10-04-2017, 08:49 PM
ABSTRACT
Stealth aircraft are aircraft that use stealth technology to make it harder to be detected by radar and other means than conventional aircraft by employing a combination of features to reduce visibility in the visual, audio, infrared and radio frequency (RF) spectrum. Well known examples include the United States' F-117 Nighthawk (1980s-2008), the B-2 Spirit "Stealth Bomber," and the F-22 Raptor. While no aircraft is totally invisible to radar, stealth aircraft limit current conventional radar's abilities to detect or track them effectively enough to prevent an attack. Stealth is accomplished by using a complex design philosophy to reduce the ability of an opponent's sensors to detect, track and attack an aircraft. Modern stealth aircraft first became possible when a mathematician working for Lockheed Aircraft during the 1970s adopted a mathematical model developed by Petr Ufimtsev, a Russian scientist, to develop a computer program called Echo 1. Echo made it possible to predict the radar signature an aircraft made with flat panels, called facets. In 1975, engineers at Lockheed Skunk Works found that an airplane made with faceted surfaces could have a very low radar signature because the surfaces would radiate almost all of the radar energy away from the receiver. Reduced radar cross section is only one of five factors that designers addressed to create a truly stealthy design. Designers also addressed making the aircraft less visible to the [censored] eye, controlling radio transmissions, and noise abatement.