Aviation fuel is an important aspect, as it accounts for the aircraft’s performance during lift or take-off and also contributes to the additional weight of the aircraft that changes throughout the flight course of an aircraft.
For these reasons, it is essential to pay attention to the storage of the fuel in the aircraft.
Throughout history, fuels tanks have been installed in various regions of the aircraft body to attain maximum efficiency; Nose, Main body, Wings, etc.
Fuel is stored in 3 tanks, however, contrary to popular belief, the 737–800 has 5 tanks. They are:
Fuel is stored in the wings of aircraft for primarily 3 reasons
First
Fuel acts as counter stress for the wings shortly after takeoff when the great stress of the aircraft’s mass acts on them.
This prevents a large change in the wing dihedral angle.
This effect is so great on the Boeing 747, that if only the center tank was filled (leaving the wing tanks empty) and the plane would take off, the wings would simply snap.
Due to this reason, fuel is first consumed from the center tank and then the wing tanks.
Conversely, during refueling, the wing tanks are filled initially and then the center tanks.
Second
Keeps the center of gravity more or less in the desired position.
If the tanks are at the nose or tail of the aircraft, there will be a large change of momentum as fuel is filled or consumed.
The longitudinal center of gravity is vital for an aircraft’s stability, and any large change in its position is not conducive to flying.
Third
The weight of the fuel provides rigidity to the wing, thereby reducing wing flutter.
Flutter is the vibration of the wings due to the airflow. Large flutter is so hazardous that it can even result in the total collapse of the wings.
The following video explains how flutter acts on aircraft and other structures.
Where Aircraft Fuel Tanks are Located?
Notably, sometimes the weight of fuel is almost a third of the entire aircraft weight!
Most of the planes both small and big have fuel stored inside of wings. 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 the aircraft center of gravity more or less in the needed position.
Counter stress
Fuel acts as 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 the total collapse of the wing.
Thus, storing fuel in the wings is an exceptionally wise decision that keeps aircraft flying!