Complied by William J. Simone
The Lockheed F-117 Nighthawk is a single-seat, twin-engine stealth ground attack aircraft operated by the United States Air Force. A product of Lockheed Skunk Works, and an off shoot of the Have Blue technology demonstrator, the F- 117 was the first operational aircraft to be designed around stealth technology. It was developed under Senior Trend.
The F-117 Nighthawk is a single-seat aircraft with a maximum speed in the high subsonic range. The first aircraft was delivered in 1982 and the last of the 59 Nighthawks procured by the US Air Force was received in 1990.
Its unusual external shape is made up of faceted shape flat surfaces rather than curved surfaces to reduce its radar cross section (RCS). The surfaces and edge profiles are optimized to reflect hostile radar into narrow beam signals, directed away from the enemy radar. All the doors and opening panels on the aircraft have saw-toothed forward and trailing edges to reflect radar.
The aircraft is mainly constructed of aluminum, with titanium for areas of the engine and exhaust systems. The outer surface of the aircraft is coated with a radar-absorbent material (RAM).
It is powered by two low-bypass General Electric F404-GE-F1D2 non-afterburner turbofan engines. The rectangular air intakes on both sides of the fuselage are covered by gratings, nicknamed the ice cube maker, which are coated with radar-absorbent material.
The F-117 reduced its IR signature with a non-circular tail pipe. The wide and flat rectangular structure of the engine exhaust area reduced the infrared and radar detectability of the aft section of the engine by minimize the exhaust cross-section and maximize the mixing of hot exhaust with cool ambient air.
The two large tail fins slant slightly outwards to provide an obstruction to the infrared and radar returns from the engine exhaust area.
It had a quadruple redundant fly-by-wire flight controls system. To lower development costs, the avionics, fly-by-wire systems, and other parts were derived from the General Dynamics F-16 Fighting Falcon, McDonnell Douglas F/A-18 Hornet and McDonnell Douglas F-15E Strike Eagle.
The aircraft was equipped with sophisticated navigation and attack systems integrated into a digital avionics suite. For navigation and weapon aiming, the aircraft is equipped with a forward-looking infrared (FLIR) and a downward-looking infrared (DLIR) with a laser designator. Targets were acquired by the FLIR, with the DLIR determining the range which designated the targets for the laser-guided bombs. The F-117A’s dual side by side internal bay could carry up to 5,000 pounds of ordnance. Typical weapons carried are the GBU-10, GBU-12, or GBU-27 laser-guided bombs.
The museum’s YF-117A (783, USAF serial 79-10783, “Scorpion 4”) is the fourth Full Scale Development (FSD) aircraft, being delivered on 5 December 1981. Lockheed pilot Tom Morganfeld flew it for the first time on 7 July 1982. Two functional check flights by Air Force pilots were followed by several weeks of infrared signature measurements. This was followed by integration of avionics for Infrared Acquisition and Designation System trials. From 24 April to 23 July 1984, 783 was flown against F-14, F-15, F-16, and EF-111A aircraft to collect air-to-air threat analysis data. Afterward, the airplane was used alternatively between low-observables tests and integration of improvements to navigation and weapon delivery systems. In October 1984, two Navy pilots used 783 to conduct a performance review to evaluate the F-117A for carrier suitability.
In March 1989, 783 was officially accepted by the Air Force. In 1998, after being assigned to the 410th Flight Test Squadron (FTS), 783 became the first F-117A modified in the Single Configuration Fleet program, a four-month test series to evaluate an optimized radar-absorbent coating to improve maintainability.
In April 2004, the airplane was used to evaluate a two-tone grey camouflage paint scheme.
The F-117A unique design made the aircraft very hard to detect by the air defense systems. But, low observability to radar alone was not sufficient to guarantee the plane to fly undetected through the enemy airspaces. Conceived for night secret missions, the “Nighthawk” was restricted to fly only with darkness. Each operation from “Just Cause” in 1989 to “Iraqi Freedom” in 2003, the F-117s only flew after sunset.
The F-117A, the museum’s YF-117A 783, was painted in gray with the task to determine if the aircraft could play a role in daytime missions. It was nicknamed the “Grey Dragon” with the operational testing being conducted at Holloman AFB, New Mexico, by the 53rd Test and Evaluation Detachment 1 (Det 1).
Flying two missions every day Det 1 pilots were able to determine their daytime capabilities and limitations. The grey paint scheme proved immediately that the black paint scheme would not meet the daylight operation requirements. In addition, the Grey Dragon was also upgraded with new software and hardware. Furthermore, the new paints were evaluated by measuring the impact that the gray had on the maintenance.
All these trials were necessary to provide an accurate evaluation of the daytime operations with the gray paint scheme, to ensure a 24-hour stealth presence above the future battlefields.
However, despite the good results of the trials, 783 was the only F-117 painted in gray.
783 was retired in March 2007 with 2,464.6 flight hours.
After its retirement volunteers with the 410th Flight Test Squadron, assigned to Edwards AFB but based at nearby U.S. Air Force Plant 42, prepared 783 for static display. In doing so the aircraft had to be modified. The original leading edges, nose assembly, pitot tubes and exhaust were removed and replaced, due to their sensitive technology. Aluminum sheet replaced the canopy and sensor glass which remains classified. Unfortunately, this also included the cockpit.
On 3 March 2008 783 was moved from the 410th FLTS to Blackbird Air Park where it was displayed for a number of years. Unfortunately, the weather took its toll on the aircraft requiring that it be relocated to Edwards AFB. During the late hours of 7 June 2012 783 was towed over 30 miles to Edwards AFB by a dedicated group of museum volunteers.
Restoration work continues at Edwards. With the Air Force relaxing some of the past security requirement it is hoped that 783’s cockpit can be restored.
