Aviation and War Machine

Development
The Advanced Tactical Fighter (ATF) contract was a demonstration and validation program undertaken by the United States Air Force to develop a next-generation air superiority fighter to counter emerging worldwide threats, including development and proliferation of Soviet-era Su-27 ‘Flanker’-class fighter aircraft.
The original Lockheed Advanced Tactical Fighter concept, 1986.
The original Lockheed Advanced Tactical Fighter concept, 1986.

In 1981, USAF developed a requirement for a new air superiority fighter intended to replace the capability of the F-15 Eagle. It was envisaged that the ATF would incorporate emerging technologies including advanced alloys and composite material, advanced fly-by-wire flight control systems, higher power propulsion systems, and low-observable/stealth technology.

A request for proposal (RFP) was issued in July 1986, and two contractor teams, Lockheed/Boeing/General Dynamics and Northrop/McDonnell Douglas were selected in October 1986 to undertake a 50 month demonstration/validation phase, culminating in the flight test of two prototypes, the YF-22 and the YF-23.

• The original Boeing Advanced Tactical Fighter concept, 1986.
• The original Boeing Advanced Tactical Fighter concept, 1986.

Following a hard-fought fly-off competition, in August 1991 the YF-22 was declared the winner and Lockheed was awarded the contract to develop and build the Advanced Tactical Fighter.

Production
The first production F-22 was delivered to Nellis Air Force Base, Nevada, on 14 January 2003. F-22 Dedicated Initial Operational Test and Evaluation occurred on 27 October 2004. As of late 2004, 51 Raptors were in service, with 22 more ordered under fiscal year 2004 funding. The first crash of a production F-22 occurred at Nellis Air Force Base on 20 December 2004, during takeoff. The pilot ejected safely moments before impact. The crash investigation revealed that a brief interruption in power during an engine shutdown prior to flight caused a malfunction in the flight-control system. The technical data for the aircraft have been amended to avoid this problem in the future.

Procurement

• Two F-22s, the one on top being the first EMD F-22, Raptor 01.
• Two F-22s, the one on top being the first EMD F-22, Raptor 01.

The United States Air Force originally planned to order 750 ATFs, with production beginning in 1994. The 1990 Major Aircraft Review altered the plan to 648 aircraft beginning in 1996. The goal changed again in 1994, when it became 442 planes entering service in 2003 or 2004. A 1997 Department of Defense report put the purchase at 339. In 2003, the Air Force said that the existing congressional cost cap limited the purchase to 277. In 2006, the Pentagon is saying it will buy 183 aircraft, which would save $15 billion but raise the cost of each plane. This plan has been de facto approved by Congress in the form of a multi-year procurement plan, which still holds open the possibility for new orders past that point. The total cost of the program by 2006 was $62 billion.

In April 2006, the cost of the F-22A was assessed by the Government Accountability Office to be $361 million per aircraft. This cost reflects the F-22A total program cost, divided by the number of jets the Air Force is programed to buy. So far, the Air Force has invested as much as $28 billion in the Raptor’s research, development and testing. That money, referred to as a “sunk cost”, is already spent and is separate from money used for future decision-making, including procuring a copy of the jet.

By the time all 183 jets have been purchased, $34 billion will be spent on actually procuring the aircraft. This will result in a cost of about $339 million per aircraft based on total program costs. The incremental cost for one additional F-22 is around $120 million. If the Air Force were to buy 100 more F-22s today, each plane would be less than $117 million and would continue to drop with additional aircraft purchases.[5]
F-22A Raptor over Utah in their first official deployment, October 2005.
F-22A Raptor over Utah in their first official deployment, October 2005.

The F-22 is not the most expensive plane aloft; that distinction likely belongs to the roughly $2.2 billion-per-unit B-2 Spirit; though the incremental cost was under US$1 billion. In fairness, orders for the B-2 went from hundreds to a few dozen when the Cold War ended thus making the unit cost skyrocket. The F-22 uses fewer radar absorbent materials than the B-2 or F-117 Nighthawk, which is expected to translate into lower maintenance costs.

On July 31, 2007, Lockheed Martin received a multiyear contract for 60 F-22s worth a total of US$7.3 billion.[6] [7] The contract extends production through 2011.[6]

[edit] Proposed foreign sales

Unlike many other tactical fighters, the opportunity for export is currently non-existent because the export sale of the F-22 is barred by federal law. There was a time in the 1970s when the then-new F-16 also had many restrictions. However, regardless of restrictions, very few allies would even be considered for export sale because the F-22 is such a sensitive and expensive system. Most current customers for US fighters are either acquiring earlier designs like the F-15, or F-16 or are waiting to acquire the F-35, which contains much of the F-22’s technology but is designed to be cheaper and more flexible.

More recently Japan reportedly showed some interest in buying F-22As in its Replacement-Fighter program for its Air Self-Defense Force (JASDF).[8] In such an event, it would most likely involve a “watered-down” export variant while still retaining most of its advanced avionics and stealth characteristics. However, such a proposal would still need approval from the Pentagon, State Department and Congress.

Some Australian defense commentators have proposed that Australia purchase F-22 aircraft instead of the F-35.[9] The Australian Labor Party, Australia’s main opposition party supports this proposal on the grounds that the F-22 is a proven, highly capable aircraft while the F-35 is still under development.[10] The current Australian Government, however, has ruled out the purchase of the F-22 as it is unlikely to be released for export and does not meet Australia’s requirements for a strike aircraft.[11] This assessment is supported by the Australian Strategic Policy Institute, a non-partisan, government-funded think-tank, claiming the F-22 “has insufficient multi-role capability at too high a price” for Australia.[12]

Also in an exclusive interview, Israeli Air Force (IAF) chief procurement officer Brigadier-General Ze’ev Snir said that, “The IAF would be happy to equip itself with 24 F-22s but the problem at this time is the US refusal to sell the plane, and its $200 million price tag.”[13]

The US Congress upheld the ban on F-22 Raptor foreign sales during a joint conference on 27 September 2006.[14] After talks in Washington in December 2006, the US DoD reported the F-22 would not be available for foreign sale.[15]

[edit] Design

[edit] Characteristics
F-22 Raptor displaying its F119-PW-100 engines on full afterburner.
F-22 Raptor displaying its F119-PW-100 engines on full afterburner.

The dual afterburning Pratt & Whitney F119-PW-100 turbofans incorporate thrust vectoring. Thrust vectoring is in the pitch axis only, with a range of ±20 degrees. The maximum thrust is classified, though most sources place it at about 35,000 lbf (156 kN) per engine. Maximum speed is estimated to be Mach 1.72 in supercruise mode and without external weapons; with afterburners, it is “greater than Mach 2.0″ (2,120 km/h), according to Lockheed Martin. The Raptor can easily exceed its design speed limits, particularly at low altitudes; max-speed alerts help prevent the pilot from exceeding the limits. General John P. Jumper, former U.S. Air Force Chief of Staff, flew the Raptor faster than Mach 1.7 without afterburners on 13 January 2005. The absence of variable intake ramps may make speeds greater than Mach 2.0 unreachable, but there is no evidence to prove this. Such ramps would be used to prevent engine surge, but the intake itself may be designed to prevent this. Former Lockheed Raptor chief test pilot Paul Metz stated that the Raptor has a fixed inlet. Metz has also stated that the F-22 has a top speed greater than 1600 mph (Mach 2.42) and its climb rate is faster than the F-15 Eagle due to advances in engine technology, despite the F-15’s thrust-to-weight ratio of about 1.2:1, with the F-22 having a ratio closer to 1:1.[16]
Aircraft wing planform shapes: a KC-10 Extender (top) refuels an F-22 Raptor.
Aircraft wing planform shapes: a KC-10 Extender (top) refuels an F-22 Raptor.

The true top-speed of the F-22 is largely unknown, as engine power is only one factor. The ability of the airframe to withstand the stress and heat from friction is a key factor, especially in an aircraft using as many polymers as the F-22. However, while some aircraft are faster on paper, the internal carriage of its standard combat load allows the aircraft to reach comparatively higher performance with a heavy load over other modern aircraft due to its lack of drag from external stores. It is one of only a handful of aircraft that can sustain supersonic flight without the use of afterburner augmented thrust, i.e. supercruise. The fuel usage from using afterburners greatly reduces flight time.

The F-22 is highly maneuverable, at both supersonic and subsonic speeds. The F-22’s thrust vectoring nozzles allow the aircraft to turn tightly, and perform extremely high alpha (angle of attack) maneuvers such as the Herbst maneuver (or J-turn), Pugachev’s Cobra,[16] and the Kulbit, though the J-Turn is more useful in combat.[16] The F-22 is also capable of maintaining a constant angle of attack of over 60°, yet still having some control of roll.[16][17] Cruise altitude is a huge factor in performance. During June 2006 exercises in Alaska, F-22 pilots routinely attributed their altitude advantage as major factor in an unblemished kill ratio.[18]

Avionics include BAE Systems E&IS (formerly Sanders Associates)[19] radar warning receiver (RWR) AN/ALR-94, and Raytheon and Northrop Grumman AN/APG-77 Active Electronically Scanned Array (AESA) radar. AN/APG-77 is possibly the most capable radar in active service, with both long-range target acquisition and low probability of interception of its own signals by enemy aircraft.

[edit] Avionics

The AN/ALR-94 is a passive receiver system capable of detecting the radar signals in the environment. Composed of more than 30 antennae smoothly blended into the wings and fuselage, it is described by the former head of the F-22 program at Lockheed Martin Tom Burbage as “the most technically complex piece of equipment on the aircraft.” With greater range (250 nm+) than the radar, it allows F-22 to limit its own radar emission from compromising its stealth. As the target approaches, AN/ALR-94 can cue the AN/APG-77 radar to keep track of its motion with a narrow beam, which can be as focused as 2° by 2° in azimuth and elevation.[20]

The AN/APG-77 AESA (active electronically scanned array) radar, designed for air-superiority and strike operations, features a low-observable, active-aperture, electronically-scanned array that can track multiple targets in all kinds of weather. The AN/APG-77 changes frequencies more than 1,000 times per second to reduce the chance of being intercepted. The radar can also focus its emissions to overload enemy sensors, giving the plane an electronic-attack capability.

The radar’s information is processed by the two Raytheon-built Common Integrated Processor (CIP)s. Each CIP operates at 10.5 billion instructions per second and has 300 megabytes of memory. Information can be gathered from the radar and other onboard and offboard systems, filtered by the CIP, and offered in easy-to-digest ways on several cockpit displays, enabling the pilot to remain on top of complicated situations. The Raptor’s software is composed of over 1.7 million lines of code, most of which concerns processing data from the radar.[21] The radar has an estimated range of 125-150 miles, though planned upgrades will allow a range of 250 miles or more in narrow beams.[18]

The F-22 has several unique functions for an aircraft of its size and role. For instance, it has threat detection and identification capability along the lines of that available on the RC-135 Rivet Joint.[18] While the F-22’s equipment isn’t as powerful or sophisticated, because of its stealth, it is typically hundreds of miles closer to the battlefield, which often compensates for the reduced capability.[18]

The F-22 is capable of functioning as a “mini-AWACS.” Though reduced in capability compared to dedicated airframes such as the E-3 Sentry, as with its threat identification capability, the F-22’s forward presence is often of benefit.[16] The system allows the F-22 to designate targets for cooperating F-15s and F-16s, and even determine if two friendly aircraft are targeting the same enemy aircraft, thus enabling one of them to choose a different target.[18][16] It is often able to identify targets hundreds of times faster than accompanying dedicated AWACS.

The F-22’s low probability of intercept radar is being given a high-bandwidth data transmission capability, to allow it to be used in a “broadband” role to permit high-speed relaying of data between friendly transmitters and receivers in the area.[18] The F-22 can already pass data to other F-22s, resulting in considerably reduced radio “chatter.”

The IEEE-1394B data bus, developed for the F-22, was derived from the commercial IEEE-1394 bus system,[22] often used on personal computers. The bus was subsequently deployed on the derivative F-35 Lightning II fighter.

Armament
An F-22 releases a JDAM from its internal bay while flying at supersonic speed
An F-22 releases a JDAM from its internal bay while flying at supersonic speed

The Raptor is designed to carry air-to-air missiles in internal bays to avoid disrupting its stealth capability. Launching missiles requires opening the weapons bay doors for less than a second, as the missiles are pushed clear of the airframe by hydraulic arms. The plane can also carry bombs such as the Joint Direct Attack Munition (JDAM) and the new Small-Diameter Bomb (SDB). It can carry weapons on four external hardpoints, but this vastly decreases the plane’s stealthiness, maneuverability, speed and range. The Raptor carries an M61A2 Vulcan 20 mm rotary cannon, also with a trap door, in the right wing root. The M61A2 is a last ditch weapon, and carries only 480 rounds, enough ammunition for approximately five seconds of sustained fire. Despite this, the F-22 has been able to use its gun in dogfighting without being detected, which can be necessary when missiles are depleted.

As other air forces upgrade capabilities in the areas of air-to-air and air-to-ground munitions, one key aspect of the Raptor must be kept in mind. Its very high sustained cruise speeds, and operational altitude (something that is often ignored), add tremendously to the effective range of both air-to-air and air-to-ground munitions. Indeed, these factors could provide a strong rationale as to why the USAF has not pursued long-range, high-energy air-to-air missiles such as the MBDA Meteor. However the USAF plans to procure the AIM-120D AMRAAM, which will have a significant increase in range compared to the AIM-120C. The launch platform, in this case, provides the additional specific impulse to the missile. This speed and altitude characteristic also helps improve the range of air-to-ground ordnance. While specific figures remain classified, it is expected that JDAMs employed by F-22s will have twice or more the effective range of munitions dropped by legacy platforms.[23] In testing, a Raptor dropped a 1,000 lb (450 kg) JDAM from 50,000 feet (15,000 m), while cruising at Mach 1.5, striking a moving target 24 miles away.[24] The SDB, as employed from the F-22, should see even greater increases in effective range, due to the improved lift to drag ratio of these weapons.

While in its air-superiority configuration, the F-22 carries its weapons internally, though it is not limited to this option. The wings are capable of supporting detachable hardpoints. Each hardpoint is theoretically capable of handling 5,000 lb of ordnance. However, usage of external stores greatly compromises the F-22 stealth, and has a detrimental effect on maneuverability. As many as two of these hardpoints are “plumbed”, allowing the usage of external fuel tanks. The hardpoints are detachable in flight allowing the fighter to regain its stealth once these external stores are exhausted. Currently, there is research being conducted to develop a stealth ordnance pod and hardpoints for it. Such a pod would comprise a stealth shape and carry its weapons internally, then would split open when launching a missile or dropping a bomb. Both the pod and hardpoints could be detached when no longer needed. This system would allow the F-22 to carry its maximum ordnance load while remaining stealthy, albeit at a loss of maneuverability. However, there is concern over this program as external carriage of fuel tanks has shown more stress placed on the wings than originally anticipated.[citation needed]

Stealth

Although several recent Western fighter aircraft are less detectable on radar than previous designs using techniques such as radar absorbent material coated S shaped intake ducts that shield the compressor fan from reflecting radar waves, the F-22A design placed a much higher degree of importance on a low radar signature, i.e. making it more difficult to see with radar.

The stealth of the F-22 is due to a combination of factors, including overall shape of the aircraft, the use of radar absorbent material (RAM), and attention to detail such as hinges and pilot helmets that could provide a radar return. The F-22 has also been designed to disguise its infra-red emissions to make it harder to detect by infrared homing (”heat seeking”) surface-to-air or air-to-air missiles.

The F-22 apparently relies less on maintenance-intensive radar absorbent material and coatings than previous stealth designs like the F-117. These materials caused deployment problems due to their susceptibility to adverse weather conditions.[26] Unlike the B-2, which requires climate-controlled hangars, the F-22 can undergo repairs on the flight line or in a normal hangar. Furthermore, the F-22 has a warning system (called “Signature Assessment System” or “SAS”) which presents warning indicators when routine wear-and-tear have degraded the aircraft’s radar signature to the point of requiring more substantial repairs.
The exact radar cross section of the F-22 remains classified.[citation needed]

Use of afterburners may apparently lead to jet emissions being quite detectable on radar, which may be a further reason for the emphasis on supercruise performance.

Comparisons

• An F-22A Raptor observes as an F-15 Eagle banks left. The F-22A is slated to replace the F-15C/D.

An F-22A Raptor observes as an F-15 Eagle banks left. The F-22A is slated to replace the F-15C/D.