Maybe this was already posted and I missed it.

 http://www.youtube.com/watch?v=npniZ6iwo30

 Looking at the B787, It is very noticeable the flex of the wings and
 changes of dihedral. Would this be less apparent in level flight?

 What would be the effects of this changes for pitch and/or roll if
 this happens while landing (low & slow).

 Your thoughts will be appreciated.

 Alfonso

 They all flex. If you look out the window in a 747 during
 turbulence it will
 scare the hell out of you :)

 Apparently this is not noticed by the pilot but I am no airline
 pilot by a long
 shot :)

 Flex up and down is OK but twist that increases the angle of
 attack at the tip
 is a no no for flutter reasons.

 Paul Lamar

 Can you give us a time point of where you see wing flex? Upon my
 first review of the vid, I see none.

 J. Johnson


I can't see active flexing, since there is no specific video of the
wings in flight but the difference in dihedral (I think that's the
correct term) between the plane in land and in air is, to me,
astonishing.

Check this one after the 51 secs. mark.

http://www.youtube.com/watch?v=Fucq5BoEfEI


Alfonso

Honestly, I don't see any flex the leading edge shape appears different from
one view to the next but I would be suprised if it's not due to the different angles.
As far as I can tell the leading edge of the wing is actually curved and this is
contributing to the flex shape. You'll notice when it comes over the hill at abt 40s
that the tips are curved up then, possibly even prior to rotation and I think it is some form of
complex dihedral [curved dihedral?] The last shots look like a fish eye lense or
something has been added to the picture.  I do see a bit of a 'bounce' to the wings
during the initial roll.. but no flexing to speak of..

Worse than this is,  this landing.. http://www.youtube.com/watch?v=-yi9C8NE3Ek
not that it's of the same type [and I'm not saying Airbus is better or worse]..
but it does illustrate how flexible the wings are on these larger aircraft.
I remember landing on a 747-400 [BA, Heathrow to Jo-burg]
and at touch-down I thought the flaps were going to drop out of their tracks.. during
the reverse phaze, they were moving what seemed like at least 10" at the tips [the flaps]

Crazy stuff...

Jarrett