Mach 6 Test Aircraft Set For Trials 131
coondoggie writes "The aspiration that jets may someday fly at over six times the speed of sound took a very real step toward reality recently, as the US Air Force said it successfully married the test aircraft, known as the X-51A WaveRider, to a B-52 in preparation for a Dec. 2 flight test. The X-51A flight tests are intended to demonstrate that the engines can achieve their desired speed without disintegrating. While the X-51 looks like a large rocket now, its applications could change the way aircraft or spaceships are designed, fly into space, support reconnaissance missions and handle long-distance flight operations. At the heart of the test is the aircraft's air-breathing hypersonic scramjet system."
Hmmm... (Score:5, Insightful)
Engines reaching desired speed without disintegrating....thats a GOOD feature to have.
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Only if you want the chimp to survive. Some stories unfold when man and ape work in close quarters that just shouldn't be allowed to be told.
Rockets vs Scramjets (Score:5, Interesting)
Which costs more energy - carrying the extra O2, or overcoming the friction from having to accelerate in an atmosphere? Which imposes more design compromises?
Which would be more economical in the long run? Bear in mind that there are 2 kinds of people that need to achieve very high velocities -- astronauts trying to make orbit and intercontinental travelers trying to get to the other side of the world.
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Depends almost entirely on how fast you can get on scramjets. I don't think Mach six is enough to make it worth the bother. But I'm pretty sure Mach twelve would be enough to make it worthwhile.
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Seriously though, when you talk about economical - you have to ask how
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Isn't it all relative?
Compare a bus ticket, to a plane ticket, to a cruise ticket...
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It's worth remembering that Mach numbers are dependent on the current speed of sound.
If a scramjet can reach over 7 miles/second in the very upper stratosphere, then the scramjet would clearly win....at least if it didn't need the same G forces as the rocket. And particularly if it could carry a sizable cargo. (I.e., anything better than an Apollo capsule, but the larger the better.)
A scramjet might make an admirable second stage for a rocket, but then you need a first stage to get it up to speed. Note t
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Scramjets would be nice for a high speed reconaissance platform or bomber though.
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You fail. Current rocket designs use multiple stages to get into orbit, that means multiple engines, plus whatever the payload is it will have its own engine as well. The thing is that rockets are incredibly simple engines, they simply throw their mass away to achieve thrust, thus the amount of mass you can move is a function of the fuel you can carry and vice versa. With scramjets you can take mass from the atmosphere, raise its energy and then throw it away, thus a portion of your fuel is collected along
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Scramjets are useless for space vehicles.
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I wasn't claiming that scramjets are without problems, I merely pointed out that current rockets already have multiple engines, which you kind of claimed they do not.
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2x regular air-breathing jet engines for low altitude operations.
2x scramjets for high altitude operations.
1x Rocket booster to get into orbit.
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Erm... In the television series Star Trek they have matter/anti-matter reactors and warp drives capable of traveling faster than the speed of light.
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You start to answer your own question with the "two kinds of people" statement. Rocket supporters and scramjet supporters, whatever those are, might take up the cause of a particular vehicle. But the point is not to use a particular vehicle, it's to get something done using the most effective and efficient vehicle available.
You start with your goal, develop flight profiles for the available vehicles, add in ground support and maintenance costs, and calculate your costs/benefits.
There are more than "2 kinds
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Which costs more energy - carrying the extra O2, or overcoming the friction from having to accelerate in an atmosphere? Which imposes more design compromises?
Seems the best answer is likely somewhere between the two. I mean the idea behind scramjets is only to get you through part of the journey anyway. You'll still need a running start, and you'll still need to carry oxygen to get you up into space.
Which would be more economical in the long run? Bear in mind that there are 2 kinds of people that need to achieve very high velocities -- astronauts trying to make orbit and intercontinental travelers trying to get to the other side of the world.
What about people trying to get a few kilometers downrange and get blown to smithereens the other end? Missiles are people too, y'know.
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"Which would be more economical in the long run? Bear in mind that there are 2 kinds of people that need to achieve very high velocities -- astronauts trying to make orbit and intercontinental travelers trying to get to the other side of the world."
I would add, bombers getting to their target and home for dinner.
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Nice to be the test pilot. "Increase the speed to mach 6, we're just gonna check that the engines don't disintegrate."
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The biggest problem for general use is to achieve speeds above about Mach 3.5.
This was roughly the maximum speed for the SR-71 and the problem was the friction heat from the air. And the SR-71 had a hull of Titanium. The Concorde did achieve about Mach 2 and had a hull from Aluminum. So for commercial use it's probably not practical to exceed the speed of the Concorde. What has to be done for commercial use is to get a more economic version and a version that has a less annoying sound bang.
But there is a us
Titanium may well get cheaper (Score:5, Interesting)
Recent advances [technologyreview.com] in the production of titanium may bring this metal into wide use in airframes. And everything else.
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How much titanium is there, laying around, if the demand would suddenly start to rise?
How much of that titanium is locked up by China, who has seen for some time that strategic metals will become a growth limiter in the not-so-distant future?
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How much titanium is there, laying around, if the demand would suddenly start to rise?
How much of that titanium is locked up by China, who has seen for some time that strategic metals will become a growth limiter in the not-so-distant future?
A lot. It's pretty abundant, actually. It's just that with current processes, it's goddamn expensive to produce, uses large amounts of chlorine and energy, etc... That's the only practical reason for its rarity as a structural material.
AFAIK, China doesn't produce a sig
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I thought about white pigment a few minutes after posting.
As for China, I said "locking up", because they're investing heavily in Africa, for instance. The stuff they want may not be on their territory, but they're very present in places where those things are.
Now that I actually take a look, Titanium is 22 and Iron is 26, and the contentious Lanthanoids are 57-71. (No doubt higher stuff will be scarcer.)
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They're present alright, but even discounting the whole continent of Africa, there's almost cerianly enough to keep the rest of the free world humping along, elsewhere. Oil or copper will be much more immediately contentious of a resource, all other things considered.
When or if it becomes more economically viable (profitable), Ti mines will certainly start up.
Re:Titanium may well get cheaper (Score:4, Informative)
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Ti is the 9th most abundant element in the crust (7th most abundant metal).
The wiki page answers all your questions.
http://en.wikipedia.org/wiki/Titanium [wikipedia.org]
Ti is abundant enough that we use it in toothpaste and toilet cleaner; I don't think you need to worry about it going anywhere.
-b
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The issue is how do you turn titanium oxide into pure titanium. This process seems somewhat similar to the Fray-Farthing-Chen process. Then again I remember that used to be a hot topic at the time, but it never got to production.
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Kids these days. Back in my days ... never mind.
With lube strip (Score:5, Funny)
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Obligatory extrapolation [robwaller.org]
Re:With lube strip (Score:4, Funny)
Fuck everything, we're doing 10 blades.
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http://www.youtube.com/watch?v=4F7TMlrDXtw
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"the aircraft's air-breathing hypersonic scramjet" (Score:5, Funny)
WHOOOSH!
(ducks)
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Actually I've heard that they're supposed to be more resilient than jet engines, because they don't have all those tiny little rapidly-spinning compressor blades. The compression is accomplished just from the pressure of the incoming air, the shape of the scramjet, and the combustion of the fuel (and doesnt it combust due to the high pressure / hence heat?)
I dunno. I've not looked into them for a while now and I'm not an experimental-propulsion-systems-making-dude, so I may be a bit off, but it's my under
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Not for aircraft. (Score:3, Funny)
While the X-51 looks like a large rocket now, its applications could change the way aircraft or spaceships are designed, fly into space, support reconnaissance missions and handle long-distance flight operations.
The Concorde flew at 2.2 Mach and in order to achieve this, it ended up too expensive to create, manufacture and maintain. It would be awkward to see airlines adopt airplanes which are more expensive to fly than current models. The trend is towards less fuel usage, and cheaper flight, in fact, at the expense of speed at times. On the other hand I'm happy to see that US is working heavily on creating a replacement for F-22, an insanely expensive jet with a nearly 30 year history that was barely ever used for something at all, before being discontinued :P...
Re:Not for aircraft. (Score:4, Interesting)
When calling the Concorde (or any other aircraft) "too expensive to create, manufacture, and maintain." on needs to take into account the ticket price the market will bear.
Since the Concorde was not designed with a range suitable for flying the Pacific routes, it was forced to try to make up it's high costs on the much tighter margins of the Atlantic routes. Had it been able to fly the higher margin Pacific routes it is quite possible it would not have been too expensive to be sustainable - even at the same (or slightly higher) cost basis.
Re:Not for aircraft. (Score:5, Interesting)
The concorde was profitable in its last years (not extremely profitable, but it made money, which is more than most airlines can currently say).
In the end, its operators decided it wasn't worth maintaining/refurbishing the planes, scrapped the program, and wouldn't let competitors purchase the unused aircraft. Richard Branson allegedly made several serious offers for the planes, all of which were rejected. Numerous allegations have been made that the grounding of the Concorde fleet was a result of a conspiracy between Airbus and the airlines (unsubstantiated, but certainly plausible, especially in light of their refusal to sell the craft to other carriers at a time when the company was losing money)
In short, we got lazy and stupid.
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And on that issue - the market has spoken loudly and clearly. "It ain't worth it".
Yeah, I know the Concorde made a paper 'profit' towards the end - but the proof is in the amount of money the airlines were willing to spend to keep this 'profitable' airliner in operation, which coincidentally is equal to the number of Concorde's s
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I assume it was unintentional that you missed the rest of my post, but let's be clear - the Atlantic market has spoken, not the market as a whole.
The Concorde could not fly the profitable Pacific routes due to limited range, and it could not fly supersonic over mainland USA or Europe due to noise regulations. This greatly limited the market segment it participated in.
This need not be the case (well, the noise issue likely doe
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This need not be the case (well, the noise issue likely does) with a future supersonic passenger aircraft.
There is no regulation against flying supersonic over the continent. The regulations are for maximum decibel levels generated over populated areas. You can fly high enough that the pressure waves have dissipated by the time they hit the ground, although this has been found to have limited effect. You can design your fuselage and wing such that the pressure wave is spread out over a longer area, and directed laterally, so it never spikes above the limits. There is been a lot of work in that area over the
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I never suggested there was.
Which is what I said.
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I think you need to refine your stance. "The Market" has not spoken loudly and clearly; "A Market" at a specific place and time has spoken. Supersonic trans-atlantic flight has been shown, in hindsight, not to work in a very specific place and time in history. That's all. It has not proven that it can never be done.
Analyzing failures are helpful for gaining insight into processes, but the failure of one instance shouldn't be taken as a broad indication that the idea itself is a failure. It may simply be the
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Horseshit. If there was money to be made in it, they'd have still been in it.
Weight isn't the problem for supersonic aircraft - you could cut the w
Re:Not for aircraft. (Score:4, Funny)
It's no concorde (Score:3, Interesting)
It's no Concorde in any sense. The Concorde was created to make an efficient aircraft, not a fast one. This is the history I learned in college:
Jet engines are more economical the faster you get. Too bad the air friction (drag) gets worse the faster you get. For subsonic aircraft with single flow engines, the optimum lies just a bit below the speed of sound. As there were only single-flow jet engines at that time, the Concorde was created to try to shift the optimum to above the speed of sound. They succeed
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The f-22 didn't take much longer than other 5th generation aircraft. Oh wait, the F-22 is the ONLY 5th gen fighter in the world. And it only just went into service. And frankly, I don't want us to ever *need* it- Needing an f-22 would require an enemy with excellent air power, which would mean that we were fighting a major power such as china, india, or russia.
Do you complain that our nukes don't get used often enough?
-b
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Lets please try to remember that the Concorde was originally designed and built 40 years ago, That's -4-0- years. Despite the fact they obviously would have refined and upgraded wherever possiblle in those 40 years, it's still a 40 year old vehicle.
Please find for me, if you can, any other aircraft which first flew on or before 1969 which is still being used, profitably, for trans-continental passenger services today.
Technology marches on. Concorde being withdrawn from service after 27 years in action prove
.. and in further news... from 1967 (Score:1)
perhaps one of the tags should have been "been there, done that"
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nasa have already achieved mach 9.6. Mach 6 should be a walk in the park
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Real step? (Score:4, Insightful)
This is actually a bigger step towards making a mach 6 missile [popularmechanics.com] rather then a mach 6 plane....
Where's my credit card? (Score:1)
For some reason at first glance I read "Mach 6 Test Aircraft for sale" and I reached for my wallet...
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Of course you'll have to learn scottish to make some of the things work.
I have Tourette Syndrome. Does that count?
Cool but... (Score:3, Interesting)
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Nothing can happen to something that doesn't exist.
That's fine for the Air Force, but ... (Score:3, Insightful)
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I so wish I had mod points.
What's great is that, even given today's security measures, 9/11 would have still happened. Nothing that those terrorists did on 9/11 would have broken today's laws.
Re:That's fine for the Air Force, but ... (Score:5, Insightful)
Hmmm...I'm reading my post, and I don't mean to say that it would be great 9/11 would still happen. Don't get me wrong - 9/11 sucked and I would never want that to happen again. But, when I say "what's great" is the fact that nobody seemed to stop and think about how pointless many/most of the security measures actually are. (AKA, I was attempting sarcasm and it definitely did not come through...my apologies.)
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They didn't kick in the cockpit door. They killed a few passengers/cabin crew and the pilots let them in. SOP at the time was: cooperate. Let them hijack the plane. The worst that will happen is a trip to Havana.
Not any more. Cockpit door, box cutters or not, odds are that the passengers will kill the hijackers. All the pilots have to do is land the plane fast.
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Gat Marriage? (Score:1)
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Since most vehicles, including aircraft, are named after girls, would this be considered a gay marriage?
No. Apparently it's gat.
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Presumably gat marriage is the gangsta equivalent of the traditional shotgun wedding [wikipedia.org].
it sorta works...we have to admit to it (Score:3, Insightful)
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You didn't think the SR 71 wasn't replaced, did you ?
Um... Yeah, it was replaced... With *satellites*.
And just a word of wisdom from someone who works for 'the dark side': Supersonic aircraft are not stealthy--http://en.wikipedia.org/wiki/Sonic_boom [wikipedia.org]
http://www.pbs.org/wgbh/nova/xplanes/stea-flash.html [pbs.org]
-b
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Yes, but the problem with sats is that everyone knows when they go by. A fast plane is not predictable. Mach five with stealth, even minimal stealth, will be in and out before the enemy can do anything.
And miss most things of any tactical value in that time. There is a place for fast places, in strategic recon, which happens to be a lot harder to hide from satellites. We are going toward slower (I prefer the term lumbering) platforms with awesome endurance for tactical recon, staring is better than glimpsing in that case.
Mach 6 (Score:1)
Worthless (Score:2)
Scramjet tech is worthless. It's not a very good weapon - a scramjet is going to have one heck of a heat signature and probably can't be very stealthy. Not just from the exhaust...at Mach 6 the entire aircraft/missile is going to be glowing red from heat. Also, air to air missiles (like the Patriot) that use rockets already go that fast.
Second, it's worthless for getting stuff into orbit. The reason is simple - the reason a rocket costs so darn much has nothing to do with fuel. It has to do with comple
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You sound very sure. I'm curious, how would a Patriot (traveling at its top speed of Mach 5) overtake and intercept something traveling at the same (or greater) speed given that the latter has a rage of 600 nautical miles and the former has a range of 99 miles?
Are you sure that stealth is a priority given the X-51's intended mission [popularmechanics.com]?
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None of those have the range necessary to overtake something at that speed. These are all anti-ballistic missiles, and the X-51 isn't a ballistic missile. At best, one would need one of these near the target site in order to get lucky. Given the purpose of the X-51, this seems unlikely.
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All of that complexity in turn stems from the insanely high mass ratios that chemical rockets require to achieve orbital velocity (93.5% of the Shuttle's weight is fuel/tank/boosters). That, in turn, means the rocket itself must be made as lightly as possible; you cannot merely overen
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A rocket engine's most complex part is also the fuel pump... Unless you use pressure-fed engines, in which case you don't even need a pump at all!
You cannot reach space using just a scramjet anyway. You need rockets. There is no air in space.
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Obviously. But a rocket that only has to add that last third or fourth of orbital delta-v can be designed a lot more conservatively and carry a lot more payload (which means a lower cost per kg to orbit). This scramjet is maneuverable - it can stay in air to breathe for as long as it takes to accelerate, then it can let the upper rocket stage finish the job.
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Scramjet tech is worthless. It's not a very good weapon - a scramjet is going to have one heck of a heat signature and probably can't be very stealthy. Not just from the exhaust...at Mach 6 the entire aircraft/missile is going to be glowing red from heat. Also, air to air missiles (like the Patriot) that use rockets already go that fast.
It's a moot point. You can't intercept something that fast, even if it's easy to see. It's hard enough to intercept a missile that doesn't go that fast..
By the way, isn'
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The demon lived at Mach 6 on the meter... (Score:1)
I like this one better (Score:1)
The Falcon [wired.com] is a DARPA vehicle that looks a lot more practical.
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But will this development be recognized outside of states like California and Massachusetts?
Don't ask, don't tell.
Sigh (Score:1)
Now, were else will this lead? Almost certainly it will lead to a new military drone (
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The Composite LH2 WERE completed, tested and worked. Sadly, they were done AFTER the X-33 was canceled by the neo-cons. And obviously you knew little to nothing of the NASP.
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NASP was vapourware.