• What is the fuselage of an aircraft?

    One of the most important elements

Of all the structural elements of an aircraft, the fuselage is one of the most essential.

The fuselage is the ‘body’ of an aircraft, its primary structure; it is the envelope that houses the cockpit, the space for carrying passengers or for the cargo hold. It is also the framework to which other fundamental parts are attached, such as the wings, tail empennage or landing gear.

Here we talk about the fuselage of an aircraft: what it is used for, what it is made of and how many different types of fuselage there are. Don’t miss it!

What is the fuselage for?

Just as in cars or other means of transport, we need aircraft to have a fuselage, as it provides the aerodynamic shape and increases the safety of the aircraft, protecting what is most valuable: what is inside it. Thus, the main functions of the fuselage are as follows:

  • It shapes the aircraft and provides the necessary aerodynamics for the type of flight to be performed.
  • It serves as an assembly base for the different parts of the aircraft.
  • It distributes the forces over its entire surface.
  • It is a protective barrier for passengers in the event of an accident.

In addition, the interior of an aircraft fuselage can have several divisions, depending on the use for which it is made: the cockpit, several areas for passengers and crew, a part for passenger baggage or the entire interior for cargo.

Types of fuselages

Aviation is an industry that is always at the forefront of research and development, so different designs for the same function are constantly emerging.

There are therefore several types of aircraft fuselage, depending on force absorption (monocoque/semi-monocoque), size (wide/narrow) or method of manufacture (lattice or tubular).

Monocoque fuselage

A monocoque fuselage is a tubular structure with frames covered with sheet metal or fibre. They are strong airframes and can fly at high altitude.

In monocoque airframes, the covering is responsible for withstanding all the forces, which is why it must be of a certain thickness. Due to its robustness and simplicity, it is the most common type of fuselage used in general aviation aircraft.

In these fuselages, the most commonly used material is fibre, which allows the desired shape to be moulded more easily, as well as being a very light material.

Semi-monocoque fuselage

For the construction of large commercial aircraft, the most commonly used type of fuselage is the semi-monocoque. This is because, in some way, it is necessary to lighten the weight of having a covering that can withstand all the forces.

For this reason, in semi-monocoque fuselages, there is a braid formed by spars, frames and the covering itself. Thus, the forces are distributed over the entire length of the fuselage, and it is possible to lighten the weight by using a much thinner metal skin.

The most commonly used material in the construction of semi-monocoque fuselages is duraluminium, also known as aircraft aluminium. This material is an alloy of aluminium with copper, manganese, magnesium and silicon.

Wide and narrow fuselage

Fuselages or airframes can also be classified according to their size, diameter, or internal volume.

Narrow-body aircraft are those with a single aisle that separates the passenger seats into two blocks of rows.

However, wide-body aircraft have more than one aisle to divide the seats. In these aircraft, we can find configurations of 3 – 4 – 3 rows, separated by two aisles, or even 3 – 5 – 3, which is the widest of all the aisle layouts.

Lattice or tubular fuselage

Another type of fuselage is the lattice fuselage, which consists of a network of steel tubes that serve to join the frames of the aircraft. It is one of the oldest forms of construction and is therefore not suited to today’s needs for speed and safety in flight.

Also called tubular, the lattice fuselage consists of frames, spars and diagonals that are covered with canvas, wood or metal. It is a very light but not very strong covering.

There are several sub-types within the lattice fuselage, such as the Warren fuselage, the Pratt fuselage or the Geodesic fuselage.

In the early days of aviation, the lattice fuselage was a safe and economical form of manufacture which, with advances in engines, has been replaced by other safer modes suitable for higher speeds.

Other elements of the fuselage: the bulkheads

You know that the fuselage is a pressurised structure, but the elements that make this possible are the pressure bulkheads.

The pressure bulkheads are responsible for sealing the entire fuselage structure, both front and rear, making it an almost airtight cabin, and ensuring that the pressure loads supported are evenly distributed.

But the bulkheads not only have the function of providing the cabin for the crew and passengers, they also fulfil a structural function by actively contributing to the increased strength of the fuselage.