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USAF Scramjet Hits Mach 6, Sets Record

CmdrTaco posted more than 4 years ago | from the get-where-yer-going dept.

The Military 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.'"

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first post (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#32362336)

first post!

FYI... (0, Troll)

TrisexualPuppy (976893) | more than 4 years ago | (#32362470)

flew autonomously for 200 seconds before losing acceleration

Google search query: 200 seconds * (mach 6) in miles

This brings us to about 254 miles in 200 seconds. Beats my morning commute speeds.

Re:FYI... (1)

HopefulIntern (1759406) | more than 4 years ago | (#32362516)

Indeed. I need one of those for when I'm visiting the in-laws (or rather, when I am leaving).

Re:FYI... (1)

muckracer (1204794) | more than 4 years ago | (#32362604)

> 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! >:-)

Re:FYI... (3, Insightful)

Anonymous Coward | more than 4 years ago | (#32362708)

Assuming the acceleration is modest, her facial expression aqt Mach 6 should be identical to when she's sitting on her living room sofa.

Interesting... (1, Interesting)

TrisexualPuppy (976893) | more than 4 years ago | (#32362342)

How useful is this in the long run? What was the burn ratio compared to other scramjet vehicles of recent design?

Re:Interesting... (2, Interesting)

AdmiralXyz (1378985) | more than 4 years ago | (#32362412)

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... (4, Informative)

joggle (594025) | more than 4 years ago | (#32362518)

According to the article there's three more vehicles which will be tested in the fall.

makes me sad.... (-1, Flamebait)

Anonymous Coward | more than 4 years ago | (#32362986)

so much energy squandered on killing people we don't get along with. Hell, most of that cold war junk never got used (thank ghod!) hopefully spin-offs and unintended side-effects can make some positive contribution to society.

Re:makes me sad.... (-1, Offtopic)

SnarfQuest (469614) | more than 4 years ago | (#32363260)

There's your typical Democrat. Hates anything military, unless it can be used for abortions.

Most of that "evil" cold war junk convinced many other nations that attacking us would be a very bad idea. Terrible that, seeing that we didn't get the chance to kill them all when they invaded. Awful thing, deterrence. Maybe we should invade Mexico and Canada, just so we can kill them all.

We should just meekly follow your path, destroy our military, and wait for some tiny country like Panama to invade us, enslaving or killing us all. Only then will you be truely happy.

Re:Interesting... (5, Interesting)

Pojut (1027544) | more than 4 years ago | (#32362524)

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 (4, Interesting)

maillemaker (924053) | more than 4 years ago | (#32362704)

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 (5, Funny)

characterZer0 (138196) | more than 4 years ago | (#32362778)

Like incandescent light bulbs?

Re:Amazing (1)

operagost (62405) | more than 4 years ago | (#32362892)

Now I know why the green movement REALLY wants us to get rid of incandescent bulbs. Clearly, they're dangerous and could explode at any time!

Re:Amazing (1, Offtopic)

Cyberax (705495) | more than 4 years ago | (#32362988)

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'.

Re:Amazing (0)

Anonymous Coward | more than 4 years ago | (#32362920)

That's not glowing metal. That's just what ZPMs look like.

I'm not the only one that sees a giant ZPM, am I?

Re:Amazing (2, Interesting)

BobZee1 (1065450) | more than 4 years ago | (#32363006)

The company I work for makes the parts in what "they call" the hot section of the engine. These are some really awesome materials. I fly a desk so I don't get to play with the goodies.

Re:Interesting... (1)

phoenixwade (997892) | more than 4 years ago | (#32362798)

I'm not trying to downplay the engineering involved with testing jet engines, but really, using the J58 as an example of a jet engine is like using an atom bomb as an example of an explosion.

Re:Interesting... (1)

tweak13 (1171627) | more than 4 years ago | (#32362878)

Why is that exactly? Sure, the J58 is a unique engine, but we've since made engines for airliners that put out three times as much thrust.

Re:Interesting... (1)

jgagnon (1663075) | more than 4 years ago | (#32363014)

Jet engine Viagra?

Re:Interesting... (3, Informative)

geckipede (1261408) | more than 4 years ago | (#32363028)

The differences are in how compact the engine is and exhaust velocity. Airliner engines are designed solely for efficiency and as such have bypass ratios that make start to look like a helicopter mounted sideways in a tube. The actual power generating bit of the engine is tiny and most of the thrust comes from shunting air through the outer parts at relatively low speeds without ever being compressed.

Generating exhaust simultaneously at high rate, high velocity and in a compact package is vastly different.

Re:Interesting... (1)

icebrain (944107) | more than 4 years ago | (#32363102)

Something like a GE90-115 might put out a heck of a lot more thrust at sea level than a J58 (and do it with less fuel to boot), but it isn't going to keep happily chugging along at Mach 3. There's more to comparing turbine engines than just looking at raw thrust at one specific condition.

It would be interesting, though, to see what a new engine meeting the J58 mission profile would look like. Of course, we'd have to spend a few years relearning/reinventing capabilities we pissed away^W^Wlost, but the end result would be pretty.

Re:Interesting... (1)

Pojut (1027544) | more than 4 years ago | (#32362926)

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 :-)

Nicely put. (1)

archer, the (887288) | more than 4 years ago | (#32362964)

Now, where'd I put those marshmallows...

Re:Interesting... (1)

Kozar_The_Malignant (738483) | more than 4 years ago | (#32362546)

>Scramjets aren't exactly easy to test in the lab.

Once, maybe, but repeatability could be a problem.

Re:Interesting... (2, Funny)

gatechman (1585777) | more than 4 years ago | (#32362506)

According to my sources scramjet technology has gone well past Mach 6. The govt. doesn't want you to know this.

Re:Interesting... (1, Funny)

Anonymous Coward | more than 4 years ago | (#32362632)

If by "...doesn't want you to know this...." you mean "...highly publicized mach 10 test of the X-43 a few years ago..." then yes, you are correct. Otherwise, well, BS.

Re:Interesting... (2, Informative)

beelsebob (529313) | more than 4 years ago | (#32362738)

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.

Re:Interesting... (1)

Lumpy (12016) | more than 4 years ago | (#32362900)

Actually Kerosene + Lox can do this. Problem is they are having problems with the exhaust temperatures are high enough to melt most aircraft components.

Re:Interesting... (1)

WillDraven (760005) | more than 4 years ago | (#32362732)

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... (0)

Anonymous Coward | more than 4 years ago | (#32363252)

Also what altitude was this operating at? "Mach 6" doesn't mean much in terms of speed relative to the earth without an altitude.

Ouch. Earth's diameter is about 13Mm (this means roughly 13000km). Atmosphere--or a noticeable effect thereof--"ends" at about 0.1Mm. Even if scramjets were able to use the little oxygen left at an altitude of 100km, that wouldn't change much about speed relative to the surface.

It would take the spaceship, err, jet some time to ascend to an altitude of 100km, of course, but I digress ...

Uh hu (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32362346)

Commercial transportation at Mach 6. That's definitely the application they're striving for. Definitely. Don't you have enough deadly toys by now?

Re:Uh hu (5, Insightful)

ShadowRangerRIT (1301549) | more than 4 years ago | (#32362464)

Commercial applications do usually follow. 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. Mach 6 might be inefficient overkill for Earth-side transportation, but it may provide a viable means of launching spaceflights one day.

Re:Uh hu (1)

Pojut (1027544) | more than 4 years ago | (#32362552)

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?

Re:Uh hu (0)

Anonymous Coward | more than 4 years ago | (#32362940)

From what I understand, it was originally designed to provide a redundant means of communication in the event that an area was destroyed. It needed to be able to route around problems.

Re:Uh hu (1)

cthulu_mt (1124113) | more than 4 years ago | (#32362962)

Re:Uh hu (1)

Pojut (1027544) | more than 4 years ago | (#32363002)

THAT'S what I was looking for. Thank you:-)

Re:Uh hu (3, Informative)

jeffmeden (135043) | more than 4 years ago | (#32363212)

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 (5, Funny)

Anonymous Coward | more than 4 years ago | (#32362606)

Fine. Except for jet engines, the Internet, cryptography, GPS, and nuclear reactors what has the military done for us?

Re:Uh hu (4, Funny)

Pojut (1027544) | more than 4 years ago | (#32362624)

Little plastic Army Men [wikipedia.org]

Re:Uh hu (0)

Anonymous Coward | more than 4 years ago | (#32363032)

I can live with military research, if they're honest about it. I am allergic to bullshit though. Even if scramjets will some far away day be used for hypersonic commercial transportation, which I don't think they will, then that is still not a factor in their development. Pretending that this is anything but weapons technology research is deeply dishonest.

Re:Uh hu (1)

notommy (1793412) | more than 4 years ago | (#32363150)

Commercial transportation at Mach 6. That's definitely the application they're striving for. Definitely. Don't you have enough deadly toys by now?

Blagh! Not another one. Go back to wheatgrass and let the men decide when we have enough deadly toys.

I think most men would agree that the answer to that is "not quite yet."

Why so short bursts? (3, Interesting)

Henriok (6762) | more than 4 years ago | (#32362358)

Why are these engines burning for such short times? Are these engines so early in development that they really can't get them to be stable and safe for more than 12 seconds? Sounds a lot like fusion: it works but it's not yet useful.

Re:Why so short bursts? (5, Insightful)

grasshoppa (657393) | more than 4 years ago | (#32362404)

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.

Re:Why so short bursts? (3, Insightful)

rufty_tufty (888596) | more than 4 years ago | (#32362628)

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? (5, Insightful)

ckaminski (82854) | more than 4 years ago | (#32362656)

Except they're not recovering these vehicles for analysis.

Re:Why so short bursts? (2, Insightful)

hargrand (1301911) | more than 4 years ago | (#32362858)

Except they're not recovering these vehicles for analysis.

That's what datalinks are for.

Re:Why so short bursts? (1)

stupid_is (716292) | more than 4 years ago | (#32362698)

I wonder how many pieces it was in after it was terminated

"Something then occurred that caused the vehicle to lose acceleration. At that point, the X-51A was terminated as planned."

Re:Why so short bursts? (3, Informative)

DerekLyons (302214) | more than 4 years ago | (#32362782)

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.

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.

Re:Why so short bursts? (1)

mrops (927562) | more than 4 years ago | (#32363054)

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? (4, Informative)

Pharmboy (216950) | more than 4 years ago | (#32362658)

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.

Feedback (-1, Flamebait)

Anonymous Coward | more than 4 years ago | (#32362418)

So, do you have a life, or do you just sit reading Slashdot so you can tell everyone the quality of your last fart? Because your comments have about the same value.

Re:Why so short bursts? (5, Insightful)

MozeeToby (1163751) | more than 4 years ago | (#32362438)

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.

Re:Why so short bursts? (1)

MouseR (3264) | more than 4 years ago | (#32362474)

Mach 6. 200 seconds. Makes a long walk home.

Re:Why so short bursts? (1)

WED Fan (911325) | more than 4 years ago | (#32362694)

About 360 km if i did the math correctly.

Re:Why so short bursts? (1)

WED Fan (911325) | more than 4 years ago | (#32362804)

Did a quick skim of the article for altitude and couldn't come up with an adjustment so I stuck with near sea level numbers.

Re:Why so short bursts? (0)

zonker (1158) | more than 4 years ago | (#32363224)

The Reg [theregister.co.uk] (yeah I know) says it got up to 70,000 feet at approx Mach 5. I'm seeing different numbers depending on the article so YMMV.

Re:Why so short bursts? (4, Interesting)

shadow349 (1034412) | more than 4 years ago | (#32362504)

Are these engines so early in development that they really can't get them to be stable and safe for more than 12 seconds?

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.

Re:Why so short bursts? (1)

mprinkey (1434) | more than 4 years ago | (#32362664)

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, because they are harder to identify and control. When it comes to cooling, etc...these are easy to fix by comparison. At least in terms of making the thing function. I can't think of anything that would have a timescale on the order of seconds...unless it is a pump failure or other supporting device. I'd bet that if it would run for 200 seconds, it would probably run for much longer. It leads me to believe that they have most of the kinks worked out and can start work on developing products instead of the technology.

Re:Why so short bursts? (2, Interesting)

icebrain (944107) | more than 4 years ago | (#32362740)

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 the Space Shuttle).

Making things even more difficult is that we pissed away a huge amount of research (from both the US and UK) on scramjets and high-speed flight a couple decades ago. Companies like Marquardt basically specialized in ramjet-style engines, and were hard at work developing scramjets and other neat high-speed propulsion 40+ years ago. They were very close to having flying hardware. But now, all of the hardware, most of the documentation, pretty much all of the institutional/unwritten knowledge, and most of the personnel are gone. We're having to reinvent the high-speed flight wheel almost from scratch, just like we're doing with heavy-lift launch vehicles, manned lunar flight, and ballistic missile defense, all of which we had operational in the 70s.

It's disgraceful, really, how we piss away useful technology and other exceptional things. There must be some kind of relationship to crabs in the human psyche that's responsible for this self-loathing anti-achievement personality trait.

Re:Why so short bursts? (1)

whitehatnetizen (997645) | more than 4 years ago | (#32362838)

150 years ago your post may have gone something like: "Why are these heavier-than-air 'Air planes' flying for such short times? Are these propellers so early in development that they really can't get them to be stable and safe for more than 12 seconds? Sounds a lot like the automobile: it works but it's not yet useful."

Re:Why so short bursts? (1)

hargrand (1301911) | more than 4 years ago | (#32362840)

Why are these engines burning for such short times

Two reasons come to mind:
1) At 4,000lbs, they don't hold enough fuel to run the engine for more than 200 seconds.
2) The various loads overwhelm the airctaft structure which subsequently disintegrates.
Not sure which one, but I'd put my money on 1.

Re:Why so short bursts? (1)

Yvanhoe (564877) | more than 4 years ago | (#32362898)

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 ?

Well, (1)

phyrexianshaw.ca (1265320) | more than 4 years ago | (#32362384)

I imagine this may have wonderful potential applications in commercial goods transportation, though it's still a few years off.

Thing that we told you about last week (1)

fishexe (168879) | more than 4 years ago | (#32362402)

...did what we said it was gonna do. Yawn.

Now can the truth come out? (1)

OzPeter (195038) | more than 4 years ago | (#32362420)

About that other Mach 6 plane that was already developed The Aurora [wikipedia.org]

Re:Now can the truth come out? (0)

Anonymous Coward | more than 4 years ago | (#32362696)

Not for another decade probably. There are other aspects of the Aurora that they probably still do not want revealed besides its propulsion.

Things like the heat-shielding needed, the avionics necessary when flying that fast, the mothership (fairly sure it gets drop launched), cooling systems, and probably a dozen things I haven't thought of.

Re:Now can the truth come out? (1)

Idiomatick (976696) | more than 4 years ago | (#32363118)

The aurora was made up because people couldn't believe all the cool shit that was being made until the end of the 70s when engineering died.

Sub-orbital transport dominates (1)

Baldrson (78598) | more than 4 years ago | (#32362450)

From the FX claim Sorb [ideosphere.com] currently trading at a 10% chance of coming true:

Suborbital transportation will exceed high-mach air transportation by the year 2020. "Suborbital" means any high-mach, non-orbital flight where the majority of the distance is covered without benefit of locally available gasses as the primary propulsion reaction mass. "High-mach" means the majority of the distance is covered at a speed of mach 2.5 or greater. "Non-orbital" means the total flight path distance is less than the circumfrence of the earth. "Locally available" excludes gasses that have been stored within the vehicle for more than 3 minutes. The metric for comparison will include passenger, luggage and cargo ton-miles over the entirety of the year 2020 as published in standard industry surveys.

For those of you who don't know how fast Mach 6 is (3, Informative)

viking099 (70446) | more than 4 years ago | (#32362452)

From Wiki Answers [answers.com] :

Mach is a relative measurment of speed and fluid temperature.
example;
Mach 1 at Sealevel (0 feet) is 761.2 MPH (Calibrated Airspeed) and 761.2 MPH(True Airspeed)
Mach 1 at FL50 (Flight Level 50,000) is 285.8 MPH(CAS) and 660.05 MPH(TAS)
Mach 6 at Sealevel (0 feet) is 4567.3 MPH(CAS and 4567.3 MPH(TAS)
Mach 6 at FL50 (Flight Level 50,000) is 3147.97 MPH(CAS) and 3960.31 MPH(TAS)

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 (5, Interesting)

vlueboy (1799360) | more than 4 years ago | (#32362826)

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 (1, Funny)

Anonymous Coward | more than 4 years ago | (#32363148)

...and Mac 7 gave us the integrated Multifinder [wikipedia.org] .

Waverider (4, Informative)

Jeng (926980) | more than 4 years ago | (#32362456)

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 (5, Informative)

bcmm (768152) | more than 4 years ago | (#32362854)

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?

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.

That's almost as fast as... (3, Funny)

GeekZilla (398185) | more than 4 years ago | (#32362466)

...how quickly my home declined in value in 2008 and 2009!

Still a long way to orbit (3, Informative)

Baldrson (78598) | more than 4 years ago | (#32362476)

Mach 6 is still a long way from Mach 22. Mach 22 is orbital velocity.

Re:Still a long way to orbit (5, Informative)

sanosuke001 (640243) | more than 4 years ago | (#32362608)

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.

Re:Still a long way to orbit (1)

Baldrson (78598) | more than 4 years ago | (#32362686)

Boy, ya learn something every day, don'cha?

Re:Still a long way to orbit (1)

beelsebob (529313) | more than 4 years ago | (#32362794)

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.

Re:Still a long way to orbit (1)

Lumpy (12016) | more than 4 years ago | (#32362992)

You just gotta keep pushing down on the stick..

Re:Still a long way to orbit (1)

Waffle Iron (339739) | more than 4 years ago | (#32362896)

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. (And you need to first reach supersonic speeds by yet some other means before you can even switch them on.) Reaching Mach 6 with an ordinary booster rocket stage is child's play in comparison.

Re:Still a long way to orbit (2, Funny)

Idiomatick (976696) | more than 4 years ago | (#32363180)

Because in space no one hears you zoom pass them in your badass scramjet missile?

Re:Still a long way to orbit (1)

batistuta (1794636) | more than 4 years ago | (#32362616)

orbital velocity of what?

2025 (1)

Baldrson (78598) | more than 4 years ago | (#32362720)

The orbital velocity of the year 2025, what else?

Re:Still a long way to orbit (2, Funny)

GeekZilla (398185) | more than 4 years ago | (#32362916)

An unladen African Swallow?

Re:Still a long way to orbit (0)

Anonymous Coward | more than 4 years ago | (#32362832)

You can't really use Mach as a unit for orbital speed. The speed of sound varies depending on the medium it's traveling through.

It also depends on the altitude of the orbit. For Low Earth Orbit (LEO) you're looking at 6.9 - 7.8 km/s (using the wiki numbers here). That's 15435 - 17448 mph. If you felt the need to convert it to mach number, that would be mach 20-23, through air, at 20 degrees Celsius.

However, I don't think orbit is what they're looking to achieve (regardless of the article). More likely these engines would be developed for surveillance or weapons. In which case, they don't need orbit. They just need to get way up high and do it very fast.

Mach 5 - Not Mach 6 (5, Informative)

Maddog Batty (112434) | more than 4 years ago | (#32362482)

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... (1)

metamechanical (545566) | more than 4 years ago | (#32362486)

Mach 6 is a little over 2 km/s, for 200 seconds, is 400 km... so in 3 minutes and 20 seconds, the plane just about crossed over the equivalent of Pennsylvania, from east to west.

Re:200 seconds at Mach 6... (1)

joggle (594025) | more than 4 years ago | (#32362578)

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.

Re:200 seconds at Mach 6... (1)

groovelator (994174) | more than 4 years ago | (#32362742)

How many football pitches is that?

Jet - Scramjet - And Questions! (4, Interesting)

Anonymous Coward | more than 4 years ago | (#32362508)

  • Jet engines still have propellers to compress air, into which the propellant is injected where this mixture then ignites.
  • Scramjets just use their immense speeds to do the compression with a funnel, but that also means they need more conventional means to reach these high speeds (such as getting a ride on a B52 plus gravity)

Questions

  • What is the fuel efficiency per kilometer traveled?
  • Can a scramjet reach escape velocity, or get close enough so that additional oxygen for the fuel doesn't make up more than half the payload?
  • Did they find a new way to lose heat at supersonic speeds? Otherwise these rides will remain short ones.

orbital velocity (0)

Anonymous Coward | more than 4 years ago | (#32362846)

is anything greater than zero if you are propelling yourself

Re:orbital velocity (0)

Anonymous Coward | more than 4 years ago | (#32362982)

I meant escape velocity of course

Re:Jet - Scramjet - And Questions! (0)

Anonymous Coward | more than 4 years ago | (#32363136)

Can a scramjet reach escape velocity, or get close enough so that additional oxygen for the fuel doesn't make up more than half the payload?

No. More precisely, a (sc)ramjet cannot work outside of atmosphere because it uses atmospheric resistance to provide compression.

I really don't have anything else to say... (0, Offtopic)

f3rret (1776822) | more than 4 years ago | (#32362540)

I want one. Why? No reason other than the fact these sorts of things are pretty damn cool, even if they still kinda suck.

So (1)

drinkypoo (153816) | more than 4 years ago | (#32362650)

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.

Test Terminated ? (1)

willyg (159173) | more than 4 years ago | (#32362736)

O.K., and the test was terminated WHY?? Thermal issues? Ran out of fuel? Test Design limit? Or is it classified?

No, I DIDN'T RTFA. Hello, this is /. ...

ummm (1)

AnAdventurer (1548515) | more than 4 years ago | (#32363034)

I thought the unpublished speed of the SR-71 was around Mach 6? Supposedly my brother met a 71 pilot who said he could fly over LA-NYC in like 40 minutes (at alt and speed). I am not saying any of that is fact, just something I remember from 25 years ago (living near Hamilton AFB)
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