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."
BBC story
Wow!
This must be twice better than Gillete Mach3 system !!
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
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/
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.
You are correct, from start to finish, if you are traveling at mach 7.6 the flight would take 2 hours. But the question was, how long would it take to get up to mach 7.6. How far along on your flight would you be before you reached that speed.
The test flight used a small craft, not a large passenger jet. It would be both easier and faster to reach that speed in a smaller light craft(and even then they used a MK 70 rocket engine, which I'm pretty sure isn't rated for passengers). Even if they were to just use a rocket or catapult(like on an aircraft carrier) to bring you to that speed faster, the G's would be immense, I'm not even sure if a G-suit would keep you from blacking out. And as stated earlier, if you gradually were to gain speed until you reached that point, you would be almost at your destination before you reached mach 7.6, and it would be time to start slowing down for landing.
Xaotik Designs
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!
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)
Almost everything. Normal jet engines have lots of moving parts - turbines, compressors, etc. Ramjets and scramjets don't have any moving parts. They also require very high velocities to work properly, whereas a turbojet/turbofan is quite happy running all day long without moving.
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."
remember, google.com is your best friend.
scramjet
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
How does Concorde get away with it?
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."
OK, I checked, and it doesn't... Concorde only goes supersonic when it gets to the water. This is why it has so few routes.
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.. :^)
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.
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.
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?
It could actually help. If it takes a normal plane 20 hours to get from Sydney to London and this one 2 that is 18 less hours in the air per flight. Of course that all depends on the exhaust ratio of the two planes.
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.
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.
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.
If the fuel burned, of course thrust was achieved. However, to answer your real question, this engine was not designed to produce net thrust. It was designed to achieve supersonic combustion within the simplest possible configuration
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
This is just the first baby-step.
Don't Bogart the fish sticks
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.
I don't think it's the first time that scientists have tested a functional scramjet.
Back in the 1990's, Russian scientists put a model of a scramjet engine on top of a former SS-20 missile and I believe they did manage to get some test results from these fights.
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
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
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
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
It isn't too often you hear the word "success" in the same article as until it began to burn up
This will revolutionize worldwide air transport.
--Blair
... 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
Scramjets melt in a few minutes. Jets usually don't melt.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"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"
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?
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
There happens to be a rather large difference between the engine on a scramjet and the engine in a muscle car. If the acceleration were not all that hard, I think that they would have found a getter way to do it than a MK70 rocket engine.
Xaotik Designs
We don't have trans-continental tunnels because continental drift is a bitch. Sure, it's only a few centimeters a year, but a high-speed vacuum tunnel has to be made to rather close tolerances. Those few centimeters per yr would add up rather quickly.
The moon and other tectonically (sp?) dead bodies are where you could get away with something like that.
And as was pointed out, a scramjet is not a rocket. Needs oxygen. In fact, that's one of the big advantages it has over rockets. It can breathe the surrounding atmosphere without having to carry it's own oxidizer.
Dyolf Knip
Well actually the scramjet was lit on the way down. Straight down. So it would have hit the ground and damn near Mach 7.6. That's got to make a good lawn dart.
Yeah but they weren't trying to transport humans with the MK70, so why invent a low-G accelerator when all they wanted to do was test the scramjet?
Karma police, I've given all I can, it's not enough, I've given all I can, but we're still on the payroll.
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.