Is the entire length of a B747 or A380 wing used as a fuel tank? It is generally understood that the fuel tanks of aircraft are in the wings, but specifically, is the entire length of the the wing of:


an Airbus A380 Jumbo used as fuel tank?
a Boeing 747-800 Jumbo used as fuel tank?


What percentage of the wing length is used as a fuel tank and for what reasons, for:


an Airbus A380 Jumbo  
a Boeing 747-800 Jumbo
Fuel tanks take most of the space in aircraft wings, but not all. There are other things on wings too. They are ailerons, flaps, slats, air brakes. On most airliners, the engines are attached to the wings too, so their assembly takes up space.

On the two aircraft of your interest, here are the pictures:

A380 (its nickname is not jumbo, but superjumbo)

Image Source

747

Image Source