Warplanes: Last F-117 Flies Off To The Boneyard


p> March 13, 2008: The U.S. Air Force is retiring the last of its F-117 light bombers. Long called the "stealth fighter," the F-117 was designed from the start as a bomber. But the aircraft is now 27 years old. It's really 1970s technology that, after years of effort, was made to work in the 1980s. But better stuff is out there, and the stealth technology of the F-117 is obsolete when it comes to some of the more recent sensor developments. The new F-22 will be a direct, and more effective, replacement for the F-117 as a light bomber. Plus, the F-22 is also a superior fighter.


Earlier attempts to take the F-117 out of service ran up against political opposition. Bases would have to be closed, which means lost jobs. The air force worked out deals to take care of that angle, and the last active duty F-117  will be retired in April, 2008. The last class of F-117 pilots graduated two years ago.  A total of  558 pilots were trained to operate the one seater aircraft. Ten aircraft were retired in late 2006, and another 27 in the last 15 months.


The first F-117 flew in 1981, and 59 were eventually built. Six crashed due to non-combat causes, and one was brought down due to the efforts of a clever Serb air defense officer, who exploited the chinks in the F-117s stealth technology. But starting in 1989, when an F-117 participated in the invasion of Panama, the aircraft proved its worth. The usual bomb load for the 24 ton aircraft, was two one-ton laser guided bombs, in an internal bomb bay. The F-117 almost always attacked at night, and took out a disproportionate number of targets compared to non-stealth bombers.


The stealth technology used was such that no two F-117s were the same. As the aircraft were produced, new techniques for applying the RAM (Radar Absorbent Materials) were developed. The first planes had sheets of RAM glued onto the airframe. More than halfway through the run, a new spray-on technique was developed. This technique was changed several times before the 59th F-117 was manufactured. Several different treatments have been used for the wing edges, cockpit rim, access panels, and other areas. As the material degraded or was damaged over time, several different repair techniques were used. Access panels were another variable, as some aircraft had to have the RAM scraped off to open them while others had treatments that provided easier (and less destructive) access. Stealth works in various ways, and stealth aircraft use a combination of techniques. The basic concept, however, is to make the stealth RAM coating one-fourth of a radar wavelength thick. In this way, some of the enemy radar beam is reflected by the surface of the RAM and more by the metal under the RAM later. Because this second element travels a half of a wavelength farther than the first element, it exactly cancels out the radar wave.


The retired F-117s are being put into storage (the "boneyard"). There, for the next decade or so, the bombers can be recalled to service.