Aircraft structures have changed drastically over time. If you looked at a Wright Flyer side by side with an SR-71 Blackbird, you’d be hard-pressed to find a single structural similarity. Incredible achievements have been made in aviation since the dawn of the 20th century. This blog will take a look at the history and evolution of aircraft structures.
Early aircraft such as the Wright Flyer were constructed from rectangular frames coupled with wiring stretched diagonally to prevent shearing or collapsing. There were two prevailing ideas behind this design. First, two parallel wings would create a lighter yet stronger structure than a single wing, and second, these wings could be supported with light wiring rather than a large, wooden piece. The dual-wing setup makes the aircraft more resistant to bending and twisting than a single-wing aircraft.
The next major innovation in the history of aircraft structure came with the creation of the semi-monocoque structure. This new design was implemented to enable the creation of passenger aircraft and took inspiration from the fuselages of early wooden flying boats. The established techniques of boat building were implemented to create aircraft with newer and smoother aerodynamic profiles. The primary advantage of the semi-monocoque structure is that the outer layer of the aircraft fuselage connector and wing not only provide aerodynamic benefits, but also carry a significant load of the structure as well. As a result, the structure as a whole is at a lower stress level and therefore provides a longer fatigue life.
After WWII, the development of turbine engines enabled higher altitude flight and brought about the need for pressurized aircraft. This meant that semi-monocoque structures needed to be made even stronger. Adjustments to fuselage materials, window style, and wing structure were made to increase the capabilities and lifespan of a semi-monocoque aircraft. Further developments came with the rise of commercial aircraft. When the jumbo jet was built, further innovation was needed to keep the aircraft strong while reducing weight. An increase in the use of composites has been a hallmark of aviation structures from the 1970s to today. As aircraft structures evolve, expect them to continue shedding weight and gaining strength.