Fighter Aircraft - Development Overview

Development Overview

Fighters were developed in World War I to deny enemy aircraft and dirigibles the ability to gather information by reconnaissance. Early fighters were very small and lightly armed by later standards, and most were biplanes built with a wooden frame, covered with fabric, and limited to about 100 mph. As control of the airspace over armies became increasingly important all of the major powers developed fighters to support their military operations. Between the wars, wood was largely replaced by steel tubing, which became aluminium tubing, and finally aluminium stressed skin structures began to predominate.

By World War II, most fighters were all-metal monoplanes armed with batteries of machine guns or cannons and some were capable of speeds approaching 400 mph. Most fighters up to this point had one engine but a number of twin engined fighters were built, however they were found defenseless against single engine fighters and were relegated to other tasks, some becoming night fighters, fitted with very primitive radar sets.

By the end of the war, turbojet engines were replacing piston engines as the means of propulsion, further increasing their speed. Since the weight of the engine was so much less than on piston engined fighters, having two engines was no longer a handicap and one or two were used, depending on requirements. This in turn required the development of ejection seats so the pilot could escape and G-suits to counter the much greater forces being applied to the pilot during maneuvers.

In the 1950s, radar was fitted to day fighters, since pilots could no longer see far enough ahead to prepare for any opposition. Since then, radar capabilities have grown enormously and are now the primary method of target acquisition. Wings were made thinner and swept back to reduce trans-sonic drag, which required new manufacturing methods to obtain sufficient strength. Skins were no longer sheet metal rivetted to a structure, but milled from large slabs of alloy. The sound barrier was broken, and after a few false starts due to required changes in controls, speeds quickly reached Mach 2—past which aircraft can't maneuver to avoid attack.

Air-to-air missiles largely replaced guns and rockets in the early 1960s since both were believed unusable at the speeds being attained, however the Vietnam War showed that guns still had a role to play and most fighters built since then are fitted with cannon (typically between 20 and 30 mm in caliber) as an adjunct to missiles. Most modern combat aircraft can carry a pair of basic air-to-air missiles and some of the larger fighters such as the Sukhoi Su-27 can carry as many as 12.

In the 1970s, turbofans replaced turbojets, improving fuel economy sufficiently that the last piston engined support aircraft could be replaced with jets, and making multi-role combat aircraft possible. Honeycomb structures began to replace milled structures, and the first composite components began to appear on components subjected to little stress.

With the steady improvements in computers, defensive systems have become increasingly efficient and to counter this, stealth technologies have been pursued by the United States, Russia, India and China. The first step in this was to find ways to reduce the aircraft's reflectivity to radar waves by burying the engines, eliminating sharp corners and diverting any reflections away from the radar sets of opposing forces. Various materials were found to absorb the energy from Radar waves, and were incorporated into special finishes that have since found widespread application. Composite structures have become widespread, and include major structural components, reducing the steadily increasing weight—most modern fighters are larger and heavier than World War 2 medium bombers.