Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Boeing Testing Laminar Flow On 787  
User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Posted (3 years 6 months 5 days 9 hours ago) and read 14961 times:

Boeing have now started the tests with laminar flow improvement technology on the 787 tail:

http://www.flightglobal.com/articles...aminar-flow-control-for-787-9.html

There is reasons to believe this article is essentially correct, if so this is exciting stuff    . Increasing the laminar flow partion on the wings have been the desire since the P58 Mustang laminar flow profiled wing, yet it has not been introduced into mainline airliners to date IIRC.

The elegance of the B system is that the suction comes from parts of the wing which has low static pressure, ie no active parts    .

I know there are test with increasing laminar flow on test wings for A in the 2015 time frame, is this similar technology? (It can only be similar as B have patented their implementation).


Non French in France
28 replies: All unread, showing first 25:
 
User currently online747classic From Netherlands, joined Aug 2009, 2214 posts, RR: 14
Reply 1, posted (3 years 6 months 5 days 7 hours ago) and read 14921 times:

The hybrid laminar flow control (HLFC) modification is installed on test aircraft ZA003 in a limited area on the leading edge of the Boeing-built vertical stabiliser, one-quarter to one-half of the way up the fin, estimated to be positioned on the adjacent forward panels between ribs 3 and 7, and below the HF antenna.

ZA003, KSBD, June 8.

Original uploaded by KSBD Photo, see for other sizes : http://www.flickr.com/photos/ksbdphotos/5813364256/in/photostream
For more photos of ZA003 see : http://www.flickr.com/photos/ksbdphotos/page6/



Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlinetravelavnut From Netherlands, joined May 2010, 1666 posts, RR: 7
Reply 2, posted (3 years 6 months 5 days 6 hours ago) and read 14873 times:

Could somebody explain laminar flow, and its advantages, in laymens terms? I get the concept, I think, from Wikipedia;

http://en.wikipedia.org/wiki/Laminar_flow

But from the Wiki article I actually get the impression that all wings have laminar flow, or am I wrong on this? Also; what's so special about the implementation on the 787 that it couldn't be done on previous airliners? And why the apparant gap between the P-51 and the 787?

Thanks!



Live From Amsterdam!
User currently offlineAutothrust From Switzerland, joined Jun 2006, 1609 posts, RR: 9
Reply 3, posted (3 years 6 months 5 days 6 hours ago) and read 14865 times:

Quoting ferpe (Thread starter):
Boeing have now started the tests with laminar flow improvement technology on the 787 tail:

What the news, that Boeing is second as always? Airbus has tested laminar flow on the A320 already in the year 1998!!

Quote:
Airbus Industrie has begun flight testing its A320 development aircraft, equipped with a newly developed vertical tailfin, which incorporates laminar flow technology to reduce air friction and significantly reduce fuel consumption.
http://www.flightglobal.com/articles...airbus-flies-laminar-flow-fin.html



“Faliure is not an option.”
User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 4, posted (3 years 6 months 5 days 6 hours ago) and read 14845 times:

Quoting Autothrust (Reply 3):
What the news


Beacuse they do not have any air pump, that is!



Non French in France
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 5, posted (3 years 6 months 5 days 6 hours ago) and read 14843 times:

Quoting ferpe (Thread starter):
the 787 tail
Quoting Autothrust (Reply 3):
vertical tailfin

I wish people would use the proper terminology! It is the "VERTICAL STABILIZER".

Quoting Autothrust (Reply 3):
What the news, that Boeing is second as always? Airbus has tested laminar flow on the A320 already in the year 1998!!

Suggest reading the following, which provides the history of Laminar Flow testing, from the 1930's.

http://www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf


User currently offlineAutothrust From Switzerland, joined Jun 2006, 1609 posts, RR: 9
Reply 6, posted (3 years 6 months 5 days 5 hours ago) and read 14821 times:

Quoting 474218 (Reply 5):
It is the "VERTICAL STABILIZER".

Tell that to Flightglobal i just pasted the text.   

The Laminar Flow testing of Airbus was a European program, called HYLTEC (HYBRID LAMINAR FLOW TECHNOLOGY)

http://ec.europa.eu/research/growth/...autics-days/pdf/posters/hyltec.pdf

[Edited 2011-06-17 07:11:26]


“Faliure is not an option.”
User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 7, posted (3 years 6 months 5 days 4 hours ago) and read 14786 times:

What you boast above is what has been acheived today, experiments.

The new thing is that a large serious player is now saying it is going to be used on my very important civil airliner.



Non French in France
User currently onlineBMI727 From United States of America, joined Feb 2009, 15828 posts, RR: 27
Reply 8, posted (3 years 6 months 5 days ago) and read 14644 times:

Quoting ferpe (Thread starter):
yet it has not been introduced into mainline airliners to date IIRC.

The Honda Jet is set to use a natural laminar flow wing.

Quoting travelavnut (Reply 2):
Could somebody explain laminar flow, and its advantages, in laymens terms? I get the concept, I think, from Wikipedia;

Having laminar flow reduces the skin friction from the air flow. Of course, the mixing of a turbulent boundary layer introduces more energy to delay flow separation so while airliner engineers are seeking to retain more laminar flow, engineers designing smaller aircraft often seek to make the flow turbulent. Airliners sometimes utilize vortex generators to get a similar effect.

Quoting travelavnut (Reply 2):
But from the Wiki article I actually get the impression that all wings have laminar flow, or am I wrong on this?

They do, for a little while. Just using rough calculations, the flow over an airliner moving at 500 mph is laminar for about 3 cm.

Quoting travelavnut (Reply 2):
And why the apparant gap between the P-51 and the 787?

Reynolds number. Airliners will work at a higher Reynolds number range than a P-51, mostly because they are bigger but are also a bit faster as well.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlineDavid L From United Kingdom, joined May 1999, 9541 posts, RR: 42
Reply 9, posted (3 years 6 months 4 days 9 hours ago) and read 14427 times:

Quoting 474218 (Reply 5):
I wish people would use the proper terminology! It is the "VERTICAL STABILIZER".

I suspect the "proper terminology" can vary from place to place. I've seen "tailfin" and "tailplane" (horizontal stabiliser) used in technical articles in the UK over the years. There are similar differences in car terminology, e.g. trunk/boot, hood/bonnet, turn-signals/indicators.


User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 10, posted (3 years 6 months 15 hours ago) and read 14071 times:

As written in the Civil Avition forum I expect B to apply this technology in full on the 797 NSA project, this will be the technology that gives B a distinct advantage over the A320NEO. One can only speculate on how much drag reduction one can achieve when applied on wings and tail but 5% should be achievable IMHO, which is quite a feat.


Non French in France
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 11, posted (3 years 5 months 4 weeks 1 day 15 hours ago) and read 13841 times:

Quoting travelavnut (Reply 2):
Could somebody explain laminar flow, and its advantages, in laymens terms?

Smooth, rather than erratic flow. Turn your water faucet on low...you'll get a nice smooth "glassy" stream for some distance (laminar) that will be come all wiggly and jagged (turbulent). Laminar flow has lower skin friction, hence lower drag.

Quoting travelavnut (Reply 2):
But from the Wiki article I actually get the impression that all wings have laminar flow, or am I wrong on this?

All airliner wings are turbulent (right now). They're too large and fast to be laminar over more than a small fraction of the wing. People often confuse turbulent with separated...they're very different.

Quoting Autothrust (Reply 3):
What the news, that Boeing is second as always? Airbus has tested laminar flow on the A320 already in the year 1998!!

Nice try...Boeing did it on a 757 in 1985 (http://www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf). Not to say that Boeing did it *first*...it's a far older idea than that, but let's keep the revisionist history to a minimum.

Tom.


User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 12, posted (3 years 5 months 4 weeks 14 hours ago) and read 13695 times:

From an intervju wiht J Leahy at Paris Airshow:

"If they (B) built an all-new airframe, it would be about up to 3% better on the airframe side. We did the studies before we did the NEO that an all-new, clean-sheet airplane aerodynamically could save us about 3% in fuel burn. Everything has to come from the engines."

http://leehamnews.wordpress.com/2011...ling-past-the-graveyard/#more-4722

He is clearly not counting on the application of laminar flow technology, once again I think this is what B has up the sleeve for the 797 and is the real reason why they want to go clean sheet. B want to exploit the technology now before the competition works out their own good and tested solutions to the problem and the advantage would be void.

[Edited 2011-06-23 22:39:22]


Non French in France
User currently offlineflipdewaf From United Kingdom, joined Jul 2006, 1578 posts, RR: 0
Reply 13, posted (3 years 5 months 4 weeks 5 hours ago) and read 13649 times:
Support Airliners.net - become a First Class Member!

Quoting ferpe (Reply 10):
5% should be achievable IMHO, which is quite a feat

Are you shocked at your own guess?   


Fred


User currently offlinetravelavnut From Netherlands, joined May 2010, 1666 posts, RR: 7
Reply 14, posted (3 years 5 months 4 weeks 5 hours ago) and read 13646 times:

Quoting tdscanuck (Reply 11):
Smooth, rather than erratic flow. Turn your water faucet on low...you'll get a nice smooth "glassy" stream for some distance (laminar) that will be come all wiggly and jagged (turbulent). Laminar flow has lower skin friction, hence lower drag.

Thanks a lot Tds!

Quoting tdscanuck (Reply 11):
All airliner wings are turbulent (right now). They're too large and fast to be laminar over more than a small fraction of the wing. People often confuse turbulent with separated...they're very different.

So what kind of changes are made to the 787 vertical stabilizer to generate this flow?

Also from your explanation I gather laminar flow over the entire wing of an airliner is impossible to achieve due to the size of the wing?



Live From Amsterdam!
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 15, posted (3 years 5 months 4 weeks 4 hours ago) and read 13628 times:

Quoting travelavnut (Reply 14):
Quoting tdscanuck (Reply 11):
All airliner wings are turbulent (right now). They're too large and fast to be laminar over more than a small fraction of the wing. People often confuse turbulent with separated...they're very different.

So what kind of changes are made to the 787 vertical stabilizer to generate this flow?

Unfortunately, I can't talk about that. NASA has a good paper on the history of laminar flow control that's a good read to give you some ideas of the techniques: www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf

Quoting travelavnut (Reply 14):
Also from your explanation I gather laminar flow over the entire wing of an airliner is impossible to achieve due to the size of the wing?

It's impossible if you don't do anything to control the boundary layer. The boundary layer is the slow moving layer of air right next to a surface. The longer the air stays there (the bigger the surface) or the faster the surface is going, the more energy the boundary layer picks up and, eventually, it goes turbulent. To prevent turbulent flow you either need to prevent energy from going into the boundary layer in the first place (natural laminar flow airfoils) or actively remove energy as you go. The latter is where most of the suction-based laminar flow control ideas come from...they use some kind of system to remove energy from the boundary layer. With active boundary layer control, you can keep the flow laminar over arbitrarily large surfaces at arbitrarily large speeds.

Tom.


User currently offlinetravelavnut From Netherlands, joined May 2010, 1666 posts, RR: 7
Reply 16, posted (3 years 5 months 4 weeks 4 hours ago) and read 13626 times:

Quoting tdscanuck (Reply 15):
Unfortunately, I can't talk about that. NASA has a good paper on the history of laminar flow control that's a good read to give you some ideas of the techniques: www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf

Thanks again Tds, got something to read this weekend 
Quoting tdscanuck (Reply 15):
The latter is where most of the suction-based laminar flow control ideas come from...they use some kind of system to remove energy from the boundary layer. With active boundary layer control, you can keep the flow laminar over arbitrarily large surfaces at arbitrarily large speeds

Ok, I think I'm starting to get this, complicated stuf though.



Live From Amsterdam!
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 17, posted (3 years 5 months 4 weeks 3 hours ago) and read 13600 times:

Quoting travelavnut (Reply 16):
Thanks again Tds, got something to read this weekend


If you would have read Reply 5 you could have read the NASA report last week?


User currently offlinetravelavnut From Netherlands, joined May 2010, 1666 posts, RR: 7
Reply 18, posted (3 years 5 months 4 weeks ago) and read 13545 times:

Quoting 474218 (Reply 17):

Completely missed that reply (and BMI's as well!), sorry!



Live From Amsterdam!
User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 19, posted (3 years 5 months 3 weeks 6 days 15 hours ago) and read 13450 times:

@Tom

I guess one could also allply this technology to the body surfaces and they should be quite effective there as well, why does one focus on a wings low pressure side? Because the air travels faster there or that boundry layer slows down because of the pressure gradient?



Non French in France
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 20, posted (3 years 5 months 3 weeks 6 days 15 hours ago) and read 13447 times:

Quoting ferpe (Reply 19):
I guess one could also allply this technology to the body surfaces and they should be quite effective there as well,

In principle, yes. However, given that the body surfaces are (usually) also the pressure vessel, the logistics of putting a bazillion little holes or vents or scoops or what-have-you in the body surfaces are more complicated.

Quoting ferpe (Reply 19):
why does one focus on a wings low pressure side? Because the air travels faster there or that boundry layer slows down because of the pressure gradient?

I'm not sure on the history on that one...in principle, it would work on either side. There may be stall benefits (delayed separation) to doing in on the upper surface though.

Tom.


User currently onlineBMI727 From United States of America, joined Feb 2009, 15828 posts, RR: 27
Reply 21, posted (3 years 5 months 3 weeks 6 days 15 hours ago) and read 13438 times:

Quoting ferpe (Reply 19):
Because the air travels faster there or that boundry layer slows down because of the pressure gradient?

My guess would be that active boundary layer control might be able to reduce the adverse pressure gradient on the rear portion of the wing, which would delay separation.

Theoretically, I would think that if one could utilize the system on both sides of the wing, it could be linked and controlled in such a way to route air from the bottom to the top in certain (likely high alpha) situations almost like having a slotted flap.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 22, posted (3 years 5 months 3 weeks 6 days 14 hours ago) and read 13415 times:

Quoting tdscanuck (Reply 20):
In principle, yes. However, given that the body surfaces are (usually) also the pressure vessel, the logistics of putting a bazillion little holes or vents or scoops or what-have-you in the body surfaces are more complicated.

Thanks Tom, actually this was my conclusion as well. Re practical implementation, I would assume laminar flow goes well with electrical de-ice as you need the slats natural plenum for your suction (instead of for bleed-air deice).

Quoting BMI727 (Reply 21):
Theoretically, I would think that if one could utilize the system on both sides of the wing, it could be linked and controlled in such a way to route air from the bottom to the top in certain (likely high alpha) situations almost like having a slotted flap.

I think you need air with much higher pressure differential then you get from those many small holes, any blown flaps or sorts need pretty high energy air. I would assume the air is not that high energy that you get in those laminar flow plenums.



Non French in France
User currently offlineCARST From Germany, joined Jul 2006, 836 posts, RR: 2
Reply 23, posted (3 years 5 months 3 weeks 6 days 5 hours ago) and read 13352 times:

Is such a system prone to icing? If a lot of water gets into the "holes" before departure and while climbing, couldn't this water freeze inside the system? Not only making it loose its advantage, but damaging the (passive) system, too and adding some pounds of weight? Or is the system heated?

User currently offlineferpe From France, joined Nov 2010, 2805 posts, RR: 59
Reply 24, posted (3 years 4 months 3 weeks 5 days 3 hours ago) and read 12536 times:

Just to add to what B is working on, here is the A program, also aiming for the next generation SA:

http://www.flightglobal.com/articles...or-next-generation-narrowbody.html

Quite an informative article, my assumption on a drag gain of about 5% seems to not be that far of  



Non French in France
25 Post contains links faro : My money is on super-smooth airframe coatings for the hardened wing/tailplane leading edges. May have something to do with the 787 nacelle leading ed
26 Post contains links and images jetmech : Perhaps. Boundary layer suction schemes generally aim to endow the boundary layer with additional momentum to penetrate further against a given adver
27 tommytoyz : Another issue with laminar flow is that you need clean surfaces. If an airline doesn't keep their places clean enough, it might significantly interfer
28 tdscanuck : It depends if you're doing it for drag reduction or lift performance. The former is more popular and less dangerous. The change between laminar and t
Top Of Page
Forum Index

Reply To This Topic Boeing Testing Laminar Flow On 787
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Any Rumours On 787 Cabin Noise? posted Thu Mar 3 2011 03:57:05 by masi1157
Comparison Of Flap Deployment On 787 posted Wed Mar 2 2011 17:01:47 by Aircellist
Xenon Lights On 787 Or Other Airliners posted Fri Nov 5 2010 11:54:15 by flybynight
Question On 787 Undercarriage Mtow Limits posted Fri Aug 6 2010 10:13:01 by Stitch
Boeing 747 Pitch Up On Touchdown posted Mon Nov 9 2009 18:05:09 by Reggaebird
Cabin Width On 787 posted Tue Sep 15 2009 14:46:37 by Propilot83
Handley Page 1957 Laminar Flow Airliner posted Mon Mar 3 2008 01:36:18 by PMN1
3 Basic Questions On 787 Fuselage Structure posted Thu Jun 28 2007 17:54:39 by Superstring
Does Bypass Flow On A Turbofan Decrease Noise? posted Tue Jul 25 2006 08:01:33 by Bio15
Why Is The Vert Stab So Small On 787? posted Fri May 6 2005 00:20:03 by Lemurs
Any Rumours On 787 Cabin Noise? posted Thu Mar 3 2011 03:57:05 by masi1157
Comparison Of Flap Deployment On 787 posted Wed Mar 2 2011 17:01:47 by Aircellist
Xenon Lights On 787 Or Other Airliners posted Fri Nov 5 2010 11:54:15 by flybynight
Question On 787 Undercarriage Mtow Limits posted Fri Aug 6 2010 10:13:01 by Stitch
Boeing 747 Pitch Up On Touchdown posted Mon Nov 9 2009 18:05:09 by Reggaebird
Cabin Width On 787 posted Tue Sep 15 2009 14:46:37 by Propilot83

Sponsor Message:
Printer friendly format