https://www.youtube.com/watch?v=XYydrnUj3iA
The Lockheed F-117 Nighthawk is a semi-retired American single-seat, twin-engine stealth attack aircraft that was developed by Lockheed’s secretive Skunk Works division and operated by the United States Air Force (USAF). It was the first operational aircraft to be designed around stealth technology.The F-117 was based on the Have Blue technology demonstrator. The Nighthawk’s maiden flight took place in 1981 at Groom Lake, Nevada, and the aircraft achieved initial operating capability status in 1983. The aircraft was shrouded in secrecy until it was revealed to the public in 1988. Of the 64 F-117s built, 59 were production versions, with the other five being prototypes.The F-117 was widely publicized for its role in the Persian Gulf War of 1991. Although it was commonly referred to as the “Stealth Fighter”, it was strictly a ground-attack aircraft. F-117s took part in the conflict in Yugoslavia, where one was shot down and another damaged by surface-to-air missiles (SAM) in 1999. The U.S. Air Force retired the F-117 in April 2008, primarily due to the fielding of the F-22 Raptor. Despite the type’s official retirement, a portion of the fleet has been kept in airworthy condition, and Nighthawks have been observed flying since 2009.In 1964, Pyotr Ufimtsev, a Soviet mathematician, published a seminal paper titled Method of Edge Waves in the Physical Theory of Diffraction in the journal of the Moscow Institute for Radio Engineering, in which he showed that the strength of the radar return from an object is related to its edge configuration, not its size. Ufimtsev was extending theoretical work published by the German physicist Arnold Sommerfeld. Ufimtsev demonstrated that he could calculate the radar cross-section across a wing’s surface and along its edge. The obvious and logical conclusion was that even a large aircraft could reduce its radar signature by exploiting this principle. However, the resulting design would make the aircraft aerodynamically unstable, and the state of computer technology in the early 1960s could not provide the kinds of flight computers which would later allow aircraft such as the F-117 and B-2 Spirit to stay airborne. By the 1970s, when Lockheed analyst Denys Overholser found Ufimtsev’s paper, computers and software had advanced significantly, and the stage was set for the development of a stealth airplane.Aircraft parked inside an open hangarF-117A painted in “Gray Dragon” experimental camouflage schemeThe F-117 was born after the Vietnam War, where increasingly sophisticated Soviet surface-to-air missiles (SAMs) had downed heavy bombers.[10] The heavy losses inflicted by Soviet-made SAMs upon the Israeli air force in the 1973 Yom Kippur war also contributed to a 1974 Defense Science Board assessment that in case of a conflict in Central Europe, air defenses would likely prevent NATO air strikes on targets in Eastern Europe.When the Air Force first approached Lockheed with the stealth concept, Skunk Works Director Kelly Johnson proposed a rounded design. He believed smoothly blended shapes offered the best combination of speed and stealth. However, his assistant, Ben Rich, showed that faceted-angle surfaces would provide a significant reduction in radar signature, and the necessary aerodynamic control could be provided with computer units. A May 1975 Skunk Works report, “Progress Report No. 2, High Stealth Conceptual Studies”, showed the rounded concept that was rejected in favor of the flat-sided approach.General characteristics:Crew: 1Length: 65 ft 11 in (20.09 m)Wingspan: 43 ft 4 in (13.21 m)Height: 12 ft 5 in (3.78 m)Wing area: 780 sq ft (72 m2)Airfoil: Lozenge section, 3 flats Upper, 2 flats LowerEmpty weight: 29,500 lb (13,381 kg) Max takeoff weight: 52,500 lb (23,814 kg)Powerplant: 2 × General Electric F404-F1D2 turbofan engines, 10,600 lbf (47 kN) thrust eachPerformanceMaximum speed: 594 kn (684 mph, 1,100 km/h)Maximum speed: Mach 0.92Range: 930 nmi (1,070 mi, 1,720 km) Service ceiling: 45,000 ft (14,000 m)Wing loading: 67.3 lb/sq ft (329 kg/m2) calculated fromThrust/weight: 0.40Armament2 × internal weapons bays with one hardpoint each (total of two weapons) equipped to carry:Bombs:GBU-10 Paveway II laser-guided bomb with 2,000 lb (910 kg) Mk84 blast/fragmentation or BLU-109 or BLU-116 Penetrator warheadGBU-12 Paveway II laser-guided bomb with 500 lb (230 kg) Mk82 blast/fragmentation warheadGBU-27 Paveway III laser-guided bomb with 2,000 lb (910 kg) Mk84 blast-fragmentation or BLU-109 or BLU-116 Penetrator warheadGBU-31 JDAM INS/GPS guided munition with 2,000 lb (910 kg) Mk84 blast-frag or BLU-109 Penetrator warheadB61 nuclear bomb
