How We Might Have Scramjets Sooner than Expected 674
loralai writes "Recent breakthroughs in scramjet engines could mean two-hour flights from New York to Tokyo. This technology, decades in the making, could redefine our understanding of air travel and military encounters. 'To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines; the fastest fighter planes barely crack Mach 1.6. Scramjets, on the other hand, can theoretically fly as fast as Mach 15--nearly 10,000 mph.'"
Just need some Unobtainium (Score:3, Insightful)
Sure, the Space Shuttle is doing 16K mph on reentry, but no scramjet is going to get a plane built like that off the ground.
Sonic Boom - Bust (Score:3, Insightful)
Re:10000mph! (Score:5, Insightful)
Re:2 hours flight time, 10 hours airport time (Score:4, Insightful)
Current speeds grossly incorrect (Score:5, Insightful)
Keep in mind that the mach 1.6 speed quoted is generally tied to the F-16, not the F-15, even though both aircraft use essentially the same engines. The difference is that the F-15 uses a complex variable geometry inlet design while the F-16 uses a fixed inlet. There are very good reasons why each aircraft uses one design or the other, but it has nothing to do with the available technology. It has to do mostly with how much cost we are willing to put up with in order to get the plane to perform up to requirements. The F-15, as our primary air superiority fighter, needed to be able to go very fast yet retain good performance at all speeds and altitudes. So the cost and weight penalty of a complex inlet design was warranted. The F-16 on the other hand, was designed from the start to be a lower cost multi-role fighter, and the cost and weight associated with a variable inlet was not justified by the performance requirements for that aircraft's role.
A similar tradeoff was made with the B-1 design. One of the big differences between the original B-1A design and the production B-1B design was the elimination of the costly and complex engine inlets that were needed to make the B-1 a high supersonic design. The B-1B has much simpler inlets and is therefore speed restricted below the original design specs.
Again, this has nothing to do with the available technology. Rather, it's the result of the basic truism that any speed freak knows, even in automotive racing, that going faster costs more. Almost any design can be pushed to a higher speed, but it's going to cost you and at some point you're throwing a whole lot of money to get marginal speed increases.
The original post's point that we haven't seen a breakthrough in this area in a long time is valid, but anyone following hypersonic technology research knows that in the last few years there have been multiple programs flying actual demonstration hardware with some success. The progress is fairly slow in part because this is considered low priority research since there simply isn't much firm demand for faster air-breathing vehicles (expecially ones that burn petrochemicals and therefore create more pollution than slower, more mature, and more efficient designs) however the research continues in the face of the harsh fact that speed is expensive.
Re:SR-71 Blackbird (Score:4, Insightful)
And it was designed 50 years ago.
Re:Sonic Boom - Bust (Score:3, Insightful)
There was only ever really one overland route that could have demanded a Concorde service: New York to Los Angeles. Concorde was barred from this route ostensibly because of the noise, but the real reason was probably that it was foreign. If it had been a Boeing supersonic jet, I'm sure all Americans would have come out of their houses to listen proudly and patriotically to their sonic booms.
Since Concorde didn't have the range for the LA - Tokyo route, that left it flying from London and Paris to New York, and so it never really made its money back. Shame. Glorious machine - entirely ridiculous, but still...
Theoretically, not even close (Score:5, Insightful)
- A need to go that fast.
- An economic way to pay for it.
- A structure that can tolerate the heat.
- Engines that can run for a long time.
- A structure that can hold all the required fuel, and still have low drag.
As far as I know, if you want to go above Mach 2.X, you have to switch to titanium alloys as aluminum softens at about that amount of friction. Mucho $$$ and much bother in construction and maintenance.Also scramjet engines tend to burn out really quickly-- the temperatures you need in there are beyond the ability of most metals, at least for longevity.
There's a heck of a safety issue too-- scramjets can flame-out and are not easily restarted.
It's also a challenge to stuff as much fuel as you need into a low-drag airframe. You need long range as there's no point in short hops when it's going to take many kilomiles to get up to speed and altitude. But people don't like cramped cabins, so you need more fuel to allow a bigger fuselage.
Also it's going to be hard to find people willing to pay maybe 15 times the usual amount to get there a few hours faster.
Re:SR-71 Blackbird (Score:3, Insightful)
Re:SR-71 Blackbird (Score:5, Insightful)
If you haven't noticed (see NASA for an example) we seem to have lots of issues recreating proven technology from 50 years ago.
Re:SR-71 Blackbird (Score:3, Insightful)
According to the article, when you try to increase the speeds to full throttle, the heat involved in slowing the air down for ramming becomes too much and the plane disintegrates. The achievement, if they can do it, will be to stablilize the scramjet with the air rushing through it at full speeds and not blow out the flames with Mach 5 winds.
Re:Skyborne Catamaran (Score:5, Insightful)
My wife and I bought our first robot, a roomba naturally. We watched it intensely as it cleaned for the first hour. When it finished it docked itself to recharge. My wife then noted that there was still some fuzzies on the carpet and that it didn't seem to pick everything up. I told her that it would probably pick it up on its next run.
After a couple days of running the roomba when we would leave the house, the carpets suddenly are cleaner than they have ever been. So clean in fact that our allergies seem to have improved (probably placebo, but that roomba does pick up the dust).
I realized that our house cleaning robots don't work like the Jetsons led us to believe they would, where they clean the house 10 times faster; they in fact take 10 times as long. They are, however, 100 times more meticulous and therefore they clean the house 10 times as well. I think this is a paradigm shift.
Perhaps there is indeed similar benefits to be reaped from a similar shift in the transportation/aerospace sector.
Very thought-provoking.
Speed is unlikely to be used in air travel... (Score:3, Insightful)
Scramjets for air travel sound nice, but the economics most likely won't support it except perhaps as a Concord-like showpiece that is mostly irrelevant.
Re:SR-71 Blackbird (Score:5, Insightful)
Its the same reason that bullets have that crack that movie goers have come to believe is the sound of a "gun shot", when it is really the sound of a sonic boom from a minuscule object travelling between one and three times the speed of sound (called "sonic crack" in the gun culture in America, not sure what the Europeans call it, can't be much different.)
Thus, I doubt the engine can mitigate the fact that a huge volume of air is being compressed and moved at very high speeds. Sure, some will get sucked in, but the very principle of the angle of attack on a wing (wing shape, profile, etc) and of the fuselage will end up causing some sort of sonic boom. Sure, the engine in a ramjet or scramjet might suck in some air but that will not mitigate the fact that air is rushing around and "below" the plane, which part will be observable as sonic boom to the ground based observer. The compression shockwave is heard from below, but is also present in different degrees to all sides of the plane/projectile from all angles in which air is being compressed out of the way, or sucked in to fill in the vacuum created by the passage of the object.
Re:The nose melts ... (Score:5, Insightful)
Re:Current speeds grossly incorrect (Score:3, Insightful)
That was made abundantly clear by the commercial failure of the Concorde [wikipedia.org] by the beginning of the 21st century (the last flight was in 2003, but it would have failed much sooner if not for supplemental financial support by the French and British governments). There is simply not enough demand, at the high ticket prices necessitated by exorbitant fuel and maintenance costs, to justify the service. There was also the issue of sonic booms limiting supersonic flight to non-populated areas (i.e. over the oceans) which further limits the number of useful routes that can be flown by these types of planes. It may be the case that technology has lowered these costs somewhat in the years following the cancellation of Concorde service, but the costs of regular airline service are influenced by many of the same factors and will thus always be in competition with super sonic transport (SST) service.
expecially ones that burn petrochemicals and therefore create more pollution than slower, more mature, and more efficient designs
Nobody would say that the Concorde was an environmentally friendly aircraft, it was dirty as heck, but the operators didn't really care because there were little or no pollution regulations over international territory or even in national territory at that time and even if there were who would enforce them? The supporting governments were supporters of the program as well so even if there were regulations the Concorde probably had waivers. This was a case of negative externality but it didn't cost the airlines (British Airways and AirFrance) any more simply because the Concorde was a pollution source.
however the research continues in the face of the harsh fact that speed is expensive.
Mostly as part of basic or military research funded by the government, not private enterprise.
Re:SR-71 Blackbird (Score:5, Insightful)
What the hell are you saying? a new one wouldn't work? That makes no sense.
"Everything presently flying is 50 year old technology. "
No it is not. Jeez. Have you heard of Glass cockpits? Carbon alloys? Fiber optics? Better rubbers? more durable plastics? Improved wing design? What the hell do you fly in?
"Even the shuttle is just a complex bottle rocket. "
The rocket is the complex part. The shuttle is about 15% light today then it was at launch because the replacement parts are stronger and lighter.
"Our knowledge of propulsion and natural forces is extremely limited and progress is very slow. It that department, very little has changed over 100 years."
Ok, now I'm just thinking your sending this post from 1940. IT has slowed in the last 20 years, yes but only compared to the 'boom' of aeronautics from about 1950, to 1980. It is still increasing, and pretty fast as well.
"But personally I'm more interested in finding alternatives in the area of power plants for the vehicle where progress has been next to nil."
Power plants are a lot more efficient then they where 40 years ago. Now, there hasn't been a lot of effort to get them to run on magic pixie dust;which is what you seem to be wanting.
Re:SR-71 Blackbird (Score:3, Insightful)
I am sure there are quite a few people (corporate executives for example) who would be happy to pay more to slash journey times that much.
Re:SR-71 Blackbird (Score:5, Insightful)
All those things are simple improvements to *existing* design methodologies. Incremental improvements are not new technology. The parent is absolutely correct: the state of the art in airplane/engine/rocket design is 50 year old tech. 50 years ago, new designs were NEW. Brilliant ideas being formed in the golden age of flight. Todays tech is: lighter/stronger plastics, computer control systems, better more efficient wing designs, etc. Most of that is brought about by computer simulation technology and materials science, NOT aeronautics engineering. We are able to design better wings because fluid dynamics solvers are much faster and better than what they had many many years ago.
Now, is that because of lack of interest? Are new, revolutionary designs being hampered by external forces? I don't know, I doubt it, because there is still lots of research going on. Its just that we have finally reached the ability to realize many of the theoretical designs of 30-40-50 years ago. They are still 40 year old ideas.
But make no mistake about it: a modern airliner or fighter jet is simply using highly advanced versions of designs from decades past. Evolutionary tech, not revolutionary. The jet engine was a revolutionary design. A highly efficient modern jet engine is not. It is just a better version.
I don't think progress has stalled, its just in the refinement stage. Eventually new paradigms will be born and start entire new veins of refinement.
Re:Someone who always flew Concorde (Score:3, Insightful)
The super rich couldn't save the Concorde.
Dow might think twice about booking its senior execs on a plane that will be on the A-list of targets for every terrorist on earth. The next best thing to bringing down Air Force One.
Re:SR-71 Blackbird (Score:4, Insightful)
Still, it's a valid point that the US has lost a lot of the experienced engineers and managers from the height of the cold war to retirement, that aeronautics is not nearly as popular a choice for students as it was, and that, in many aspects, it is more difficult to design such things today.
Re:Skyborne Catamaran (Score:3, Insightful)
Re:SR-71 Blackbird (Score:5, Insightful)
You obviously have never been in any military (at least not in a civilized country). Fanatics are the idiots who want to die for their country. To paraphrase Patton, you don't win a war by dieing for your country. You win it by making the other poor dumb bastard die for his country. Fanatics make for a lot of uncontrollable soon to be dead people. This is the last thing you want in your military. People who make a game of it are likely to get both themselves and others killed playing rather than thinking and planning. Again, this is not what you want in your military. You want people who are thinking and planning for the best way to keep the most people on your side alive. You certainly don't want anyone thinking all those people dieing is a game.
Re:SR-71 Blackbird (Score:5, Insightful)
You obviously do not have an engineering background. What the parent post said is true. You need to keep in mind there is a lot more to building something than simply following a blueprint. While shocking today, construction methods were often undocumented. Minor changes to designs often were not drawn up.
Let me give you an example. Today, when a piston airplane is created, it takes 150%-250% more labor to build the same airplane than it did forty years ago. Why do you think that is? Because the people that had all the experience, long ago retired. When they retired, they took their experience with them. Many of the people that built those airplanes were the same ones that learned how to do it during war time, where every plane mattered.
Still don't believe me? Every year the military tests new equipment at environmental test ranges. And every year, lessons learned 50+ years ago must once again be hammered into the young brains making the new equipment.
Hear is another one for you. The B-2 flying wing bomber, after an independent redesign, almost exactly matches the original design and dimensions. Modern engineers scratch their in wonder as they find it incredible how much they got right on slide rulers; especially given how many years it took us to do what they did in half the time with slide rulers.
Believe it or not, even today, we are relearning the same old lessons and yes, still struggle to re-implement some 40-50 years latter. Still doubt me. Go read up on modern rocket engine designs. You'll notice ALL of the current rocket scientists complain about EVERYTHING I just pointed out above. The same old lessons are being relearned, most of the experience has retired, and the same old mistakes are being repeated. In other words, just because it's new doesn't mean it's improved. After all, how can it be improved if they are making the same mistakes which were already resolved 50 years ago?
Just some food for thought.
Re:SR-71 Blackbird (Score:2, Insightful)
You have to rememeber they were planning to compete with their TU-144.
However, despite having all the schematics, they were unable to reproduce the plane as their enginneer/workers did not have the know-how of their french and english peers.
They had to deviate substantially from the design, like adding canards control surfaces, and the structure integrity of the aircraft itself was way behing the Concorde's.
Re:SR-71 Blackbird (Score:3, Insightful)
I'm also confident that they could build those shoe-zappy thingies into the floor and save us at least that much trouble. I hate to be gratuitously cynical, but I have to wonder how much of this is just to be seen doing something security-ish.
Re:SR-71 Blackbird (Score:5, Insightful)
Hear is another one for you. The B-2 flying wing bomber, after an independent redesign, almost exactly matches the original design and dimensions. Modern engineers scratch their in wonder as they find it incredible how much they got right on slide rulers; especially given how many years it took us to do what they did in half the time with slide rulers.
Back in those days they picked a few with passion, practical knowledge and zeal for their jobs, isolated them in think tank labs devoid of suits and dead weight brass. They spent a lot more effort on small team management. If they needed something made, it was just made or farmed out to another small team of juniors. Very clear pecking orders and no juniors wagging the dog. They were focused on what mattered and the pride showed. Today it is just a herd of people most of which know squat about what they are doing but play good politics. Simply put, top heavy with too many incompetents.
Re:SR-71 Blackbird (Score:2, Insightful)
I would like to believe that even today potentially revolutionary research is being done and designs are being made. Some guy out there has probably already had an idea that will change the world, but the fact of the matter is we won't know this guy's name or hear of this technology until we realize 50 years from now how revolutionary that idea and initial research was. It will take time for that to make it out of the research labs and Skunkworks of the world and in to an average aircraft I can fly in. As someone else pointed out, people are already considering new paradigms - airships, anti-gravity, giant dragon powered crafts, what-have-you - and the truth is that half of that will probably be horrible ideas, but the ones that do survive and become commonplace in 2050 will be looked back as revolutionary. As the article points out, it took 40 years to go from concept to a usable jet engine. So I don't doubt that 20 years from now we will be looking at a new kind of propulsion system for aircraft that is even better than a jet.
Re:SR-71 Blackbird (Score:1, Insightful)
Most will say you've missed the point and I can't help but agree. The point is simple. Despite "modern" methods and various modernization efforts, some engineering tasks still take longer today than what was done yesterday. The point is not strictly about missing knowledge, which you seem to focus on it; while missing the point. Since you've missed the point, I'll bluntly state it. Just because it is built today doesn't mean it is engineered any better or built faster.
You example about cars continues to prove you miss the point. Cars today are not better because of better engineers. They are better because of billions of dollars in technological evolution, on which the current engineers are able to stand. And to boot, car engineering is hardly rocket science. Building planes is even easier but it's not had the billions of dollars thrown at it like the car industry has. As such, with the exception of Cessna, most planes are still hand built yet take significantly longer to build while construction methods are often simplified and refined.
Re:SR-71 Blackbird (Score:2, Insightful)
Re:Therein lies the actual problem (Score:3, Insightful)
Years ago I was visiting the family of a Chinese friend of mine, and his father somehow got on the topic of the WWII. He had been a refugee as boy in China, and had experienced first hand being bombed and strafed by the Japanese in a refugee column. He was still angry and bitter. When you compare his experience watching friends and family die to your experience at an airport, you demean him, you demean millions and millions of people.
Stop it.