474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 1, posted (9 years 4 days 19 hours ago) and read 3486 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.
Buzz From United States of America, joined Nov 1999, 697 posts, RR: 20
Reply 6, posted (9 years 1 day 17 hours ago) and read 3025 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.