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MIT and NASA Designing Silent Aircraft
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."
It's called a balloon.
These aircraft will be silent, but deadly?
Sorry, just had to sneak that in...
Enclosed engines? That is not going to be as easy to maintain as the 'drop off' ones that currently sit under the wing.
Never saw that coming.
Oh, yeah, it's not easy to pad these out to 120 characters.
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;-)
If brevity is the soul of wit, then how does one explain Twitter?
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).
I will shred my adversaries. Pull their eyes out just enough to turn them towards their mewing, mutilated faces. Illyria
"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.
Didn't hear it coming neither!
Nobody ever thinks of us poor runway maintenance folk when designing their 400ton aircraft :(
which is totally what she said
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.
I used to have a better sig but it broke.
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.
Oh, yeah, it's not easy to pad these out to 120 characters.
Here's a picture of the prototype.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
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.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
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)
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
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.
There's nothing Intelligent about Intelligent Design.
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?
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.
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?
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.
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
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.
tm
Support TBI Research: http://www.raisinhope.org
See: Boeing 787.
Could you make me a silent refrigerator first?
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
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.
It's about time that the stolen UFO technology currently being used in silent black helicopters is finally trickling down to private enterprise.
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.
Gliders are near silent, and are aircrafts !
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.
I prefer the "u" in honour as it seems to be missing these days.
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.
which is totally what she said
able to hear them coming.... Like, in California and Maryland:
Hybrids vs. pedestrians
http://latimesblogs.latimes.com/uptospeed/2008/08/hybrids-vs-pede.html
Are Hybrid Cars A Danger To Pedestrians?
http://www.manufacturing.net/article.aspx?id=157148
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...
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
is a ROFLcopter Soi soi soi soi soi soi soi soi soi soi soi soi soi soi
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 ;).
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
Airship Ventures
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.
I don't read AC A human right
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.
The airlines could care less about noise, comfort, and environmental impact. If it saves them some gas then it may fly.
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!
May the Maths Be with you!
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.
Are a paranoids wet dream, cloaked black helicopters in whisper mode are already following me everywhere I go, I know they're there because I don't see or hear anything, really!
I killed da wabbit -Elmer Fudd
http://www.globalsecurity.org/org/news/2001/010325-a51.htm
So the Black Triangular plane thing that I saw hover over my campsite in Arizona (back in '94) and which was dead silent even as it shot off to the horizon at a crazy speed wasn't a government aircraft? Then what was is... Xenu?
Suppose a Tesla driver is cruising toward a red light, and a blind person is standing at the corner preparing to cross. The light turns green. The Tesla driver keeps going. The blind person hears no car engine, and starts moving forward. The blind person gets hit by the Tesla. What happens next?
A. Tesla driver gets blamed for running down a person, even if there was a green light and the person suddenly stepped in front of the vehicle.
B. Blind person gets blamed, even though there was no indication of a car coming.
C. Profit.
D. Other _____________________________
Fairly large numbers of people are killed by internal combustion cars, even with all the noise they make; anything that addresses that will also address the safety of quieter cars, and given that for the foreseeable future cars that usually move with an engine running are going to far more common than those that don't, will probably provide vastly more public benefit for the same amount of effort.
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.
Not quite: s/governor/Governator/
Now it's fixed.
David Gould
main(i){putchar(340056100>>(i-1)*5&31|!!(i<6)<< 6)&&main(++i);}
Don't worry, they'll be forced to install beeping horns. That way the people crossing runways won't accidentally think it's clear because they failed to look both ways.
I knew there was a car analogy in there somewhere.
... quieter operations. Take the USAF T-37 training jet for example. It's engines are enclosed fairly well inside the fuselage where the wings attach, and it's one of the most obnoxiously loud little jets still flying (though not for much longer as the remaining fleet is being retired soon).
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.
No, obviously blind people should not cross the street unless they are using a crosswalk designed for use by the blind. All cross walks should be, but I'm sure that some are not.
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.
It's not a decent idea, but seeing eye dogs can perform this function better than one minimum wage worker.
SWM seeks new sig for a brief fling
...NASA's way of ensuring the entire space program doesn't get gutted from the government budget.
Why the fuck wasn't this kind of research taking place by default to begin with? We're suppose to be 'proud' that they're doing this now? /me rolls eyes ...please.
There is an aural warning. With most modern cars travelling at, say, city speeds of 30 mph, you hear the tire roar long before you hear the engine. A car that is coasting to a stop, you won't hear the engine at all - it'll be totally drowned by tire noise. It's only vehicles being accelerated hard, or large diesel engines that you get to hear before the tire roar. But even an electric car being accelerated hard will make motor noises.
Oolite: Elite-like game. For Mac, Linux and Windows
After looking at the CCW site and thinking about it, you have me convinced that putting the props behind and above the wing is far superior to putting them in front and below it.
This is because at low airspeed, your prop wash speed does become significant.
However, my configuration of props being below and in front does stand up equally well at any reasonable airspeed, because the prop wash velocity is less important.
However, that was a case of not considering the low-airspeed case, not a case of not knowing my aerodynamics. Or, if you will, it was a case of ignoring the aerophysics (in Custer's language), not the aerodynamics. For my explanation of why I put it there, look at this reply to another respondant: http://slashdot.org/comments.pl?sid=1036433&cid=25837275
The idea of putting the props in front and above (or below and behind) the wing, though, would be bad at any reasonable airspeed.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's