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

Soulskill posted more than 3 years ago | from the in-other-news-aircraft-refuelers-laid-off dept.

Transportation 459

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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459 comments

hmmm (4, Interesting)

meerling (1487879) | more than 3 years ago | (#32243518)

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

Re:hmmm (0, Funny)

Anonymous Coward | more than 3 years ago | (#32243556)

interesting. Does anyone else like to stuff sausages up their asshole?

Re:hmmm (4, Interesting)

gyrogeerloose (849181) | more than 3 years ago | (#32243622)

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.

Re:hmmm (1)

Qzukk (229616) | more than 3 years ago | (#32243896)

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:hmmm (1, Redundant)

h4rr4r (612664) | more than 3 years ago | (#32244010)

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:hmmm (2, Interesting)

robot256 (1635039) | more than 3 years ago | (#32244176)

Yeah...except it hasn't actually ended yet. Will Obama veto a budget with irrationally-mandated Constellation spending? Only time will tell.

Re:hmmm (1, Troll)

h4rr4r (612664) | more than 3 years ago | (#32244392)

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 (4, Interesting)

ircmaxell (1117387) | more than 3 years ago | (#32243984)

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 (1)

jcr (53032) | more than 3 years ago | (#32244418)

If you're thinking of the QSST project, that looked pretty interesting, but i think they might have gone out of business already. Their web site seems to have gone missing.

-jcr

Re:hmmm (1)

EdZ (755139) | more than 3 years ago | (#32244124)

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.

Re:hmmm (1)

GameMaster (148118) | more than 3 years ago | (#32244210)

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.

Re:hmmm (1)

h4rr4r (612664) | more than 3 years ago | (#32244422)

They also magicked the fuel cost away?

The faster you go the more drag you have the more fuel you burn.

Re:hmmm (1)

MBGMorden (803437) | more than 3 years ago | (#32243694)

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 ;).

We already have those (-1)

Anonymous Coward | more than 3 years ago | (#32243550)

They're called blimps.

How Fast? (1, Interesting)

Bruiser80 (1179083) | more than 3 years ago | (#32243578)

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 ;-)

Re:How Fast? (1)

fahrbot-bot (874524) | more than 3 years ago | (#32243982)

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:How Fast? (1)

Kell Bengal (711123) | more than 3 years ago | (#32244444)

What the longer wings make me wonder is "Where are you going to park it?" Apron space at airports is already critically limited. How on earth do they expect to dock something with absurdly long wings?

So Lets See, (-1, Troll)

rshol (746340) | more than 3 years ago | (#32243592)

They've built one of these things, flown it around and measured its fuel consumption. No you say? Then all there are artists' renderings of speculative aircraft that on some computer models appear to perform in the manner stated. Nothing to see here, move along.

Re:So Lets See, (3, Informative)

MBGMorden (803437) | more than 3 years ago | (#32243744)

Having a viable prototype design that's gone through simulations and the like is a lot more than artists renderings. What the hell do you think they do to make an airplane? Take some steel, rivets, and aluminum out to the hangar and just see where things end up?

Re:So Lets See, (1, Funny)

Dun Malg (230075) | more than 3 years ago | (#32244048)

No, you're supposed to throw a bunch of airplane parts in a hangar and have a hurricane assemble them into a 747.

That's how creationists think evolution works, anyway.

Re:So Lets See, (1)

Red Flayer (890720) | more than 3 years ago | (#32244090)

Take some steel, rivets, and aluminum out to the hangar and just see where things end up?

The hospital or the morgue, most likely.

Actually, that sounds like a really fun time. Back in college my pals & I used to do junkyard builds once or twice a year... go salvage parts and see what we could build. We never built anything cooler than a go-cart from scrap, but one of the guys made some pretty interesting bongs.

Re:So Lets See, (1)

FuckingNickName (1362625) | more than 3 years ago | (#32244200)

Argh, you're missing the point: designing a novel structure in a CAD tool optimised for some known series of simulations (i.e. knowing which parameters are relevant to each simulation and adjusting for them) is not the same as proposing a design which can be prototyped, built, tested, flown... and paid for.

Re:So Lets See, (1)

asukasoryu (1804858) | more than 3 years ago | (#32243778)

Now that the designs have been revealed the teams are awaiting news in the next few months of which designs will receive funding to go on to the second phase of the program.

You have to start somewhere. You can't just go around funding every breakthrough concept and building real-world prototypes with the necessary instrumentation to measure impact. But I agree. This would be more newsworthy if MIT had actually been chosen to receive further funding.

Re:So Lets See, (1)

Goaway (82658) | more than 3 years ago | (#32243808)

Yes, simulating the performance of an airplane is impossible, even for a computer!

Re:So Lets See, (3, Funny)

EdZ (755139) | more than 3 years ago | (#32244186)

It's not impossible. I used to bullseye flow dynamic calculations on my Ti-15 back home, they're not much bigger than two OOM.

Re:So Lets See, (0)

Anonymous Coward | more than 3 years ago | (#32244496)

It's not impossible. I used to bullseye flow dynamic calculations on my Ti-15 back home, they're not much bigger than two OOM.

Then man your calculator. And may calculus be with you.

Re:So Lets See, (2, Informative)

Chris Burke (6130) | more than 3 years ago | (#32244158)

I would like to give you the benefit of the doubt as a result of the flattering implication that engineering involves artistry, but on the whole you've got such an ignorant and insulting view of aerospace engineering that I can't call it anything but ignorant and insulting.

Burt Rutan drew up some "artists' renderings" (they're called CAD models usually) of a plane that in computer models appeared to be able to circumnavigate the world without refueling. Then they built it and it did.

Aerospace firms around the globe rely on computer models to predict the aerodynamic behavior of everything from commercial airliners to supersonic fighters. They use these models because they work. They may not be perfect, but they can be used to reliably predict the behavior of designs in the real world within a margin of error.

The idea that just having the computer model means there's "nothing to see here" is simply wrong. Anyone with a clue would be impressed that they could demonstrate these fuel savings even though they are just in a simulation.

Intrigued to know more (3, Insightful)

ICLKennyG (899257) | more than 3 years ago | (#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.

Re:Intrigued to know more (5, Insightful)

AnonymousClown (1788472) | more than 3 years ago | (#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:Intrigued to know more (2, Funny)

blair1q (305137) | more than 3 years ago | (#32243962)

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...

Re:Intrigued to know more (0)

Anonymous Coward | more than 3 years ago | (#32244486)

Hey sounds like my university.

Fear not... (0)

Anonymous Coward | more than 3 years ago | (#32244480)

In 20 years, we'll still be flying on broken-down MD-80s, praying that the fuel tanks don't ignite. But feel free to continue buying your carbon indulgences. Algore will thank you.

Re:Intrigued to know more (4, Informative)

Chris Burke (6130) | more than 3 years ago | (#32243772)

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. :)

Re:Intrigued to know more (1)

e2d2 (115622) | more than 3 years ago | (#32244450)

Also to add to your argument, one should measure usable lifting capacity and not the number of passengers. Relative comparisons would also need a great deal more in order to be a fruitful comparison.

For instance relevant speeds such as cruising speed and climb speed, useful altitudes such as cruising altitude (big difference in ground speed as you climb in altitude), total weight, take off weight, total usable weight, take off distance, landing distance, etc etc. Too many to list here.

Re:Intrigued to know more (1)

buback (144189) | more than 3 years ago | (#32243970)

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)

Re:Intrigued to know more (1)

rainmouse (1784278) | more than 3 years ago | (#32244098)

Speed should probably also be a factor, otherwise surely a blimp design would beat all other entries.

Slower than current aircraft (5, Interesting)

sunderland56 (621843) | more than 3 years ago | (#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?

Re:Slower than current aircraft (5, Informative)

sznupi (719324) | more than 3 years ago | (#32243832)

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....)

Re:Slower than current aircraft (1)

StikyPad (445176) | more than 3 years ago | (#32244040)

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:Slower than current aircraft (2, Informative)

pittance (78536) | more than 3 years ago | (#32244366)

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.
Generally you can get higher efficiency by flying slower but you have to make changes to the aircraft, as seen here where much of the efficiency probably comes from the lower lift dependent drag that you can get from the larger spans of these aircraft. They probably get quite a lot of gain from engine improvements also, perhaps half.

*all bets are off with open-rotor or propellor engines, broadly these like to fly slower overall and you lose efficiency steadily the faster you fly.

Re:Slower than current aircraft (1)

sznupi (719324) | more than 3 years ago | (#32244368)

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 destination, had to land midway for refueling; that was on local trips, most likely with fuel tanks full at the start)

Re:Slower than current aircraft (0)

Anonymous Coward | more than 3 years ago | (#32244398)

Unfortunately also jet engines efficiency curves drop of sharply at lower thrust, so most economical cruise is not the slowest.

Oh well.

Re:Slower than current aircraft (2, Informative)

thrich81 (1357561) | more than 3 years ago | (#32244488)

Sorry to differ here, but "using anything over the minimal amount of fuel you need to move will necessarily result in decreased efficiency" -- is not accurate. Aside from the parasitic ("wind resistance") drag which increases non-linearly with airspeed, all aircraft suffer another drag, "induced drag" which is a direct effect of generating lift. Induced drag is greater at low airspeeds and decreases with increasing airspeed. So for any given aircraft weight and configuration there is a compromise ("max range") airspeed which gives the best fuel economy per mile traveled. It is not even true that the airspeed which gives the best endurance (least fuel per minute) is the slowest speed at which the aircraft will stay airborne. Again this is a compromise between parasitic and induced drags. Max range airspeed is pretty fast in jet aircraft -- I'm not an airline pilot but I suspect that they fly near max range airspeed a lot.

Re:Slower than current aircraft (1)

buback (144189) | more than 3 years ago | (#32244112)

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

Re:Slower than current aircraft (1)

nelsonal (549144) | more than 3 years ago | (#32244370)

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:Slower than current aircraft (1)

Aviation Pete (252403) | more than 3 years ago | (#32244436)

the current booking systems sort the flights in order of flight time, fastest first. So buying and flying slower jets means that you end up not on page one, but way behind the competition. That's why the A 380 had to be designed for a cruise speed of Mach 0.85, quite a bit more than what would have been the optimum speed for efficiency.

Re:Slower than current aircraft (1)

PitaBred (632671) | more than 3 years ago | (#32244462)

Hell, even if it was an extra hour. The people who care about getting there NOW already have their own planes.

Re:Slower than current aircraft (1)

Aviation Pete (252403) | more than 3 years ago | (#32244372)

acually, the current jets fly at optimum transport performance, meaning that they fly quite a bit faster than the speed at which the fuel consumption per distance traveled is minimal. The idea is that the plane will fly more trips per day, thus earning more money (and eating up more fuel per trip than necessary). On the whole, this is the most efficient use not of fuel, but of money.

Re:Slower than current aircraft (5, Interesting)

h4rr4r (612664) | more than 3 years ago | (#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:Slower than current aircraft (2, Interesting)

vlm (69642) | more than 3 years ago | (#32244172)

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 flightplan makes 3 trips per day. And the 10 hour flightplan (drumroll as slashdotters get out their HP-48 calculators) makes 2.4 flights per day.

So, your 10 hour flightplan, in addition to lowering revenue by 30%, lowers total DAILY revenue, just due to scheduling by (3-2.4)/3 = 20%. Now you can play games with percentages all day, but be careful adding them or applying one on top of another. Even worse, To continue shipping the same number of bodies around in their current cattle car style, they need 20% more planes. And 20% larger maintenance facilities to process 20% more planes. And 20% more management overhead to supervise the 20% increase in staff. And a 20% higher bond/rent payment to pay for those planes.

And some people simply don't enjoy sitting in a cattle car. So they'll spend a little more dough to avoid it.

I would casually estimate that slowing the planes down with that discount would lower revenues "about" 50% while increasing expenses across the board roughly 25%. Profit margins are low enough that its unlikely any airline could survive that.

If anything, to survive, an airline that slows down "to save the planet!" is going to have to increase ticket costs modestly.

Re:Slower than current aircraft (1)

pavon (30274) | more than 3 years ago | (#32243914)

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.

Re:Slower than current aircraft (4, Informative)

schon (31600) | more than 3 years ago | (#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.

Re:Slower than current aircraft (4, Interesting)

LWATCDR (28044) | more than 3 years ago | (#32244284)

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.

How to pressurize it? (2, Insightful)

mangu (126918) | more than 3 years ago | (#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.

Re:How to pressurize it? (3, Interesting)

ThreeGigs (239452) | more than 3 years ago | (#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.

Delivery date (1)

Anonymous Coward | more than 3 years ago | (#32243616)

Wtf, they aim to do this by 2035. There will be better designs by then. And probably not just in theory...

Re:Delivery date (0)

Anonymous Coward | more than 3 years ago | (#32244096)

yes because designing, testing, and putting into production a new airplane is a near instant process due to the magic of technology.

if you didn't pick up on the sarcasm there, it takes a long fucking time for a new airplane design to actually get used for commercial air traffic. unless someone has a better design ready to go right now, it's not gonna be in the skies by 2035.

Re:Delivery date (1)

zz5555 (998945) | more than 3 years ago | (#32244330)

Not likely. There's not a lot new in aerospace engineering. The hybrid wing body version has been around for a long time - I had a friend that was a senior engineer at Douglas aircraft and he tried pushing the idea in the '80s. But it was always rejected back then as being too different. I wouldn't be surprised if someone had already considered the double bubble before, as well - it looks familiar. They might be able squeeze a bit more efficiency, but aerodynamics is a pretty well understood science. The big challenge will be to get a manufacturer to build one. Boeing and Airbus are used to building something that looks roughly like a 747 and it may take some "encouragement" (ie, money) to get them to change. And they're not likely to build them unless an airline or two commits to buying them (which is usually how new planes get built).

Questions (1)

Thelasko (1196535) | more than 3 years ago | (#32243654)

The picture of the plane raises all kinds of questions? What are the wings made of? Where do they store the fuel?

Re:Questions (2, Insightful)

blair1q (305137) | more than 3 years ago | (#32244108)

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.

Re:Questions (1)

amicusNYCL (1538833) | more than 3 years ago | (#32244122)

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!

Re:Questions (1)

KlaymenDK (713149) | more than 3 years ago | (#32244238)

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.

Wing length is a Really Big Deal (4, Interesting)

PPalmgren (1009823) | more than 3 years ago | (#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.

Re:Wing length is a Really Big Deal (0)

Anonymous Coward | more than 3 years ago | (#32243846)

Biplanes?

Re:Wing length is a Really Big Deal (0)

Anonymous Coward | more than 3 years ago | (#32243930)

The bent tips of plane wings have nothing to do with lift or maximum wing length, theyre to prevent vortices forming

Re:Wing length is a Really Big Deal (1)

AndersOSU (873247) | more than 3 years ago | (#32244164)

Which increases lift...

Re:Wing length is a Really Big Deal (1)

dwye (1127395) | more than 3 years ago | (#32244244)

No, decreases drag.

Re:Wing length is a Really Big Deal (1)

AndersOSU (873247) | more than 3 years ago | (#32244404)

both actually.

The vertical winglets keep the high pressure air on the bottom of the wing and the low pressure air on the top of the wing. The elimination of that spill-over increases lift.

Votricies are aerodynamically messy, causing drag.

Re:Wing length is a Really Big Deal (0)

Anonymous Coward | more than 3 years ago | (#32244446)

No, decreases drag.

Which has the effect of an increase in lift.

Basically, you have your actual lift (L), which is then impacted by your drag (D), resulting in your effective lift (EL). Simply put, EL = L - D. If you decrease D, you increase EL.

Re:Wing length is a Really Big Deal (1)

KlaymenDK (713149) | more than 3 years ago | (#32244364)

Parent is absolutely correct; those "bent tips" prevent the air near the tip of the wing from "slipping off sideways" instead of taking the longer, more lift-producing, route straight back across the wing. You can then trade that added lift for a shorter wing.

Re:Wing length is a Really Big Deal (4, Informative)

pavon (30274) | more than 3 years ago | (#32243992)

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

Re:Wing length is a Really Big Deal (0)

Anonymous Coward | more than 3 years ago | (#32244166)

You are correct. Basically the largest plane is the 747 at least as an airport is concerned. For example jetways are made to load and unload at specific heights and locations. Distance between jetways is set at a particular width plus equip that needs to get around between the planes. This also effects the 'lounge' areas. Some airports are a bit more flexible in what they can do. However many are not. It would still cost a fortune.

Consider somewhere like ohare where there are literally 40 parking spots lined up down both sides in 1 concourse. A 737 is about 95 feet across. 10 feet more means you lost 400 feet. That means 4 less planes can park and fill up and wait for their launch window. You can get 100-150 people in 1 737 depending on how you configure it. So the new way better have capacity for about 20-50 people extra as you can spread it out over all the other planes. For smaller airports they are going to want even more capacity.

A *GOOD* majority of the airports out there are designed for three planes. The 747, 737, and the DC10. Most of the new construction I have seen has been in adding in 'commuter' style concourses. With 'turboprop' planes. More planes in the same area. Some of them doing away with the jetway all together. This gives airlines more flexibility into which airports they can fly into. It also lets the 'grow/shrink' routes more easily.

If they had done this same 70% thing with a commuter style plane that would have been much more interesting.

Re:Wing length is a Really Big Deal (1)

blair1q (305137) | more than 3 years ago | (#32244168)

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:Wing length is a Really Big Deal (2, Interesting)

dwye (1127395) | more than 3 years ago | (#32244508)

> 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.

Great... now its up to the aerospace companies... (1)

jacks smirking reven (909048) | more than 3 years ago | (#32243668)

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:Great... now its up to the aerospace companies. (1)

91degrees (207121) | more than 3 years ago | (#32243890)

I think it's more that it's really expensive than too regulated. To get a positive return on investment, the big aircraft companies need to sell hundreds of planes. You're investing billions before you get a penny back.

Re:Great... now its up to the aerospace companies. (2, Informative)

sznupi (719324) | more than 3 years ago | (#32243994)

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...

Re:Great... insurance (4, Interesting)

dltaylor (7510) | more than 3 years ago | (#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.

Can it fit into most airport's taxiways and gates? (2, Interesting)

gront (594175) | more than 3 years ago | (#32243696)

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

Re:Can it fit into most airport's taxiways and gat (1)

Taibhsear (1286214) | more than 3 years ago | (#32244144)

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.

Re:Can it fit into most airport's taxiways and gat (1)

pittance (78536) | more than 3 years ago | (#32244474)

It's not beyond current capability even in civil aviation, in fact Boeing offered a folding wing option for the 777 but (so far) no-one's bought it.

This is partly due to lack of driver (gates at airports were either wide enough or made wide enough) but also because any driver to wing folding's got to be pretty strong to overcome the weight penalty

If you were to see a _big_ increase in span for aircraft of these capacities I'd imagine that folding wings might become more popular...

Re:Can it fit into most airport's taxiways and gat (1)

Chakotay (3529) | more than 3 years ago | (#32244182)

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 approaches, though, and if you were to have to break off your approach for some reason the advantage would be completely lost...

Type D ment to work with existing airports (4, Informative)

buback (144189) | more than 3 years ago | (#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.

Wallpaper (0)

Anonymous Coward | more than 3 years ago | (#32243792)

I would love to see a higher-resolution of these pictures to use as a wallpaper.

Ceteris Paribus? (1)

ShadyG (197269) | more than 3 years ago | (#32243796)

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.

H-series looks like existing concepts... (1)

fauxhemian (1281852) | more than 3 years ago | (#32243852)

The MIT H-series looks rather like the Boeing X-48B: http://www.boeing.com/news/releases/2006/q4/061027b_nr.html [boeing.com] Regarding the D-series - is it using ducted Propfans? - I couldn't find any information. The biggest problem with the Propfan technology appeared to be the noise produced by blades spinning at near or above supersonic speed. But it didn't seem insurmountable and ducting would seem like an obvious place to start in order to mitigate it. Although obvious to someone who has no aerospace training whatsoever, probably means "obviously stupid" in engineering terms.

Sensationalism from the article (1)

jareth-0205 (525594) | more than 3 years ago | (#32243932)

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]

Both of TFA's linked sadly lacking in details (5, Interesting)

Larson2042 (1640785) | more than 3 years ago | (#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.

Expected in 2035? (1)

ClickOnThis (137803) | more than 3 years ago | (#32244206)

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.

Re:Expected in 2035? (1)

Frekja (982708) | more than 3 years ago | (#32244346)

Yeah - 2035? Emissions from aircraft are the fastest rising source of emissions in UK, and I'd be surprised if that wasn't the case in the rest of the EU and the US as well. If we can design this now - assuming we don't need to invent anything new to build it - why not build it by 2020 (allowing for a generous 10 year design, testing and roll-out?)

Maybe because Boeing/Airbus have just spent huge amounts of money on their current generation of plane and want to recoup R&D costs over the next 25 years the way they have with the ridiculously old airframes (eg. 747 - designed in the 60s) that we are now flying. These are precisely the sort of technological changes that we need to be building if we're going to be able to keep flying and keep the climate somewhat liveable.

NASA outsourcing. (1)

irreverant (1544263) | more than 3 years ago | (#32244400)

Seems a smart way of outsourcing initial research and conceptual design of a project while working with a diminishing budget.

I wonder which engines they used ... (2, Interesting)

Aviation Pete (252403) | more than 3 years ago | (#32244502)

So far, two thirds of efficiency improvement has been gained by the engine makers, not the airframe designers. If those planes are intended for 2035, I suspect that the guys at MIT extrapolated the current engine efficiency a quarter of a century into the future and had already half of the savings pocketed, without having to improve the airframe a bit. Attaching glider-like winks did the rest, easily.

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