Editing Radar cross section (section)

===Purpose shaping===
With purpose shaping, the shape of the target's reflecting surfaces is designed such that they reflect energy away from the source. The aim is usually to create a "cone-of-silence" about the target's direction of motion. Due to the energy reflection, this method is defeated by using [[Passive radar|passive (multistatic) radar]]s.

Purpose-shaping can be seen in the design of surface faceting on the [[F-117 Nighthawk|F-117A Nighthawk]] stealth attack aircraft. This aircraft, designed in the late 1970s though only revealed to the public in 1988, uses a multitude of flat surfaces to reflect incident radar energy away from the source. Yue suggests<ref>{{cite web | author= The Tech | year= 2001 | title= Detection of the B-2 Stealth Bomber And a Brief History on "Stealth" | url= http://tech.mit.edu/V121/N63/Stealth.63f.html | access-date= 2016-02-01 | archive-date= 2009-06-10 | archive-url= https://web.archive.org/web/20090610041304/http://tech.mit.edu/V121/N63/Stealth.63f.html | url-status= dead }}</ref> that limited available computing power for the design phase kept the number of surfaces to a minimum. The [[B-2 Spirit]] stealth bomber benefited from increased computing power, enabling its contoured shapes and further reduction in RCS. The [[F-22 Raptor]] and [[F-35 Lightning II]] continue the trend in purpose shaping and promise to have even smaller monostatic RCS.