RJ (![[info]](http://p-stat.livejournal.com/img/userinfo.gif){kind=small} rjlippincott) wrote,@ 2008-04-22 14:38:00 |
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Another sad career milestone
Alas, another aircraft that I worked on retires...
New Mexico base sends last F-117s to retirement in Nevada
HOLLOMAN AIR FORCE BASE, N.M. — Holloman Air Force Base has bid farewell to the F-117 Nighthawk.
The last four stealth fighters left the base Monday. They will be mothballed at the Tonopah Test Range in Nevada.
The Air Force’s 49th Fighter Wing and its F-117s was brought to Holloman in 1992. The F-117s will be replaced by the F-22 Raptor, which also has stealth technology.
The 49th Fighter Wing’s commander, Col. Jeff Harrigian, says the first F-117 prototype flew in 1979 and the first Nighthawk was delivered to the Air Force in 1982. Eventually, 59 F-117s were made.
Actually, that last sentence isn't quite accurate.
There were five YF-117A prototypes. These were instrumented aircraft used to test flight and low observable characteristics. Externally they looked just the same, internally there were a few differences. For example the YF-117A used a "steam gage" type control panel (in other words, traditional dials and indicators) while the production F-117 used a three-screen video display system essentially identical to the one used in the F/A-18 Hornet.
The Air Force contracted for 60 F-117A aircraft. The first airplane completed had a mis-wired flight computer (the data inputs were cross-connected). On its first flight, it took off, promptly rolled over onto its back, and crashed. (The pilot was injured but survived.) That left 59 airplanes on contract, they were all delivered successfully.
59 delivered plus 1 crash plus 5 prototypes equals 65, not 59.
Oh yeah, and the engineers modified the flight computer data connectors so that the cross-connection would never be repeated.
The F-117 airframes still have a lot of life in them, but the first-generation stealth coatings are labor-intensive. It takes too many man-hours to strip and re-coat the airplane in order to perform routine maintenance, the more advanced coatings on the F-22 make the job easier and faster. Right now, the Air Force is going broke and can't afford to pay for the man-hours to do the maintenance, so a good airplane is getting grounded.
Only one was ever lost to combat fire (over Serbia in 1999), and even that wouldn't have happened if politics hadn't dictated that the airplanes be sent in along the same attack route night after night. You don't need a solid radar lock to hit an airplane if you've figured out where it's going to be and can pepper the sky with surface-to-air missiles. (Funny, you'd think that the government would have learned that lesson in 1972. I guess not.)
By the way, there is no big secret to stealth. It's simply all in the shape. Any high school student who passed geometry could work out the basics of designing a stealthy airframe. The key is in the precision of the tolerances: the precise angles and tight fits. In Ben Rich's book Skunk Works, he tells the story of YF-117 radar cross section testing and the day an airplane showed up on radar two or three times the expected size. After it landed, a very close inspection of an area (where they'd done maintenance the previous day) revealed a single screw-head that was one-quarter turn out of alignment, leaving the slot on the head perpendicular to the direction of flight instead of parallel. That was enough to make a difference.
If your country has an industrial base that can guarantee multiple airframe construction with consistent tolerances to the degree necessary for precise alignment of structure and components, your country can build a stealth aircraft. If your country doesn't have that degree of precision, your country can't do it.
That's the only "secret" to stealth.
Alas, another aircraft that I worked on retires...
New Mexico base sends last F-117s to retirement in Nevada
HOLLOMAN AIR FORCE BASE, N.M. — Holloman Air Force Base has bid farewell to the F-117 Nighthawk.
The last four stealth fighters left the base Monday. They will be mothballed at the Tonopah Test Range in Nevada.
The Air Force’s 49th Fighter Wing and its F-117s was brought to Holloman in 1992. The F-117s will be replaced by the F-22 Raptor, which also has stealth technology.
The 49th Fighter Wing’s commander, Col. Jeff Harrigian, says the first F-117 prototype flew in 1979 and the first Nighthawk was delivered to the Air Force in 1982. Eventually, 59 F-117s were made.
Actually, that last sentence isn't quite accurate.
There were five YF-117A prototypes. These were instrumented aircraft used to test flight and low observable characteristics. Externally they looked just the same, internally there were a few differences. For example the YF-117A used a "steam gage" type control panel (in other words, traditional dials and indicators) while the production F-117 used a three-screen video display system essentially identical to the one used in the F/A-18 Hornet.
The Air Force contracted for 60 F-117A aircraft. The first airplane completed had a mis-wired flight computer (the data inputs were cross-connected). On its first flight, it took off, promptly rolled over onto its back, and crashed. (The pilot was injured but survived.) That left 59 airplanes on contract, they were all delivered successfully.
59 delivered plus 1 crash plus 5 prototypes equals 65, not 59.
Oh yeah, and the engineers modified the flight computer data connectors so that the cross-connection would never be repeated.
The F-117 airframes still have a lot of life in them, but the first-generation stealth coatings are labor-intensive. It takes too many man-hours to strip and re-coat the airplane in order to perform routine maintenance, the more advanced coatings on the F-22 make the job easier and faster. Right now, the Air Force is going broke and can't afford to pay for the man-hours to do the maintenance, so a good airplane is getting grounded.
Only one was ever lost to combat fire (over Serbia in 1999), and even that wouldn't have happened if politics hadn't dictated that the airplanes be sent in along the same attack route night after night. You don't need a solid radar lock to hit an airplane if you've figured out where it's going to be and can pepper the sky with surface-to-air missiles. (Funny, you'd think that the government would have learned that lesson in 1972. I guess not.)
By the way, there is no big secret to stealth. It's simply all in the shape. Any high school student who passed geometry could work out the basics of designing a stealthy airframe. The key is in the precision of the tolerances: the precise angles and tight fits. In Ben Rich's book Skunk Works, he tells the story of YF-117 radar cross section testing and the day an airplane showed up on radar two or three times the expected size. After it landed, a very close inspection of an area (where they'd done maintenance the previous day) revealed a single screw-head that was one-quarter turn out of alignment, leaving the slot on the head perpendicular to the direction of flight instead of parallel. That was enough to make a difference.
If your country has an industrial base that can guarantee multiple airframe construction with consistent tolerances to the degree necessary for precise alignment of structure and components, your country can build a stealth aircraft. If your country doesn't have that degree of precision, your country can't do it.
That's the only "secret" to stealth.
