Methods used to render an aircraft, or other vehicle, nearly
invisible to radar, heat, and visual detection.
To achieve "invisibility", a stealth aircraft must have sympathetic airframe
design (all radar-reflecting "hard" edges smoothed away), engine exhaust
dampers that mask and disperse jet efflux, and radar absorbent material
that "holds" electronic emissions rather than reflecting them. This coating
has to be regularly applied, since it is to sensitive to water and wear.
In 1983 the American Lockheed F-117A became the first "stealth" aircraft
to enter frontline service; it was followed a decade later by the Northrop
B-2. The F-19 stealth fighter was used in the Gulf War (1991). Few aerodynamic
advances have had such a profound effect on military aviation as stealth
|Lockheed F-117A flying over Yosemite National Park,
California. The F-117A employs stealth technology to render itself
practically invisible to radar. The aircraft's materials and design
are such that its radar cross-section (RCS) – the imaginary
size of a perfectly reflecting object that would reflect the same
amount of energy – is reduced to within the levels of background
radiation. To achieve this, compromises are required in terms of the
aircraft's performance and operating and maintenance costs.