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MIT and NASA Designing Silent Aircraft

samzenpus posted more than 5 years ago | from the Fly-the-silent-skies dept.

Transportation 176

Iddo Genuth writes "Researchers at the Massachusetts Institute of Technology Department of Aeronautics and Astronautics recently won a contract from the National Aeronautics and Space Administration to design quieter, more energy efficient, and more environmentally friendly commercial airplanes. The two-million-dollar contract from NASA is just an initial step in bringing green technologies to the sky."

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It's called a balloon. (5, Funny)

Anonymous Coward | more than 5 years ago | (#25833689)

It's called a balloon.

Re:It's called a balloon. (4, Interesting)

VeNoM0619 (1058216) | more than 5 years ago | (#25833745)

Only 2 million...? For a new plane design?

Re:It's called a balloon. (5, Funny)

SimonTheSoundMan (1012395) | more than 5 years ago | (#25834361)

What I thought. My last university spent £2m getting one of the campus buildings into Second Life.

Re:It's called a balloon. (1)

Kagura (843695) | more than 5 years ago | (#25834783)

Just "more quiet" jets would be a godsend. I hate sitting in the back half of the cabin to the rear of the jet engines.

Re:It's called a balloon. (1, Funny)

Anonymous Coward | more than 5 years ago | (#25834193)

Snake Plisken called: He wants his glider back before the capsules lodged in his arteries explode and he'll be dead in ten or fifteen sec...(*strangle/choke*)

Re:It's called a balloon. (4, Funny)

Thanshin (1188877) | more than 5 years ago | (#25834223)

Or a slingshot.

Catapult?

Ballista?

Trebuchet?

Mankind can't consider itself advanced till we can send satellites to space using a trebuchet.

Re:It's called a balloon. (3, Insightful)

inviolet (797804) | more than 5 years ago | (#25835915)

Catapult?

Just so you know, 'catapult' is the category of all heavy leverage throwers. Onagers and trebuchets are catapults; slingshots are not; ballistas, being composed of two small opposing onagers, might be ("paracatapult"?).

Re:It's called a balloon. (2, Funny)

lawaetf1 (613291) | more than 5 years ago | (#25836285)

That'll do.. Can we resume our Magic game now please?

Re:It's called a balloon. (1)

SimonTheSoundMan (1012395) | more than 5 years ago | (#25834423)

MIT have experience with balloons from experimenting with them in the 1950/60's.

Reminds me of Walter Lewin.

Re:It's called a balloon. (1)

Deadstick (535032) | more than 5 years ago | (#25834741)

Certainly not a hot-air balloon...the noise from those can stampede horses.

rj

Re:It's called a balloon. (1)

osfancy (877444) | more than 5 years ago | (#25834761)

Or a large hang glider perhaps, but you heard it here first and I expect to be fully compensated if that is in fact what they end up developing.

Re:It's called a balloon. (2, Funny)

SkyDude (919251) | more than 5 years ago | (#25835067)

it's called The Hindenburg

Re:It's called a balloon. (2, Funny)

QuantumRiff (120817) | more than 5 years ago | (#25835637)

They've had this feature in black helicopters for over a decade. http://en.wikipedia.org/wiki/Black_helicopter [wikipedia.org] How else is the UN and the Federal government going to control every aspect of our lives?

First Pork (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#25833697)

fucken diddy-doughnuts.

Nice (1)

kingsteve612 (1241114) | more than 5 years ago | (#25833701)

MIT rocks. Very large brains coming out of that place.

So, you're saying... (5, Funny)

liquidMONKEY (749280) | more than 5 years ago | (#25833727)

These aircraft will be silent, but deadly?

Sorry, just had to sneak that in...

Re:So, you're saying... (4, Funny)

CRCulver (715279) | more than 5 years ago | (#25833827)

Yes, you'll know them by their vapour trails, but you won't hear them coming.

Re:So, you're saying... (2, Interesting)

Ethanol-fueled (1125189) | more than 5 years ago | (#25833883)

Don't expect your airport-side property values to rise just yet.

Despite strides in cleaner and quieter engine technology, there will still be many older planes flying without the retrofits.

Certain airports have restrictions on takeoff hours to quell the noise during bedtime hours but note that the same airports still must allow landings at all hours!

Re:So, you're saying... (1)

Remloc (1165839) | more than 5 years ago | (#25834157)

And the rub there also is a modern 7x7 aircraft in is much lower for most of its descent than it is for its takeoff....

Re:So, you're saying... (1)

fbjon (692006) | more than 5 years ago | (#25834315)

But the engines are quieter since they're at lower thrust while landing, since the plane is lighter and is only going down or level.

Re:So, you're saying... (1, Informative)

Anonymous Coward | more than 5 years ago | (#25834463)

Let me preface: I'm not an aeronautics scientists, I merely fly all the time (entertainment industry does that to you.)

Planes are much louder when they land, at least from the inside. Taking off you get the high pitch scream of the engine, which is loud and annoying. As you're landing, the wing flaps drop and you get not only the sound of the engine as it's trying to reverse (slow you down) but you get the loud rumbles of the drag on the wings that too is also trying to slow you down.

Again, no science here, just my observation (which is the start to all science...no?)

Re:So, you're saying... (1)

fbjon (692006) | more than 5 years ago | (#25836321)

The issue was airport-side properties. The thrust reversers will not deploy until the wheels have touched down, so they won't really affect anyone living nearby. The flaps and slats will make some noise, but I would guess the engines are still louder, even though they're at fairly low thrust, and even idle just before touchdown. The cabin is insulated, so a large part of internal noise is vibration of the airframe during landing. Outside noise is mostly wind (wing) and engine noise, however.

Land next to airports. (0)

Anonymous Coward | more than 5 years ago | (#25836301)

Anyone who buys land next to an existing airport has zero right to bitch about the aircraft noise. The airport was there first. This is exactly the same thing as someone who buys land downwind of a sewage treatment plant has no right to bitch about the smell.

Re:So, you're saying... (1)

GeneralSense (1410793) | more than 5 years ago | (#25833933)

Well aren't you a little stinker?

Re:So, you're saying... The victims need to be (1)

davidsyes (765062) | more than 5 years ago | (#25835381)

able to hear them coming.... Like, in California and Maryland:

Hybrids vs. pedestrians
http://latimesblogs.latimes.com/uptospeed/2008/08/hybrids-vs-pede.html [latimes.com]

Are Hybrid Cars A Danger To Pedestrians?
http://www.manufacturing.net/article.aspx?id=157148 [manufacturing.net]

These planes could be so quiet that foreign nations or even domestic animal rights groups might call for noise-makers to be added. Maybe those whistles for rural area dears might be affixed, but stronger so they don't fall off and kill people and animals and destroy property on the ground...

Re:So, you're saying... The victims need to be (1)

ultranova (717540) | more than 5 years ago | (#25835607)

These planes could be so quiet that foreign nations or even domestic animal rights groups might call for noise-makers to be added.

Yeah. Otherwise they could kill all those airborne pedestrians and moose.

The only flying animals of note are insects and birds. Birds tend to be on the lookout for things gliding towards them silently, since that is the predation tactic used by many birds of prey, and as for insects... well, I think I can sleep at night even if a few mosquitos get sucked in jet engines ;).

Engine maintance costs. (4, Insightful)

Zebadias (861722) | more than 5 years ago | (#25833779)

Enclosed engines? That is not going to be as easy to maintain as the 'drop off' ones that currently sit under the wing.

Silent... aircraft. Huh. (0)

ciaohound (118419) | more than 5 years ago | (#25833809)

Never saw that coming.

Re:Silent... aircraft. Huh. (2, Funny)

somersault (912633) | more than 5 years ago | (#25833935)

Didn't hear it coming neither!

Nobody ever thinks of us poor runway maintenance folk when designing their 400ton aircraft :(

Re:Silent... aircraft. Huh. (1)

ciaohound (118419) | more than 5 years ago | (#25834055)

Tell me if you can hear this: Whoosh!

Sorry, couldn't resist. I don't mean to be insensitive to workers' hearing loss or any other physical or psychological effects.

Re:Silent... aircraft. Huh. (3, Funny)

Amouth (879122) | more than 5 years ago | (#25834285)

wonder if CA will try to pass a law making these jets have a noise generator so that the blind can hear them coming (you know like their trying to do with eletric cars)

Re:Silent... aircraft. Huh. (3, Informative)

DragonWriter (970822) | more than 5 years ago | (#25835147)

wonder if CA will try to pass a law making these jets have a noise generator so that the blind can hear them coming (you know like their trying to do with eletric cars)

CA is not "trying" pass a law that would make electric cars have noise generators (it doesn't even makes sense to talk about a state "trying" to pass a law: an interest group might lobby a state for a law, but that's not the state trying anything.)

California rejected (the legislature passed and the governor, citing that the issue was appropriately handled at the federal level, vetoed) a bill that would create a study to committee to determine what the sound requirements were for the safety of the blind around quite vehicles and to investigate means of meeting those requirements.

Presumably, the findings on this could have been used in the future to support legislative proposals for requirements, if both sound types levels which provided notable safety benefits and reasonable means of meeting those were determined; they just as easily could have provided fuel to support the argument that the necessary sound levels would have other adverse effect, be unreasonably expensive, etc., against such a future proposal.

It's true that in many places, in the East Coast and in California, advocates for the blind have lobbied for requirements for noise generators (not just study of the issue), but that's very different from any particular state passing (or even "trying to pass") a law requiring that.

Re:Silent... aircraft. Huh. (4, Funny)

somersault (912633) | more than 5 years ago | (#25835357)

the governor, citing that the issue was of paramount import for stealth in the imminent rise of the machines, vetoed

There we go, fixed that for you.

Re:Silent... aircraft. Huh. (1)

kabocox (199019) | more than 5 years ago | (#25835975)

It's true that in many places, in the East Coast and in California, advocates for the blind have lobbied for requirements for noise generators (not just study of the issue), but that's very different from any particular state passing (or even "trying to pass") a law requiring that.

This reminds me of one of the first things that my mom taught me whenever I went into the front yard. Stay in the yard, don't go into the street, and if you ever need to actually cross the street look both ways first. Well, obviously blind people should never cross the street.

To flip this around. Why not make a law that requires blind people to hire a min wage worker to look both ways for them whenever they need to cross the street? Obviously that's a silly idea, but it would create lots of new jobs and it helps the disabled from killing themselves due to their disadvantages so it must be a somewhat decent idea.

Re:Silent... aircraft. Huh. (1)

ObsessiveMathsFreak (773371) | more than 5 years ago | (#25836089)

If you've ever had roll a car down an incline to start it, or have ever been startled by a cyclist coming up behind you, you'll understand exactly why cars NEED to be noisy. It's not a spurious thing, driver or no.

Modern cars are essentially completely silent when their engines are off. An extremely dangerous situation occurs when someone has forgotten to put up their handbrake and has left their car on even a slight incline. A rolling car with its engine off is a gliding metal girder of death, silent as it is deadly. You simply will not hear it, especially if there is other traffic noise. A car does not have to be traveling very fast to maim or kill pedestrians or indeed drivers of other cars in its path.

Without an aural warning, people will be killed by electric cars. A good example of the need for these warnings, actually comes from video games. Many enemies and bosses in 3D video games have "audio cues" which occur just before they attack or perform some other noteworthy action. This is so that the player has a chance to react, often to a threat which is "offscreen". Without these cues, enemies and bosses become much more difficult to cope with. Since in a city, most oncoming traffic is "offscreen" to pedestrians, they need audio cues. They're playing for real!

Re:Silent... aircraft. Huh. (2, Funny)

$RANDOMLUSER (804576) | more than 5 years ago | (#25834209)

Here's a picture [wikimedia.org] of the prototype [wikipedia.org] .

Been there, done that. (2, Funny)

Shadow Wrought (586631) | more than 5 years ago | (#25833811)

After all we've already had the "Whisper Jet." Of course anyone who's heard a 727 take-off knows that that is a relative term;-)

Re:Been there, done that. (2, Interesting)

WindBourne (631190) | more than 5 years ago | (#25835127)

hehehe. My dad was air force. Ever heard a b-47 with a JATO pac take off? Makes the 727 a whisper jet. Even the DC8's (which were much noisier than 727 or 707). What was cool was to see the practiced take off for a squadron. something like 10-15 seconds apart. pitch black. My understanding is that only the lead could see anything. If an accident occurred on take off, my understanding is that it would be SEVERAL aircrafts collosion before it was realized that a problem had occurred.

I understand the idea (1)

Thyamine (531612) | more than 5 years ago | (#25833899)

But it seems like this is something the military would have already spent time and money on. Or would it be that they don't care if you hear them, they just want the stealth to avoid being 'seen' by radar at longer distances (which makes sense).

Re:I understand the idea (1)

faffod (905810) | more than 5 years ago | (#25834341)

If you are traveling at super sonic speeds they can't hear you coming. The Military solved their problem domain a long time ago, but not in a way that is useful to civilians; dead targets don't complain about the shattered windows as much as civilians do (I know, I know... but shooting the civilians means that you don't have an economy to build newer planes...)

Re:I understand the idea (1)

Thyamine (531612) | more than 5 years ago | (#25834811)

I was thinking in more of a patrol fashion or no-fly zone where (I am guessing) they don't fly at supersonic speeds all the time. Where some guy can be sitting in a burned out building with a rocket launcher type weapon.

Re:I understand the idea (1)

compro01 (777531) | more than 5 years ago | (#25834989)

2 (B-2 and B-52) out of the USAF's 3 (other one is the B-1) active bombers are subsonic, as are all 3 dedicated ground-attack planes (Harrier, Thunderbolt II, and the AC-130).

Re:I understand the idea (2, Informative)

Warshadow (132109) | more than 5 years ago | (#25835145)

Have you ever been on the ground when a B-2 is flying over? It's insanely quiet even at low altitudes. It's accomplished via an insanely simple method too. The exhaust is vented on the top side of the plane, so it does not resonate downwards as much.

Re:I understand the idea (1)

CompMD (522020) | more than 5 years ago | (#25835889)

"Stealth" aircraft are quiet. I get buzzed by B2s rather frequently, since they are based only 90 miles from me. With four big, fully enclosed engines, the B2 is surprisingly quiet given how big it is.

Jet tehcnology can't do it ever (4, Informative)

erroneus (253617) | more than 5 years ago | (#25833917)

"Silent" is a relative term, but the presumption is one that has noise levels approaching that of an automobile.

That simply is never going to happen. Moving air around to create thrust will always be noisy. Even if all engine noises are reduced to zero, the vibrations of the air moving at the extreme speeds we would expect will cause more than enough noise. The only way I can imagine to combat that fact would be to distribute the effect over very large areas... and even then, as the size of the air moving system approaches "too big to be practical" it would still likely be way to noisy.

Helicopter style systems would be more of the same.

They are going to go back to Roswell and Area-51 and figure out how the aliens did anti-gravity so we can have aircraft that fly with less thrust requirement.

Re:Jet tehcnology can't do it ever (2, Funny)

jornak (1377831) | more than 5 years ago | (#25834013)

The truth is out there.

Re:Jet tehcnology can't do it ever (2, Insightful)

Sir_Lewk (967686) | more than 5 years ago | (#25834205)

And the problem with setting an unrealistic goal but still achieving *some* progress is what?

I can think how I'd do it. (2, Interesting)

MickLinux (579158) | more than 5 years ago | (#25834251)

I'd put many smaller, distributed brushless electric-motors all along the wing, especially towards the wingtips.

In order to help increase lift based on pressure (active pressure differences), I'd place the propeller centers below the wing, rather than above the wing.

To counteract some of the loss of lift from wingtip vortex pressure losses, I'd make the propellers spin with the bottoms moving towards the fusilage.

In order to reduce explosion risk, I'd use Lithium-ion phosphate batteries.

I'd probably also have to have a very long aspect ratio for the wing, so the plane wouldn't be flying all that fast.

But it could be done, and be economical (in terms of cost per flight hour, cost per mile) too. It wouldn't be economical for someone who wanted to go from here to there fast.

So if you were an automobile executive who wanted to declare that your company was about to go bankrupt unless you got a few spare billion (and then declare that bankruptcy is not an option if you don't get it), you'd have to use a lear jet instead, preferably retrofitted with a zillion pulse jets. But they make a tad more noise, and use a tad more fuel.

Different economic situations require different answers, I guess.

oh, and one other thing... vary the prop speeds.. (0)

Anonymous Coward | more than 5 years ago | (#25834355)

One other thing... I'd also have the propellers all turning at different frequencies, to help whiten what noise there was. Which means they'd all need to have variable pitch props. You don't want the chop-chop-chop of a helicopter.

Re:I can think how I'd do it. (2, Funny)

Conditioner (1405031) | more than 5 years ago | (#25834957)

This idea was invented by Shampoo.

Re:I can think how I'd do it. (1)

marcosdumay (620877) | more than 5 years ago | (#25835111)

Well, I'd do some similar things, but I'd insist on putting those properlers above the wings, maybe we are thinking on different properlers (different sizes), but as I see it, putting them under the wing would decrease lift. By the way, exept for under the wings, there is no place where one couldn't gain by putting a propeler.

Now, that would be a great design if it weren't for a few engineering troubles. The first, and most obvious one, is that big propelers are cheaper to produce, and, being noise an externality to the air-transport companies, there is no economic incentive to use them. That could be solved by the eletrical motors you propose, but then we get to the second problem...

Li-ion batteries have a quite low energy density, it is not merely lower than kerosene, it is at least one order of magnitude difference, and that is quite a problem to an equipement that is as sensible to weight as a plane. Hydrogen fuel-cells would solve that problem, if not by the fact that the containment and fuel-cell weight a lot, also, the cell needs to be kept wet what is hard to do at low tempereatures. I really doubt that with current technology one could build a viable passenger plane with eletrical motors.

Those wings would also be problematic. Yeah, long wings will make your plane fly using less energy, but will also cause a lot of problem while on land. Worse yet, those wings will increase the overall weight of the plaine, increasing the needed energy to put it on air, thus, increasing the noise problem. Also, they would complicate the taking-off manouvers, increasing the area where the noise is present and changing the area of procection around airports.

Anyway, those are theoreticaly good solutions. I'd recomend anybody that want to research the area, but wouldn't recomend somebody to invest on it with today's technology.

Oh, I almost also had to post a reply to myself :) I'd make those propelers run at exorbitantly hight frequencies. Since they are small, they can support it. Of course, you'd need a turbine designed for hight frequency, normal propelers wouldn't be efficient. Make the frequency bigger than 40kHz and the noise problem would go completely away!

Re:I can think how I'd do it. (1)

mccrew (62494) | more than 5 years ago | (#25835725)

In order to help increase lift based on pressure (active pressure differences), I'd place the propeller centers below the wing, rather than above the wing.

Could you explain this one? I would expect that you would have more lift by pushing the higher-speed air behind a propeller (higher speed = lower pressure by Bernoulli's equation) - one example of which was the Boeing YC-14 [wikipedia.org] .

I would expect that the only time you would have a lift benefit with the propeller centers below the wing would be when the aircraft is very close to the ground. Early versions of the 737 had problems with their thrust reversers because they were blowing too much air under the wing and it was difficult to get the aircraft to compress the landing gear enough to trigger the "squat switch" which allows the spoilers to deploy. That's why the thrust reverser blocker doors are canted at an odd angle on 737s, but now I am way off in the weeds.

Missing one little point... (1)

Firethorn (177587) | more than 5 years ago | (#25835783)

The single biggest problem I see with your idea is simple - the larger the propeller/fan, the more efficient it is at moving air. By the same token, the fewer blades the more efficient.

Secondary, even Lithium type batteries store a couple orders of magnitude less energy than hydrocarbons.

Personally, I'd like to see cross-country high speed passanger(and cargo) rail.

Re:Missing one little point... (1)

erroneus (253617) | more than 5 years ago | (#25836219)

That is by far the best solution to transportation across the CONUS. And at this point in time, it may be an excellent time to put that into motion. It has been Big Auto that has been keeping people-trasport off of trains for all this time. It may be the perfect time to strike since they are apparently floundering with no recovery plan other than to spend more money.

Re:Jet tehcnology can't do it ever (1)

Ofloo (1378781) | more than 5 years ago | (#25834309)

You just said that it was the moving air that created the sound, I don't see how anti-gravity is going to prevent this movement, but anyways.. I think the best way is to improve the aerodynamics of the plain so they will get less resistance and create less turbulence. Probably why NASA is involved, since they have a lot of experience with aerodynamics..

Wow dude, you just said never. (1, Interesting)

deft (253558) | more than 5 years ago | (#25834321)

Theres a whoooole lot of people that said never. As in; we were never supposed to fly, never supposed to break the sound barrier, never supposed to get to space, etc.

Noone said it would be easy, or that they have an idea how to do it. but thats why we do these studies.

Luckily people that don't like to say "never" work at NASA.

Re:Jet tehcnology can't do it ever (1)

dkleinsc (563838) | more than 5 years ago | (#25834409)

Gliders aren't silent, but they're a heck of a lot quieter than your average airplane and well below the noise level of, say, a motorcycle.

The B2 is relatively silent (2, Interesting)

Tmack (593755) | more than 5 years ago | (#25834823)

For a large bomber craft, its supprisingly quiet [youtube.com] , especially if compared to something like a C5 galaxy [youtube.com] or C17 Globmaster [youtube.com] , or even an F-18 [youtube.com] (well, it did have its afterburner lit).

tm

Re:Jet tehcnology can't do it ever (1)

Deadstick (535032) | more than 5 years ago | (#25834843)

"Silent" is a relative term, but the presumption is one that has noise levels approaching that of an automobile. That simply is never going to happen.

It did with this airplane: http://www.globalsecurity.org/military/systems/aircraft/x-26-pics.htm [globalsecurity.org]

Not exactly a fighter or bomber, but it has interesting applications for reconnaissance.

rj

Re:Jet tehcnology can't do it ever (1)

cool_arrow (881921) | more than 5 years ago | (#25835037)

It's an unpowered glider and it looks like it requires a noisy conventional propeller aircraft to tow it up.

Re:Jet tehcnology can't do it ever (1)

Deadstick (535032) | more than 5 years ago | (#25836049)

Look past the first row of pictures, that show the sailplane it was derived from.

rj

Re:Jet tehcnology can't do it ever (1)

AliasMarlowe (1042386) | more than 5 years ago | (#25835775)

"Silent" is a relative term, but the presumption is one that has noise levels approaching that of an automobile.

Modern jets are already as quiet as that. Just listen to the average moron driving around with the automobile's mega stereo sound system cranked up.

Silent, I don't think so (0)

squoozer (730327) | more than 5 years ago | (#25834001)

Unless the aircraft is lighter than air type craft with no directional control I can't see this being "silent". It just takes way to much power to get off the ground for any realistic aircraft to even be classed as quiet at moderate range. Having said that I'm sure they can do a lot to make planes quieter I just hope they don't sacrifice efficiency for it though.

Re:Silent, I don't think so (2, Interesting)

Joce640k (829181) | more than 5 years ago | (#25834127)

I don't see how efficiency can go down because noise and efficiency go hand in hand. Noise is caused by air turbulence, reducing air turbulence will increase efficiency.

Having said that, two million is a drop in the ocean for this sort of thing. How come the USA can spend trillions bailing out stupid bankers but only has a couple of million for this sort of thing?

Re:Silent, I don't think so (1)

slmouradian (1276674) | more than 5 years ago | (#25834259)

2m is enough to come up with a conceptual design that 'works'. They'll use this money to work on technologies that will make such an aircraft feasible. For the actual manufacture, you'd need a budget in excess of 40 million USD. As for 'silent', it is a relative term, and does in fact mean 'quieter'. This can be done by simply steering the noise into a direction where no one can hear it (up?) and by improving the aerodynamic performance of the aircraft.

Re:Silent, I don't think so (1)

girlintraining (1395911) | more than 5 years ago | (#25834507)

Well, because if a banker is stupid a hundred businesses go bankrupt. If a plane is too loud... it's an irritation.

Re:Silent, I don't think so (1)

GeneralSense (1410793) | more than 5 years ago | (#25834645)

How come the USA can spend trillions bailing out stupid bankers but only has a couple of million for this sort of thing?

It's just further proof that grad students give an amazing bang-for-buck.

Re:Silent, I don't think so (1)

Bemopolis (698691) | more than 5 years ago | (#25834723)

It's just further proof that grad students give an amazing bang-for-buck.

My recollection of grad school is that it involves few bangs or bucks.

Re:Silent, I don't think so (1)

squoozer (730327) | more than 5 years ago | (#25835977)

I don't think that is necessasarily true. I could easily imagine that they would simply build some sort of sound suppression system into the engine. Anything like that would reduce efficiency just like the baffle boxes on a car do. With a budget of just 2 million that would be a quick fix.

Re:Silent, I don't think so (2, Insightful)

Deadstick (535032) | more than 5 years ago | (#25834891)

It just takes way to much power to get off the ground for any realistic aircraft to even be classed as quiet at moderate range.

The noise an airplane makes at its home base doesn't count. The noise it makes over an enemy position in the night does.

rj

What about the inside? (1)

cashman73 (855518) | more than 5 years ago | (#25834333)

Noise reduction from outside things like engine noise is always good. But can they also work out a way to make the plane quieter on the inside, too? Like, can they make it so we don't have to listen to that screaming baby in 7E, and can they shut up the annoying passenger in 13F that won't stop talking about his entire life story?

c0Mm (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#25834343)

all; in order to go The mobo blew One Hesre but now these rules will

I don't understand why this is tagged as vaporware (2, Informative)

faffod (905810) | more than 5 years ago | (#25834505)

This is research money. In my understanding of the term, that means that the money is to be spent to try and find solutions that don't exist today. They might succeed, they might fail. Even if they succeed, there's no guarantee that the research will make it into a commercial product. That is true of all research. Furthermore, I don't see any comments that substantiate the vaporware tag. Shouldn't it be a requirement that if you're going to add a tag to an article you have to add a comment too?

About time... (3, Insightful)

JoeMerchant (803320) | more than 5 years ago | (#25834579)

Sure, they will never be silent, but they haven't been doing much improvement in the last 30 years. The old 707 engines were remarkably loud - going to turbo-fans made a big improvement, but I feel like they haven't made any further reductions since the "hush kits" of the late 1970s.

The entire Florida peninsula is severely noise-polluted from aircraft. Even when they are flying over at 30,000 feet, they're louder than the breeze in the trees, or an idling car engine, 6' away. If they can reduce the sound output to where the noise from a jet at cruising altitude is less than normal ambient noise in a suburban neighborhood, that would be a big accomplishment. I doubt they'll get it down to where you can't hear them while standing in a quiet field away from air-conditioners noise of passing cars - but they can try....

Also, don't forget the military aspect of this - F4 Phantoms were intimidating, but they certainly wouldn't sneak up on anyone, even if the person was deaf they could feel an F4 coming. F16s are a huge improvement, noise wise. I've never heard a stealth fighter in person, but I assume their noise signature could be reduced too. A fighter jet capable of silent approach and supersonic response speeds would have plenty of applications.

Re:About time... (1)

427_ci_505 (1009677) | more than 5 years ago | (#25834729)

The F22 is a stealth fighter wrt. radar cross section. But its twin F119 engines, each outputting 35000lbs. of thrust, are anything but silent.

Re:About time... (2, Insightful)

Anonymous Coward | more than 5 years ago | (#25834829)

Just a quick fyi, a supersonic aircraft outruns its own noise. You don't hear them coming.

Re:About time... (1)

Chirs (87576) | more than 5 years ago | (#25835483)

But your distant observation post can hear them and warn you...

Re:About time... (1)

Yo-Yo-boy-wonder (1180359) | more than 5 years ago | (#25835229)

I go to college at UNL (Lincoln NE) And at the Husker games they do fly-overs all the time. A couple of times they've had stealth craft. You can't hear them coming, but after they get past you it feels like your ear drums are going to burst.

Re:About time... (1)

jafiwam (310805) | more than 5 years ago | (#25835633)

Keep in mind the typical "flyby" sequence involves applying full power on the climb out.

They could be throttling up. For a hint, look for a burst of smoky exhaust that indicates increase in throttle.

Re:About time... (1)

LeadSongDog (1120683) | more than 5 years ago | (#25835233)

Ok, I'll bite. Where in Florida do you get away from the sound of passing cars? A football game?

Re:About time... (1)

JoeMerchant (803320) | more than 5 years ago | (#25835489)

Central... some places in the everglades, and really all the way up to just south of I-4, there are places you can get a several miles away from the nearest roads with 40MPH+ traffic. We've got a place [mangocats.com] in Desoto county where we camped out one new year's eve and listened to a couple have a screaming fight over 1/2 mile away, they were just a little louder than the passing jets.

Re:About time... (1)

Atlantis-Rising (857278) | more than 5 years ago | (#25835267)

...silent approach and supersonic response speeds?

At the same time?

Re:About time... (0)

Anonymous Coward | more than 5 years ago | (#25835843)

Would that make for a "silent boom?"

Re:About time... (2, Interesting)

bendodge (998616) | more than 5 years ago | (#25835671)

Also, don't forget the military aspect of this - F4 Phantoms were intimidating, but they certainly wouldn't sneak up on anyone, even if the person was deaf they could feel an F4 coming. F16s are a huge improvement, noise wise. I've never heard a stealth fighter in person, but I assume their noise signature could be reduced too. A fighter jet capable of silent approach and supersonic response speeds would have plenty of applications.

I disagree. The Phantom can most definitely sneak up on you from behind. I took pictures of it at an airshow recently. Taking a picture and immediately plugging my ears afterwards was quite a trick, since it was flying very low and I forgot earplugs. You see it coming and then at about 30 yards hissssBOOM! I'd call that sneaking up. You don't have time to do anything but dive. There was also an F22 on display, but nobody was considerate enough to fly it. :(

Re:About time... (1)

JoeMerchant (803320) | more than 5 years ago | (#25836233)

Ok... point taken, but you must agree about the deaf guy also feeling it go by. Also, it's kind of hard to hit a target when you're pushing close to Mach 1.

Re:About time... (2, Interesting)

Shotgun (30919) | more than 5 years ago | (#25836189)

If they can reduce the sound output to where the noise from a jet at cruising altitude is less than normal ambient noise in a suburban neighborhood, that would be a big accomplishment. I doubt they'll get it down to where you can't hear them while standing in a quiet field away from air-conditioners noise of passing cars - but they can try...

Attend a large (or military) airshow sometime. The US's newest military transport, the C-14 Globemaster, is absolutely eerie. A huge, lumbering aircraft that is close to silent for it's size.

Already Flying (0)

Anonymous Coward | more than 5 years ago | (#25834779)

Im not sure why it is tagged vaporware since a similar blended wing body design that Boeing and NASA are working on flew in 2007. http://www.boeing.com/phantom/news/2007/q3/070726c_nr.html [boeing.com]

Anonymous Coward (0)

Anonymous Coward | more than 5 years ago | (#25834821)

Everyone knows that this technology was developed long ago, but the big aviation suppliers bought up the patents so it wouldn't put them out of business.

Quieter airplane? (1, Informative)

CompMD (522020) | more than 5 years ago | (#25834825)

See: Boeing 787.

Before you make that aircraft... (1)

TokyoJimu (21045) | more than 5 years ago | (#25834837)

Could you make me a silent refrigerator first?

Re:Before you make that aircraft... (2, Insightful)

cool_arrow (881921) | more than 5 years ago | (#25835079)

Better yet, how about a silent leaf blower. Far more annoying IMHO.

Blended Wing (1)

Warshadow (132109) | more than 5 years ago | (#25834853)

I wonder if they missed the rather awesome blended wing designs that cover at least part of what they're trying to accomplish.

http://en.wikipedia.org/wiki/Blended_wing [wikipedia.org]

X48 and the new tanker program (1)

WindBourne (631190) | more than 5 years ago | (#25835203)

I am amazed that W did not use the tanker program to develop the X48. 600+ aircrafts. Boeing could then spin it into a new set of bombers as we as cargo. By that time, small airlines would pick it up and within a short time ALL AIRLINES WOULD DEMAND IT.

I am hoping that Obama will take this opportunity to do just this.

This article is mis-informative (0)

Anonymous Coward | more than 5 years ago | (#25834873)

All the images in are of the Ultra Wide Body aircraft that NASA/MIT/Boeing have been developin gfor quite some time. Contrary to the article, these are being developed for noise reasons, they are being built because they offer superior lift and lower fuel consumption when compared to the traditional tube design. The lower noise is just an added benefit due to the engines being mounted above the frame, instead of below it, and they would be far from silent.

Black Helicopters (4, Funny)

ZirbMonkey (999495) | more than 5 years ago | (#25835141)

It's about time that the stolen UFO technology currently being used in silent black helicopters is finally trickling down to private enterprise.

s/Silent Aircraft/Silent powered Aircraft/ (2, Insightful)

dorfsmay (566262) | more than 5 years ago | (#25835171)

Gliders are near silent, and are aircrafts !

What they should be making (0)

Anonymous Coward | more than 5 years ago | (#25835585)

is a ROFLcopter Soi soi soi soi soi soi soi soi soi soi soi soi soi soi

closer (1)

zogger (617870) | more than 5 years ago | (#25835621)

Airship Ventures [airshipventures.com]

Efficiency is Key (2, Insightful)

llZENll (545605) | more than 5 years ago | (#25835991)

The airlines could care less about noise, comfort, and environmental impact. If it saves them some gas then it may fly.

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