stealth aircraft

Stealth aircraft are designed to avoid detection using a variety of technologies that reduce reflection/emission of radar, infrared, visible light, radio frequency (RF) spectrum, and audio, collectively known as stealth technology. The F-117 Nighthawk was the first operational aircraft explicitly designed around stealth technology. Other examples of stealth aircraft include the B-2 Spirit, the F-22 Raptor, the F-35 Lightning II, the Chengdu J-20, the Shenyang J-35, and the Sukhoi Su-57.

While no aircraft is completely invisible to radar, stealth aircraft make it more difficult for conventional radar and radar-guided weapons to detect or track the aircraft effectively. Stealth is a combination of passive low observable (LO) features and active emitters. LO features encompass the geometric stealth shaping of the aircraft, often using a lambda wing or trapezoidal wing, and radiation-absorbent material. Active emitters consist of low-probability-of-intercept radars, radios and laser designators. These are typically combined with operational measures to minimize the aircraft's radar cross-section (RCS), since common hard turn maneuvers or opening bomb bay doors can more than double a stealthy aircraft's radar return. Stealth aircraft are sometimes complemented by reduced heat, sound, and other emissions. Countermeasures to stealth include infrared search and track systems to detect even reduced heat emissions, long wavelength radars, which counter stealth shaping and material focused on shorter wavelength radar, or radar setups with multiple emitters to counter stealth shaping.