F-22 RAPTOR  (Stealth)     As of yet, the F-22 Raptor is the only 5th Generation fighter in the world.

  The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack,electronic warfare, and signals intelligenceroles. Lockheed Martin Aeronautics is the prime contractor and is responsible for the majority of the airframe, weapon systems and final assembly of the F-22. Program partner Boeing Defense, Space & Security provides the wings, aft fuselage, avionics integration, and all of the pilot and maintenance training systems.The aircraft was variously designated F-22 and F/A-22 during the years prior to formally entering USAF service in December 2005 as the F-22A. Despite a protracted and costly development period, the United States Air Force considers the F-22 a critical component for the future of US tactical air power, and claims that the aircraft is unmatched by any known or projected fighter, while Lockheed Martin claims that the Raptor's combination of stealth, speed, agility, precision and situational awareness, combined with air-to-air and air-to-ground combat capabilities, makes it the best overall fighter in the world today. Air Chief Marshal Angus Houston, Chief of the Australian Defence Force, said in 2004 that the "F-22 will be the most outstanding fighter plane ever built."The high cost of the aircraft, a lack of clear air-to-air combat missions because of the lengthy delays in the Russian and Chinese fifth generation fighter programs, a US ban on Raptor exports, and the development of the cheaper and more versatile F-35 resulted in calls to end F-22 production. In April 2009 the US Department of Defense proposed to cease placing new orders, subject to Congressional approval, for a final procurement tally of 187 Raptors. The US Senate and House each passed 2010 budget bill versions without F-22 production funding in July 2009. Congress worked to combine these versions into one bill, and President Obama signed the National Defense Authorization Act for Fiscal Year 2010 in October 2009, without funding for F-22 production As of yet, the F-22 Raptor is the only 5th Generation fighter in the world.

The F-22 Raptor is a fifth generation fighter that is considered a fourth-generation stealth aircraft by the USAF. Its dual afterburning Pratt & Whitney F119-PW-100 turbofans incorporate pitch axis thrust vectoring, 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, without external weapons, is estimated to be Mach 1.82 in supercruise mode; as demonstrated by General John P. Jumper, former US Air Force Chief of Staff, when his Raptor exceeded Mach 1.7 without afterburners on 13 January 2005. With afterburners, it is "greater than Mach 2.0" (1,317 mph, 2,120 km/h), according to Lockheed Martin; however, the Raptor can exceed its design speed limits, particularly at low altitudes, with max-speed alerts to help prevent the pilot from exceeding them. Former Lockheed F-22 chief test pilot Paul Metz stated that the Raptor has a fixed inlet. The absence of variable intake ramps generally limits speeds to approximately Mach 2.0. Such ramps would be used to prevent engine surge resulting in a compressor stall, but the intake itself may be designed to prevent this. Metz has also stated that the F-22 has a greater climb rate 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. The US Air Force claims that the Raptor cannot be matched by any known or projected fighter types, and Lockheed Martin claims that, "the F-22 is the only aircraft that blends supercruise speed, super-agility, stealth and sensor fusion into a single air dominance platform."

The F-22's avionics include BAE Systems E&IS radar warning receiver (RWR) AN/ALR-94,AN/AAR 56 Infra-Red and Ultra-Violet MAWS (Missile Approach Warning System) and the Northrop Grumman AN/APG-77 Active Electronically Scanned Array (AESA) radar. The AN/APG-77 has both long-range target acquisition and low probability of interception of its own signals by enemy aircraft. The AN/ALR-94 is a passive receiver system capable of detecting the radar signals in the environment. Composed of more than 30 antennas smoothly blended into the wings and fuselage that provide all around coverage plus azimuth and elevation information in the forward sector, it is described by Tom Burbage, the former head of the F-22 program at Lockheed Martin, as "the most technically complex piece of equipment on the aircraft." With greater range (250+ nmi) than the radar, it enables the F-22 to limit its own radar emission to preserve its stealth. As a target approaches, the receiver can cue the AN/APG-77 radar to track the target with a narrow beam, which can be as focused down to 2° by 2° in azimuth and elevation. The AN/APG-77 AESA radar, designed for air superiority and strike operations, features a low-observable, active-aperture, electronically-scanned array that can track multiple targets in any 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 aircraft an electronic-attack capability.

The radar's information is processed by two Raytheon Common Integrated Processor (CIP)s. Each CIP can process 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 avionics software has some 1.7 million lines of code, written mostly in the DoD's Ada programming language. Most of the code concerns processing data from the radar.The radar has an estimated range of 125–150 miles, though planned upgrades will allow a range of 250 miles (400 km) or more in narrow beams. In 2007, tests by Northrop Grumman, Lockheed Martin, and L-3 Communications enabled the AESA system of a Raptor to act like a WiFi access point, able to transmit data at 548 Megabit/sec and receive at Gigabit speed; this is far faster than the current Link 16 system used by US and allied aircraft, which transfers data at just over 1 Megabit/sec. When the aircraft was introduced in January 2003, the Lockheed Martin F-22 Raptor's cockpit represented a zenith in the so-called "glass-cockpit" without any traditional flight instruments and was a marked improvement on the cockpit design of previous advanced aircraft.  The leading features of the F-22 cockpit, which continue to be emulated or matched by other modern military fast jets, include: simple and rapid start-up, highly developed human-machine interface (HMI), lighter helmet, large anthropometric accommodation and highly integrated warning system. Of particular note also is the large single piece canopy and improved life support. Much information about the cockpit is available in the public domain.

 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-22 design placed a much higher degree of importance on low observance throughout the entire spectrum of sensors including radar signature, visual, infrared, acoustic, and radio frequency.

The stealth of the F-22 is due to a combination of factors, including the 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. However, reduced radar cross section is only one of five facets that designers addressed to create a stealth design in the F-22. The F-22 has also been designed to disguise its infrared emissions to make it harder to detect by infrared homing ("heat seeking") surface-to-air or air-to-air missiles, including its flat (rather than round) thrust vectoring nozzles. Designers also made the aircraft less visible to the naked eye, and controlled radio and noise emissions. The Raptor has an under bay carrier made for hiding heat from missile threats, like surface-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. 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. In early 2009 Lockheed Martin released information on the F-22, showing it to have a radar cross section from certain critical angles of -40dBsm — the equivalent radar reflection of a "steel marble". However, the stealth features of the F-22 require additional maintenance work that decreases their mission capability rate to approximately 62-70%.

The effectiveness of this emphasis on stealth characteristics during the F-22 design process is difficult to measure. While its radar cross-section is almost nonexistent, this is merely a static measurement of the aircraft's frontal or side area and is valid only for a radar source in a stationary location relative to the aircraft. As soon as the F-22 maneuvers, it exposes a different set of angles and a greater surface area to any radar, increasing its visibility. Furthermore, the use of stealth contouring and radar absorbent material are chiefly effective against high-frequency radars, the type usually found on other aircraft. Low-frequency radars, including weather radars and warning stations in areas of the former Soviet Union, are allegedly less affected by stealth characteristics and are more capable of detecting some of the aircraft employing them.

2017 (c)