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.
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 Gulf War of 1991.
Although it was commonly referred to as the “Stealth Fighter”, it was strictly an attack aircraft.
F-117s took part in the conflict in Yugoslavia, where one was shot down by a surface-to-air missile (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.
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 favour of the flat-sided approach.
The resulting unusual design surprised and puzzled experienced pilots.
A Royal Air Force (RAF) pilot who flew it as an exchange officer stated that when he first saw a photograph of the still-secret F-117, he “promptly giggled and thought [to himself] ‘this clearly can’t fly'”.
Early stealth aircraft were designed with a focus on minimal radar cross-section (RCS) rather than aerodynamic performance.
Highly stealthy aircraft like the F-117 Nighthawk are aerodynamically unstable in all three aircraft principal axes and require constant flight corrections from a fly-by-wire (FBW) flight system to maintain controlled flight.
It is shaped to deflect radar signals and is approximately the size of an F-15 Eagle.
The single-seat Nighthawk is powered by two non-afterburning General Electric F404 turbofan engines.
It is air refuellable and features a V-tail.
The maximum speed is 623 mph (1,003 km/h; 541 kn) at high altitude, the max rate of climb is 2,820 feet (860 m) per minute, and service ceiling is 43,000 to 45,000 feet (13,000 to 14,000 m).
The cockpit was quite spacious, with ergonomic displays and controls, but the field of view was somewhat obstructed with a large blind spot to the rear.
Variants
F-117N Seahawk
The United States Navy tested the F-117 in 1984 but determined it was not suitable for carrier use.
In the early 1990s, Lockheed proposed an upgraded, carrier-capable variant of the F-117 dubbed the “Seahawk” to the Navy as an alternative to the cancelled A/F-X program.
The unsolicited proposal was received poorly by the Department of Defence, which had little interest in the single mission capabilities of such an aircraft, particularly as it would take money away from the Joint Advanced Strike Technology program, which evolved into the Joint Strike Fighter.
The new aircraft would have differed from the land-based F-117 in several ways, including the addition of elevators, a bubble canopy, a less sharply swept wing and reconfigured tail.
The “N” variant would also be re-engined to use General Electric F414 turbofans instead of the older General Electric F404s.
The aircraft would be optionally fitted with hard points, allowing for an additional 8,000 lb (3,600 kg) of payload, and a new ground-attack radar with air-to-air capability.
In that role, the F-117N could carry AIM-120 AMRAAM air-to-air missiles.
F-117B
After being rebuffed by the Navy, Lockheed submitted an updated proposal that included afterburning capability and a larger emphasis on the F-117N as a multi-mission aircraft, rather than just an attack aircraft.
To boost interest, Lockheed also proposed an F-117B land-based variant that shared most of the F-117N capabilities.
This variant was proposed to the USAF and RAF.
Two RAF pilots formally evaluated the aircraft in 1986 as a reward for British help with the American bombing of Libya that year, RAF exchange officers began flying the F-117 in 1987, and the British declined an offer during the Reagan administration to purchase the aircraft.
This renewed F-117N proposal was also known as the A/F-117X.
Neither the F-117N nor the F-117B were ordered.
Specifications
Crew
1
Length
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 Lower
Empty weight
29,500 lb (13,381 kg)
Max take-off weight
52,500 lb (23,814 kg)
Powerplant
2 × General Electric F404-F1D2 turbofan engines,
10,600 lbf (47 kN) thrust each
Performance
Maximum speed
594 kn (684 mph, 1,100 km/h)
Maximum speed
Mach 0.92
Range
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 from Thrust/weight: 0.40
Armament
2 × internal weapons bays with one hard point each (total of two weapons) equipped to carry
Bombs
GBU-10 Paveway II laser-guided bomb with 2,000 lb Mk84 blast/fragmentation
Or
BLU-109 or BLU-116 Penetrator warhead
GBU-12 Paveway II laser-guided bomb with 500 lb Mk82 blast/fragmentation warhead
GBU-27 Paveway III laser-guided bomb with 2,000 lb Mk84 blast-fragmentation
Or
BLU-109 or BLU-116 Penetrator warhead
GBU-31 JDAM INS/GPS guided munitions with 2,000 lb Mk84 blast-frag
