MIT reveals designs for future airplanes

An MIT aeronautics team revealed this design for a new generation of airplanes that would be quieter and up to 70% more fuel-efficient than the ones we fly in now. The research was funded by a $2.1 million NASA program — called N+3 — aimed at developing more eco-friendly, high-performance planes over the next 25 years.

Air travel is becoming more frequent and is expected to double by 2035; without going through major overhaul, the current system won't scale. As Ed Greitzer, the lead investigator in this project, points out, airplanes have looked pretty much the same for the last half century, and are way too inefficient when it comes to fuel, noise, and runway usage. So he changed it by coming up with two designs: the 180-passenger D series to replace the Boeing 737 and the 350 passenger H series to replace the 777.

The engineers conceived of the D series by reconfiguring the tube-and-wing structure. Instead of using a single fuselage cylinder, they used two partial cylinders placed side by side to create a wider structure whose cross-section resembles two soap bubbles joined together. They also moved the engines from the usual wing-mounted locations to the rear of the fuselage. Unlike the engines on most transport aircraft that take in the high-speed, undisturbed air flow, the D-series engines take in slower moving air that is present in the wake of the fuselage. Known as the Boundary Layer Ingestion (BLI), this technique allows the engines to use less fuel for the same amount of thrust, although the design has several practical drawbacks, such as creating more engine stress.

Fly the eco-friendly skies [MIT News]

• [Dr Kilovolt]

  Structure and weight-wise, a pressurized fuselage is a really good reason to make it cylindrical. I’m no engineer, but it seems to me that both MIT designs require either tension members toward the middle of the cabin, or vastly stronger frame members than are currently used.

  • [catskill]

    Correct.

• [Anonymous]

  I want a return to airship-based journeys. Let’s face it, blimps are awesome.

• [Anonymous]

  From TFA, “aircraft silhouettes have basically remained the same over the past 50 years,” stated like that is a bad thing. I wonder if it ever occurred to these students that there might be good engineering reasons that all big airliners pretty much look the same? That said, the design looks an awful lot like one proposed by Boeing a number of years ago. [but maybe this is just sour grapes from a scientist who didn't go to MIT, and is tired of constantly having to hear about how great MITers are]

  Also, I don’t understand how either of these designs are supposed to help the air transport system scale. Airlines mostly use regional jets (Embraer 1×5′s, CRJ’s, and the like) to keep frequency up, without allowing too many seats to go unsold. RJs are generally less efficient than larger airliners, so I don’t see why most routes couldn’t just be upgraded to already existing jets. Heck, no domestic US airline uses 747s or A380s!

  Finally, as one of the above posters noted, the runway acceptance rate is currently the critical bottleneck in the system. All the wizz-bang ATC upgrades in proposal right now aren’t going to help acceptance rate. Handling more aircraft is really just a matter of building more runways at this point.

• [bcsizemo]

  I do always love how engineers look at something and go yeah I can make that better. And where do they start? With all the area they want to make better. And what don’t they do? Talk to anyone who has any long term experience in the field, with the equipment, and study the WHOLE issue before just building something new.

  Sometimes I wish they would add a class in how to engineer to the curriculum.

  • [Anonymous]

    Wow. I don’t think you know how many people were involved in this project, including MANY people who have had many years of experience in industry. Do you think someone just arbitrarily drew this cartoon? Lots of design reviews were held with experienced engineers, aircraft manufacturers, and engine companies. Don’t criticize a design process you know nothing about. End.

• [Art]

  I dunno’.

  Perhaps the MIT people have just a eeny-teeny bit of a technical edge, conceptually, over the average blog commenter.

  I’m just sayin’.

  • [Moriarty]

    Wrong! The average blog commenter has technical expertise in every field, is a close family friend of everyone of significance, and can see the future.

  • [querent]

    That’s my knee-jerk too, but science is open-source and position =! credulity.

    Even so, “Extraordinary claims require extraordinary evidence,” or some such.

    :)

• [Anonymous]

  Are you really questioning Mark Drela?

• [tim]

  Uncontained engine failures – by which I must assume you mean fan blades etc going whizzing all over the place – are very very rare. I know a bit about this stuff since I worked (a long time ago admittedly) for Rolls-Royce Aero and actually managed some of the tests done to try out ways of preventing this problem. For example, the ring around the main fan blades was a pretty sizeable chunk of titanium that stopped failed blades from heading off to slice up nearby passengers – believe me, to a 3ft chunk of titanium alloy shaped like a large ginsu, all passengers are nearby. Later versions used some kevlar as well, as a way of absorbing some of the energy and trying to reduce the total extent of damage to the engine.

  Although it is uncommon on typical airliners you can find quite a few planes with pairs of jet engines next to each other. Consider some models of military fighter for example. There aren’t too many cases of one engine shredding its neighbour.

  The issue I suspect might arise based purely on that illustration is that the reverse thrust setting looks a bit tricky to manage. But you know what? This wasn’t a student class exercise; it was a serious study involving experienced aeronautics engineers. I know Mark Drela and his work and he is *good* at it.

  I do always love how engineers look at something and go yeah I can make that better

  That is kinda the entire point of engineering. And if engineers didn’t do that you’d be sat on the mud trying to work out how that over-smart geek over there managed to kill more springbok than you did so now his family can eat through the dry/cold/whatever season and yours won’t.

• [Anonymous]

  Flying Subsonic! Boring!
  How about Hypersonic. You will be in Tokyo before the high altitude waitresses finish snacks for the passengers.

• [holtt]

  I really wonder about the psychological comfort (or lack of) riding in a really wide bodied plane. There’s something about being near(ish) to a window that’s comforting. If you take it to an extreme where you’ve got 20-30 seats across in a row, I really wonder about how that would feel to be seated in the middle.

  I seriously think you need to start looking at giving each passenger a video screen where they can switch between different live camera views to see “out”

  • [iguanoid]

    “If you take it to an extreme where you’ve got 20-30 seats across in a row, I really wonder about how that would feel to be seated in the middle.”

    If they made the cabin 20 feet high and had big picture windows that curved into the ceiling, I wouldn’t care if I was sitting in the middle. It would be awesome to see the sunrise illuminating a big cathedral-like jumbo plane cabin.

    The thing *looks* like if the engines went out the pilot would just coast it down nice and easy and it would land like a paper airplane. Whether that is true or not I haven’t the foggiest idea. No would be my guess.

    • [holtt]

      Hmm big open cathedral ceilings – I’ll take it!

      While we’re adding to the engineering wishlist…

      How about having dozens of doors on each side of the airplane like your typical metro train? Plane arrives, walkways attach on both sides, doors open, everyone steps out and the plane is empty in a matter of minutes.

• [iguanoid]

  Didn’t Launchpad fly one of those on Ducktales?

• [knoxblox]

  Uh-oh, I see a “riding in a cool-looking airplane upgrade fee” in my future.

• [apoxia]

  “Air travel is becoming more frequent and is expected to double by 2035″

  Yeah right. Where are we going to get the fossil fuels required to make twice as many air trips? I’m dubious that there will be cars in 2035.

• [Anonymous]

  there will be plenty of oil left for airlines when a majority of cars switch to electric motors

  • [Anonymous]

    Although you may think that aiplanes and cars run on the same fuel, you are wrong. When a gallon of crude is refined the different layers(qualities) go to different uses, plastics, Diesel, octane, Jet fuel, pavement. If you reduce cars dependence on oil you just make jet fuel more expensive and gasoline less expensive. Funny enough there is a reason why we love oil so much, it is because it is extremely useful. Nothing is wasted. Yup we can run cars on electricity and it will be mainstream someday, but I have not seen a viable alternative for jet travel other than fossil fuels.

• [Anonymous]

  How is “D” type powered? Shrouded propfan?
  Also, will increased wingspan reduce airport capacity because of required ground space? Tradeoff similar to A380′s intent to add capacity with a larger aircraft, it requires greater airborne separation because of higher turbulence/wake vortices, reducing flights/hr.

  I don’t understand how concept “H” is any different from a BWB or X-48.

  from apr06
  http://www.gizmag.com/go/5587/

  They need to do is figure out pressurization and also stall prevention, like they did with the transition from YB-49 to B-2.

• [elevatedprimate]

  Maybe it’ll work, and maybe it won’t. Maybe it’ll be unsafe because the engines are clustered too closely together. All totally valid questions.

  The more crucial questions come down to aesthetics, though, because that thing is gawdawful ugly.

  • [Art]

    ‘Gawdawful ugly’ is certainly an understatement.

    Aesthetically, it bears all the resemblance to a “design by committee”

    Pity.

• [Chas44]

  Any time you place multiple aircraft engines tightly together, as in this design, you are asking for trouble when one of them has an uncontained failure. It would be interesting to see how that issue would be addressed. I’d also like to find out what the “flat-plate” drag of such a wide fuselage would be. Looks like it would be enormous.

• [technogeek]

  Before we worry about scaling up vehicles, how about we finish scaling up the air traffic control system, which is decades behind where it needs to be?

• [stegodon]

  but can it blend?

• [kmoser]

  Air travel is becoming more frequent and is expected to double by 2035

  Any time I see quotes like this I get suspicious. With such a demand, why aren’t more airlines thriving and even raking in big bucks?

  • [Anonymous]

    The answer to that is simple economics: Supply and Demand.
    “A free market is always at the mercy of its most suicidal competitor”.
    In short, the big players are stepping all over each other, competing on price, cutting each other’s prices – and financial throats.
    That I can fly from Chicago to CA cheaper than I can take a train, and competitive with a bus indicates how relatively cheap air travel is.

  • [Anonymous]

    The Airline companies have been so heavily subsidized for the past have decade that they aren’t thinking about expansion, just survival. They do not turn profits.

  • [ncm]

    Airlines aren’t thriving because of systemic problems in the structure of the industry. Over the reasonably long term, the average airline cannot make a profit, and depends on periodic bankruptcies and similar stunts to continue operating.

    Therefore, airlines go through periodic bankruptcies and similar stunts, and their executives’ salaries continue, while their investors take frequent baths. Strange, isn’t it?

    I don’t believe in that wing. The H looks more plausible.

• [wiredfool]

  The biggest traffic chokepoints currently seem to be runways. Will this help?

  • [Anonymous]

    You’re right about the choke points. The aircraft itself doesn’t help that problem, in fact that is a separate issue. The increase in traffic will likely result in overflows to smaller satellite airports, which makes more and more sense as metro areas expand and access to a central airport becomes more difficult. This aircraft I believe was sized for operations on shorter runways to accommodate this situation.

    The big advantage of the aircraft itself, in terms of the doubling of air traffic, comes in the reduced emissions and fuel burn. If you cut fuel burn and emissions in half but double traffic, you have a chance at keeping tabs on aviation’s overall emissions and oil dependency. You also prevent local communities from getting angry at the increase in traffic, by eliminating particulates and reducing noise on an aircraft basis.

• [Anonymous]

  Some day when I have the money, I want one of these:

  http://www.youtube.com/watch?v=G7G1I6WUIpE&feature=related

  100% less fuel, especially if you connect it to solar cells. Speed, distance, and passenger room might rule it out for commercial use.

• [EdFox]

  Chas44 was right about clustering engines together being a bad thing. Putting them right between the vertical stabilizers also gives me the hives. One bad uncontained fan failure and you might be lacking control surfaces. They’re also in the perfect place to ingest a huge amount of precipitation and/or ice that accumulates on that big, flat fuselage before takeoff.

  Then there’s that glider-like high aspect ratio wing. Very efficient, yes, but structurally a pain and has a low wing loading so you’re in for a nasty ride in turbulence. To say nothing of making it fit in a gate.

  Yeah, I know, all negative. I will give it points for being able to be evacuated and looking like what the public thinks an airliner should look like. Some of the really odd designs I’ve seen you’d have large numbers of people just refusing to board.

• [Anonymous]

  As someone who is involved in the credit card rewards industry, I can tell you that demand for air travel is plummeting. It is being replaced in its most profitable segment – business travelers – with on-line conferencing. Expect that to accelerate as businesses become extremely cost conscious and on-line technology goes through the roof. These air travel projections are grossly exaggerated to serve the needs of airline builders and the grant seekers of MIT. Please remember that this grant was issued long before the economic meltdown and is woefully behind the times. Duane

• [JohnStClair]

  Putting the engines together in the back of the fuselage will create wormholes into hyperspace. When airplanes of this design take off from Florida, the crew finds itself somewhere near Africa after having passed through the wormhole. The wormhole is created by environmental oscillators having a range of frequencies and temperature. This changes Planck’s constant causing the electron and proton to move out of dimension. In order to return to Florida, the plot retraces the path back through the wormhole and the crew and passengers are back to where they started. Also, a turbine failure in one engine will rip through the other engine as has already happened with the Boeing 727. MIT should concentrate on developing soft space-time teleportation systems where the passenger simply steps through a black inky soft water-like space-time in order to teleport to another teleporation mall. Airplanes and launch rockets are obsolete.

  • [Anonymous]

    I *loved* your comments! Very, very clever.

  • [2k]

    Look out Sam!!!
    The Langoliers are right behind you!
    NOM NOM NOM.

  • [millrick]

    “This changes Planck’s constant”

    Dude! You cannot change a constant! It’s a constant, not a variable.
    However, by inverting the protonic phase polarity you can ride the electron flux through into a alternate universe of your choice. Simple really…