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Single-color Nacelles: 30,000 Gal Per Year Saving  
User currently offlineKeta From Germany, joined Mar 2005, 448 posts, RR: 0
Posted (8 years 2 months 2 weeks 5 days 14 hours ago) and read 3167 times:

Boeing is telling customers to paint the engine nacelles of the B-787 in a single color, rather than having multiple colors to match the livery, as appeared on the Aviation Week and Space Technology magazine this July, thought it was interesting. I found a link in the Boeing website:

http://www.boeing.com/commercial/787...amily/news/2006/q3/060710d_nr.html

"The 787 nacelle has a tightly controlled smooth surface to preserve laminar flow over a greater distance than that on a standard design. "Aircraft drag is reduced because laminar flow has much lower skin friction drag than turbulent flow," said Ron Hinderberger, propulsion leader for the 787 program."

"If you interrupt the laminar flow by adding paint layers, which are common with airline liveries, you could increase fuel burn by 30,000 gallons per year per airplane," Hinderberger added."

That's quite a saving, I don't know how much money is it, but it's enough for another flight.

Now, if this small thickness of a paint layer is capable of interrupting the laminar flow, how is it that the junctions between the different parts of the nacelle don't? The junctions in airplanes are very precise, but more than a paint layer? I guess Boeing has done a good job there (Goodrich produces the nacelles actually). And it surprises me how this simple feature makes these savings!

Oh, and why gray?  bored  Don't you get the same results with a prettier color?  smile 


Where there's a will, there's a way
21 replies: All unread, jump to last
 
User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 1, posted (8 years 2 months 2 weeks 5 days 12 hours ago) and read 3135 times:

Yes...good article, but the 74-800 will not have the same color "restriction" for the same engine...

User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 2, posted (8 years 2 months 2 weeks 5 days 12 hours ago) and read 3125 times:

The topic was discussed once before. If I remember, gray is used because of something to do with protecting the composites, and gray also doesn't need as many layers of paint as other colors. The main thing here, is that Boeing wants the lip of the intake and the surrounding paint of the nacelle to be precisely flush, any more layers means the paint will stick out above the intake lip and into the airstream (even though it may be several 1/1000 of an inch or micrometers), and increase drag and fuel consumption.

User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 3, posted (8 years 2 months 2 weeks 5 days 12 hours ago) and read 3125 times:

Quoting N231YE (Reply 2):
and gray also doesn't need as many layers of paint as other colors


Bad guess; note the reference...gray matches the inlet lip of the nacelle.

[Edited 2006-10-04 21:52:52]

User currently offlineLegoguy From United Kingdom, joined Jun 2006, 3314 posts, RR: 39
Reply 4, posted (8 years 2 months 2 weeks 5 days 12 hours ago) and read 3095 times:

If such a small layer of paint can interupt an aircraft's slipstream... can the same be said about current aircraft flying?

Will an all white aircraft with no writing or design save more on fuel costs in a year than an identical aircraft with several patterns/designs on it?



Can you say 'Beer Can' without sounding like a Jamaican saying 'Bacon'?
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 2 months 2 weeks 5 days 11 hours ago) and read 3094 times:

Indeed it was:
RE: 787 Livery Limitation By Boeing? (by Rheinbote Aug 5 2006 in Civil Aviation)
Quoting in my opinion, the best explanation:

Quote:
The color has nothing to do with the aerodynamics. When you have two or more colors the tape line at the border of the colors is not smooth. The resulting ridge would disrupt laminar flow and create drag. The transition could be made smoother by clearcoating and sanding. But this is not normal for commercial aircraft painting and would cost extra.

Boeing wants gray because lighter colors reflect heat from the sunlight better than darker colors. Heat is one of composites worst enemies.

DL757Md


User currently offlineEssentialpowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 6, posted (8 years 2 months 2 weeks 5 days 11 hours ago) and read 3083 times:

Quoting N231YE (Reply 5):
Indeed it was:
RE: 787 Livery Limitation By Boeing? (by Rheinbote Aug 5 2006 in Civil Aviation)
Quoting in my opinion, the best explanation:

Quote:
The color has nothing to do with the aerodynamics. When you have two or more colors the tape line at the border of the colors is not smooth. The resulting ridge would disrupt laminar flow and create drag. The transition could be made smoother by clearcoating and sanding. But this is not normal for commercial aircraft painting and would cost extra.

Boeing wants gray because lighter colors reflect heat from the sunlight better than darker colors. Heat is one of composites worst enemies.

DL757Md

1. So someone's guess is better than what Boeing says in its own press release; ie that gray matches the inlet?

2. What does heat absorption have to do with this specific topic?

3. Boeing will still paint the nacelles any desired color the airline (note, customer...wants), but in order to maximize the aerdynamics, Boeing recommends 1 thin color (gray, matching the inlet) with no graphics.

[Edited 2006-10-04 22:39:41]

User currently offlineMrFord From Canada, joined Jan 2001, 144 posts, RR: 1
Reply 7, posted (8 years 2 months 2 weeks 5 days 11 hours ago) and read 3053 times:

Quoting Essentialpowr (Reply 6):
3. Boeing will still paint the nacelles any desired color the airline (note, customer...wants), but in order to maximize the aerdynamics, Boeing recommends 1 thin color (gray, matching the inlet) with no graphics.

All they need now is to find a way to replace grey with chrome  Wink



"For radar identification throw your jumpseat rider out the window."
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 8, posted (8 years 2 months 2 weeks 5 days 11 hours ago) and read 3054 times:

Quoting Essentialpowr (Reply 6):
1. So someone's guess is better than what Boeing says in its own press release; ie that gray matches the inlet?

I don't understand where you are getting "grey matches the inlet"?

Quoting Essentialpowr (Reply 6):
2. What does heat absorption have to do with this specific topic?

As said in the quote:

Quote:
Boeing wants gray because lighter colors reflect heat from the sunlight better than darker colors. Heat is one of composites worst enemies.



Quoting Essentialpowr (Reply 6):
3. Boeing will still paint the nacelles any desired color the airline (note, customer...wants), but in order to maximize the aerdynamics, Boeing recommends 1 thin color (gray, matching the inlet) with no graphics.

That's a given. Notice I said Boeing "wants" its Customers to have grey paint: in English, want is a synonym for desire. Boeing is not forcing their customers to use grey paint. Also, the 787 is all about efficiency...so why would an airline pay all the money for a state-of-the-art airplane centered around efficiency, and then blow it off by not following Boeing's recommendations for keeping this money-saving airplane as money-saving as possible?


User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 9, posted (8 years 2 months 2 weeks 5 days 9 hours ago) and read 3002 times:

Quoting N231YE (Reply 8):
I don't understand where you are getting "grey matches the inlet"?

Directly from the Boeing press release in the opening post!:

"The design parameter for the nacelles is based on thickness of the paint formulation for a single color; Boeing has chosen gray to complement the metallic appearance of the nacelle's inlet."

Quoting N231YE (Reply 8):
As said in the quote:

Quote:
Boeing wants gray because lighter colors reflect heat from the sunlight better than darker colors. Heat is one of composites worst enemies.

??? There are a multitude of composite parts on a/c...heat is not the issue. If some one on anet feels it is, but I will caution you that there is much more incorrect info on these threads than correct. The fact that it is a composite in and of itself is not the topic either. The topic was about single color nacelles saving gas...

Quoting N231YE (Reply 8):
Notice I said Boeing "wants" its Customers to have grey paint: in English, want is a synonym for desire.

You again miss the point. Boeing, again, doesn't "want" or care what color they are painted, but notes that the nacelles must be 1 color to achieve stated fuel economy specifics. That is in "English" as you put it.

Quoting N231YE (Reply 8):
Also, the 787 is all about efficiency...so why would an airline pay all the money for a state-of-the-art airplane centered around efficiency, and then blow it off by not following Boeing's recommendations for keeping this money-saving airplane as money-saving as possible?

That question is for those that write the checks for the airplanes to decide now, isn't it?


User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 10, posted (8 years 2 months 2 weeks 5 days 5 hours ago) and read 2921 times:

Okay, okay, lets just get this strait...

Boeing wants the color grey to a) compliment the color of the inlet, b) just grey so that no extra layers are used and thus to edges and protrusions into the airflow

Heat does affect composites:
http://adsabs.harvard.edu/abs/1993BUAAJ...2....7Z

And just to clear some more things up, since there is some problem in communication here; "Boeing urges (yes urges, does not force customers) to use grey paint"

Bada Bing?  idea 

[Edited 2006-10-05 05:16:22]

User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 11, posted (8 years 2 months 2 weeks 5 days 4 hours ago) and read 2912 times:

Quoting N231YE (Reply 10):
strait...

straight? English right? Or are you in fact referring to a geological feature?

Quoting N231YE (Reply 10):
Boeing wants the color grey to a) compliment the color of the inlet, b) just grey so that no extra layers are used and thus to edges and protrusions into the airflow

Yes.

Quoting N231YE (Reply 10):
Heat does affect composites:
http://adsabs.harvard.edu/abs/1993BU......7Z

Of COURSE heat affects composites. It affects the rate at which you digest food! It affects the germination of corn! What does heat not affect? (Take a thermodynamics course for that...a materials science class would be better to investigate "Thermal Fatigue of (non metallic) Composite Materials 2214"...did you miss those in the course catalog?

Quoting N231YE (Reply 10):
And just to clear some more things up, since there is some problem in communication here; "Boeing urges (yes urges, does not force customers) to use grey paint"

If an airline thinks their logo and multi paint colors on the cowlings of a new flagship a/c is worth 30k per year in fuel, they will do it. They have that option, and Boeing won't stop them...Boeing urges them to recognize it may not meet the range specs...You remember the MD11, right?

Here's one more perspective: McDonald's PREFERS to build its cheese burgers with a non sesame bun, cheese slice, premeasured catchup squirt, premeasured mustard squirt, 1 pickle, 1 pattie, onion shake. But you can get it dry with no oinions if you want, right?

[Edited 2006-10-05 05:28:00]

[Edited 2006-10-05 05:37:16]

User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 12, posted (8 years 2 months 2 weeks 5 days 4 hours ago) and read 2893 times:

Quoting EssentialPowr (Reply 11):
McDonald's PREFERS to build its cheese burgers with a non sesame bun,

I don't think I've ever been given the option of a non-sesame bun.

Quoting EssentialPowr (Reply 11):
What does heat not affect?

Sodium Chloride (Na^+2Cl^-2)


User currently offlineBAe146QT From United Kingdom, joined Sep 2006, 996 posts, RR: 0
Reply 13, posted (8 years 2 months 2 weeks 4 days 21 hours ago) and read 2820 times:

I can confirm that McDonalds cheeseburgers - in the UK - are prepared with a non-sesame bun.

There was an experiment in the 1970s with sesame buns where the seeds were used as vortex generators to improve laminar flow, but the weight penalty imposed by the seeds negated any lift benefits.

I understand they're going to produce a chamfered patty to further improve area rule aerodynamics next year though.



Todos mis dominós son totalmente pegajosos
User currently offlineKeta From Germany, joined Mar 2005, 448 posts, RR: 0
Reply 14, posted (8 years 2 months 2 weeks 4 days 18 hours ago) and read 2781 times:

Quoting N231YE (Reply 5):
Indeed it was:
RE: 787 Livery Limitation By Boeing? (by Rheinbote Aug 5 2006 in Civil Aviation)

Oops my bad, I didn't notice this was already discussed.

If gray is used just to match the inlet color, I guess any other color can be used to achieve the same results. I don't think gray is for heat protection, they'd have used white instead since it reflects more.



Where there's a will, there's a way
User currently offlineLemurs From United States of America, joined Mar 2005, 1439 posts, RR: 4
Reply 15, posted (8 years 2 months 2 weeks 4 days 15 hours ago) and read 2737 times:

Quoting BAe146QT (Reply 13):
I understand they're going to produce a chamfered patty to further improve area rule aerodynamics next year though

There was also talk of cutting chevrons into the lettuce to reduce lip-smacking noise during consumption.

On a different note, this may spell the end for R-R's plaques on the 787. If paint layer transitions are that big a deal, it's hard to imagine that chrome effect emblem is going to be very popular, unless R-R pays their customers for estimated lost fuel. (Which admittedly might not be as huge as Boeing's almost assuredly worst-case estimate, since it is a small logo.)



There are 10 kinds of people in the world; those who understand binary, and those that don't.
User currently offlineBAe146QT From United Kingdom, joined Sep 2006, 996 posts, RR: 0
Reply 16, posted (8 years 2 months 2 weeks 4 days 15 hours ago) and read 2730 times:

The chevrons are for the pickles. The lettuce is getting a hush-kit.

There was a thread about manufacturer logos on engines not that long ago. I believe the concensus was that the practice was falling out of favour anyway. The average punter doesn't care whether the engines are Pratt or Rolls, (unless something in the media alarms him about one or the other), and IIRC, the manufacturer has to pay the airline to display it - so they don't bother as much.



Todos mis dominós son totalmente pegajosos
User currently offlineLemurs From United States of America, joined Mar 2005, 1439 posts, RR: 4
Reply 17, posted (8 years 2 months 2 weeks 4 days 15 hours ago) and read 2723 times:

(Damn, I should have thought of that...some sandwich pickles literally have chevrons. You're better at this than I am.) It does seem like the extensive lightening program on tomatoes has paid off. There is virtually no remaining taste in them at all. It's like they're not there.

Do they actually pay for the logo you think, or offer a reduced rate on the engine and/or maint contracts to the airline? It does seem to offer very limited return on value outside of a few specific places where that brand means anything. It's not like the average Joe sitting in his window seat can either 1) buy his own airplane. 2) be so impressed with the jet engine that he decides to buy a "cheap" Rolls-Royce product, like a car.



There are 10 kinds of people in the world; those who understand binary, and those that don't.
User currently offlineBAe146QT From United Kingdom, joined Sep 2006, 996 posts, RR: 0
Reply 18, posted (8 years 2 months 2 weeks 4 days 14 hours ago) and read 2716 times:

One must be the burger. Only then can one redesign the burger. Incidentally, there is a move toward ABS tomatoes as well. Stops the special sauce getting on your tie.


Yeah, and as far as I know, Pratt and Whitney don't make anything that a normal consumer *could* buy.

I will have to dig out the thread where it was discussed, but there was definitely a statement there that said something along the lines of, "I bought your darned engines - I ain't going to advertise them for free for you as well!"

Actually, I wish that attitude was more prevalent in other walks of life.



Todos mis dominós son totalmente pegajosos
User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 19, posted (8 years 2 months 2 weeks 3 days 5 hours ago) and read 2553 times:

Quoting BAe146QT (Reply 18):
Yeah, and as far as I know, Pratt and Whitney don't make anything that a normal consumer *could* buy.

Maybe a T shirt or coffee cup off the web site??


User currently offlineFSPilot747 From United States of America, joined Oct 1999, 3599 posts, RR: 12
Reply 20, posted (8 years 2 months 2 weeks 1 day 16 hours ago) and read 2442 times:

Based on that info, I'd bet that a dirty aircraft burns a lot more fuel, too.

User currently offlineBOE773 From , joined Dec 1969, posts, RR:
Reply 21, posted (8 years 2 months 2 weeks 1 day 14 hours ago) and read 2416 times:

Quoting Keta (Thread starter):
"The 787 nacelle has a tightly controlled smooth surface to preserve laminar flow over a greater distance than that on a standard design. "Aircraft drag is reduced because laminar flow has much lower skin friction drag than turbulent flow," said Ron Hinderberger, propulsion leader for the 787 program."

Since they are getting all hung up with smooth surfaces on the pods,
they need to go after the wing skin joints especially the spanwise ones at the leading edge of the one that meets up to it's neighbor over the front spar, upper and lower caps. These butt joints are filled with a sealant that is underflush with the skins and negatively impacts the boundary layer of airflow.
Spoiler, aileron and flap to wing skin joints also need an 'extreme makeover'.


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