And the 747-8I Finally Takes Flight

[Evodesire]

The 747-8 is such a beauty on its classic form, made better, flying with grace!

[speedfierce]

ako lang ba, o parang hindi prominent yung wing flex ng 747-8i, unlike the 787?

[Evodesire]

Allow me to put this in simple terms as you may get mixed up with the techy terms.

The wing flex which you are discribing is called a dihedral angle or wherein the wingtips of an aircraft is angled upward from the fuselage.

The purpose of this is to improve stability of an aircraft when dihedral effect occurs. The dihedral effect is the amount of roll on the aircraft's center axis produced by side slipping. Side slipping happens when an aircraft moving forward is pointed not straight but on a different angle. This creates undesired roll creating instability and this is where the dihedral wings comes in effect.

The angle is dependent on an aircraft's size, weight, fuselage height, center of gravity and wing design. Sometimes, a more swept wing would need a higher angle but since the 747-8 is a large aircraft, the angle is not as high as the one you notice on a 787. The center of gravity also changes depending on the aircraft's angle of attack or its horizontal angle relative to the ground.

Sometimes, uncompensated lift produces a side force which causes an aircraft to side slip. The dihedral wing angle then corrects the roll on these situations by having the lower wing upwind to a higher angle of attack resulting to the stability of an aircraft during a roll moment.

So why does the roll and side slip have to be corrected? Because if not, this will lead the aircraft to vear away from its original flight path because of the roll which may cause the aircraft to bank and to sideslip, pointing the nose on a different direction.

To cap this all, the so called "flex" is measured up to a certain angle. Too much flex may cause the aircraft to further roll the opposite direction during a side slip. The lack of flex may further lead the aircraft to a steeper roll on its present angle.

So it all varies per aircraft.

Hope this explains this all!