Automobile design has changed drastically over the last half century, and computers have gone from filling entire rooms to fitting neatly in our briefcases. The Boeing 737, however, has changed very little. An MIT team aims to bring aviation into the 21st century with two bold new designs for commercial airliners that could trim fuel use by up to 70 percent while increasing passenger capacity.
The designs -- dubbed D series and H series -- are part of a $2.1 million research contract from NASA to develop the next generation of subsonic airplanes (separate grants were given to Boeing and Lockheed Martin to design supersonic concepts). Competing with designs from GE Aviation, Boeing and Northrop Grumman, the object was to create a passenger jet that burns 70 percent less fuel, cuts emissions of nitrogen oxides by 75 percent, takes off from shorter runways, and reduces sound pollution.
MIT's solution: A "double bubble" architecture that relies on a dual fuselage design -- that is, two cylindrical structures placed side by side to make up the fuselage rather than a single tube-and-wing structure (such that a cross section would resemble two soap bubbles fused together). The design allows for a wider, shorter fuselage that should help passenger loading and unloading as well as increase seating capacity.
But the real innovation is in the engine placement. Rather than wing-mounted turbines that scoop up the untouched fast-moving air away from the fuselage, the tail-mounted D series engines suck up the slower-moving air coming off the wake of the fuselage. This Boundary Layer Ingestion (BLI) technique allows less fuel to be burned while generating the same amount of thrust, allowing the D series design to hit the 70 percent fuel reduction goals outlined by NASA.
NASA envisions aggressive designs like the D series taking flight by 2035, when air traffic is expected to double from current levels. To bridge the gap, MIT also mocked up an H series plane based on the same design principles but using current jet technology and conventional aluminums that achieves a 50 percent fuel burn and could serve as an alternative until something like the D series becomes standard.
There are drawbacks to both designs of course. The rear engine layout would increase engine stress, and both planes would travel about 10 percent slower than a 737. But given the fuel savings and reduced runway real estate needed to launch and land the D series, a small concession in flight time sounds pretty reasonable.
I would strongly vote for increasing speed as a major requirement, as time is becoming even more valuable and travel in a plane is usually not the best way to spend one's time. I'd drop subsonic plane designs completely in lie of supersonic, as they are able to travel both sub and super sonic speeds thus minimizing air pollution at takeoff/landing, while going full speed in between.
@javamann888 I agree... also, supersonic speeds also yield other benefits such as higher altitudes and smoother air-travel. The technology exists to "supercruise" at supersonic speeds with out the need to after-burn, saving fuel and reducing noise. In addition, many advancements have been made in quieting or redirecting the sonic boom which is in most cases a deal-breaker (esp. in metropolitan areas).
Javaman, I don’t see how using supersonic transports would create less pollution. As a general rule supersonic aircraft are extremely inefficient when they are low and slow. They would use much more gas than a subsonic aircraft of similar weight at takeoff/landing and therefore create more pollution.
I'm not sure concentrating on supersonic would be cost effective. For one, as democedes pointed out, they are horribly inefficient when going slow. Secondly, i would be willing to bet that the majority of all flights taken worldwide don't fly long enough to make a supersonic aircraft cost effective. The majority of fuel burnt also happens in the first hour of flight. So, you would need a good amount of flight time to make it worth the extra cost of fuel while in that first hour (which would likely be almost all subsonic.)
Supersonic aircraft also require a narrower fuselage and wing then subsonic. This results in a lower passenger and cargo capacity. So you would need more supersonic to carry the same amount of passengers/cargo then a sub. Maintenance costs per supersonic are also significantly higher then compaired to subsonic (not to mention the afore mentioned increase amount of aircraft needed.)
It would be nice to get place to place faster, however, cost and convienance have to balance out. For now, supersonic doesn't meet that. Perhaps when better, more cost effective, materials are developed then they will be effective.
Well i think these are good starts, but making the concession to reduce speed should not be accepted. Not saying supersonic should be the goal, but 737's arent flying that fast as it is. But i really like this thinking. the current 737 replacement is just going to be an improved 737 basically. A complete redesign of the airline industry should be our goal, and these planes are based off knowledge of aerodynamics and general knowledge of decades ago.
How would combing these plane designs with those housing-free plane engines? (article couple weeks ago i think)
Why so much fuss about speed?
It would take a long ten hour flight just to add one hour of time. Most people waste far more than an hour a day just vegging out in front of a screen.
70% fuel savings, however, means a 35% reduction in ticket price, which means that prices will stay the same - without the 30th airline bailout from the government. Since I never fly, I would like to not have my tax money propping up the airlines.
@ oakspar. if we spend 10 hrs infront of a screen then why not just put a screen infront of the person on the plane?
that takes care of the time waiting and sitting and also provides entertainment and communication
Increased time in flight means reduced number of flights per day, means reduced potential profit, so i dont see that reducing bailouts. The goal should be to get something done fast and efficiently, not one or the other. domestic flight times havent changed much in the past 30 years or more. Increased flight times with out substantial passenger capacity increases means they will either need larger fleets of planes, or reduced number of flights per day.
The seeker of knowledge who seeks to reach beyond the stars to go where no mans gone before to see things no man has seen and bring these experiences back for the whole world to hear and see.
Well let me lighten your ideas. we as a modernized culture havent really expanded our civilian planaes in a long time mainly becouse of the cost and their wasnt a need to they were making plenty of money on the design aircrafts they had in service already but do to higher fuel costs and larger quantities of people commuting and traveling through
airports has now given them probable couse to switch to a more efficient design so they can save money while maintaining the original cost to fly for civilians. they will make tons of money. while you get to enjoy a longer flight time thats what i have derived from this article it's a pity our nations more for buisness than the civilians that make them rich.so i hope you dont expect anything greater than better looks couse you're going to pay the same fee while they save money and you get to enjoy a longer flight time. Now i don't want to shun the technical extravigance of it couse the air craft are very beutiful and are less of an eye sore the it's previouse behemith and this will cut down on the large co2 emitions that traditional air craft spue.But don't expect you're plane ticket to cost less it just may raise .Good job nasa for their fabuluse design i just hope these major corps will pass the saving to their customers.all who don't know much about this kind of stuff this is a great step forward in our evolution and i look forward to this new addition to our technical magnifigence.and who ever's reading this have a great day i mean it and even in dark times if you stay strong your path will be lit and you will be guided in due time dont let things get you down and find the good everythings.have a great day to all and a even greater week.
Teleportation is the answer for fast pollution free transportation but that will probably take 100-200 years of human engineering. It will require paradigm shifts about time and space (time I suspect being an illusion: there is no past present or future, there just is.)
For now, I agree that these planes need to be supersonic in addition to being quiet and fuel efficient.
The double bubble idea was explored by Airbus for the initial studies for the A380 (it was going to use two A340 fuselages side by side), but was dismissed for being impractical and not a little bit comical. Interesting how the idea hasn't quite died.
There are complications with a rear engine arrangement, such as balance considerations. Even small increases in engine weight means a much longer fuselage ahead of the center of gravity. That's why later versions of the DC-9/MD-80 looked the way they did.
The upper-body mounted engines are also harder to maintain. There's a good reason why airliners all look very similar. Aviation history is riddled with the carcasses of a lot of unusual design configurations that never got near to leaving the ground.
Exploring and adopting alternative fuels, such as those derived from jatropha plants (already test-flown by at least 3 airlines) and algae, sound like a much better way to go.
The airlines would just cram more people in and give business class even more space. Lets face it the idea of travelling to far away places is great but the reality is crap; having to book in 2 hours before the flight going through the security check, then the boring flight and finally waiting for your luggage and getting through customs.
MIT was one of 4 teams doing subsonic design. Boeing, GE Aviation and Northrop Grumman are also in the mix.
Next step is for NASA to decide who goes forward.
Interesting to see that similar concepts have been tried before. Not saying that this can't work, but it doesn't seem to be a 'gimme'.
@nizeke they did mention capacity increases, which in some of the designs of seen from companies is 50%. So with a 10% increase in time but a 50% increase in passengers, I think they will get there money. These planes won't be used on every flight though, only ones between major cities where flights fill up more. If they were to implement them in destinations where people don't fly much, then yes, your point is very valid because no matter how much you add on to the capacity, if you don't fill the flight, the money isn't coming in.
You have to look at that its not just the fuel savings but the capacity increase. So when you fly one of these new fangled airplanes, you can ride for much cheaper than todays rate, but there profit margin will be greater. That all still depends on how much these cost to build and maintain, and of course, how long they last. Especially if the extra stress starts causing planes to rip apart mid flight.
Awesome! More profit for the Airlines! Because I have zero hope that the reduced cost for fuel would ever translate into cheaper tickets for the rest of us.
Cutting fuel consumption by 70% is well worth the extra flight time, in my opinion. Yes, I do believe that we do need to be increasing our transportation speeds, but such a large fuel cut is worth it.
It is true that planes are have relatively evolved very little since they jet airliner came out, when cars have changed a lot. This seems to be a wonderful idea, but it might upset some people who want the hyper-sonic jetliner that goes from London to Sydney in 2 hours. Either way this MIT idea is better and more practical, for now.
I wrote to Boeing shortly after they announced the SonicCruiser - about 8 - 10 years ago - saying that they should be building planes that travelled more slowly, for the sole purpose of using less fuel. Sonic was to travel within a few % of the speed of sound - thankfully it was forgotten, soon we will have the Dreamliner.
But anything we can do to further reduce fuel use - fossil or sustainable - is an excellent goal. 70% in my mind is unattainable, & cannot see how the much larger surface area of a double fuselage over say a cylindrical or elliptical section can save fuel.
Nobody is that important that they have to fly fast at the expense of the environment. Is anybody more important than the earth?
Decrease by 70% - YES PLEASE!
Check out cookaerospace.net for a seaplane version of the blended wing body type airplane pictured on the right above. The seaplane is intended for disaster relief when airports with long concrete runways are not available or swamped with traffic.
The cookaerospace.net seaplane would not be fuel efficient, but would be a VSTOL transport and a very heavy lifter of disaster relief supplies.
this is the kind of plane we need, who cares if it goes 10% slower, I would rather have a cheaper plane ticket, then getting there faster on a gas guzzling 737, and the design looks super cool
I dont look busy because I did it right the first time
A huge problem with supersonic airplanes if you forget about fuel use, increased sound, increased runway length, and all the other things is fatigue. A plane going through the sound barrier gets much more fatigue then other planes. The sound barrier really is a barrier planes take a real beating going through it. They require extra maintenance especially from metal fatigue when a plane goes faster than sound it actually gets longer as it breaks the barrier. They require fewer windows because those are very high stress points. When something does go wrong at supersonic speed usually its catastrophic. I do think a new line of planes should fly faster if they can get the increased fuel efficiency. Being able to use shorter runways for takeoff and landing would really help. A bunch of technology that has been added on to planes such as the 737 could be integrated from the beginning. I think one of the biggest things though would require a combination between aircraft and upgraded air traffic control. With more and more planes flying being able to run them closer together so a airplane based system that could monitor all other aircraft around it and a ground system that could do the same have them linked where they share info and planes would be able to fly much closer together then they do today and do it safely.
H Series, eh?.. *Cough Cough* Can I say Burnelli?
Pixurman: IF the designers were actually interested in transporting PASSENGERS in their "Magnificent Flying Machines", they would design them for OUR comfort, NOT their PR VERSIONS. I love to fly, but absolutely HATE to fly COMMERCIAL SARDINE CLASS. I'd rather fly 12 hours in a Cessna than 2 hours in their NOT Friendly Skies. Corporate greed has made flying and misery as one in the same.Don't move and don't breathe.
These days I DRIVE more than I fly. Last trip was 2 days down and 2 days back from Wisconsin to Florida, and it was the best trip to Florida in 10 years, with more ROAD trips to come.