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Cleen - AA 738 "Specially Modified"  
User currently offlineN62NA From United States of America, joined Aug 2003, 4256 posts, RR: 6
Posted (1 year 7 months 4 days 3 hours ago) and read 11758 times:

I wasn't aware of this program.

http://www.faa.gov/news/updates/?newsId=69327

Deputy Secretary of Transportation John Porcari and Federal Aviation Administration (FAA) Acting Administrator Michael Huerta saw firsthand progress in making air travel more environmentally and energy efficient. This September, the Boeing Aircraft Company flew its first “ecoDemonstrator*,” a modified American Airlines 737 aircraft, to Washington Reagan National Airport to show Porcari, Huerta and other aviation stakeholders new aircraft technologies that offer the promise of cleaner and quieter flying.


Here's one of the new things they're working on:

One of the promising technologies fitted on the wings of the ecoDemonstrator is the CLEEN Adaptive Trailing-Edges to improve fuel-saving aerodynamic efficiency and also decrease aircraft noise during approach.

13 replies: All unread, jump to last
 
User currently offlineiFlyLOTs From United States of America, joined Apr 2012, 433 posts, RR: 0
Reply 1, posted (1 year 7 months 4 days 3 hours ago) and read 11711 times:

There's a video on the Boeing website about it too.
http://www.boeing.com/Features/2012/...bca_eco_demonstrator_09_17_12.html
It sounds like some really interesting concepts

[Edited 2012-09-18 15:23:07]

[Edited 2012-09-18 15:23:31]


"...stay hungry, stay foolish" -Steve Jobs
User currently offlineStitch From United States of America, joined Jul 2005, 29690 posts, RR: 84
Reply 2, posted (1 year 7 months 4 days 3 hours ago) and read 11604 times:
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Boeing is hoping to implement some of the CLEEN items in the 737 MAX.

User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12064 posts, RR: 52
Reply 3, posted (1 year 7 months 4 days 3 hours ago) and read 11577 times:

CLEEN technology, including the adaptave wing trailing edge device could save an additional 2% in fuel. Boeing is planning to do CLEEN testing next year on a B-787-800, too.

My guess is Boeing hopes to develope this technology in time to put it on the B-737MAX and B-777X.


User currently offlineRoseflyer From United States of America, joined Feb 2004, 9379 posts, RR: 52
Reply 4, posted (1 year 7 months 4 days 3 hours ago) and read 11371 times:

Boeing regularly works with a select group of airlines on new technology. Boeing is working with American Airlines to borrow one of their brand new 737s prior to delivery and instrument it up to test various new technologies. A couple years ago Boeing was using a Continental 737 to test various other improvements. Southwest has offered new airplanes as well for testing. Many of the new technologies that are being developed need to be tested on an actual airplane. Boeing will borrow airplanes from airlines to conduct flight tests and then return them to their normal configuration prior to delivery. This saves the cost of having to maintain an airplane for flight test purposes and airlines benefit because Boeing pays them for their airplane and also they get improved products.


If you have never designed an airplane part before, let the real designers do the work!
User currently offlineN737AA From United States of America, joined Aug 2008, 270 posts, RR: 0
Reply 5, posted (1 year 7 months 3 days 14 hours ago) and read 10641 times:

This aircraft is leased to Boeing and is in "experimental" status.

N737AA


User currently offline777222LR From United States of America, joined Feb 2012, 131 posts, RR: 1
Reply 6, posted (1 year 7 months 3 days 13 hours ago) and read 10445 times:

The video doesn't really show any of these features in detail. Does anyone have a link to diagrams of the trailing edge devices and variable engine nozzles?

User currently offlineDocLightning From United States of America, joined Nov 2005, 18704 posts, RR: 58
Reply 7, posted (1 year 7 months 3 days 10 hours ago) and read 8630 times:

Quoting 777222LR (Reply 6):
The video doesn't really show any of these features in detail. Does anyone have a link to diagrams of the trailing edge devices and variable engine nozzles?

Seconded. Can someone explain how "CLEEN" is supposed to improve efficiency?


User currently offlinehorstroad From Germany, joined Apr 2010, 226 posts, RR: 0
Reply 8, posted (1 year 7 months 3 days 9 hours ago) and read 8039 times:

aren´t these new trailing edge devices just smaller flaps?

this variable fan nozzle sounds interesting. I would really like more details


User currently offlineStitch From United States of America, joined Jul 2005, 29690 posts, RR: 84
Reply 9, posted (1 year 7 months 3 days 8 hours ago) and read 7080 times:
Support Airliners.net - become a First Class Member!

Here's is Boeing's 2011 presentation to the FAA that includes some info on the ATE - http://www.faa.gov/about/office_org/...Boeing_CLEEN_Projects_Briefing.pdf

User currently offlineShany From Germany, joined Jul 2008, 111 posts, RR: 0
Reply 10, posted (1 year 7 months 3 days 8 hours ago) and read 7051 times:

http://www.faa.gov/about/office_org/...02010%20-%20Unlimited%20Rights.pdf


ETOPS - Engines Turn Or People Swim
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 11, posted (1 year 7 months 3 days 7 hours ago) and read 5866 times:

Quoting 777222LR (Reply 6):
Does anyone have a link to diagrams of the trailing edge devices and variable engine nozzles?

The test nozzle is fixed on a per-flight basis (they can change the nozzle profile between flights). It all goes to the trade between weight/complexity and fuel savings of being able to vary the nozzle in flight.

Quoting DocLightning (Reply 7):
Seconded. Can someone explain how "CLEEN" is supposed to improve efficiency?

Adaptive trailing edge is designed to tweak the wing camber for lower induced drag in cruise.
Variable nozzle is designed to tweak engine exhaust velocity for improved propulsive efficiency (higher TSFC).

Quoting horstroad (Reply 8):
aren´t these new trailing edge devices just smaller flaps?

Basically, yes. The art is in exactly where to put them for various flight configurations.

Tom.


User currently offlineDocLightning From United States of America, joined Nov 2005, 18704 posts, RR: 58
Reply 12, posted (1 year 7 months 3 days 5 hours ago) and read 4003 times:

Quoting tdscanuck (Reply 11):
Adaptive trailing edge is designed to tweak the wing camber for lower induced drag in cruise.

Can you give me a hand-waving explanation on how that works? So far back on the wing, the flow would be pretty separated, right? So how would a little flap thingie sticking down from the underside alter the aerodynamics to improve efficiency?


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 13, posted (1 year 7 months 2 days 23 hours ago) and read 2086 times:

Quoting DocLightning (Reply 12):
Can you give me a hand-waving explanation on how that works?

You only get best L/D for a wing at a particular C_L...but, since airlines fly by dynamic pressure (aka IAS), the actual C_L will vary with weight. As a result, there's only one weight/speed combination where the wing is performing at its best and it slowly drops off as you go to either side. The drop off isn't dramatic, which is why this wasn't much of a focus until the last decade or so, but it is there.

Since the drop off isn't dramatic, the changes required to tweak the wing back to its optimum point are also small, hence you can do it with a tiny flap.

Quoting DocLightning (Reply 12):
So far back on the wing, the flow would be pretty separated, right?

There is very very little flow separation on the wing at cruise. There's really just the wake and that's not much thicker than the trailing edge itself. It doesn't take much. This idea, as far as I can tell, is basically a souped up version of a Gurney flap (http://en.wikipedia.org/wiki/Gurney_flap) and they're only 1-2% of chord.

Quoting DocLightning (Reply 12):
So how would a little flap thingie sticking down from the underside alter the aerodynamics to improve efficiency?

By making very small adjustments to the wing C_l to push it towards the optimum point.

The concept is already validated on the 787 as Variable Camber Trailing Edge, and soon to be seen on the A350, but they integrated it right into the flap drive on those aircraft. The 737 already has a flap drive system that they don't want to play with very much, so this is basically a retrofit cruise flap system.

Tom.


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