Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
What Exactly Causes And/or Are These Bubbles?  
User currently offlineGolftango From United States of America, joined Feb 2006, 314 posts, RR: 0
Posted (8 years 1 month 4 days 3 hours ago) and read 3077 times:

Right in front of the speed brakes? Just air under the panels?



[Edited 2006-07-29 00:17:48]

8 replies: All unread, jump to last
 
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 1, posted (8 years 1 month 3 days 22 hours ago) and read 2934 times:

Those are bonded honeycomb panels, honeycomb core with the upper and lower skins bonded to the core. The bubbles are delaminations, of areas where the skin has come un-bonded from the core. There are limits to the amount of delamination allowed before it must be fixed.

User currently offlineMeister808 From United States of America, joined Jan 2000, 973 posts, RR: 1
Reply 2, posted (8 years 1 month 3 days 20 hours ago) and read 2863 times:

In addition, these somewhat loose pieces of skin will bulge a little bit during flight due to aerodynamic forces.

-Meister



Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 3, posted (8 years 1 month 3 days 18 hours ago) and read 2810 times:

Looks like Delamination to the Honeycomb Panels.
The Coin tap test is the best method to check this.
regds
MEL



Think of the brighter side!
User currently offlineKaddyuk From Wallis and Futuna, joined Nov 2001, 4126 posts, RR: 26
Reply 4, posted (8 years 1 month 2 days 11 hours ago) and read 2660 times:

Quoting HAWK21M (Reply 3):
The Coin tap test is the best method to check this.

According to the CAA, the reccomended taps per second is 4. Which i think is stupidly high...



Whoever said "laughter is the best medicine" never had Gonorrhea
User currently offlineZeke From Hong Kong, joined Dec 2006, 9030 posts, RR: 75
Reply 5, posted (8 years 1 month 2 days 10 hours ago) and read 2643 times:

Its called postbuckling, its due to the panel being in compression, its efficient structural design.

Its not an aerodynamic effect, nor does it have anything to do with the composites or delamination.

If you every get to fly a PA28/PA38, or some other low wing trainer, have a look at the wing in a steep turn you will see the same thing happen, when you roll wings level it goes away.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineBuzz From United States of America, joined Nov 1999, 697 posts, RR: 21
Reply 6, posted (8 years 1 month 21 hours ago) and read 2473 times:

Hi Golftango, Buzz here. Zeke has it about right, the (relatively) thin panels are in compression right now, and the have bowed upwards a little. Take a look at the panels forward of the outboard aileron... not much distortion, but visible due to the sun angle. And if we could see a front view of the airplane, I wonder how many feet of flex those wingtips have? Is that a 747-400?

If there were that many square inches of panel delamination, there would be a flutter problem and it could lose pieces of upper skin.

g'day


User currently offlineMeister808 From United States of America, joined Jan 2000, 973 posts, RR: 1
Reply 7, posted (8 years 1 month 20 hours ago) and read 2465 times:

Quoting Zeke (Reply 5):
Its called postbuckling, its due to the panel being in compression, its efficient structural design.

Its not an aerodynamic effect, nor does it have anything to do with the composites or delamination.

Hm. I, officially, am an idiot.

Good call.

-Meister



Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 8, posted (8 years 1 month 17 hours ago) and read 2439 times:

Quoting Buzz (Reply 6):
Is that a 747-400


View Large View Medium
Click here for bigger photo!

Photo © Montague Smith-WorldWide Aviation Photos


United Airlines B744. checkmark 

regds
MEL



Think of the brighter side!
Top Of Page
Forum Index

Reply To This Topic What Exactly Causes And/or Are These Bubbles?
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...
What Are These Intakes For On The 777? posted Wed Nov 1 2006 04:13:28 by Gh123
What Exactly Is N1 And N2? posted Tue Sep 5 2006 00:04:45 by Jamesbuk
What Type Are These Seats From? posted Tue Feb 28 2006 22:39:34 by BaylorAirBear
What Are These Called? posted Sat Jan 21 2006 00:52:10 by United787
What Are These "wires" On Bae146 posted Sat Aug 27 2005 21:40:13 by Goinv
Well I Know What A Vasi And A Papi Are posted Fri Sep 5 2003 12:05:43 by L-188
What Are These 747 Cargo Types? posted Sat Feb 15 2003 00:23:26 by QANTAS747-438
What Are These JT3D Cowling Openings For? posted Sun Dec 29 2002 06:51:49 by Happy-flier
Are These Airliner Or Military Contrails? posted Wed Aug 14 2002 18:49:50 by Mr Spaceman
What Are These Cartridges Good For? posted Sat Aug 3 2002 19:04:22 by Domi.ga

Sponsor Message:
Printer friendly format