F-117A Nighthawk, Lockheed


F-117 Nighthawk stealth fighter

The F-117 (the logic behind its out-of-series designation still remains a bit mysterious) is a 'Stealth' attack aircraft. It uses a flat, angled fuselage and wing panels to direct radar reflections in a few sharply defined directions. Despite the aerodynamic disadvantages of such design, computer controls make it easy to fly. The F117 can execute precision attacks on point targets with impunity, but has a limited weapons load. On 27 March 1999 a NightHawk was shot down over Yugoslavia, two years earlier (14 September 1997) a F-117 broke apart during an air show and crashed. On 22 April 2008, after 25 years of service, the F-117 Nighthawk, the US Air Force's first stealth fighter retired. The technology that once made it a unique weapon system has now caught up to it and newer fighter aircraft like the more effective F-22 Raptor are joining the fleet.

Type: F-117A
Function: attack
Year: 1982
Crew: 1
Engines: 2 * 48kN G.E. F404-GE-F102 turbofans
Wing Span: 13.20 m
Length: 20.08 m
Height: 3.80 m
Wing Area: 105.9 m2 (some other sources report 73 m²)
Empty Weight: 13609 kg
Max.Weight: 23814 kg
Max. Speed: 1130 km/h
Service ceiling: 10000 m
Combat range: 1112 km with max load
Armament: 5000 lb carried in 2 internal weapons bays with one hardpoint each (total of 2 weapons)
Unit cost: 120 million USD (US$45 million in 1983)


Mission

The F-117A Nighthawk is the world's first operational aircraft designed to exploit low-observable stealth technology.

Features

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

The F-117A can employ a variety of weapons and is 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 is accomplished by an automated mission planning system developed, specifically, to take advantage of the unique capabilities of the F-117A.

Design and operation

About the size of an F-15C Eagle, the single-seat, twin-engine F-117A is powered by two non-afterburning General Electric F404 turbofan engines, and has quadruple-redundant fly-by-wire flight controls. It is air refuelable. In order to lower development costs, the avionics, fly-by-wire systems, and other parts are derived from the F-16 Fighting Falcon, F/A-18 Hornet and F-15E Strike Eagle (so that these parts could be described as spares on budgets to keep the project secret).

Among the penalties for stealth are 30% lower engine power and a very low wing aspect ratio, thanks to the high sweep angle (67.5 degrees) needed to deflect incoming radar waves to the sides. The radar cross-section of the F-117 has been estimated at between 10-100 cm2, this means that a typical radar will not be able to detect an F-117 at a range any greater than 8-16 miles.

The F-117A is equipped with sophisticated navigation and attack systems integrated into a digital avionics suite. It carries no radar, which lowers emissions and cross-section. It navigates primarily by GPS and high-accuracy inertial navigation. Missions are coordinated by an automated planning system that can automatically perform all aspects of a strike mission, including weapons release. Targets are acquired by a thermal imaging infrared system, slaved to a laser that finds the range and designates targets for laser-guided bombs.

The F-117A's split internal bay can carry 5,000 lb (2,300 kg) of ordnance. Typical weapons are a pair of GBU-10, GBU-12, or GBU-27 laser-guided bombs, two BLU-109 penetration bombs, two Wind-Corrected Munition Dispensers (WCMD), or two Joint Direct Attack Munitions (JDAMs), a GPS/INS-guided stand-off bomb. It can theoretically carry two examples of nearly any weapon in the USAF inventory, including the B61 nuclear bomb. There are a number of bombs that it cannot carry, either because they are too large to fit in its bomb bay, or are incompatible with the F-117's carry system.

Sensors and Flight Management

For stealth, the F-117A does not rely on radar for navigation or targeting. For navigation and weapon aiming, the aircraft is equipped with a forward-looking infrared (FLIR) and a downward-looking infrared (DLIR) with laser designator, supplied by Raytheon. The aircraft uses a Honeywell inertial navigation system. The aircraft has multi-channel pilot static tubes installed in the nose. Multiple ports along the length of the tubes provide differential pressure readings. The flight control computers compare these in order to provide the aircraft's flight data.

Before flight, mission data is downloaded on to the IBM AP-102 mission control computer, which integrates it with the navigation and flight controls to provide a fully automated flight management system. After take-off, the pilot can hand over flight control to the mission program until within visual range of the mission's first target. The pilot then resumes control of the aircraft for weapon delivery. The aircraft is equipped with an infrared acquisition and designation system (IRADS), which is integrated with the weapon delivery system. The pilot is presented with a view of the target on the head-up display, first from the FLIR and then from the DLIR. The weapon delivery and impact is recorded on the aircraft's internally mounted video system, which provides real-time damage assessment.

Background

The first F-117A was delivered in 1982, and the last delivery was in the summer of 1990. The F-117A production decision was made in 1978 with a contract awarded to Lockheed Advanced Development Projects, the "Skunk Works," in Burbank, Calif. The first flight was in 1981, only 31 months after the full-scale development decision. Air Combat Command's only F-117A unit, the 4450th Tactical Group, (now the 49th Fighter Wing, Holloman Air Force Base, N.M.), achieved operational capability in October 1983.

Streamlined management by Aeronautical Systems Center, Wright-Patterson AFB, Ohio, combined breakthrough stealth technology with concurrent development and production to rapidly field the aircraft. The F-117A program has demonstrated that a stealth aircraft can be designed for reliability and maintainability. The aircraft maintenance statistics are comparable to other tactical fighters of similar complexity. Logistically supported by Sacramento Air Logistics Center, McClellan AFB, Calif., the F-117A is kept at the forefront of technology through a planned weapon system improvement program located at USAF Plant 42 at Palmdale, Calif.

Designation

The F-117 Nighthawk has a seemingly "out-of-series" number designation, but there might be a credible answer.

If you look back at US fighter aircraft starting in World War II, you'll notice the trend of increasing numbers (P-40, P47, P-51, etc.). Well that's all logical and seemed like a good system so it continued into the jet powered aircraft age. That's why the F-86 wasn't the "F-1". They never stopped counting when they changed the designator from Pursuit (P) to Fighter (F). It continued with the "century series" of aircraft: the F-100 Super Sabre, F-101 Voodoo, F-102 Delta Dagger, F-104 Starfighter, F-105 Thunderchief, and F-106 Delta Dart.

It turns out that one of the most historic US Fighters of all time was originally designated the F-110. (all aircraft not mentioned, like the F-107, 108, and 109 were actually aircraft that were proposed to be built/flown, but got the ax at a certain stage in their development) The F-110 is better known today as the F-4 Phantom. So why the number switch? It turns out that Robert McNamara, the Secretary of Defense at the time, wanted to simplify the numbering scheme. So they basically started back over at 1 and renumbering all the fighter aircraft. This was with the notable exception of aircraft that were more "strike" aircraft than actual air to air bred planes. Thus, the F-111 which, as you can tell was the next plane produced after the F-4/F-110 kept its number of 111, since it was designed primarily for ground attack.

So then why isn't the F-117 the F-112? Simply put, they didn't stop counting even though the new aircraft had designations like F-5, F-14, and F-15. By some weird coincidence, the numbers even lined up. The F-14 under the old system would have been the F-114. The F-15 would have been the F-115. And, you guessed it, the F-16 would have been the F-116. Of course, the F/A-18 is the next aircraft, but where is the elusive F-17? Well, the YF-17 lost the competition for the lightweight fighter to the F-16, so they threw the number out. Thus the Hornet became the F/A-18. However, the Nighthawk came into service between the F-16 and the F/A-18. So they couldn't use the F-17 moniker because it had already been used. No one had planned a number for it since it was a "black project" that no one supposedly knew about It would raise a lot of eyebrows to have the F/A-18 be the F/A-19, since people would be wondering what happened to 18. That would cause them to research for a plane in the making and compromise the secrecy of the program.

In coming up the the F-117 name, the US Air Force was trying to trick the Soviets (at the time) into thinking we had something we didn't. According to treaties signed by both sides, we weren't allowed to develop any new bomber aircraft. So, the Air Force decided to give it the prefix of "F" so that it wouldn't look like a heavy bomber. Since our old century series planes using 3 digit identifiers mostly attacked ground targets, the idea came to just continue along those numbering lines. So they counted up, and arrived at 117. Thus was born the "F-117" Nighthawk.

General Characteristics

Primary Function: Fighter/attack
Contractor: Lockheed Aeronautical Systems Co.
Unit Cost: $45 million
Power Plant: Two General Electric F404 engines
Length: 65 feet, 11 inches (20.3 meters)
Height: 12 feet, 5 inches (3.8 meters)
Weight: 52,500 pounds (23,625 kilograms)
Wingspan: 43 feet, 4 inches (13.3 meters)
Speed: High subsonic
Range: Unlimited with air refueling
Armament: Internal weapons carriage
Unit Cost: $45 million
Crew: One
Date Deployed: 1982
Inventory: Active force, 53; (the Air Force site lists 54, they probably don't watch the news)

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