In order to reach necessary destinations, especially located far from the point of departure, planes are carrying enormous volumes of fuel. Notably, sometimes the weight of fuel is almost the third of the entire aircraft weight! But have you ever thought where it is stored?
Inside of the WINGS. Yes, you have got it right. Most of the planes both small and big have fuel stored inside of wings. Wondering why? Here are several key reasons:
Weight balance. Inside of the aircraft it is important to consider not only the configuration of the seats or location of cargo, but also keep in mind the place where heavy fuel is situated. Particularly the fuel keeps aircraft centre of gravity more or less in the needed position.
Counter stress. Fuel acts as a counter stress for the wings shortly after take-off when the stress of the aircraft mass acts on them (during take-off it is always the largest). This prevents a large change in the wing dihedral angle. In bigger aircraft, leaving the wing tanks empty might result in wings simply snapping off.
Reduced wing flutter. The weight of the fuel provides rigidity to the wing, thereby reducing wing flutter (vibration of the wings due to the airflow). Large flutter is so hazardous that it can even result in total collapse of the wing. Thus, storing fuel in the wings is an exceptionally wise decision which keeps aircraft flying!
On the whole, there are many more reasons to mention. Maybe you can list at least one more?