MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#1

Post by cwan » Wed, Oct 06, 2010, 7:45 PM UTC

MIT proposes to Reinvent the 737 for 70% greater fuel efficiency
nextbigfuture.com

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#2

Post by jws » Wed, Oct 06, 2010, 10:13 PM UTC

From browsing http://aviationweek.typepad.com/files/mit_n3_final_presentat... …

• It's all about radically different fuselage design.

• 10% slower than current, think they might pick it up by saving 15 minutes on load and unload because of multiple aisles.

• The 777 model has no windows in economy class, and apparently no doors visible either. They are 9 row deep pods with 3/2 seats and a lateral aisle at the front. That is going to take some getting used to.

• There is a slide that says the N+3 numbers are reached with "advanced technology insertion". I am reminded of a Sidney Harris cartoon: http://avionod.wordpress.com/2009/04/06/and-then-a-miracle-h...

• They will fly higher, 40k feet and 45k feet. No word on how that changes turbulence, I presume it helps.

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#3

Post by edfrtghjkjh » Wed, Oct 06, 2010, 10:17 PM UTC

5% saving with better aerodynamics - at huge cost in changing every runway, taxiway, jetbridge, hanger and terminal to handle the new shape/size/layout

65% saving from new engine design based on unobtanium

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#4

Post by hugh3 » Wed, Oct 06, 2010, 10:19 PM UTC

edfrtghjkjh wrote: post #3

5% saving with better aerodynamics - at huge cost in changing every runway, taxiway, jetbridge, hanger and terminal to handle the new shape/size/layout 65% saving from new engine design based on unobtanium

Is that so? I'm struggling to understand how the 70% fuel usage reduction is supposed to occur just by feeding in slower-moving air. Anyone have any insight here?

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#5

Post by jws » Wed, Oct 06, 2010, 10:23 PM UTC

edfrtghjkjh wrote: post #3

5% saving with better aerodynamics - at huge cost in changing every runway, taxiway, jetbridge, hanger and terminal to handle the new shape/size/layout 65% saving from new engine design based on unobtanium

I don't think that is what they mean to say. The slide on page 128 of http://aviationweek.typepad.com/files/mit_n3_final_presentat... for instance breaks down the fuel savings by various changes:

  D8.1 configuration (double bubble)   49%
  Airframe Advanced Materials           8%
  High BPR Engines                      4%
  .. and a long tail that might be 8% more for the engines.

Now maybe the D8.1 configuration is only possible with impossible engines. I can not say.

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#6

Post by notahacker » Wed, Oct 06, 2010, 10:56 PM UTC

jws wrote: post #2

From browsing http://aviationweek.typepad.com/files/mit_n3_final_presentat... … • It's all about radically different fuselage design. • 10% slower than current, think they might pick it up by saving 15 minutes on load and unload because of multiple aisles. • The 777 model has no windows in economy class, and apparently no doors visible either. They are 9 row deep pods with 3/2 seats and a lateral aisle at the front.…

Emergency passenger evacuations for the 777 model could be interesting...

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#7

Post by tailrecursion » Wed, Oct 06, 2010, 11:09 PM UTC

The article claims a 70% fuel efficiency increase, and another quoted part claims a 70% reduction in fuel use. Which is it?

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#8

Post by aidenn0 » Wed, Oct 06, 2010, 11:17 PM UTC

Some of this savings has to be from by going 10% slower? Since drag is quadratic, doesn't that mean a 20% reduction in drag alone?

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#9

Post by sprout » Wed, Oct 06, 2010, 11:42 PM UTC

aidenn0 wrote: post #8

Some of this savings has to be from by going 10% slower? Since drag is quadratic, doesn't that mean a 20% reduction in drag alone?

Sure, but presumably the 737 would not be getting its optimal fuel efficiency if it went slower (every vehicle has some sort of a target speed that it's optimized for.)

Re: MIT proposes to Reinvent the 737 for 70% greater fuel efficiency

#10

Post by icegreentea » Thu, Oct 07, 2010, 12:07 AM UTC

"Reinvent the 737" is a horrible way of putting this. They used the 737 and 777 has baselines/references of their design goals. Perhaps they based some of the fuselage/wing work on the existing planes, but they are so different, you could say they reinvented any two engine passenger liner built since the 737.

These designs also rely on some very advance (for commercial jets) engines. PW was involved in the engine redesign of this project, so I imagine the numbers they pulled out for increases in efficiency, while optimistic, are not pulled out of their ass, and definitely achievable. One of the things they're trying to to shift towards lean burning (so more oxygen than required for "complete" combustion), to reduce pollutants. They also want to use thrust vectoring in their hybrid wing concept, which I guess would do wonders for runway length requirements.

Regardless of how feasible actually getting these into production (imagine Boeing actually redesigning one of their planes based on what some outside source came up with... at the very least, it would be completely reinvented in house at Boeing... well, that's my guess anyways), it's nice to see how much detail they put into this. They even went to try to reduce vortices at takeoff/landing so you could cycle planes faster through a runway.