Lu Xiaopeng was appointed chief designer of this project. Lu also designed the J-12 fighter jet. Although based on the MiG-19, the new design, designated Qiangjiji-5 (fifth attack aircraft design), had a longer fuselage, area ruled to reduce transonic drag and accommodate a 4 m (13-ft) long internal weapons bay. The air intakes were moved to the fuselage sides to make space in the nose for a planned target radar (which was never actually fitted). New wings with greater area and reduced sweep were incorporated. The Q-5 shares the J-6's Liming Wopen WP-6 A (Tumansky RD-9) turbojet engines. The redesign cost some high-altitude speed, but the Q-5 is as fast as the MiG-19/J-6 at low level, thanks largely to the area-ruled fuselage.