F-22 Raptor

Overview:

The Lockheed Martin/Boeing F-22 Raptor is a 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 intelligence roles. 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 Integrated Defense Systems 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 airpower, and claims that the aircraft cannot be matched 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. 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." 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 F-22 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 easily 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; but while the absence of variable intake ramps may theoretically make speeds greater than Mach 2.0 unreachable, there is no evidence to prove this. 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 top speed greater than 1,600 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. The US Air Force claims that the Raptor cannot be matched by any known or projected fighter, 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 true top-speed of the F-22 is unknown to the general public. The ability of the airframe to withstand the stress and heat is a further 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 (and its associated high fuel usage). This ability is now termed supercruise. The F-22 is highly maneuverable, at both supersonic and subsonic speeds. It is extremely departure-resistant, enabling it to remain controllable at extreme pilot inputs. The Raptor'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, and the Kulbit, though the J-Turn is more useful in combat. The F-22 is also capable of maintaining a constant angle of attack of over 60°, yet still having some control of roll. During June 2006 exercises in Alaska, F-22 pilots demonstrated that cruise altitude has a significant effect on combat performance, and routinely attributed their altitude advantage as a major factor in achieving an unblemished kill ratio against other US fighters and 4th/4.5th generation fighters. The Raptor has internal weapons bays that can carry a maximum of six missiles or four bombs in the center bay, and one missile in each side bay. Carrying missiles and bombs internally maintains its stealth capability and maintains lower drag resulting in higher top speeds and longer combat ranges. Launching missiles requires opening the weapons bay doors for less than a second, while the missiles are pushed clear of the airframe by hydraulic arms. This reduces the Raptor's chance of detection by enemy radar systems due to launched ordnance. The aircraft can also carry such air-to-surface weapons as bombs with the Joint Direct Attack Munition (JDAM) guidance system, and the new Small-Diameter Bomb (SDB). 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. The F-22 has been able to use its gun in dogfighting without being detected, which can be necessary when missiles are depleted. The Raptor's very high sustained cruise speed and operational altitude add significantly to the effective range of both air-to-air and air-to-surface munitions. These factors may be the rationale behind the USAF's decision not to pursue long-range, high-energy air-to-air missiles such as the MBDA Meteor. However, the USAF plans to procure the AIM-120D AMRAAM, which is reported to have a 50% increase in range compared to the AIM-120C. The Raptor launch platform provides additional energy to the missile which 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. 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 (39 km) away. 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. The AIM-120 is the primary missile and the AIM-9 Sidewinder is the short-range missile. 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. Designers also made the aircraft less visible to the naked eye, and controlled radio and noise emissions.[81] The Raptor has an under bay carrier made for hiding heat from missile threats, like surface-to-air missiles.

Specifications:

Role

• Stealth Air superiority fighter.

National Origin

• United States.

System

• Boeing Integrated Defense Systems.

First Flight

• 7 September 1997

Introduction

• 15 December 2005

Status

• In service.

Primary User

• United States Air Force.

Number Built

• 141 as of May 2009

Program Cost

• US$65 billion.

Unit Cost

• US$137.5 million (2008 flyaway cost).

Crew

• 1 pilot.

Length

• 62 ft 1 in (18.90 m).

Height

• 16 ft 8 in (5.08 m).

Airfoil

• NACA 64A?05.92 root .
• NACA 64A?04.29 tip.

Empty Weight

• 43,430 lb (19,700 kg).

Loaded Weight

• 64,460 lb (29,300 kg).

Max Takeoff Weight

• 83,500 lb (38,000 kg).

Powerplant

• 2× Pratt & Whitney F119-PW-100 Pitch Thrust vectoring turbofans.
• 35,000+ lb (156+ kN) each.

Fuel Capacity

• 18,000 lb (8,200 kg) internally.
• Or 26,000 lb (11,900 kg) with two external fuel tanks.

Weapons

• Guns: 1× 20 mm (0.787 in) M61A2 Vulcan gatling gun in starboard wing root with 480 rounds.

Air to air loadout:

• 6× AIM-120 AMRAAM.
• 2× AIM-9 Sidewinder.

Air to ground loadout:

• 2× AIM-120 AMRAAM.

2× AIM-9 Sidewinder for self-protection, and one of the following:

• 2× 1,000 lb (450 kg) JDAM.
• 2× Wind Corrected Munitions Dispensers (WCMDs).
• 8× 250 lb (110 kg) GBU-39 Small Diameter Bombs.

Avionics

• RWR (Radar warning receiver): 250 nmi (463 km) or more.
• Radar: 125-150 miles (200-240 km) against 1 m2 (11 sq ft) targets (estimated range).