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More On Silent Supersonic Planes
Reverberant writes "Popular Science describes the latest attempt at developing a supersonic plane designed to minimize sonic booms. The article describes some of the history behind the research, and recent attempts at validating the theory. Also note that researcher Ken Plotkin is a frequent contributer to alt.sci.physics.acoustics."
Where is that Hedgehog when you need him? Can't we tell him just to be quiet?
Friends help you move...
REAL Friends help you move dead bodies... ^_^
Conjugate much?
is it just me being paranoid, or is not having any windows and having cameras send external images to the cockpit a "bad thing." obviously, without computer systems, the planes are almost useless, but if anything happens to the camera, the pilot can't even *see* outside the plane.
BSD is for people who love UNIX. Linux is for those who hate Microsoft.
If it's been published on the prestigious trade journal 'alt.sci.physics.acoustics', it must be true!
Since when has this country used intellectual elite as a pejorative term?
Was so when the US bombs their next nation, they can catch them by surprise.
Pilots rely on more than just being able to see outside. They have literally dozens of instruments that they have to monitor in addition to the view outside. During the night and over the ocean, you have nothing but your insturments to rely on, so it's not like this is a new thing for pilots. Still, if it were ME I would want a window :)
As I grew up I watched so many programs like "Beyond 2000" on discovery channel and felt excited about being in the years beyond 2000. This is 2004 and none of the promises came true. We are at about the same level as we were in 1999 technologically. Or even worse as concorde is gone. Somebody, move us into the future!
If you lost your job today, don't despair. You may die tomorrow anyway.
"Popular Science." No such thing, man. More like, "nerdular nerdance."
--
If you don't get it, don't moderate!
Was so when the US bombs their next nation, they can catch them by surprise.
Sorry but we're ALL expecting it already.
The article has the date JULY 2004 on it. Because Companies send out magazines a month early. You receive the JULY edition in JUNE. I subscribe to Pop Sci...I read this article in June. Hardly News for Slashdot in August.
I think he enjoys flipping way too much.
if a plane breaks the sound barrier and no one is around to hear it, does it make a boom?
...can be found here.
Slashdot looked deep within my soul and assigned
me a number based on the order in which I joined
no kidding.
I happen to think that instruments are FAR more important and relavant and visual flying. Windows are nice for those clear, blue days, but what about when it's dark and rainy? No help there from the view!
Other conditions can contribute to being totally disoriented (like the cause of JFK Jr.'s crash). In his case, he wasn't authorized to fly at night due to the fact that he wasn't instrument-only rated.
"...Well, there's egg and bacon; egg sausage and bacon; egg and spam; egg bacon and spam; egg bacon sausage and spam..."
...they'll be halfway there.
Quoth the grammar-challenged poster: note that researcher Ken Plotkin is a frequent contributer to alt.sci.physics.acoustics.
One might also note that Leo Plotkin was the one who created alt.sex.bestiality.
Contributing to alt. newsgroups doesn't really mean that much, unless the newsgroup in question is alt.sysadmin.recovery.
We just need to tell Guile to lay off his Sonic Booms too.
As long as Chun-li keeps making those sexy noises when she fights, all the rest of them can be mutes for all I care!
I've never heard a sonic boom... so I'm not really sure how loud they are, but a co-worker described it as "pretty much sounds like thunder".
Is that really a big problem? It seems kind of dumb to me to ban supersonic flight over cities.
What the fuck kind of idiocy is this? First of all, we already have stealth technology so we're already catching our opponents by surprise. Second, sonic booms are detected AFTER the aircraft flies overhead -- not before! The whole phenomenon of a sonic boom is that the aircraft is racing ahead of the "information" of its arrival (in the form of sound waves).
I'm not saying that a sonic-boom-free aircraft is of no military use. The shockwaves responsible for sonic booms cause drag to increase signficantly, thus requiring much more fuel. But the motivation certainly isn't one of trying to catch someone off guard.
GMD
watch this
That's very interesting, but would not it make more sense to make the normal, subsonic planes more silent? They are much more in use, and the noise causes a lot of grief near airports, especially at night. Here in Brussels, this problem is already for years on the political agenda, being a very difficult problem to solve (economics vs. health...), so silent planes are really a must!
16?
Get a grip on reality, buddy. It'll do you some good, mmkay? Being such a liberal douche as yourself does no one any good.
I've never heard a sonic boom... so I'm not really sure how loud they are, but a co-worker described it as "pretty much sounds like thunder".
EVERYONE has heard a sonic boom at one point: the crack of a whip. That sound you hear is not the tip of the whip hitting anything. It's the sound of the tip accelerating beyond the speed of sound and creating a mini-sonic boom. That little flick at the end causes the tip to snap out at incredible speed.
Now as far as a big sonic boom, I haven't heard one either. I'm sure there are some pretty strict regulations about not creating sonic booms in civilian areas.
GMD
watch this
I am almost certain that people wont want it flying over their neighborhoods. I can remember watching a show about all of the hubub people made about the Concord landing at their local airport. You would have thought the world was going to end!
Then, once they heard the landing (which wasn't any louder than a regular plane landing), they went back to their caves and silently watched the news for another issue to get their panties in a bunch about. *sigh*
It seems that they are doing this using the traditional method of changing the shape of the aircraft. What about more novel methods such as striation, the same way tha dolphins achieve much higher efficiency than their shape would suggest. I'm surprised I never hear about this being applied to aircraft because it seems like such a simple thing to do.
Or an interesting method I heard about involving many tiny flaps on the surface which can dynamically shape the airflow to minimize turbulence?
"The Bureau of Land Management's instructions were strict: Startling the endangered animal could threaten its life."
So now we are more worried about not scarying a bunch of silly animals than we are successfully completing an experiment?
"Aerospace engineer David Graham and his three colleagues had a deadline.....It was 15 long minutes before the beast waddled on its way. "
4 engineers times 15 minutes seems a bit expensive to waste so they don't "frighten" a tortois.
One f4 or tornado (dont remember which) pilot went a BIT to fast at 35000 feet, he didnt actually fly over my city, so the actuall distace was 20-30 km (my room-plane).
It sounded like an bomb explosion a few 100m away. No high pitch noises, but a solid "whooop" that made me check if any window had cracks. In fact the window need my desk vibrated visibly. Even through the windows it could be felt in the belly like an effect in a thx theatre.
To make it short, its not a sound, its more like a shockwave. Being closer than 1 or 2 km to the plane will not only blast away all windows, but even crack some walls.
S
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
How much did the modified aircraft mitigate the boom? What is theoretically possible? What seems technically feasible based on current design limitations? Really...why couldn't they have straight-out addressed these simple items: the Bottom Line?
doom 3 owns your soul.
...if the cliff is short he won't fall very far...
Call me a dirty pinko hippie, but how is this fun for geeks? How will this help mankind? This is just another piece in the war machine puzzle that really won't do anyone any good. What we should try to do with the defense money is research that would benefit mankind, like medical research and things like that. It worked for ARPA.
I do not intend to celebrate that the US war machine just got one notch more deadly, and is estimated to kill up to 20% more people.
This won't solve anything. This won't make anything better for anyone.
toresbe
so they finaly resolved the secret of those nazi ufos? was about time!
The research airplane in this experiment failed to reduce the sound of the sonic boom as much as hoped.
In fact, this research is primarily intended for the next generation business jets , not the military. The future of such planes is up in the air in the moment, because not only do they have to reduce the wake of sonic booms (they shatter windows and suprise people), the regulations have to change. I for one know that the FAA is slow at that.
Regarding the need for windows in airliners: A Boeing 777 pilot today needs to be able to see a few hundred feet ahead of him on takeoff, but after rotating off the runway, he doesn't need to see anything at all. Modern airliners can land and auto-flare... that is, land themselves in ZERO visibility conditions. The pilots undergo extra training for this, of course.
FAA Certified Flight Instructor
Actually, on a serious note, I got pretty frustrated with the article. Actually, I only read the first page and then got bored. I'll never understand why science writers always clutter up their articles with crap like that turtle in the story. We want to read about advanced aerodynamics, not wildlife. Then they go on and on talking in detail about the test. Just tell us what happened at the test; we don't need a blow-by-blow account.
Extra clutter like that really makes the article seem amateurish. You have to be really damn interested in the topic to wade through all that extraneous crap at the beginning of the article no less! Maybe they think they are humanizing the dry science. But do you think people who buy a magazine that has Science in the title really find science boring? Or that they need this high-school-like prose at the beginning?
And don't even get me started on when an article tries to make an analogy with something real-life. I read an article in Scientific American some years ago that was using the swordfight between Zhang Ziyi and Michelle Yeoh in Crouching Tiger, Hidden Dragon as an example of how the new technology can better the "old standbys". The whole point of that scene was that Yeoh could have killed Ziyi even with that fancy Green Destiny in her hands. What a terrible analogy! And this is the way you start off a science article?
Sorry, just had to rant,
GMD
watch this
With half the world not having access to clean water or sufficient food and 20% of Africans infected with AIDS, it's reassuring to see the crying need for CEOs to save a couple of hours getting in and out of Vegas from JFK for some top class whoring and cocaine snorting is not being forgotten.
Just what is happening to this country?
Seriously confortable aircraft like airbus A380 (flash required) is a better choice on my humble opinion.
Yes. (note the period at the end of the fragment, noting that there is nothing more to discuss about this tried, cliched, and anything-but-philosophical joke of a question)
a sonic "boom" isn't a one time event. The shockwave is continuous, so long as the aircraft is flying at supersonic speeds. Therefore, people on the ground for the entire flight corridor will hear/feel the boom as the plane flies overhead.
In fact, no kidding the people at the airport the plane lands at dont hear a boom! Obviously, the plane slows down to subsonic speeds prior to landing. But for everyone in between the takeoff and landing airport that the plane flies over, will be subjected to it.
Hence the reason the concorde was banned from flying over the US, but landing on coastal airports isnt a big deal.
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This is off-topic, but am I the only one who found the thread on alt.sci.physics bizarre and vaguely reminiscent of a Gary Larson cartoon?
One common argument used by sceptics is that many UFO reports are not credible because they describe supersonic movement with no sonic boom.
My counter-argument was to imagine a craft designed as a rapidly spinning disk which could absorb air molecules on its leading half (perhaps using some form of nanotech) and then expell the molecules from its trailing half. As it isn't displacing the air, it generates no shockwave and no sonic boom. And if it expelled the molecules at a greater velocity than at which it absorbed them, it would not only suffer no drag, but would generate extra thrust.
By pure coincidence, many reports of UFOs are of rapidly spinning disks.
While the Thuds and Blue Angels occassionally break a few windows on Front St, they don't break the sound barrier. The shockwave you speak of is probably condensation that's often formed by pockets of low pressure created by the plane in humid air. Very cool, but not directly related to sonic booms. As for the noise, notice those engines don't have mufflers. ;)
One would have thought the implied joke was the obvious part.
Well, many of them.
Those aren't really the same though. Same principle, but the effect is much smaller.
I heard my first real plane sonic booms when I heard SpaceShip One break the sound barrier returning from space. It had a quiet sonic boom. It had a double boom actually because the boom echoed off the nearby mountains.
You're all missing the point. Sonic booms essentially aren't allowed over residential areas. They are limited in there use everywhere else, because of damage to animals.
As long as this is true, we will never see a supersonic commercial flight become commonplace. That's why this is important.
Well, hopefully, since it will be invented by the yankees (unlike the Concorde), the technology will not be sunk down...
...is nothing new. The Tridents, BAC 1-11s and VC10s (all British!) of the early 1960s had it. Don't try and pretend Boeing invented everything - they are the Microsoft of the skies - not much invented here....
Sometimes my farts are like sonic booms, and other times they are super-silent but deadly...
I may be incorrect about this, but I seem to recall that the mathematician Paul Garabedian independently developed the mathematical theory for shockless supersonic flight at the same time that people in AE developed a theory. The Popular Science article does not mention Garabedian.
The review by N. Geffen of "Analysis of Transonic Airfoils", Comm. Pure Appl. Math. 24 (1971), 841--851 by Garabedian, P. R.; Korn, D. G.
"Calculation of inviscid, subsonic-supercritical flow around prescribed airfoils is described. This supplements the authors' previous design of a shockless transonic wing using real and complex characteristics in the hodograph plane. The flow about the designed wing is calculated for a range of off-design conditions.
"Neumann's problem for the flow-potential equation is solved numerically in a plane where the exterior of the airfoil is conformally (also numerically) mapped onto the interior of the unit circle. Following E. M. Murman and J. D. Cole [AIAA J. 9 (1971), 114--121], a second-order finite-difference scheme is used in the subsonic region, while an implicit second-order scheme is used in the hyperbolic zone, introducing artificial viscosity of the right sign. The Kutta condition is satisfied by an iterative scheme. Results with relatively narrow shocks (i.e., steep gradients) are given and compared with wind-tunnel experiments."
I used to live directly under the Concorde's flight path a little west of Heathrow. Yes, it was loud. But, I'd trade loud for cheap seats any time.
BTW, the loudest aircraft I've heard is a water-injected C-141 taking off about 3 miles away. Most have been painful for the crew.
-- Slashdot: When Public Access TV Says "No"
I've never heard a whip crack- but up here at the lake we used to hear sonic booms from SR71s about one day every 4 months or so. One boom was strong enough to shake the spoon out of my Lucky Charms on a Sunday morning in our mobile home. (all those happy memories)
... they call it the "Dutch oven" effect.
It's great for greedy fat ass CEO, *cough* Enron *cough* type wankers for whom a "night out" means spending more of somebody elses money than the average Joe earns in a lifetime.
Whole thing will be illegal anyway. All I'd need to do is buy one of these 100 million dollar fuckers, taxi it over to the nearest cinema, poke the nose-cone in through the emergency exit and who-ho I've got myself a device capable of being used for the illegal duplication of copyrighted materials
I've never heard a sonic boom... so I'm not really sure how loud they are, but a co-worker described it as "pretty much sounds like thunder".
Is that really a big problem? It seems kind of dumb to me to ban supersonic flight over cities.
There are certainly very important military implications to being able to go supersonic without a boom. If you have a plane capable of going supersonic, but is indistinguishable from noise on radar thanks to stealth technology, a sonic boom is one thing that could give you away in enemy territory. If you can't be heard on the ground, or easily seen on radar, that makes your mission that much easier.
A lot of rookies think they're better at IFR (Instrument Flight Rules) than they really are. They fixate too much on a single dial or meter, and end up augering in (with perhaps perfect speed) in a sim. Skilled IFR is mostly actually flying by the seat of one's pants; looking at all those instruments eventually gives a pilot an almost intuitive knowledge of how the aircraft behaves. He need only glance down a few times per several seconds to have a fair idea of what the plane's doing, using his experience to connect the pieces of data.
If, a few years from now, a new jet is produced that produces an insignificant sonic boom, and flights between non-US cities are successful, you can bet some billionaire somewhere will pay enough money to someone in the right position to amend the law so they can get where they need to be when they want to be there.
Get rid of everything Micro and Soft: Buy Viagra and/or Linux
Don't be alarmed... MY ASS!
If you watch cable TV shows much, no doubt you've seen your share of close-calls in airplanes.
Yes, there are plenty of occasions where all the instruments fail, the power goes out, the hydraulics go out, etc. People still survive because, despite the high-tech systems, there is still JUST ENOUGH under manual control that a very good pilot in decent weather can land such a crippled plane.
Good luck doing that when they can't even see! And don't bother telling me that they're going to have multiple cameras, with backup systems and all that, I've already heard of plenty of cases where all 3 computer systems on 747s have failed. That's not one case, but MANY independant cases.
As you can probably assume, I'm not afraid of technology in the slightest. However, I do know that even the most advanced and well-tested technology in the real world can fail. If you aren't willing to trust electronic voting machines, are you really ready to give technology 100% control over matters of life and death?
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Actually, jet engine manufacturers have done a very commendable job reducing engine noise, thanks to high-bypass turbofan engines that use mostly the front fan to generate thrust and the use of acoustically-treated and tuned jet engine nacelles.
A less-known problem is that of the noise rushing around the airframe at flight speeds, which can also generate a lot of noise that could be heard from the ground. Fortunately, modern computational fluid dynamic research has reduced this problem, even on the upcoming Airbus A380 super jumbo airliner.
And note that this boom-diffuser approach increases drag, which means more fuel consumption. As a rule of thumb, supersonic flight uses 3x as much fuel per unit distance as subsonic flight already. This is worse. And it still produces an 0.5psi overpressure, which is above what the FAA allows now.
It can probably be made to work, but as a commercial product, it seems marginal.
Remember, this comes out of your pension fund.
I have this feeling that with Northrop's validation of the research that shows reshaping a plane's profile CAN dramatically reduce the effects of the sonic boom, Boeing may be seriously looking at the possibility of a supersonic airliner again.
Imagine something derived from the shelved Sonic Cruiser design, but carefully shaped to eliminate the pressure wave buildup that causes the sonic boom in the first place. The result could be a Mach 1.7 airliner that could:
1. Fly at 55,000 feet with just about no sonic booms audiable to observers below on the flight path.
2. Fly at least 6,500 to 7,000 nautical miles nonstop.
3. Carry around 200 passengers in two-class seating.
4. Be able use make extensive use of composite materials because at Mach 1.7 the heating effects of supersonic flight will be less than that Mach 2.0 speed of Concorde. This means lower weight for the whole airframe itself.
5. Use variable-cycle engines that will allow the plane to meet today's stringent jet engine noise and exhaust emission standards on takeoff and landing but still allow for efficient supersonic cruise.
If you look at the Sonic Cruiser design, it appears that Boeing has some ideas already in place about reducing that pressure wave buildup to start with. Why not take those concepts and build a truly "green" SST that could carry twice the number of passengers as the Concorde and be able to fly most transpacific routes nonstop?
Concorde did use a/b to get through the transonic drag bump, but as you say, it did not need a/b to cruise at M2
I don't think fuel cost was the real killer, Concorde used about 1 tonne of fuel per passenger, so (say) $500 of fuel for a ticket that was probably around $4000, one way.
If a tortoise is scared in the desert and no-one sees, does it still die of shock???
Then you are lucky enough not to have seen the crap that is the trailer for catwoman
Now if they could find a way to mitigate the booms from the lowriders playing their loud music! THAT would be practical!
Visualize Whirled Peas
So if we know what the women's magazines are, what are the men's magazines? I suppose the feminists would snarl "Playboy", but which men above the age of say, 15, have any interest in that.
No, the men's magazines are PS/PM, and the men's magazine all time was the issue with the cover story "We Fly the B-2 Stealth Bomber." Every man wants to know! (By the way, it is side-stick controlled fly-by-wire with computer-generated control laws, and it handles pretty much like the Airbus A320 jet airliner, should that give you any basis for comparison.)
FYI: USAF F-15's when they are put back together after periodic depot maintenance, have to be tested before they are sent back to their home unit. Pre- 9/11 this was done off of the coast of Georgia. They run them as fast as they can go.
Post 9/11 due to fears of Norad having to figure out what the heck a jet is inbound off of the coast of Georgia( a newly rebuilt F-15 that might have a faulty radio could be a problem,) The F-15s now do their testing over middle Georgia ( near Macon ). Sonic booms can be loud. They shake the roof of some buildings pretty good. Never heard of any broken glass because of ( altitude of the test ? ) To me they sound more like a man made explosion ( like from an artillery piece or aerial bomb ) than the sound of thunder.
But they would still need to be able to see the runway to land. They can't just rely on their instruments to tell them within a few feet where they and the runway is.
You don't always need to see the runway to land. Not if your aircraft is equipped with a radar altimeter and an "autoland" autopilot that handles everything from short final through the flare and touchdown, plus braking and applying the thrust reversers on the engines.
Now once the aircraft is slowed to taxi speed, then it sure would be nice to see where to turn off at the taxiway. I don't of any autopilot systems that are made for ground operations, but I guess you could make one with a GPS system, or have somebody sitting in a control tower with visual oversight steer the thing like a big R/C toy.
Not to mention, you can't stick your arm out the window when you're cruisin'.
Try that at supersonic speeds and it'll rip yer fool arm off!!!!!
.. like on my dad's '67 Chevy. It really does make a difference!
Not having Windows in an airplane is a very good
thing.
Would *you* fly a plane controlled by that OS???
Come on now.