USAF Scramjet Hits Mach 6, Sets Record 326
s122604 writes "The [X-51A Waverider]'s scramjet engine accelerated the vehicle to Mach 6, and it flew autonomously for 200 seconds before losing acceleration. At that point the test was terminated. The Air Force said the previous record for a hypersonic scramjet burn was 12 seconds. Joe Vogel, Boeing's director of hypersonics, said, 'This is a new world record and sets the foundation for several hypersonic applications, including access to space, reconnaissance, strike, global reach and commercial transportation.'"
Interesting... (Score:2, Interesting)
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How useful is this in the long run? What was the burn ratio compared to other scramjet vehicles of recent design?
Are there even any other scramjet vehicles in the operational testing phase? I was under the impression that the X-51, and the other vehicles in the Hyper-X program, are the only ones that've actually flown. Scramjets aren't exactly easy to test in the lab.
Re:Interesting... (Score:5, Informative)
According to the article there's three more vehicles which will be tested in the fall.
in the fall? (Score:5, Funny)
you mean in the autumn?
or in the spectacular screaming descent towards land?
Re:Interesting... (Score:5, Interesting)
Scramjets aren't exactly easy to test in the lab.
Hell, even normal jet engines are tough to test. Have you seen the equipment used to keep those things stationary while testing them? Holy fuck [rob.com].
Amazing (Score:5, Interesting)
It's amazing to me that they can make a machine who's parts are GLOWING they are so hot and the metal still functions without failing.
Re:Amazing (Score:5, Funny)
Like incandescent light bulbs?
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You may laugh, but I did have a lightbulb explode above me. Picking out shards of glass out of my hair is not what I'd call 'fun'.
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Oh, I thought you said Cinnabons.
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Re:Amazing (Score:4, Funny)
You fly a desk and complain about the goodies? Your company must have some Awesome goodies.
Just out of curiosity, what's the air-speed velocity of your unladen desk?
Also, describe some of those goodies to me.
Re:Amazing (Score:4, Funny)
Just out of curiosity, what's the air-speed velocity of your unladen desk?
And, GP, do you have the European or African market version?
Glowing metal = black body radiation (Score:5, Informative)
The temperature of objects produces (from what i recall of physics) black body radiation - meaning it produces light wavelengths. Just because we associate melted iron being red hot, doesn't mean other metals melt when they start to glow. It just means they are hot enough to produce enough black body radiation that we can see. Look at mercury for example as an opposite.
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Re:Interesting... (Score:4, Informative)
Generating exhaust simultaneously at high rate, high velocity and in a compact package is vastly different.
Re:Interesting... (Score:5, Informative)
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Chose that one because it was the first picture I came across that you could see good detail on the rig keeping it in place. But yeah, I agree, it is a bit overkill :-)
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I agree that using the J58 as an example of a typical jet engine is rather like using an atom bomb as an example of an explosion.
At the same time, since the J58 is essentially a turbojet/ramjet hybrid, it might be said to be the distant forefather of the X51 engine.
Oh, and anything that makes me go look at pictures of the most beautiful aircraft in the world, the SR-71, is a good thing.
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>Scramjets aren't exactly easy to test in the lab.
Once, maybe, but repeatability could be a problem.
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Yes, but not scramjet technology that uses ordinary jet fuel to power the engine. Said scramjets used hydrogen instead, and can't maintain flight for long because of how bulky the large hydrogen tanks are.
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Actually Kerosene + Lox can do this. Problem is they are having problems with the exhaust temperatures are high enough to melt most aircraft components.
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Also what altitude was this operating at? "Mach 6" doesn't mean much in terms of speed relative to the earth without an altitude.
Re:Interesting... (Score:5, Informative)
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The usefulness, overlooked in the summary and (brief) article, but reported in The Register [theregister.co.uk] (longer article), is that this vehicle used jet fuel (JP-7) instead of Hydrogen. Additionally, it apparently flamed out at Mach 5, not 6.
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Useful??? They had to use a B-52 to get into the air. Then a rocket booster to go to 4.5Mach. Then this precious little stove pipe took it to 5.0 Mach.
Yeah! How can you call that useful? And speaking of wastes of time during our war with the Japs and the Nazis, did you hear what those crazy eggheads over at Los Alamos are doing? They're trying to build a "nuclear bomb" -- but all they've managed to do so far is irradiate a bunch of scientists. How is that useful?
(/snark)
This is a *test program*, not a f
Why so short bursts? (Score:4, Interesting)
Re:Why so short bursts? (Score:5, Insightful)
Proof of concept. Scientists can only go so far on theory ( and it's impressive how far they do go ). At some point their research hits a point where they need to perform experiments.
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Likewise you want to stop the test before failure so you can look for signs of component wear and material stress so that you know what to improve for next time. Stopping at 200 seconds and finding this out is very useful. Stopping at 201 seconds after it has exploded and you have to work out from the pieces what went wrong is not as informative.
Re:Why so short bursts? (Score:5, Insightful)
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Except they're not recovering these vehicles for analysis.
That's what datalinks are for.
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How much do you think is left after it hits the sea at Mach 6?
Re:Why so short bursts? (Score:4, Informative)
Since the vehicle was deliberately crashed into the ocean and not recovered - there's nothing to examine for wear and stress, whole or in pieces.
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Not sure how fast it reached Mach 6, however, at Mach 6 in 200 seconds, you have covered over 250 miles (400 km). That's a lot of ground. No point continuing the experiment if whatever you are monitoring can't be monitored because its so far out.
Re:Why so short bursts? (Score:4, Interesting)
Scramjets have no moving parts; it's a duct and a fuel injector. That's it. Wear is a non-issue here.
Figuring out what shape that duct needs to be in order to get stable combustion, however, is far from a trivial problem; it's not just the fluid dynamics of the supersonic flow that must be considered ... thermodynamic losses can be large enough to quench the flame, and where in the duct those losses occur is as important as their magnitude. With most sorts of engines, second-law analysis is only something you look at to refine the efficiency of the technology once it's mature and functional. With scramjets, it's critical to making them work at all. Building one of these, with all our modern computer modeling technology, is kind of akin to building the first rockets with no computers at all.
Re:Why so short bursts? (Score:5, Informative)
Not only that, but you can't always be sure which part is the weak link, what will break. A few tests at hypersonic is guaranteed to make an engineer say "ok, that's an issue we weren't aware of", and confirm much of what they already knew. They may have to make some part that they *thought* would be ok out of a different, stronger alloy, etc. Of course, at this speed, every tiny error in engineering is amplified, as at Mach 6, you cross a lot of real estate in just a few seconds, so the word "precision" doesn't adequately describe the level of perfection required in the test system build.
Being a pioneer at anything guarantees surprises, and best of all, learning new things.
Re:Why so short bursts? (Score:5, Insightful)
Keep in mind that at mach six 200 seconds is 400 kilometers. That's already enough range to make a useful weapon (and yes I realize there was some acceleration time in there). Heck, that's already longer range than the most advanced missiles that many countries have. Increase the stability to just 10 minutes of burn time and you've got a missile that can go 5% of the way around the world.
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ICBMs do not do any jetting at all, its not a comparison, as they are ballistic rockets. You can think of them as flying mortars more than missiles. The closest applicable missile would be a cruise missile, but honestly, they are designed more for distance than speed. You don't need your cruise missile to get there ridiculously fast, but you do want a ridiculous range for them, at a sufficient speed to not be destroyed or give advanced warning, while still making it to the target in time for intercept.
Re:Why so short bursts? (Score:5, Insightful)
It's all part of the Prompt Global Strike program. Eventually the goal is to have scramjet powered missiles with a range of 12000+ miles. Allowing you to fire an obviously non-nuclear missile from Kansas to North Korea and have it hit the target in less than 3 hours. Basically, even launching a B2 for a direct strike takes days or weeks. Refueling planes need to be put into the air, mission plans drawn up, clearance over foreign airspace cleared, pilots briefed, etc. They want to be able to say "Fire" and have the missile in the air within minutes and at target within hours; with the added benefit of not putting any American lives in harms way.
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Mach 6. 200 seconds. Makes a long walk home.
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Re:Why so short bursts? (Score:5, Interesting)
Are you talking about the scramjet or the events at Kitty Hawk in 1903 [wikipedia.org]?
Because Wilbur already had the first chance, Orville took his turn at the controls. His first flight lasted 12 seconds for a total distance of 120 feet (36.5 m) - shorter than the wingspan of a Boeing 707.
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It is a question of stages. The timescale that need to be designed for initially are based on the engine size divided by gas flow speed. That is maybe 10s of microseconds. The next timescale may have to do with longer scale oscillations in the engine structure...that is probably on the order of 1 - 100 milliseconds (10-1000 Hz). After that, you need to start worrying about heat...things melting, expanding, coating eroding...those are probably 1-100 seconds.
The smallest timescales are the hardest to fix,
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A couple reasons:
Testing scramjets on the ground is really, really hard, and you can only do it for a very short time (much less than a second).
Testing scramjets in flight is really, really expensive. And when your funds are limited, you can only build subscale air-dropped missile-sized vehicles instead of full-sized, self-launching, reusable ones (in part because of the "cheaper now and more expensive long-term" being prefereable to "more expensive now and cheaper in the long run" thinking that brought us
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Sounds a lot like fusion: it works but it's not yet useful.
Mach 6 during 12 seconds is 23 kms. During 200 seconds it is 790 km. Useless for a plane, but imagine what a drone or a missile could do. Short range but no possibility of missile interception : it is already useful despite being a prototype.
I am however disappointed : I thought it was supposed to achieve Mach 10 ?
Thing that we told you about last week (Score:2)
Now can the truth come out? (Score:2)
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Sub-orbital transport dominates (Score:2)
From the FX claim Sorb [ideosphere.com] currently trading at a 10% chance of coming true:
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New Mexico's already building their space port [spaceportamerica.com]. Will be interesting to see if sub-orb traffic takes off.
For those of you who don't know how fast Mach 6 is (Score:3, Informative)
From Wiki Answers [answers.com]:
So that's like going from Atlanta, Ga to Honolulu in just over an hour.
Re:For those of you who don't know how fast Mach 6 (Score:5, Interesting)
Mac 5 melts aluminum steadily
Mac 6 melts steel [modernmechanix.com]
And don't forget that keeping this friction heat down also requires a good deal of power.
Re:For those of you who don't know how fast Mach 6 (Score:5, Funny)
Even at Mach 3 [wikipedia.org], you want a layer of foam to avoid burning.
Waverider (Score:5, Informative)
So not only does this do Mach 6, but it also uses its own sonic booms to help with propulsion? Or did they just choose Waverider because it sounds neat?
http://en.wikipedia.org/wiki/Waverider [wikipedia.org]
Re:Waverider (Score:5, Informative)
It uses it's own shockwave for lift, not propulsion. This does, however, help it go faster, by eliminating the drag that adding wings would cause.
Re:Waverider (Score:5, Funny)
That's almost as fast as... (Score:4, Funny)
...how quickly my home declined in value in 2008 and 2009!
Still a long way to orbit (Score:4, Informative)
Mach 6 is still a long way from Mach 22. Mach 22 is orbital velocity.
Re:Still a long way to orbit (Score:5, Informative)
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Boy, ya learn something every day, don'cha?
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It's entirely possible to do orbital velocities and not be in orbit... It tends to end up in being turned into smush, and/or being propelled out the atmosphere at some point, but that doesn't change the fact that it's possible.
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You just gotta keep pushing down on the stick..
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As there is no atmosphere in orbit
There's no fundamental reason why you couldn't orbit within the atmosphere at Mach 22, with the occupants experiencing weightlessness. We don't currently have the materials and engines to withstand such conditions, nor would it make any sense to try, but it could be done in theory.
Anyway back to the OP's point, since kinetic energy is proportional to the square of the velocity, Mach 6 is only 7% of the energy needed to reach orbit. IMO, scramjets are just a complex diversion if the goal is to go into orbit.
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there *is* atmosphere (Score:3, Informative)
No it isn't. Mach is the speed sound travels in a medium (the atmosphere). As there is no atmosphere in orbit, you can't associate a mach speed value to orbital velocities.
You start out in the atmosphere, chief. Also, Wikipedia specifies a Mach number for LEO [wikipedia.org].
Even in LEO, there is air- it's just very, very, very thin. The atmosphere doesn't end at a hard line.
Why do you think objects in LEO gradually slow down and re-enter? Answer: aerodynamic (and solar) drag.
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2025 (Score:2)
The orbital velocity of the year 2025, what else?
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An unladen African Swallow?
Mach 5 - Not Mach 6 (Score:5, Informative)
Boeing announcement here:
http://boeing.mediaroom.com/index.php?s=43&item=1227 [mediaroom.com]
"In its first flight attempt, the Boeing [NYSE: BA] X-51A WaveRider today successfully completed the longest supersonic combustion ramjet-powered flight in history -- nearly three and a half minutes at a top speed of Mach 5."
My understanding is that it didn't reach the 300 seconds Mach 6 burn it was hoping for. 200 seconds and Mach 5 isn't all that bad though...
More here:
http://www.theregister.co.uk/2010/05/27/x51_first_shot/ [theregister.co.uk]
200 seconds at Mach 6... (Score:2)
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Well, that was its top speed. It would have taken some time for it to accelerate from the cruise speed of the B-52 up to mach 6 so it wouldn't have gone quite that far.
Still, it probably would have gone at least half-way across Pennsylvania.
Jet - Scramjet - And Questions! (Score:4, Interesting)
Questions
Re:Jet - Scramjet - And Questions! (Score:4, Interesting)
If it is capable of propelling whatever it's carrying to 11.2 km/s (just under Mach 33 at the Earth's surface). Since this one only goes to 6, there's still a ways to go.
Just as a foot note - if you're travelling at 11.2 km/s in a circle with a 6,378 km radius (Earth's equator), you will experience an acceleration opposite to gravity of 19.67 m/s^2 (aka 2 g). Just slightly slower if you do it at an altitude of 10 km (19.64 m/s^2). At the altitude this one reached, you'd hit 19.6 m/s^2
Re:Jet - Scramjet - And Questions! (Score:5, Interesting)
The scramjet will circulate the fuel behind engine walls to cool the structures. Without such active cooling, the temperatures in a scramjet could reach 5,000 deg. Fahrenheit, high enough to melt virtually any metal on Earth. Solving the cooling challenge is a major AFRL/Pratt & Whitney achievement.
Source [spaceflightnow.com]
My wager is that the entire vehicle took thermal control into its design considerations and it uses a combination of geometry, aerodynamics, and fuel management to help sink heat at an appropriately high rate to prevent too much for a build up. However, since I don't have the design specs, and I doubt anyone outside of the military will, for awhile at least, I can only speculate. You also have to understand that at those speeds, your gas dynamics become a problem of rarified gasses [wikipedia.org] and heat management becomes a very tricky problem indeed, one that can't be approached by traditional cooling means. So in summation I would guess yes, they have probably found some very cool new ways to sink heat at hypersonic speeds.
Re:Jet - Scramjet - And Questions! (Score:5, Informative)
Atmosphere isn't just compression, it's reaction mass. The compression creates the conditions for acceleration when the fuel is burned, but it's heating of the compressed air that causes the high force that accelerates the air backwards, accelerating the vehicle forwards.
You can bring your own oxygen, but it's just going to make a pretty flame coming out both sides of the combustion chamber unless there's mass flowing into the inlet and being pushed out through the nozzle.
I said this above already, but what you do here is you use a first-stage rocket motor to get up to scram-jetting speeds. Then the second-stage motor gets you to a certain point in the atmosphere where it loses thrust. Then you light your third stage.
This makes sense only if the specific impulse (look it up) from the scramjet exceeds that from a rocket motor, or it's ridiculously cheap and still gets the job done. I'm guessing it's not ridiculously cheap. But given that you don't have to bring the reaction mass for the scramjet with you, it might be more efficient than a rocket of the same mass. Meaning you can omit a heavy rocket motor and use a lighter scramjet and put the saved mass into the payload.
So (Score:2)
When do we get a combination turbojet/ramjet/scramjet? Or will we be launching aircraft piggyback (or underwing) for the foreseeable future? This seems like a great technology for amazingly pissed-off artillery shells, I can imagine a ramjet that turns into a scramjet pretty easily if it doesn't have to turn back.
Didn't hit mach 6, just mach 5! (Score:5, Informative)
Hello,
The story is in error. Per this link, the plane only hit Mach 5, not Mach 6. This is still a pretty successful test, however.
Link: http://www.msnbc.msn.com/id/37377401/ns/technology_and_science-space/ [msn.com]
--PeterM
Re:Uh hu (Score:5, Insightful)
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Whether or not you agree with it, military research has led to an enormous number of scientific advances that were initially used by the military but later disseminated more broadly. Jet engines, the Internet, cryptography, GPS, nuclear reactors, etc
My Google-Fu seems to be failing at the moment, but wasn't the internet originally conceived to keep track of nuclear weapons?
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THAT'S what I was looking for. Thank you:-)
Re:Uh hu (Score:4, Informative)
Are you trying to point out that the internet wasn't a military innovation by stating its purpose was to track nuclear weapons (*military* nuclear weapons)?
And for what it's worth, the original purpose was to allow communication between points with no single path of failure (insert beneficial military application here like giving combat orders in the event of a nuclear strike); it started in universities, national labs, and large military bases who had the budget to pull the wires, and before we knew it there were all kinds of fun uses for it like MUD games and e-mail and slashdot and finally facebook; the ultimate military weapon.
Re:Uh hu (Score:5, Funny)
Re:Uh hu (Score:5, Funny)
Little plastic Army Men [wikipedia.org]
Re:Uh hu (Score:5, Informative)
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Re:Uh hu (Score:4, Funny)
Brought peace!
Re:Uh hu (Score:4, Funny)
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and those guys who forcibly sent that kid back to Cuba.
Janet Reno?
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It is almost assured that they would have happened later, though, since they didn't beat the military research to begin with.
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> I need one of those for when I'm visiting the in-laws (or rather, when I am leaving).
No...you need one of those when you are flying with the in-laws. Personally I can't wait to see my mother-in-law's facial expression at Mach 6! >:-)
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Assuming the acceleration is modest, her facial expression aqt Mach 6 should be identical to when she's sitting on her living room sofa.
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Re:FYI... (Score:4, Insightful)
Or you just lie flat on the earth and let gravity do about the same.