Fixed-Wing Aircraft Structures

A fixed-wing aircraft is an aircraft that achieves flight by using wings to produce lift. They are called “fixed-wing” because their wings are stationary, as opposed to rotary-wing aircraft, which generate lift by rapidly spinning rotors or blades. To work properly, the wings of an aircraft have to attach to a structure. In the case of fixed-wing aircraft, the aircraft wings are attached to the body of the aircraft, known as the fuselage. There are three types of fixed-wing aircraft fuselage structures: Truss, Monocoque, and Semimonocoque.


Truss type fuselages are made up of a rigid framework of beams, struts, and bars to support loads and forces applied to it. This type of fuselage is usually covered with fabric rather than metal or wood. The frame itself is generally manufactured from steel tubes welded in such a way that any part of the truss can support weight and stress. Truss frames can be made from aluminum, but usually only in very light, single-engine models.


Monocoque, French for ‘single shell,’ use formers, frame assemblies, and bulkheads to give the fuselage its tubular shape. The strongest structural supports are spaced to carry concentrated loads at points where the components such as wings, power plants, and stabilizers are affixed to the fuselage. Because these members are the primary load bearing tools, the skin of the aircraft has to put up with significant stress and keep the fuselage together. This means the key problem in monocoque construction is making it strong enough to withstand extreme conditions without it being too heavy.

Semi monocoque

The semi monocoque was introduced to solve the strength to weight ratio problems experienced by the monocoque. It is the most common fuselage in modern aircraft and features the same structural components of a monocoque, but also has longitudinal supports called longerons. Longerons extend across the frame and help the exterior support bending loads. Another unique feature of semi monocoque fuselages are stringers. Stringers are shorter, lighter versions of longerons that serve a similar purpose. All of these features give the semi monocoque superior strength at a lighter weight.

Most aircraft cabins are pressurized for the comfort of crew and passengers, but this pressure causes even more stress on a fuselage and adds to the complexity of the design. Not only the stress from the differing pressures inside and outside the fuselage, the metal fatigues over time as the interior changes from pressurized to unpressurized. Fuselages are put under a lot of stress during flight, and must withstand it and remain functionally proficient.

At Paragon Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the aircraft structural parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at or call us at +1-714-705-4780.


November 20, 2023

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