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
University of Queensland researchers today (August 16) claimed success for the world`s first flight test of supersonic combustion, the process used in an air-breathing supersonic ramjet engine, known as a scramjet.
h p
"Our honest understanding from preliminary data is that the experiment worked," said international HyShot(TM) program leader Dr Allan Paull, of UQ's Centre for Hypersonics.
"We received data for the full length of the 10-minute flight. All indications are that supersonic combustion occurred. We'll now be submitting the results to international peer review."
On July 30 a safe and successful launch of a Terrier Orion Mk 70 rocket containing a scramjet payload was held at Department of Defence's Woomera Instrumented Range, 500km north of Adelaide, in the South Australian desert.
The aim of the HyShot(TM) program is to provide the world's first in-flight tests of scramjet technology, validating experiments held in ground test facilities.
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.
University of Queensland Vice-Chancellor Professor John Hay congratulated the international HyShot(TM) team on its success, which he said put Australia at the forefront of this new technology and enhanced the country's international prestige in space research.
"It's a magnificent example of international collaboration, involving researchers from Australia, the United States, Britain, France, Germany, Korea and Japan," he said.
Professor Hay is chair of the Group of Eight, Australia's leading research-intensive universities which produce the majority of Australian scientific research.
"Australia has proved we can develop this technology at a fraction of the cost of overseas programs. We must now build on success and secure the program in Australia so the intellectual property is not lost to the country. The danger is that the program could move offshore.
"Dr Paull has received approaches from top Australian researchers based in NASA, Boeing and other organizations keen to return to Australia to work on the HyShot program if suitable funding is available."
Professor Hay said these researchers were trained at UQ's Centre for Hypersonics, which is directed by Professor Richard Morgan. This is the largest group of hypersonics researchers in Australia and the largest University-based hypersonics group in the world, with some of the world's most advanced equipment for simulating velocities of eight times the speed of sound to 50 times the speed of sound, the speeds experienced by reentry vehicles such as space shuttles and after interplanetary missions.
"HyShot(TM) provides a significant opportunity for Australia to reverse the brain drain," Professor Hay said.
Dr Paull said he was negotiating with various groups to conduct an extensive, ongoing and advanced $50 million program of six flights over five years, leading to a free flying scramjet engine. The program would provide information to determine a cost effective launcher based in northern Australia to launch small, lightweight satellites.
"The program has generated lot of international interest," he said. "We currently don't have funding for future flights, but the Japanese, through NAL, have provided funding to build a new payload." Dr Paull will visit international collaborators in the next few weeks for talks on future flight programs.
The recent HyShot(TM) launch was designed to take the scramjet engine to a speed of Mach 7.6 (or more than seven times the speed of sound) for the experiment, using a Terrier Orion rocket. The rocket and payload reached an altitude of 314km before the rocket was configured to fly in a new trajectory pointing the payload back down to earth. The flight experiment took place within only the last few seconds of the flight, lasting almost 10 minutes.
After the Terrier booster had finished its work and subsequently fell 5km downrange, the Orion continued on with the scramjet payload and impacted some 370km downrange of the launch site, very close to the nominal impact point predicted by the scientists.
Radar and four sets of telemetry (radio) tracked the flight. One telemetry station was at Woomera Instrumented Range, while three telemetry officers were stationed at three points of a triangle more than 300km downrange in the middle of the desert. They not only captured the final seconds when the experiment occurred, but one site, to its credit, also captured all but the first 15 seconds of the flight.
Dr Paull said this was a "tremendous achievement."
"All those who were involved in producing this most exciting result are to be commended," he said.
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.
Dr Paull said everything appeared to have worked to plan, with only a minor glitch of a horizon sensor to turn the rocket failing half way through the flight, but a backup system had kicked in, using all their software capabilities.
Astrotech Space Operations senior engineer Dr Morgan Windsor said the job that so few with so little undertook was incredible and the fact that it worked was almost anti-climactic.
"Allan said a number of times that just getting the payload launched was a great success and indeed it was. But now that he has achieved combustion in flight this represents a huge accomplishment and a first internationally. I am so pleased that I had the opportunity this late in my career to support UQ, Allan and his team and have not sensed a greater feeling of accomplishment," Dr Windsor said.
Professor Hay and Dr Paull thanked all consortium partners and sponsors, in particular:
Astrotech Space Operations/DTI
QinetiQ
Defence Science and Technology Organisation (DSTO)
Defence Corporate Support
Aircraft Research and Development Unit, Australian Defence (ARDU)
the Australian Research Council
NASA Langley Research Center
NAL (National Aerospace Lab. Japan)
AFRL (Air Force Research Laboratory, USA)
DLR (German Aerospace Center)
Seoul National University
DISR
Australian Space Research Institute (ASRI)
BAE Systems Australia
Alesi Technologies
GASL
Aerospatiale Matra
NQEA
UniQuest
Institution of Engineers Australia (Queensland)
Jet Air Cargo
AECA
Luxfer Australia
Media contacts:
UQ Communications - Jan King, telephone 0413 601 248 or 07 3365 1120, Peter McCutcheon, telephone 07 3365 1088 or 0413 380012
Hyshot(TM) stories are available at www.uq.edu.au/hyshot. Photos, attributed to The University of Queensland (photographer Chris Stacey), can be downloaded from http://www.uq.edu.au/news/hyshot/hyshot-gallery.p
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
At a practical level, once you're travelling at 7.6 Mach, wouldn't you already be at your destination by then? Granted, it may be nice to circle the globe a couple of times effeciently (i.e. spy planes, etc) -- but for actual travel.. is the plan to try and get this effect to occur at a lower speed for it to be useful?
SELECT * FROM USERS WHERE A_WINNER = "YUO";
Scramjet success makes history
(subtitle:) University of Queensland researchers are celebrating the world's first successful test flight of an air-breathing hypersonic "scramjet" engine.
Data for last month's flight at Woomera in South Australia indicates the rocket achieved supersonic ignition in the atmosphere, a world first.
'Hyshot' project leader Allan Paull says the engine reached Mach 7.6, or 7.6 times the speed of sound during the test on July 30.
It has taken until now for the team to analyse the full flight data.
A speed of Mach 7.6 would allow airliners to travel from London to Sydney in two hours, compared to more than 20 now.
"We do believe we achieved supersonic flight for the first time," Mr Paull said.
The test over the central Australian desert was the first time engineers have made the supersonic scramjet engine work outside an air tunnel.
The team fired the scramjet engine into the sky on the back of a Terrier Orion Mk70 rocket, which took it into the upper atmosphere.
The engine kicked into action on the way back down at 35 kilometres above the earth, with data transmitted by radio until it began to burn up.
A year ago, the US space agency NASA's test of its multi-million dollar unmanned X-43A scramjet prototype failed.
A previous attempt by the HyShot crew went awry when a rocket used to launch the engine spun out of control.
Wow!
This must be twice better than Gillete Mach3 system !!
This is a question posed out of honest ignorance. How can they be unsure of their success? You can tell if the jet broke the sound barrier by the sonic boom, and if you know supersonic speeds were obtained, you know the jet's propulsion system worked. What is the uncertainty about?
"the engine achieved combustion in flight after reaching Mach 7.6. "
I'm quite sure I would combust as well when I'm going mach 7.6!!
"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)
1. You can get from England to Australia in two hours, but what about going to America. You'd be up there for all of like 5 minutes and pay millions of dollars to do it.
2. Military applications, huuuge negative. Yeah, we might be able to move people and equipment faster. But then again crazies in various countries will be able to lob things at us faster. The Star Wars program isn't really ready to stop this yet.
3. What do they feed you on these things, roasted peanuts or Tang?
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.
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
It doesn't matter as long as you don't accelerate too quickly, I guess.
Btw - did you know people raised the same point you just did about cars: "what? 60 km/h - no man can survive that!".
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.
what are military applications of this technology? when used in commercial flight (if it is possible) jobs will be lost and no more plane food and crappy movies!
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.
There's nothing physically stressfull about traveling at high speeds. The g force would only come into play when the plane changed speeds. This leads to the question of how long does it take to accelerate to Match 7.6? 7.6 G's would be bad for you, but a constant 1 G over a period of time would not. IIRC, a scramjet needs to be at very high speeds to work at all, so acceleration probably would pose a problem for commercial flights.
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;
Gs are NOT MACH NUMBERS!!!!! SPEED is NOT ACCELERATION! Please, people, buy a CLUE.
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.
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.
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.
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.
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?
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.
I throught the computer evolved and created the wings itself.
Only how to control muscle, most of us learn that in a couple months.
they mean 'supersonic combustion' - conventional jet engines have to slow the air down in order to ignite it. A scramjet does not.
Old joke. Sorry.
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?
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
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.
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.
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?
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
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
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
One quick thought - isn't 100,000ft high enough where radiation becomes a problem?
I read the whole article.. but it doesn't seem very interesting. Hooray for engines that need rockets to take off, go faster than is even useful, and destroy themselves after flight.
I can't wait 'til these hit the market, boy oh boy. How long has the Concorde been around? When was the last time you flew on it? That's what I thought.
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.
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"
.. 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
Admittedly, this isn't a perpetual motion machine, or that antigravity scam.
But a scramjet is simply a stupid idea. A vehicle using them would be *less* practical than a rocket, because it would weigh more, and it would be more complicated. And its shape would be heavily contrained, since the vehicle's shape contols the airflow to the scramjet intake. A rocket's shape is much less constrained, which is important because the designer also has to cope with heat shielding, and multiple constraints often mean a bad design.
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.