Washington — For two years the United States has been secretly flying tactical air craft that are virtually invisible to air defense systems, the Armed Froces Journal reports in its September edition. It says four or five of the "stealth" aircraft have been flown as prototypes, and a strategic-bomber version is on the drawing board.
The techniques used to shield the aircraft from detection "apparently involve special shaping or contouring of the aircraft's structure; nonmetallic materials that absorb electromagnetic energy or cause such a weak return of it for the signal to be ambiguous or almost undetectable; infrared shielding of an aircraft's engine exhaust and other 'hot spots'; special paints to absorb, deflect, and shroud signals . . . and electronic techniques and countermeasures to generate false returns which show plane's position far away from the plane's actual flight path."
Defense officials are quoted as saying the enw techniques "pretty much invalidate the whole set of air defense systems existing today."