you get 4560 mph, In other words, a tad faster than the fastest speed reached by the X-15 decades ago.
The point of this thing is to test technology that might allow operational craft to go faster for less money. Very practical if you need to launch small satellites or get people or cargo from, say, Berlin to Tokyo in 3 hours. Or New York to Los Angeles in about 40 minutes.
-- Slashdot: When Public Access TV Says "No"
If you're flying at about 5,000 mph, you could cover the London-New York distance in about 40 minutes. Add a bit more time for acceleration and decceleration.
-- Slashdot: When Public Access TV Says "No"
Keep the acceleration at the one-gee level and everyone would be as comfortable as they are in their living room. (Believe me, a space propulsion system that could maintain a constant one-gee acceleration level would revolutionize space travel.
-- Slashdot: When Public Access TV Says "No"
Too bad you were bored. Going faster for less money is usually considered a good thing. This is a proof of concept of a technology that promises to dramatically lower the cost of getting payloads to orbit. The fact that it plowed into the ground is irrelevant: the point was to get the scramjet to ignite. We know how to land aircraft. (BTW, the Concorde is expensive because it uses 40-year old technology. France and the UK subsidized development for reasons other than creating cost-effective travel. If someone would market a commercial aircraft that could do New York-London at 1,500 mph and cost no more to operate per passenger than a 747, that would be interesting, too.
-- Slashdot: When Public Access TV Says "No"
.. but why do they always say "at sea level" when qualifying the speed of sound?
The main reason the scramjets are melting is the friction with the air correct? Why not use them in a vacuum?
Build large systems of vacuum tunnels (overseas would be difficult) for continent travel. Inside the vacuum you wouldn't have friction, so you could get to these higher speeds easily yes? Magnet levitation and all that should make them fairly efficient. Imagine having an hour trip from New York to California.. I gotta imagine that would bring in some extra business. I'd sure as hell go on vacations every weekend if I could be back in time for supper.
With respect to whom? If you don't answer that question, then you're justing spouting gas... once speeds around that of light are involved, relativity is king and you must always keep your reference frame clear. Do you? No, because very soon after, you say,
which is not even bullshit -- it's just wrong. With respect to yourself, by definition you are rest (that's what "with respect to" means). And relativity says that things can't look odd for anything at rest. There is no mass increase because with respect to yourself, you're not moving near lightspeed. With respect to yourself, you're not moving.
I don't know if you're sloppy or silly. First you say "I was talking about weight, not mass". Then you immediatel say, "The finite mass gains more mass." Which is it?
Bzzzt. But thank you for playing again.
The Mongrel Dogs Who Teach
Agreed, if you say "first uses". Later, who knows? I fly SF to Japan frequently, and there are sceduled flights NY to Tokyo, which could benefit from this technology, later, when it is more developed. (Comment about banning cars right on. Applies to guns, too.)
There was one supersonic ramjet cruise missile that actually reached hypersonic speeds. I forgot the name. But during one test, the fuel feed got stuck on full throttle, and the cruise missile reached Mach 5.5 with no problem.
Ramjets have been around for years and can reach Mach 5. Why not use them? All that you would need is a couple of turbojets to reach transonic speeds, then you can fire the ramjet and your are off.
(BTW, a scramjet would need a turbojet to reach supersonic speeds, a ramjet to reach low hypersonic speeds, and finally a scramjet to accelerate to high hypersonic speeds)
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
2 traditional jet engines and 2 scramjets, you take off and land with the traditional engines and cruise with the scramjets.
Actually, you would need three sets of engines: Turbojet to reach supersonic speeds, ramjet to Mach 4 so the scramjet can operate.
The practical limit of turbojet engines is about Mach 2.5, not nearly fast enough for the scramjet. The reason the SR-71 exceeds Mach 3 is that it uses a turbo-ramjet engine. When it gets to a certain speed, all the air and fuel is bypassed and burns independant of the turbines (which completely shut off). This allows the turboramjet to reach higher speeds that a turbojet.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
So what would it be like to hit turbulence at Mach 7.6? Or for that matter if a rivet was not quite flush? I'll bet you'd get a lot of Gs then, maybe too many to notice.
The higher the altitude, the less turbulence. The Concorde travels at 50,000 feet. It has almost no turbulence. This scramjet would travel more in the neighborhood of 80,000 feet. The turbulence would basically be zilch.
In response to an earlier poster: Humans can withstand Mach 7.6. The withstand Mach 25 in rockets. What matters is the acceleration. This scramjet would likely accelerate no faster than a regular jet liner. Fighter pilots only need pressure suits when they do high-g turns. No jet engine has enough thrust to cause blackouts during acceleration.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Is "cruise" a synonym for "nonballistic"? To me the word implies that speed is not an issue -- and ramjets, though slower than ballistic missles, are certainly faster than the fanjets used on cruise missles.