An airframe refers to an aircraft's mechanical structure. Generally, both the inner supporting structure as well as the outer skin are included in the airframe designation. Working in concert, the outer and inner components of an airframe maintain the aircraft's structural integrity and strength. Science has benefited greatly in the understanding of metallurgy, stress and fatigue when examining airframe construction and failure. From wood to aluminum and steel construction, airframe technology has grown to include space-age composite materials in the manufacturing of modern aircraft designs.
One of the most difficult factors facing early aircraft designers was designing an airframe that would survive the stresses of takeoff and landing while remaining light-weight enough to allow flight. Inventors Orville and Wilbur Wright solved the problem by designing an airframe made from wood and wire bracing. Their machine first flew in Kitty Hawk, North Carolina, in the United States. While the flight was not nearly as long as most modern runways, it changed aviation forever.
Most dramatic airframe design changes occurred due to war. The aircraft used in World War I were typically wooden-framed designs covered with canvas. The aircraft performed well; the fuselages, however, provided no protection from bullets for the pilots. Many pilots were even killed from ground fire as they flew over the battlefields.
World War II brought new alloys into the production combination, and manufacturers created frames and coverings for aircraft out of aluminum. The new material was light-weight and provided added protection for the pilots. Heavy steel plates were located in the cockpit to give additional protection from bullets. Some of the most important designs of the era remain flying after more than 60 years after the war. This is credited to the design and manufacturing practices of the times. Examples of the American fighter planes such as the P51 Mustang as well as the German ME109 and Japanese Zero can be seen at air shows around the world.
As aircraft design moved into the jet age, airframe technology was forced to evolve yet again. The stresses and strain asserted by the powerful jet engines demanded stronger yet lighter materials be used in the manufacturing of the aircraft. Exotic and space-age composite materials soon made up the construction of both the inner framework of the aircraft and the outer covering of the craft. Aircraft designers began using body panels that made up the framework of the aircraft. Bullet-proof materials as well as radar-absorbing materials now make up the framework and covering of military aircraft worldwide.