Shockwave Images Help NASA In Development of 'Quiet' Supersonic Jet (go.com) 63
An anonymous reader writes: NASA is working on developing a next-generation supersonic jet that can break the sound barrier with a soft "thump" instead of a sonic boom. They are using a technique called schlieren imagery to "visualize supersonic flow phenomena with full-scale aircraft in flight" with the sun as the backdrop for the photos. According to a NASA blog post, viewing shock waves and their density is crucial to the project so engineers can work on a design to minimize those reverberations. While the Quiet Supersonic Technology (QueSST) research aircraft is being developed, stunning images were captured of a supersonic jet flying at Mach 1.05 with the sun in the background. NASA says when QueSST is operational, it could "unlock the future to commercial supersonic flight over land," essentially ushering in a new era of aviation that could allow us to get from point A to point B faster and without the loud roar of the Concorde as it breaks the sound barrier.
Re:Great (Score:5, Insightful)
Actually, being able to get from point A to point B faster than a day's worth of travel will probably save countless billions in time and money for everyone from executives to a family going to Disney World, or Europe.
To get from the middle of the country to either coast takes about 4 hours in the air. Add in the precursor activities and post arrival activities and it's an entire day wasted.
Consider a Family of four going to Disney on either coast. A one hour flight vs. 4 (at best, if you get a straight through) will save you four meals, two hotel rooms for a night, and take up one less day of your vacation time.
With the Supercruise capabilities we see on F-22's it may even mean lower fuel consumption per hour.
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Actually, being able to get from point A to point B faster than a day's worth of travel will probably save countless billions in time and money for everyone from executives to a family going to Disney World, or Europe.
Poor modern day Americans. They have not found out yet that the journey is the important part. When I read posts like this, I think of Chevy Chase in Family Vacation, impatiently giving his family five seconds to look at the Grand Canyon because, Wally World!
I've been to Disney World twice, and Disneyland once. And what I remember is the fun I had getting to those places, not a whole lot about the places themselves, except for standing in line a lot. Sunrise in the High desert, the spookieness of the Josh
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If you are going to drive, then drive. Enjoy the sites.
If you are flying, then you obviously have no interesting in those things. So it is in the best interest of everything to fly there as quickly as possible.
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If you are going to drive, then drive. Enjoy the sites.
If you are flying, then you obviously have no interesting in those things. So it is in the best interest of everything to fly there as quickly as possible.
Or just watch a TV show. That's even quicker.
But you are right. I just have different tastes in entertainment. I suspect it's because while I am enjoying the ride, others care only about the destination. I get there as well, and get a whole lot more entertainment. Others settle for much much less.
I've done a lot of flying, but am an experience whore.
Re:Great (Score:4, Informative)
Actually, being able to get from point A to point B faster than a day's worth of travel will probably save countless billions in time and money for everyone from executives to a family going to Disney World, or Europe.
Bah humbug! YMMV, but for me, most of my travels are within 400-1000 miles or so (or 1 - 3 hours in the air). For those on the shorter end of that, it often takes less time to just drive it once you take into account time to get to/from the airports, screening, baggage claim, etc. While supersonic may provide a noticeable difference in some cases, they really need to reduce the end point issues if they want it to seem significantly faster.
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Also, it seems like somebody finally found a use for Adobe Shockwave, I never thought this would happen and I am impressed that this somebody is the NASA.
http://krebsonsecurity.com/201... [krebsonsecurity.com]
More important than the sonic boom (Score:5, Interesting)
Are modern engines as efficient at Mach 1.5 as they are at Mach 0.9?
Re:More important than the sonic boom (Score:4, Informative)
No, which is what doomed the Boeing Sonic Cruiser. Airlines prefer cheap operating costs over aircraft speed. In fact, they typically run their current fleet slower than the aircraft are able to cruise, for fuel economy reasons.
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There's a bit more to the story than that.
While Boeing was developing its own supersonic airliner, they were faced with the tough task of competing against Concorde, which was already established and flying. Instead of competing, the entrenched US aviation industry smeared the supersonic airline industry and encourage an FAA sanction prohibiting Concords (or any supersonic airliner) from flying supersonic over land.
It's funny that they are now looking into this again, and all their old fear-mongering is bit
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I have no doubt that a low-level flyover at supersonic speeds would be absolutely nuts, and potentially dangerous for people and animals on the ground.
But at cruising altitude??
From the Wikipedia page: "Concorde had a maximum cruise altitude of 18,300 metres (60,039 ft)" which is almost twice as high as most subsonic airliners. A Boeing 777 cruises at 11,000 m (35,000 ft).
Anyway, all I was trying to say is that it would be really nice to see some reliable ground measurements of the noise from a Concorde fly
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I'd like to know how cruising supersonic at 60,000 ft compares with cruising subsonic at 35,000 ft in terms of fuel economy (theoretically based on the best engine tech we have today, not empirically comparing Concorde vs. 777).
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... and developed with French and British government funding. While the Concorde was operationally profitable for a while, it never made anywhere close to its original development costs. I can understand Boeing sour about it.
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The reason the Concorde wasn't operational profitable was because it ws limited in routes. if it could fly, london, to newark, to la, to toyko, and then back to london it would have been better.
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The Sonic Cruiser was never intended to go as fast as Mach 1.5, it was intended to hang around in the trans-sonic region (Mach 0.98 - 1.02 ish) and it was also intended to use the same engines as the Boeing 777 was using at the time. In the end, it was the fact that the aircraft was smaller than a 777, had much the same operating costs as the 777 and only arrived twenty or thirty minutes earlier than a 777 that killed it.
Of course, Boeing received a lot of NASA funding for development into composite struct
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No, which is what doomed the Boeing Sonic Cruiser. Airlines prefer cheap operating costs over aircraft speed. In fact, they typically run their current fleet slower than the aircraft are able to cruise, for fuel economy reasons.
Many modern airliner engines have enough power to go supersonic. Obviously the airframes would make that not a good idea.
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You can adjust the speed of the air in the engine (Score:2)
Are modern engines as efficient at Mach 1.5 as they are at Mach 0.9?
You get to adjust the speed and pressure of the air in the engine - by a factor of several, if necessary - so the engine works well and makes good tradeoffs. That's much of what those cones, scoops, and funny-shaped housings are about, at least at the front. (Along the sides they're more about making room for the engine in the passing air without creating excessive drag.)
Re:More important than the sonic boom (Score:5, Informative)
Are modern engines as efficient at Mach 1.5 as they are at Mach 0.9?
No. The engine doesn't notice the speed, the intake takes care of that. But to create thrust, the exhaust flow must be faster than the intake flow, and making the exhaust flow faster lowers the overall efficiency of the engine. This is why subsonic engines have a high bypass ratio while for supersonic engines bypass ratio must be kept low.
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the engine efficiency is most not the problem, engines are actually slightly more efficient at higher speeds due to the relatively efficient ram-compression (concorde olympus is I think the most efficient aero-engine ever). The real problem is that the lift to drag ratio of supersonic aircraft is only 7-10 which is only 30-40% of high subsonic commercial jets taht are now in range 20-22. That means (all other things being equal) that you need ~3x the fuel to travel the same distance.
This supersonic L/D deficit is pretty fundamental, and even the best possible configurations (oblique flying wings that are basically unworkable due to massive wing spans needed) will only bring supersonic L/D up to perhaps low teens. While subsonic jets are eventually targeting 30:1 L/D with strut braced wings or blended wing bodies.
But fuel is typically only 20-40% of ticket costs, so this is not necessarily a show stopper for commercial service. And if we can do cheap nuclear power synthesized fuels gradually increasing wealth of world should eventually make supersonic flight in 1-4 person pilotless aircraft (to eliminate noise issue) ubiquitous.
At the same time, all jet engines are terrifically inefficient at low speeds. Even modern subsonic planes lose a comparably huge amount of fuel when taxiing around the airport. Swept-wing SST's would be worse, because they have to accelerate to a higher speed before they can take off (unless you rig them with folding wings like the F-14 [wikipedia.org], but that would weigh too much if scaled up for a commercial aircraft).
Thinking F-14's leads to an idea, though... rig airports with catapults to save a little fuel and mak
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The Japanese effort to developer supersonic passenger jets is looking to offset lower engine efficiency by reducing drag through aerodynamics and flying higher. Ideas include reconfigurable geometry and some advanced computer modelling that wasn't available when the last one was being designed in the 60s.
It's still very experimental and may not work out, but maybe there is a way to overcome the issues.
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Yes. [howstuffworks.com]
The Raptor's two Pratt & Whitney F119-PW-100 engines pump out 35,000 pounds of thrust each (compare that to the 25,000-29,000 pounds of thrust for each engine on an F-15). Combined with the sleek aerodynamic design, the engines allow the Raptor to cruise at supersonic speeds with less fuel consumption than any other aircraft.
So the technology is out there.
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the engines allow the Raptor to cruise at supersonic speeds with less fuel consumption than any other aircraft.
"Most efficient supersonic engines" != "More efficient than subsonic engines"
NASA or NACA? (Score:4, Interesting)
This headline could have been from the 40's or 50's. This is the way supersonic flow has been visualized as long as it has been studied. The supersonic wind tunnel and the Schlieren setup at the university I attended appeared pretty ancient to me in the 1980s.
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As mentioned in Wikipedia, Schlieren optics were developed to study supersonic motion in **1864**. Yes, 152 years ago. I'm happy to see it mentioned as it's a very simple but effective tool. When grinding my own Newtonian telescope mirror in 8th grade (1967) I noticed the Foucault knife test performed as a Schlieren system when a hand was placed near the mirror - the rising air currents from the warm hand are strikingly obvious.
But headlining NASA's use of this is like headlining that Accountants use Arithm
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I remember my prof saying that it was German for "smear." I also remember thinking he was making that up, and assuming (wrongly, I find out 30 years later) it was really named for some guy named Schlieren. Thanks for the info!
Great, just what we need (Score:1)
There aren't many people who complain that air travel isn't fast enough. The bigger issues are the hassles in airports and the cramped seating in planes, not that flights aren't fast enough. The real effect of this will be to increase carbon emissions, which is the last thing we need to be doing. After the past few years have been the hottest on record, we should be concerned with making travel more fuel-efficient instead of faster.
Re: Great, just what we need (Score:3)
Being cramped in a plane for two hours instead of 10 sounds like an improvement to me.
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Yeah, imagine if it was actually available. Normal flight, and express. Once you got used to flights five hours or less where ever you're going, it would be really hard going back to "slow" planes no matter how far back the business-seat reclines.
If you never have to fly long distances, obviously you won't care. But if you do, particularly if you have to for business or family, paying up to save time becomes a real thing. In the day, business travelers loved the Concorde, 'cause they could fly to London
The Aliens Already Gave Us This Technology (Score:2)
Why are they wasting tax dollars when the technology already has been known in Area 51 since the 1940s? The 1943 Wizarding
Accords, of which the author of the Declaration of Independence, Labach the Elder, was a signatory, allowed such advanced technology to be exploited for civilian purposes. Smarten up, NASA!
FUD (Score:1)
NASA has to get a press release out about something. Can not have SpaceX making all the new science.
nice images would be wrong way to design (Score:2)
this makes great copy with images (which seems to be required thing for so called technology and science news stories regardless of substance ) but to design aircraft based on way they are photographed under particular conditions seems not to be the correct or safe way go about it.
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this method is not the best way to take images, or find and test airflow over an airplane, with too much atmospheric distortions, and with inability to recreate the same images and tests, and other inherent disabilities in the method .
This will only be used on business jets, if at all (Score:4, Interesting)
But there is a pocket of aviation where progress has been made in flight speed: Business jets! While the first generation flew more slowly than airliners (Lockheed JetStar, Lear Jet 25), the latest designs are quite a bit faster (Cessna Citation X, Gulfstream V) at up to Mach 0.935. Why? There is a peeing contest going on among their owners who is the fastest. A very small segment of mankind is licking their fingers at a new chance for showing off. A supersonic business jet would be a sure sell to this crowd, even if the operating cost per mile doubles.
Well, see it this way: This is a chance for the other 99.9% of mankind to lower the Gini coefficient [wikipedia.org] a bit.
Re:This will only be used on business jets, if at (Score:5, Informative)
> Supersonic flight adds a new source of drag, called wave drag [wikipedia.org],
As the author of the article you are linking to (if you don't believe me, click History and look) I find it somewhat odd that you apparently didn't *actually read it*.
Wave drag is primarily and effect in the *transonic* from about M0.8 to 1.1 or 1.2, and then basically disappears at speeds above that. Jet airliners spend a significant portion of their flight time dealing with it, which is why it is important for modern air travel.
Supersonic aircraft do indeed use much more fuel than subsonic, but it's not due (primarily) to wave drag, and designing to lower boom does not necessarily upset it for the worse.
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Wave drag is primarily and effect in the *transonic* from about M0.8 to 1.1 or 1.2, and then basically disappears at speeds above that.
Wrong. Why don't you do some basic fact-checking yourself before wrongly accusing others?
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"The effect is typically seen on aircraft at transonic speeds (about Mach 0.8)..."
I found it in less than 30 seconds.
I'm certainly willing to completely trust conclusory statements simply thrown out there by "Aviation Pete." Especially ones that contradict the very source that such a self-professed fount of chose to cite in the first
I thought this seemed familiar (Score:1)
http://m.phys.org/news/2015-08... [phys.org]
Oblig... (Score:2)
Ummm (Score:2)
"technique called schlieren imagery"
This is a terrible summary, and the linked articles aren't great either.
This technique has been used since the 1800's, and specifically for supersonic aircraft design since the 1930s. If you poke about in Google Images you'll find German war-era photographs of swept-wing designs being tested. It was used for artillery design long before that.
The real "news" here, which is hardly news because it's been used for a while now, is the use of outdoor photography to produce thes
Roar? hmm. (Score:2)
Concorde "roar" was the takeoff power with reheat. The sonic boom is not a roar, it is a short bang [youtube.com]
No-one near land heard Concorde's sonic boom. They all heard the engines, which were louder than a modern high-bypass turbofan.
You really want faster travel? Fire the TSA. (Score:5, Insightful)
You really want to travel faster? Fire the TSA.
Not feasible in the US until we get rid of TSA (Score:1)
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The 1% that will be able to fly on this thing will just pay for preferential treatment at security screening [tsa.gov].
They don't even bother to pretend this is a democracy anymore.
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Then we need better body scanners [beyondthemarquee.com].