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MIT Designs Aircraft That Uses 70% Less Fuel Than Conventional Planes 459

Posted by Soulskill
from the in-other-news-aircraft-refuelers-laid-off dept.
greenrainbow writes "Today a team of researchers at MIT unveiled their design for an airplane that uses 70% less fuel than conventional aircraft. The MIT design comes thanks to a NASA-funded initiative to increase fuel efficiency, lower emissions, and allow planes to take off on shorter runways. The team accomplished all of NASA's set goals with their innovative D-series plane, lovingly referred to as the 'double bubble,' which has thinner, longer wings and a smaller tail, and engine placement at the rear of the plane instead of on the wings."
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MIT Designs Aircraft That Uses 70% Less Fuel Than Conventional Planes

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  • hmmm (Score:5, Interesting)

    by meerling (1487879) on Monday May 17, 2010 @04:12PM (#32243518)
    Looks like it's fuselage is also a lifting body.
    • Re:hmmm (Score:5, Interesting)

      by gyrogeerloose (849181) on Monday May 17, 2010 @04:17PM (#32243622) Journal

      Looks like it's fuselage is also a lifting body.

      On the larger one, yeah, it does.

      Interestingly, TFA mentions that NASA was also soliciting new designs for a supersonic transport aircraft; given the reluctance of nations to allow those in their airspace and the resulting eventual demise of the Concorde (which, IIRC, never made a profit anyway), one has to wonder why.

      • by Qzukk (229616)

        TFA mentions that NASA was also soliciting new designs for a supersonic transport aircraft; given the reluctance of nations to allow those in their airspace and the resulting eventual demise of the Concorde (which, IIRC, never made a profit anyway), one has to wonder why.

        At this point, it's probably because NASA is really hoping for military funds to save it.

        • Re: (Score:2, Redundant)

          by h4rr4r (612664)

          Why? NASA just got a budget increase and they finally killed off that worthless budget leach program. NASA might actually be able to afford some science now that the shuttle manufacturers welfare program has been ended.

          • Re: (Score:3, Interesting)

            by robot256 (1635039)
            Yeah...except it hasn't actually ended yet. Will Obama veto a budget with irrationally-mandated Constellation spending? Only time will tell.
            • Re: (Score:2, Troll)

              by h4rr4r (612664)

              It would be about the first thing he did that I agreed with.

              Seems we got GWB3 no matter who we voted for last election.

      • Re:hmmm (Score:5, Interesting)

        by ircmaxell (1117387) on Monday May 17, 2010 @04:33PM (#32243984) Homepage
        Well, it's possible to travel supersonic with a minimal or even no sonic boom (I remember someone came out with a design for a boom-less Learjet recently). IF they can do that reliably, perhaps the countries will open up their airspace to it... Or perhaps it's a losing battle. Either way, some good science should result from it (What NASA is ultimately, a science organization. It's not Airbus)...
        • Re:hmmm (Score:5, Interesting)

          by Grishnakh (216268) on Monday May 17, 2010 @05:36PM (#32245062)

          Who cares if there's a sonic boom? A large portion of long-distance air travel happens over the Atlantic and Pacific Oceans. As long as a SST plane slows to subsonic speed before crossing over land, which it'll probably need to do anyway because it's preparing to land, there shouldn't be a problem.

          Think about it, most really long flights are going to be trips like LA to Tokyo, LA to Beijing, LA to Sydney, NYC to London, NYC to Paris, etc. The vast majority of the distance is over international waters, and these airports are mostly very close to the water. Obviously, trips over Western Europe will have to be subsonic, but it's really not that far from the Ocean to any airport in Western Europe so the subsonic leg shouldn't be a big deal. Trips over North America can be supersonic, since it's doubtful the American government will care about sonic booms. If they do, I'm sure a few "campaign donations" will fix that....

          Even trips from LA to Western Europe shouldn't be a problem, since most of the journey is over the North Pole IIRC.

          • Re:hmmm (Score:5, Interesting)

            by cmiller173 (641510) on Monday May 17, 2010 @05:56PM (#32245396)
          • Re: (Score:3, Insightful)

            by daBass (56811)

            Booms aren't just loud, they also smash Windows and American law-makers care; the FAA specifically bans not sonic booms, but *all* supersonic flight. So even if you came up with a boomless SST, you'd still need the get permissions to go supersonic!

            Your views on trips are also rather US-centric. There are a lot of aircraft flying from Europe to Asia, all over land.

            If it had not been for this minor boom problem, Concorde would have been a much bigger success.

            • Re: (Score:3, Insightful)

              by Grishnakh (216268)

              Booms aren't just loud, they also smash Windows and American law-makers care; the FAA specifically bans not sonic booms, but *all* supersonic flight.

              I don't know about the FAA, but I've heard tons of sonic booms from F-16s, and they fly supersonic here all the time. I live in a large metro area near an F-16 training base.

              Your views on trips are also rather US-centric. There are a lot of aircraft flying from Europe to Asia, all over land.

              Yep, those won't be able to go supersonic. I didn't say all planes co

              • Re: (Score:3, Interesting)

                by daBass (56811)

                The larger the aircraft, the bigger the boom. A conventional 200 passenger airliner will create a very big boom.

                I was surprised because the Mythbusters couldn't break any windows with an F-18 unless they were at tree-top level. But big booms from big airliners are real.

                And it's not just the boom, it's also the engines. Hard to create a supersonic airliner using quiet high-bypass turbofans. Concorde used straight turbojet with after burners: very loud.

                Right until the Paris crash, Concorde between London and

          • Re:hmmm (Score:4, Informative)

            by Martin Blank (154261) on Monday May 17, 2010 @07:47PM (#32246838) Journal

            The FAA has prohibited overland supersonic flight except for explicitly-approved military flights for decades now. Even the military has to get permission when outside of established supersonic corridors, most of which are controlled by the FAA. (Many people are often amazed at how much authority the FAA has over military flights within US borders.)

            NASA has conducted a great deal of research into quieting sonic booms, either by deflecting them upward or by canceling them out. I imagine those will be or have been factored into MIT's proposals.

          • Re: (Score:3, Informative)

            by westlake (615356)

            Trips over North America can be supersonic, since it's doubtful the American government will care about sonic booms. If they do, I'm sure a few "campaign donations" will fix that....

            It didn't work for Boeing in the '70s:

            The anti-SST paperback, "SST and Sonic Boom Handbook" edited by William Shurcliff, which claimed that a single flight would "leave a 'bang-zone' 50 miles wide by 2,000 miles long" along with a host of problems that would cause. In tests in 1965 with the XB-70 near Oklahoma City, the path ha

      • by EdZ (755139)
        More accurately, it's a Blended Wing Body craft, and they've been around for quite a while. Boeing's own X-48 [wikipedia.org]concept has been around a few years, and is almost identical to the 'H-series' concept. I also recall an old passenger craft comncept very similar to the 'B-series' concept, except with an even wider, taller body, and with stubbier wings. Unfortunately, I can't remember what it was called.
      • Previous research done by NASA went into designing aircraft bodies which mitigated the ground effects of sonic booms. My understanding was that those experiments produced some promising potential designs. If they made use of that tech, the issues most people had with the Concord would disappear.

    • by MBGMorden (803437)

      Looks that say, because it is, which is clearly stated in the TFA if you'd read it instead of just looking at the pictures ;).

  • How Fast? (Score:2, Interesting)

    by Bruiser80 (1179083)
    Long, thin wingspans taking off from shorter runways makes me think it's considerably slower.

    However, TFA says it could replace the overseas market, so the range must be there. If it carries the same amount of fuel as a 777, it must fly faster than 30% of the speed of a 777 ;-)
    • by Bruiser80 (1179083) on Monday May 17, 2010 @04:18PM (#32243636)
      NASA's link says the 777 design flies 10% slower. A pretty good return!
    • Long, thin wingspans taking off from shorter runways makes me think it's considerably slower.

      That model "D series" (180 passenger) has the really long, thin wings and is designed to replace the 737, the "'hybrid wing body' H-series" (350 passengers), has wider, less long wings (blended into a lifting body) and is designed to replace the 777.

    • Re: (Score:3, Insightful)

      by Falconhell (1289630)

      The ratio of length to chord of a wing is refered to as aspect ratio.

      To simplify somewhat, the tip of a wing is always
      producing a vortex, which reduces the lift contribution of that part of the wing, and increases drag. Winglets are desigend to help reduce this loss.

      So the longer the wing the less percentage of it is tip, and the efficency increases.

      Hence gliders having high aspect ratio wings.

      At low speeds this is good, but at mach speeds a low aspect ratio delta wing gets better results.

      It is difficult to

  • by ICLKennyG (899257) on Monday May 17, 2010 @04:16PM (#32243600)
    I wonder how the seating configurations are for these planes. There is no scale provided so you wonder what they are calculating on, is it fuel per mile per passenger? Anything else would be irrelevant.
    • by AnonymousClown (1788472) on Monday May 17, 2010 @04:21PM (#32243710)
      Seating is usually dictated by the individual airline that buys the planes. Rest assured that all of the US based carriers will cram as many seats in as possible so even a little guy like me - 5' 7" 155lbs - will feel cramped.

      Of course, when the airlines get these, there will be a "green" fee, a "designed by MIT" fee and an "environmental feel good" fee added onto your ticket price along with all the junk fees.

      • Re: (Score:3, Funny)

        by blair1q (305137)

        Of course, when the airlines get these, there will be a "green" fee, a "designed by MIT" fee and an "environmental feel good" fee added onto your ticket price along with all the junk fees.

        And then there's the fee for adding on the fees...

    • by Chris Burke (6130) on Monday May 17, 2010 @04:24PM (#32243772) Homepage

      There is no scale provided so you wonder what they are calculating on, is it fuel per mile per passenger? Anything else would be irrelevant.

      The two designs carry the exact same number of passengers as the planes they are hypothetically replacing, the 180-passenger 737 and 350-passenger 777, so there's no difference in this case between miles per gallon and passenger-miles per gallon. :)

    • by buback (144189)
      The type D is to replace a 737 class for domestic flights (about 180 passengers), While the type H is to replace a 777 class international sized plane (about 350 passengers)
  • by sunderland56 (621843) on Monday May 17, 2010 @04:16PM (#32243604)
    One way they save fuel: flying slower than current aircraft. First, will customers accept that? And second, why not just fly current 737s a bit slower right now, to save on fuel?
    • by sznupi (719324) on Monday May 17, 2010 @04:26PM (#32243832) Homepage

      While I'm sure you can devise a design which, as part of greater fuel economy, flies slower (turboprops might be just that...) - it won't really work for existing aircraft, like mentioned by you 737s. Airlines take care to fly them at optimal speed, not the greatest speed; optimal for fuel economy.

      For example Rynair (which cares greatly about lowering costs...), some time ago, changed the guidalines for cruising speed by...2 or 3 km/h. Accidentally in this case it was lowering it, but might have been just as well an increase; what works best for given airplane / engines / routes / weight combo (didn't stop local journalists from proclaiming "Ryanair will fly slower to save fuel", which was technically correct, but....)

      • by StikyPad (445176)

        Unfortunately drag is a nonlinear function with respect to velocity/wind resistance, so using anything over the minimal amount of fuel you need to move will necessarily result in decreased efficiency. I don't know the minimal velocity (and corresponding fuel consumption rates) to keep a 737 aloft, but I suspect it's well below cruising speed. In any event, the chosen cruising speed is almost certainly a balance between fuel consumption and travel time, rather than an exclusive function of the former.

        • Re: (Score:2, Informative)

          by pittance (78536)

          You're correct that drag has a large influence, engines have a part to play also.
          Turbofans have a 'bucket' speed where their efficiency (specific fuel consumption or the fuel they burn per second per pound of thrust) is best*
          The result is that, when the aerodynamics and engine efficiency are combined, there will be a best efficiency speed (best range speed) that's not far below the theoretical 'design' speed. However many airlines fly faster than this, depending on their balance of fixed vs. hourly costs.
          G

        • by sznupi (719324)

          Unfortunately drag is a nonlinear function with respect to velocity/wind resistance

          But so is the efficiency of the engines. And both of them in relation to altitude / air density.

          Also, modern airplanes actually fly, at altitude, almost on the verge of stalling...that's at their cruising speed.
          And another thing: during the recent closure of airspace over Europe, some companies tested flights at much lower altitude (most likely much slower, too). They quickly abandoned it whet it was clear how much fuel was wasted (some test flights actually weren't managing to get to their intended destina

      • by buback (144189)

        I think people defiantly compare flight time to, say, taking a train or car. But do customers really care that much about flight time? it's not like that's a big selling point when you chose your flight.

        If your flight from new york to LA took an extra half hour and cost 30% less, i don't think anybody would complain

        • by nelsonal (549144)
          Well part of the reason for not caring about the flight speed, might be that buyers looking at overall travel time which usually includes a layover or two.
        • Re: (Score:3, Insightful)

          by vlm (69642)

          If your flight from new york to LA took an extra half hour and cost 30% less, i don't think anybody would complain

          For scheduling reasons, moving the same amount of cattle will now take something like 8% more aircraft. That means that several internal empires will need to expand by at least 8%, in some cases much more. Hourly crew costs and massive management overhead always scales super-linearly. Financing costs for 8% more planes on less revenue will demand a higher interest rate, so financial costs will increase super-linearly.

          If an airline did the "slowdown" thing for marketing to "save the planet" they're going

    • by h4rr4r (612664) on Monday May 17, 2010 @04:29PM (#32243894)

      They sure will. If you can give me a 30% reduction in ticket price but a 10 hour flight instead of an 8 hour one across the atlantic that would be fine by me.

      Provided it is a nice European carrier like Lufthansa, who actually has free beer and back of the seat entertainment systems. Unlike American carriers who charge for beer and have 70s entertainment systems in the aircraft.

      • Re: (Score:2, Interesting)

        by vlm (69642)

        They sure will. If you can give me a 30% reduction in ticket price but a 10 hour flight instead of an 8 hour one across the atlantic that would be fine by me.

        Doesn't work exactly like that. Levitating a million pounds of aluminum costs a certain amount per unit time, no matter how slowly you move it. Also the hotel loads of pressurizing, electricity, air conditioning, hydraulics, all are mostly invariant. And cost of inflight food/entertainment increases linearly with flight duration.

        The real killer, however, is financial.

        To simplify, lets assume the plane instantly loads and departs and magically requires no maintenance nor cleaning. That means the 8 hour f

      • Re: (Score:3, Informative)

        by ubercam (1025540)

        Fly with Air Canada next time. They offer the same amenities as Lufthansa.

      • Re: (Score:3, Funny)

        by BitHive (578094)

        Uh, excuse me I'm pretty sure anything American beats the pants off anything European. That's home come it's America, jackass.

    • by pavon (30274)

      And second, why not just fly current 737s a bit slower right now, to save on fuel?

      It wouldn't help nearly as much. From another article I read, the main reason that they chose to fly slower wasn't to save additional fuel but because their aerodynamic design, while more efficient, puts higher strain on the engine and thus they need to fly slower to stay within safe margins.

    • by schon (31600) on Monday May 17, 2010 @04:31PM (#32243918)

      One way they save fuel: flying slower than current aircraft.

      No. While they do fly slightly (10%) slower than existing aircraft, they do that to mitigate engine stress.

      will customers accept that?

      Well, they seem to "accept" waiting 2-3 hours in security lines, so I'm guesing yes.

      why not just fly current 737s a bit slower right now, to save on fuel?

      You honestly believe that flying a 737 10% slower will reduce fuel consumption by 50%? I can tell you that if an airline reduce their costs anywhere close to that much, they'd do it in a heartbeat.

    • by LWATCDR (28044) on Monday May 17, 2010 @04:49PM (#32244284) Homepage Journal

      Actually it is a lot more complex than that.
      The higher you fly the less fuel you burn but the higher the stall speed as well as the speed that offers you the best lift to drag.
      Also engines have an optimum power setting as well.
      Also the higher you fly the more fuel you burn in climb so there is a function of distance, altitude, and airspeed where the plane gets the best efficiency.
      The concept D looks like it is using the classic trick of increasing the aspect ratio of the wing. That increases climb rate and improves the lift to drag at a given speed.
      My guess by looking at the pictures they are using engines that have a much lower disk loading than current turbofans and a wing that is optimized for cruise at a lowers speed.

      The problem will be the increase in weight. When you increase the aspect ratio you increase the weight of the wing. If you decrease the disk loading of a turbo fan the weight goes up. It will be interesting to see if all the lines cross where they think they will.

    • Re: (Score:3, Insightful)

      by marcosdumay (620877)
      To fly a 737 slower, you'd need to also fly it lower. The net effect is that increases drag instead of reducing it.
  • by mangu (126918) on Monday May 17, 2010 @04:17PM (#32243612)

    A non-cylindrical cabin would be significantly heavier than a cylindrical cabin, if the plane is meant to fly at the same altitude as current planes.

    • by ThreeGigs (239452) on Monday May 17, 2010 @04:37PM (#32244078)

      It's actually two cylindical (or semi-cylindrical) cabins joined together lengthwise, with a stressed interior partition framework. Kinda like a number 8 laying on its side. Pressurization isn't difficult in that case, and the interior stressed partition can be a latticework. It's not a new idea, although it's never been done for reasons of practicality, just a lot simpler to make the body a long tapered tube and be done.

  • The picture of the plane raises all kinds of questions? What are the wings made of? Where do they store the fuel?
    • Re: (Score:3, Insightful)

      by blair1q (305137)

      By 2035 it's almost certain those will be carbon-fiber aircraft.

      The fuel will be somewhere in the fuselage, possibly in the seat cushions (oh don't roll your eyes like that would make flying any more dangerous).

      Moving the moment of inertia in will make the aircraft less stable about its forward axis, but computer flight algorithms will keep it from wobbling too much.

    • The picture of the plane raises all kinds of questions?

      I don't know the answer to that.

      What are the wings made of?

      Wingstuff!

      Where do they store the fuel?

      Fuel tanks!

    • by KlaymenDK (713149)

      Oh don't worry about the wings. If you notice, the floors are a little thicker. This is to allow room for the extra chains and comfy foot-rest pedals that will be made freely available to every passenger.

  • by PPalmgren (1009823) on Monday May 17, 2010 @04:18PM (#32243656)

    I remember watching a documentary on the new Airbus plane. There are regulations on wing length, and that plane *has* to use the perpendicular tips at the end of its wings to help with lift, or its wings would be too long. If you require longer wings per pound, you will fit less passengers per plane to fit in regulation. They will have to find a way to collapse the wings without adding significant weight or complications to make this practical for larger planes. That is a very big hurdle, maybe they should focus on that next.

    I can't remember why, but I remember them stating that the wing length regulations had very good reasons behind them (logistics of current airports being a major one if I recall). I don't think changing the regulations would be practical if that was the case.

    • by pavon (30274) on Monday May 17, 2010 @04:33PM (#32243992)

      According to the article the proposed 737 replacement has standard wing length and is suitable for existing airports.

    • by blair1q (305137)

      The regulations will be changed as airports are reconfigured to fit planes with longer wings.

      The 70% savings in fuel cost will be sucked up somewhere, as long as the airlines end up with an 0.25% profit increase in the quarter in which their first passenger flight is flown.

      • Re: (Score:3, Interesting)

        by dwye (1127395)

        > The 70% savings in fuel cost will be sucked up somewhere,

        The article mentioned that moving the engines to the rear increased stresses. Replacing engines will use up that savings; replacing airframes even more so. There is a reason that commercial jets have engines in separate nacelles, nowadays, despite the obvious benefits of locating them inside the wing or fusilage.

        OTOH, the super-wide bodies might be a real win, unless moving the fuel tanks from the wings decreases crash safety too much.

  • Who are fairly averse to risk and bold updates. Boeing was inching closer [wikipedia.org] to something refreshing before 9/11 happened, and now even its "replacement" is riddled with delays.

    With all these private rocket companies (SpaceX, Armadillo, Bigelow etc) why no venturing into the commerical airspace market? I would assume its too regulated and just impossible to compete with Boeing/Airbus/Tupolev and make a profit, even with a killer design.
    • Re: (Score:3, Informative)

      by sznupi (719324)

      You're forgetting about Embraer or Bombardier. Companies which start to introduce ever bigger planes, ever closer to competing directly with Boeing/Airbus/Tupolev mainstray (B737, A320). And also using "classical" design...

    • by dltaylor (7510) on Monday May 17, 2010 @04:51PM (#32244322)

      It took FOREVER to get a composite commercial aircraft into production because the insurance companies had no data on hull integrity to do the underwriting. As a result, the proposed premiums were based on utter disaster.

      It may have been the Beech Starship http://www.wingsoverkansas.com/legacy/article.asp?id=775 [wingsoverkansas.com] that provided some useful data. Although a turboprop, it is pressurized, and the more-frequent pressure cycling of a corporate hauler may have given them some idea that composites aren't highly more likely than conventional aluminum hulls to become convertibles (Aloha 737) in flight.

      If the US gov't really wanted to help advance the aircraft industry, they'd create an insurance agency for new designs and materials.

  • Sure, long thin wings, or a flying wing design are great, but widening aircraft past existing designs would be a nightmare for airports. There is a certain amount of space to fit airplanes while they are moving around on the ground, and wider planes = more of a hassle.

    http://blog.flightstory.net/272/airbus-a380-hits-hangar-in-bangkok/

    http://home.iwichita.com/rh1/hold/av/avhist/abs/a380flys.htm

    • So make the wings foldable. That's hardly beyond current capabilities. They mention in the article that they are trying to get the design to fit to current airport layouts so I'm sure they've considered the space problems.

    • by Chakotay (3529)

      True, but think of what 70% fuel usage reduction would bring. Fuel accounts for 30 - 40% of the ticket price, so a 70% reduction in fuel would cut ticket prices by 20 - 30%.

      In Norway or Sweden (can't really remember which) there was also a trial with fuel efficient approaches, which reduce fuel consumption by up to 10% for shorter hauls. Instead of coming in high and fast, the plane would more gradually descend and decelerate, basically glide itself down to the airport. This requires stricter planning of ap

    • by buback (144189) on Monday May 17, 2010 @04:43PM (#32244198)

      The type D is specifically designed to work with existing airports without drastically changing the terminals.

      The type H, however, would require changes to current airports. The article says that these designs are planed for a 2035 deployment, though, so plenty of time to make the requisite changes, if the airlines so chose.

  • How close did they come to keeping all other factors equal? 70% less fuel actually doesn't sound like much of an improvement if they don't include all the mechanicals, safety equipment, navigation, expected weight of passengers and luggage, and other inevitable additions to a normal passenger aircraft. I've seen endless lists of super efficient cars that lack headlights, seat belts, air conditioning, power windows/locks, airbags, etc.
  • while teams from Boeing and Lockheed-Martin were entrusted with creating supersonic commercial aircraft — passenger planes traveling faster than the speed of sound!

    Wow! Supersonic commercial aircraft! We haven't done that ever before!

    Oh, no, wait, Mach 2 in the 60s...

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

  • by Larson2042 (1640785) on Monday May 17, 2010 @04:37PM (#32244086)
    I'm disappointed in both of the linked articles. Some real substance about the design would have been nice, but as it is, I'm left with a lot of questions:
    -70% less fuel? How much of that is aerodynamic savings and how much of that is engine efficiency savings?
    -Did they do any wind tunnel testing of their model? How close were their CFD and tunnel test results?
    -Are they using engines based closely off existing ones, or are they projecting fuel savings 25 years into the future (the 2035 time frame from the article)?
    -What sort of structural weight-saving advances are they assuming, or projecting from?
    -So they made the tail smaller, what makes up for the reduction in control authority there?
    -Plus other more detailed questions based on the answers to those questions. Would it have been so hard for MIT to link a design document pdf or something? I guess not being a public university, they don't have to if they don't want to. Too bad.
    • Re: (Score:3, Informative)

      by denzacar (181829)

      -70% less fuel? How much of that is aerodynamic savings and how much of that is engine efficiency savings?
      5% here, 5% there...

      the design mitigates some of the drawbacks of the BLI technique by traveling about 10 percent slower than a 737. To further reduce the drag and amount of fuel that the plane burns, the D series features longer, skinnier wings and a smaller tail. Independently, each tweak might not amount to much, but the "little 5-percent changes add up to one big change," Drela said.

      -Did they do any wind tunnel testing of their model? How close were their CFD and tunnel test results?
      No actual model. Just the ones in the computer.

      They have proposed evaluating the interactions between the propulsion system and the new aircraft using a large-scale NASA wind tunnel. Even if the MIT designs are not chosen for the second phase, the researchers hope to continue to develop them, including testing smaller models at MIT's Wright Brothers' Wind Tunnel and collaborating with manufacturers to explore how to make the concepts a reality.

      -Are they using engines based closely off existing ones, or are they projecting fuel savings 25 years into the future (the 2035 time frame from the article)?
      Mostly projection and wishful thinking. Right now, they could MAYBE do 50%.

      Not only does the D series meet NASA's long-term fuel burn, emissions reduction and runway length objectives, but it could also offer large benefits in the near future because the MIT team designed two versions: a higher technology version with 70 percent fuel-burn reduction, and a version that could be built with conventional aluminum and current jet technology that would burn 50 percent less fuel and might be more attractive as a lower risk, near-term alternative.
      .
      The researchers acknowledge that some propulsion system technology still needs to be explored.

      -

  • According to the article, these designs are expected on the scene in 2035. WTF? That's a long time from now. Surely, they can have something flying long before then.

    And even if it does take until 2035, how much more will technology change in the meantime? Maybe by then they'll be able to run the plane on what people leave behind in the bathroom, and they'll actually pay you to make a trip to the john, instead of the other way around, per the current trend.

  • Icing (Score:3, Informative)

    by arikol (728226) on Monday May 17, 2010 @05:08PM (#32244618) Journal

    Interesting designs. Looking at the first one I have some reservation to this. Structural integrity of the wings is one. A wing has to effect a mass-flow large enough to lift the aircraft, and so has to be fantastically strong, as well as large enough to cause this massflow. A problem (or rather a limitation) with gliders is that when the aspect ratio gets very high that means that there is precious little internal volume to the wing for load bearing members. This is a very real limitation on sailplane wings and means that 20 metre wingspan is a real world limit (some types have gone longer, but the extreme flex of that length of wing means that they are impractical). This seems like a very real issue here.
    Of course, high aspect ratio wings are more efficient due to a number of effects, an important one being wingtip vortices affecting a smaller percentage of the wing. I have no idea how that pans out at high speeds, though. When you're reaching M0.8 I would imagine that interesting effects might start happening, but I'm sure that the MIT kids have calculated all that as well as can be done (I doubt them being dumb).

    Icing would also be a concern, both for the wing (high aspect ratio, laminar flow) and (more seriously) for the whole fuselage which pollutes the airflow into the engines. MD80's (and other jets with rear fuselage mounted engines, the CL60 is another example) had some accidents due to ill visible icing forming on the wings prior to take-off, detaching from the wing on take-off and flying into the engines. This design would be quite sensitive to this sort of problem.

    But all in all, a very intriguing design idea. Would be interesting to see if the real world problems can be solved as well.

    • Re: (Score:3, Informative)

      by Falconhell (1289630)

      (some types have gone longer, but the extreme flex of that length of wing means that they are impractical)

      I am quite sure my friend who owns an ASH 25 (26M span) http://en.wikipedia.o/wiki/Schleicher_ASH_25 [en.wikipedia.o] would disagree, he flys it nearly every weekend.

      I have flown 25 hours in it myself and whilst it is slow in roll the flexibibity of the long high aspect ratio wing makes for a vey comfortable ride. (Think of the wing as a leaf spring, supporting the fuselage)

      The largest production glider is the E

  • by DieByWire (744043) on Monday May 17, 2010 @05:27PM (#32244894)

    the design mitigates some of the drawbacks of the BLI technique by traveling about 10 percent slower than a 737.

    I wonder if they accounted for the added weight of beefing up the trailing edge of the wing to withstand bird strikes.

  • by tyrione (134248) on Monday May 17, 2010 @05:28PM (#32244898) Homepage
    Get this down to 2020 and I'd be impressed.
  • Certification (Score:3, Informative)

    by konohitowa (220547) on Monday May 17, 2010 @09:15PM (#32247648) Journal

    Prototypes are fun and all, but let's see the numbers once it has customers lined up and has gone through FAA certification. That's a bit like coming up with a car that gets 175MPG (of actual gasoline or diesel, not "gallons" of electricity) -- until you've gotten it past the EPA and the DOT and can still sell the thing to more than the wealthy toy market, it's just a show car.

    Believe it or not, they actually have one or two smart people working at Boeing & Airbus (possibly one at each) and it's not like they're in bed with BIG OIL!!!! or whatever other tinfoil hatted fantasy people like to believe in this week.

    And, in regard to some other post here, I seem to recall winglets being there to break up parasitic drag from vortices spewing off of the wing tips. But that's just my recollection from working on MD-11 (software, not mechanical design, so take that for what it's worth). They're fairly common now.

  • by Simonetta (207550) on Monday May 17, 2010 @10:17PM (#32248146)

    ...while accounting for the changes in air travel in 2035 -- when air traffic is expected to double -- would require "a radical change,"

        These guys are in a clusterfuck headspace. They are basically throwing fantasies off each other.

        Given the present state of known oil reserves (and the difficulties in accessing those reserves), the current depletion rate, and the expanding rate of oil usage in the developing world, NO ONE seriously expects air traffic to double by 2035. No one except a handful of tech nerds in NASA and the Defense Department think-tanks who get paid big bucks to let their imaginations run wild without any consideration of the conditions in the real world.

        The airlines will be lucky to exist at all by 2035. In all likelyhood, there will be one airline in the world that offers once daily flights across the major oceans at enormous cost for the public, and small-jet charter service for the ultra-rich. The hoards of lower-middle-class masses (that you and me and rest of the Slashdaughters reading this) are not going to jetting to Vegas or Hawaii for wild-weekends as they did during the millenium years 1985-2010. Every six months we read in the business sections about another national airline merging with a major carrier and the major carriers merging with each other. What was it last month? Oh yeah, United and Continental merging because they are both going broke as individual companies.

        I also fail to see how a plane design that looks more or less exactly like all the other plane designs is going to be able to fly 100+ passengers with 70% less fuel. Maybe I missed the football-field-sized helium balloon that was attached to the fuselage (and cropped from the picture). Oh yeah, the front nose looks beveled. And this is supposed to give it 'super lift'. If this were the case, don't you think that Boeing and/or Tupolev would have figured that out twenty years ago?

        Again, these guys get paid to fantasize. Not produce reality. They're the same type of guys who promised us Howard Johnson's restaurants on space stations and PanAm weekly service to luxury hotels on the moon in the film 2001:A Space Odyssey forty years ago. And what was 2001 in reality? Millions of screaming kids and dorks in shorts riding a trashy 30-year old 737 to Branson and Disneyland.

        Trust your instincts. Don't trust MIT/NASA reports.

  • Pushing tin (Score:3, Funny)

    by ArundelCastle (1581543) on Monday May 17, 2010 @11:19PM (#32248548)

    and engine placement at the rear of the plane instead of on the wings.

    Rear wheel drive? Nuh-uh. Bigger chance of hydroplaning. ;)

    Or as they like to say on WestJet... "should this flight become a cruise..."

  • Move along... (Score:3, Interesting)

    by Evtim (1022085) on Tuesday May 18, 2010 @04:56AM (#32250178)

    You know, people, it is perhaps shameful to admit in front of this audience but despite working at the cutting edge of technology I only shrug at news like this one. Instead of all the exiting engineering/scientific thoughts that most of you exhibited and made the discussion interesting the only thing that crossed my mind was something like:

    "So, we are going to save 70% of the fuel. What would happen in such "vacuum" Well, we will just build 70% more plains, fly even more people around, cheaper perhaps so the "gain" in efficiency will be quickly drowned by the increased volume of planes and passengers. Move along, nothing to see here..."

    I don't want to rain on anybody's parade but every time when some new technological development frees us time, it is immediately filled with more work, not more recreation or hobbies or family life. When it comes to food and water it is even worst. Just consider the "green revolution" from the 70's. Population pressure due to the baby boom after the war. Solution - industrial agriculture which completely kills the taste of food (especially fruits and vegetables) but its efficient and easier to transport and preserve. When it was all over , did we wipe out the noble sweat and sat down to enjoy the fruits of our ingenuity (pun intended)?

    No, because the population pressure was already pushing us again. We will never catch up with this. And as every scientist will tell you , every next step will require more energy and more effort to squeeze maximum yield from minimum volume. Asymptotic approach to use the proper term. Like trying to accelerate a mass to the speed of light. As long as we do not stop the geometrical progression of our multiplication we will never be able (most of us) to enjoy what the progress is all about - giving MORE time for ourselves and our personal development and personal life. Giving MORE and higher quality goods and services per person (population flat, but efficiency increases).

    Globally as humans we experience what we people in the west experience with the constant inflation - you have to run ever harder just to stand still. Miss one year's promotion or a raise and your buying power goes down. The effect of missing one year only is accumulative like compound interest. I am sick to the teeth that I have to run like a mouse on an endless tread just to stand still. Just to exists. And being told all the time how good I have it.

You can do this in a number of ways. IBM chose to do all of them. Why do you find that funny? -- D. Taylor, Computer Science 350

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