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F-117A Nighthawk

The Air Force decided to retire the F-117 fleet because a new generation of stealth aircraft including the B-2 Spirit, F-22 Raptor and soon-to-be-fielded F-35 Joint Strike Fighter have better capabilities, and because the F-117 is expensive to fly and maintain. Holloman's pilot and maintenance teams launched their last "4-ship" of stealth fighters on 21 April 2008. They made a brief overnight stop at the F-117s logistics support center in Palmdale, CA, for a final ceremony before retiring to Tonopah where their wings and tails removed and the aircraft stored in protective hangars.

The F-117s will be placed in storage at an airfield in the Tonopah Test Range, Nev., where the jets flew in total secrecy and only at night until November 1988. The F-117 was nearly completely covered with a radar absorbing material which is laborious and expensive to maintain. After each mission, maintenance specialists closely examine the aircraft's special coating to identify any needed repairs. If required, coatings were reapplied, allowed to cure, and re-inspected. A portion of the fleet is rapidly recallable to fly again, if ever needed.

Five F-117 development aircraft were built and tested between 1981 and 1982. The first F-117 squadron was declared operational in 1983. Lockheed built a total of 59 F-117s for the Air Force. The F-117 was a highly secret aircraft during most of the 1980s. It was finally unveiled in 1989 and became famous in 1991 when it was used in heavily defended skies over Iraq during the Persian Gulf War. In 1999, an F-117 was shot down by a Russian-built missile over Yugoslavia, demonstrating that stealth was not invincible.

The F-117A Nighthawk was the world's first operational aircraft designed to exploit low-observable stealth technology. The F-117A was a single-seat attack and defense suppression aircraft for the Air Force. The F-117 was designed to penetrate dense threat environments as well as attack high value targets with pinpoint accuracy.

The unique design of the single-seat F-117A provided exceptional combat capabilities. About the size of an F-15 Eagle, the twin-engine aircraft was powered by two General Electric F404 turbofan engines and has quadruple redundant fly-by-wire flight controls. Air refuelable, it supported worldwide commitments and adds to the deterrent strength of the U.S. military forces.

The F-117A could employ a variety of weapons and was equipped with sophisticated navigation and attack systems integrated into a state-of-the-art digital avionics suite that increases mission effectiveness and reduces pilot workload. Detailed planning for missions into highly defended target areas was accomplished by an automated mission planning system developed, specifically, to take advantage of the unique capabilities of the F-117A.

Constructed principally of aluminum with RAM applied to external skins, the F-117 employed a largely conventional internal structure including the use of two spar wings. Constructed primarily of aluminum, the F-117A's fuselage comprises flat panels known as facets mounted on the aircraft's subframe, their purpose being to reflect radar energy away from the transmitter itself, thus denying the operators a visible 'return'. All surfaces were coated with various radar absorbent materials. All doors and panels have serrated edges to further minimize radar reflection. Grid covers on the intakes and the use of narrow-slot 'platypus' exhausts surrounded by heat-absorbing tiles further reduce the chances of IR detection. Ahead of the flat-plate five-piece cockpit glazing is a FLIR sensor, recessed in a mesh-covered housing; in the forward starboard underfuselage there is a retractable DLIR and laser designator. These sensors were used in conjunction with LGBs, two of which can be carried in the double-section weapons bay.

The Lockheed F-117 Nighthawk was one of the most dramatic examples where shaping was tailored toreduce RCS. Of faceted construction with wing and empennage surfaces of 67.5 and 20 leading edge sweep respectively, the F-117 was aerodynamically unstable, particularly in pitch. While proven to serve as an excellent weapon system of very low RCS, the F-117 was known for its high takeoff and approach speeds of 165 Kts and 150 kts respectively despite a relatively low wing loading at MTOW of approximately 46 Ibs/sq ft. These high speeds are in part due to the aerodynamics of highly swept wings in combination with a close coupled empennage of relatively low volume coefficient as well as being the result of faceted wing airfoils. Despite high stall speed, the F-117 demonstrates significantly high degrees of maneuverability, responsiveness and controllability due to four channel Fly-By-Wire (FBW).

With the engines inside the fuselage, an extra effort must be made to inspect for loose objects or missing hardware before any engine run was attempted. This was not news to all those personnel who regularly worked on or around this aircraft.

An extremely affordable aircraft, average per unit flyaway cost was estimated at only $42.6 million. Responsible for hitting over 31 % of the tar-gets during the first day of war in Desert Storm I, one of the only major shortcomings of the F-117, asidefrom high maintainability requirements associated with RAM coatings, was the fact only 59 were procured with a 1991 potential order for 24 more aircraft being scrubbed.

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Page last modified: 07-07-2011 02:30:19 ZULU