Fairchild Aircraft Company, fighter planes were not their specialty originally, and they were only active in the field of transport aircraft after the war. But in 1965, fairchild bought Republican Aircraft Company. The latter has produced a number of excellent fighters, such as P-47 Thunderbolt, F-84 Thunderbolt Jet and F-105 Thunderbolt, which gives Feichai-Gonghe a place in the fighter field. At the same time, the Air Force F-X plan entered the scheme stage, and Fei Chai naturally went all out to compete. Four suppliers, McDonald Douglas, North America, General Dynamics , Fairchild, but it seems that due to the unhappiness of the F-111 project, the Air Force directly rejected General Dynamics, and Fei Chai became one of the remaining three. After internal elimination, Fei Chai finally chose FX-8 based on LFAX-9 scheme to deepen his FX.This is a design that is now classified as "lifting body". The twin engines are located in the distant engine room. In the middle of the two engines, there is a wing-body fusion fuselage, the length of which extends from the air inlet to the tail, and finally there is an aerodynamic surface. The truncated triangular wing is relatively short, with a huge vertical tail and a small horizontal tail.

Obviously, the fuselage will produce a large proportion of lift, thus reducing the weight of the structure. Another advantage of lifting body is its excellent transonic lift-drag ratio, which can significantly improve the range. NASA obviously found lifting body's advantage in the wind experiment. The Grumman F-14 which won the VFX project finally adopted some lifting body features, and Tomcat will test it in practice.

The design tradition of Gonghe Company is "pushing bricks vigorously", so it is unrealistic to expect them to make a pneumatic breakthrough in FX, and Feichai FX has no special achievements in maneuverability.

According to the tradition of Republican Company, if it wins, it is estimated that this plane will not be named "Eagle", and it is very likely that the nickname "Thunderbolt II" later given to A-10 will be used to commemorate the P-47 Thunderbolt.