Military


F-22 Raptor Weapons

For its primary air-to-air role, the F-22 will carry six AIM-120C and two AIM-9 missiles. For its air-to-ground role, the F-22 can internally carry two 1,000 pound-class Joint Direct Attack Munitions (JDAM), two AIM-120C, and two AIM-9 missiles. With the Global Positioning System-guided JDAM, the F-22 will have an adverse weather capability to supplement the F-117 (and later the Joint Strike Fighter) for air-to-ground missions after achieving air dominance.

The weapons bay played a huge role in the design evolution of the F-22. The aircraft is essentially wrapped around its internal bay, which is an essential characteristic of the F-22's stealthy design. The limited space drove the configuration of the launchers and acoustic suppression devices. Launching weapons from an internal bay is not a new problem. The F-111 and F-117 have internal bays as well as older aircraft like the F-102, F-105, and F-106. Historically, bay acoustics and weapon re-contact with structure during separation have been issues. The F-22 has a requirement to launch weapons throughout the service envelope at roll rates up to 100 degrees per second. This is a groundbreaking requirement made even tougher by tight clearances and flow fields that result from internal carriage.

The F-22 carries its primary armament, the AIM-120C Advanced Medium-Range Air-to-Air Missile (AMRAAM) internally on the EDO Corp.-built LAU-142/A pneudraulic (pneumatic and hydraulic) launcher, called the AMRAAM Vertical Eject Launcher (AVEL). Six launchers mounted in the main weapon bays carry and launch the AMRAAMs. The AVEL is very stiff in order to control missile movement in the weapons bay and supply the proper ejection forces on the missile. The AVEL, which is made mostly of aluminum, has a nine-inch stroke, and ejects the missile out of the bay at more than 25 feet per second, with a force of 40Gs. The long stroke and high velocity are required to safely separate the missile from the aircraft in all combat conditions. Unlike conventional missile launchers, the AVEL requires no explosive pyrotechnics cartridges, (which means the AVEL requires less logistics support and maintenance) but instead uses the aircraft's hydraulic system to eject the missile. The entire missile launch sequence --door opening, AVEL ejecting the missile, missile ignition and flyout, door closing --takes just seconds.

The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission.

There are two basic external configurations for the F-22:

  • Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks.
  • Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations.

An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration.

End-to-end weapons integration missile shots have had mixed results in testing, according to DOT&E. Four shots have demonstrated the capability to engage and destroy enemy aircraft in specific, discreet combat representative scenarios. However, three other shots indicated fire control deficiencies exist that need to be resolved in development. Some F/A-22 weapons separation, fully integrated guided missile test launches, and JDAM testing are planned to be done concurrently with IOT&E. JDAM employment is planned for follow-on test and evaluation, to be conducted after IOT&E. DOT&E believes that a large F/A-22 development risk, from both a technical and schedule perspective, lies in the integration of the avionics suite with realistic air-to-air and, eventually, air-to-surface weapons employment.

AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM)

The F-22's primary weapon is the AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM). This missile is a replacement for the AIM-7 Sparrow, which was developed in the 1950s, and was still in front-line service into the early 1990s. The AIM-120 was developed to provide an all-weather, all-launch environment capability for the F-22, as well as the Air Force's in-service F-15 Eagle and F-16 Fighting Falcon, and the Navy's F-14 Tomcat and F/A-18 Hornet.

The AIM-120 (which has no official nickname, but is called "Slammer" by pilots) is carried internally in the F-22's main weapons bay that is located on the underside of the fighter tucked under the inlets. The main bay is covered by two thermoset composite bifold doors that open outward. When the F-22 is in first-day-of-a-war combat configuration, all missiles are carried in the main weapons bay only. The typical combat load is six AIM-120C. Three in each side of the main weapons bay with the center missile staggered ahead of the inboard and outboard missiles. The F-22 can carry four of the older, longer-finned AIM-120A if necessary.

Each missile is carried on an EDO Corp.-built LAU-142/A pneudraulic (pneumatic and hydraulic) launcher, called an AMRAAM Vertical Eject Launcher (AVEL). The AVEL is substantial (nearly 113 pounds each) in order to minimize missile movement in the weapons bay. The AVEL, which is made mostly of aluminum, has a nine-inch stroke, and ejects the missile out of the bay at more than 25 feet per second with a force of 40 G (40 times the force of gravity) at peak acceleration. Unlike conventional missile launchers on other aircraft, the AVEL requires no pyrotechnics, and it requires less logistics support than other launchers.

The missiles are loaded from the opposite side of the aircraft AIM-120 Loading in Main Weapons Bay (missiles in the left side of the weapons bay are loaded from the right and visa versa), in order to clear the open main weapons bay doors. The current MJ-1 load vehicle (called a jammer) is used to load the missiles into the F-22. The missiles are staggered in the bay so fins on adjacent missiles do not interfere with each other when they are launched.

The missile gets target information from the aircraft prior to launch via a Military Standard (Mil Std) 1760 data bus. Once launched, the missile can operate independent of the launch aircraft, as it has its own inertial guidance system and an active radar, allowing the F-22 pilot to launch the missile and leave the area, thus avoiding a close-in dogfight. However, if necessary, the missile can also receive mid-course target updates from the launch aircraft. The entire launch sequence (door opening, AVEL ejecting the missile, missile ignition and flyout, door closing) takes just seconds. The combination of the aircraft's stealth characteristics, its integrated avionics, and the AIM-120 missile gives the F-22 a "first-look, first-shot, first-kill" capability.

AIM-9M Sidewinder

The F-22's short-range missile armament is the AIM-9M Sidewinder. This missile has been continuously updated since its forerunner (then designated N-7) destroyed a radio-controlled drone in a test at China Lake, Calif., in September 1953. Developed essentially from spare parts by the Naval Ordnance Test Center, Sidewinder entered service with the Air Force in 1956. Today, the AIM-9 is used on nearly every U. S. Air Force and Navy fighter (including F-15, F-16, A-10, F-14, and F/A-18) and those of many allied nations. It can even be fired from several types of military helicopters. Well over 150,000 Sidewinders have been built.

The AIM-9M is currently the only operational Air Force variant. This model has all-aspect (any direction) intercept capability. It also has improved defenses against infrared countermeasures, enhanced background discrimination capability, and a reduced-smoke rocket motor. These upgrades increase the missile's ability to locate and lock-on a target and decrease the missile's chances for detection. Deliveries to the Air Force began in 1983. A new variant, AIM-9X, is now in development. This missile will retain many of the Sidewinder's capabilities while strengthening the design with airframe improvements and advanced seeker technology, including staring focal plane arrays, adaptive compensation techniques, and infrared signals processing.

On the F-22, one AIM-9 is carried in each of the aircraft's side weapons bays, which are located on the outside of the engine inlets. There are no plans to carry the AIM-9 in the F-22's main weapons bay. The side bays are each covered by two thermoset composite doors that run the length of the compartment and are hinged at the top and bottom of the bay. Although AIM-9X is slightly longer than the AIM-9M, it will still fit in the F-22 without modification to the side weapons bays.

The missiles are carried on a Lockheed Martin Tactical Aircraft Systems-built LAU-141/A hydraulic launcher, called a Trapeze Launcher. This launcher, which uses some components from the existing LAU-128/A launcher, is basically the wingtip launch rail from an F-16 with a swing out mechanism that extends rapidly. The LAU-141/A is also fitted with a missile motor plume deflector, which prevents damage to the side weapons bay as the missile launches off the rail. Each missile is loaded by opening the doors, extending the rail, sliding it on the rail, retracting the missile, and closing the doors. Nearly all Sidewinders are loaded manually, using a three-person load crew. AIM-9 loading for F-22 will be no different.

As the AIM-9 uses infrared guidance, the missile first has to acquire the target. To launch a Sidewinder from the F-22, the side weapons bay doors open; the Trapeze Launcher, with missile attached, extends to put the missile's seeker into the slipstream; the seeker acquires the target; the missile ignites and flies off the rail. The Trapeze Launcher then retracts, and the weapons bay doors close. Once launched, the F-22 pilot can leave the fight, as Sidewinder is autonomous, following its seeker to the target, after it leaves the launch rail. The entire Sidewinder launch sequence, from door opening to door closing, takes just seconds.

GBU-32 JDAM Joint Direct Attack Munition

JDAM is a tail guidance kit that converts existing unguided free-fall bombs into near precision-guided "smart" munitions. It also includes strap-on strakes that attach to the bomb's body for stability. Adding a new tail section containing an Inertial Navigation System (INS)/Global Positioning System (GPS) guidance control unit to existing inventories of Mk. 83 1,000-pound-class general purpose conventional bombs gives the F-22 a highly accurate, autonomous, high altitude all-weather conventional bombing capability. Currently, the JDAM tail guidance kit gives existing "iron bombs" a circular error probable (CEP, the measure of weapons accuracy) of under 15 meters, but a planned improvement program will give the weapon a CEP of considerably less than 10 meters. JDAM is intended for use on a variety of Air Force and Navy aircraft including B-1, B-2. B-52, F-15E, F-16, F-117, and F/A-18.

The F-22 can carry the 1,000-pound class JDAM weapon. For the F-22, the JDAM tail guidance kit fits on the Mk. 83 1,000-pound-class conventional bomb. Weight of the Mk. 83 bomb and tail guidance kit is approximately 1,015 pounds The combination of the stealthy F-22 and the precision capability of the GBU-32 allows the F-22 pilot to drop the weapon from altitudes of approximately 40,000 feet to a range of approximately 15 miles.

The GBU-32 is only carried in the F-22's main weapons bay. A typical combat load consists of two GBU-32. One GBU-32 is carried inboard in each side of the main weapons bay. When loaded with GBU-32, there is still sufficient room in the F-22's main weapons bay to carry two AIM-120C air-to-air missiles (one in each side of the bay, in addition to the two AIM-9 Sidewinders in the side weapons bays), which means that even on a mission to attack ground targets, the F-22 retains significant air-to-air combat capability.

Each 1,000-pound-class GBU-32 will be loaded from the opposite side of the F-22 (the JDAM in the left side of the weapons bay is loaded from the right and visa versa), in order to clear the open main weapons bay doors. The current MJ-1 load vehicle (called a jammer) is used to load the GBU-32 into the F-22. The GBU-32 is carried on the Air Force's standard BRU-46/A bomb rack (which is built by EDO). The weapon is carried on the inboard side of the bay with an adjacent AIM-120C missile staggered on the outboard side. This is so tail fins on the bomb and the missile's wings do not interfere with each other when the weapons are either released or launched.

The GBU-32 gets target information from the aircraft prior to release via a Miltary Standard (Mil Std) 1760 data bus. JDAM can be dropped by an aircraft from up to 15 miles from the target. In addition to its own inertial guidance system, the weapon receives in-flight position updates from the 24-satellite GPS satellite constellation which help guide the bomb to the target. The GPS constellation provides 24-hour navigation information to military and civilian users. The GBU-32's autonomous operation allows the carrying aircraft to release the weapon and leave the area, thus avoiding an enemy's integrated air defense (surface-to-air missiles, antiaircraft artillery ("triple A"), and radars) system, but still delivering the weapon to the target.

GBU-39/B Small Diameter Bomb

The F-22A has the capability to carry a variety of conventional and Long Range Stand-Off Weapons (LRSOW) for air-to-ground ordnance delivery. When performing air-to-ground missions, the F-22A can internally carry two Global Positioning System-aided 250-pound GBU-39/B Small Diameter Bomb in place of two AIM-120s and two AIM-9 missiles. The Small Diameter Bomb (SDB) (Guided Bomb Unit [GBU]-39/B) is designed to provide the F-22A with multiple targeting capabilities. Langley munitions crews loaded the new GBU-39 Small Diameter Bomb onto an operational F-22A Raptor 15 July 2006. The fit test, conducted by members of the 27th Aircraft Maintenance Unit and observed by experts from Lockheed, Boeing, Edwards AFB, Calif., and Eglin AFB, Fla., was the first time the new weapon had been loaded into a combat-ready Raptor.

Weighing in at 250 pounds and a diameter of only six inches, the advantage of the GBU-39 is the amount that can be loaded into an F-22. It increases the target capabilities of the F-22 by 400 percent. Instead of two JDAMs, it will carry eight SDBs internally.

The Air Combat Command commander declared initial operational capability for the Guided Bomb Unit-39/B Small Diameter Bomb 02 October 2006 and the weapon made its combat debut just three days later. Boeing, the GBU-39B manufacturer, describes the bomb as "the next generation of low-cost and low-collateral damage precision strike weapons for ... employment from fighters, bombers and unmanned aerial vehicles." The F-15E Strike Eagle was initially the only aircraft equipped to carry the SDB. However, future potential platforms include the F-16 Fighting Falcon, B-1 Lancer, B-2 Spirit, F-22 Raptor and F-35 Lightning II. The SDB have high precision capabilities. They are lightweight and small which means increased aircraft payload. The bomb, a mere 250 pounds, has a smaller lethality radius, but its advanced technology makes the small blast a benefit, not a liability.

Its small size enables aircraft to carry more weapons, allowing commanders "to service more targets on a single pass." Its mounting carriage, the BRU-61/A, fits four bombs on one weapon pylon. It is also a versatile weapon. The SDB range is more than 50 nautical miles when launched at 40,000 feet at Mach .95. This enables an aircraft to launch SDBs to multiple targets, while beyond the range of many anti-aircraft systems. Additionally, it is an all-weather weapon, effective day or night and can be fired at targets in front of, to the sides, and behind the employing aircraft. It is effective on stationary targets within 1.2 meters. Typical targets include hardened aircraft bunkers, early-warning radar, stationary SCUD missile launchers, stationary artillery and more,

M61A2 20-mm Cannon

The F-22's close-range weapon is the M61A2 20mm cannon and its associated components. The M61 is a proven gun, having been the U. S. military's close-in weapon of choice dating back to the 1950s. The F-104, F-105, later models of the F-106, F-111, F-4, B-58, all used the M61, as does the Air Force's current F-15 Eagle and F-16 Fighting Falcon, and the Navy's F-14 Tomcat and F/A-18 Hornet. The system is integrally mounted in the aircraft and located on the right side of the aircraft between the wing (top side) and fuselage. It is a fixed-forward firing mount. A gun door, located in the wing root area, is hydraulically controlled to open when firing the gun, which allows the rounds and blast pressure to clear the muzzle. A 480-round closed loop ammunition feed and storage subsystem is housed integrally under the right wing root/fuselage for easy ammo upload and download of empty casings. The gun system consists of the M61A2 gun, the Linear Linkless Ammunition Handling System (LLAHS), the hydraulic drive system, and the gun door/gun port and gas purge system.

The M61A2 is a lightweight version of the M61A1. Most of the weight savings was achieved by machining down the barrel thickness. The M61A2 is Government Furnished Equipment (GFE), that is, purchased by the government under separate contract and provided to the F-22 contractor team. Power to operate the gun is provided by hydraulic pressure supplied by the aircraft's hydraulic system. Each of the gun's six barrels fires only once during each revolution of the barrel cluster. The six rotating barrels contribute to long weapon life by minimizing barrel erosion and heat generation. The gun's rate of fire, essentially 100 rounds per second, gives the pilot a shot density that will enable a "kill". With 480 rounds, the pilot has roughly five shots with the gun.

The inherent capabilities of the F-22 (stealth, advanced avionics, supercruise) and advanced air-to-air missiles such as AIM-120 AMRAAM and AIM-9 Sidewinder, will likely render use of the gun unnecessary in combat. However, as history has demonstrated (most glaringly with the F-4 in Vietnam), at some point, the air battle comes down to a dogfight, and the M61A2, along with the F-22's superior maneuverability, gives the pilot one more option.

The General Dynamics Armament System-developed Linear Linkless Ammunition Handling System (LLAHS) consists of a 480 round ammunition storage container with drive train and integral access (reload) unit, an ammunition conveyor assembly, a hydraulic drive unit, a rounds limiter, and a last round switch. There are no links between rounds (hence the term "linkless") an innovation that eliminates completely any potential jamming of the gun breech. Ammunition is transported from the container to the gun breech by a direct extension of the carrier chain, which also carries the empty cartridges back to the ammunition storage container to form a closed loop system. The LLAHS is loaded manually from the ground. The rounds limiter is an electromechanical device that is preset to limit the number of rounds that can be fired on a training flight. The last round switch shuts down the gun when it senses the empty casing of the first round fired. The LLAHS is located very near to the aircraft's center of gravity, so by retaining the casings, even after all the rounds are fired, there is no change forward or aft to the aircraft's center of gravity. Also, by not ejecting the casings, a potentially serious foreign object debris (FOD) problem (i.e. ingesting casings into the engines) simply does not exist.

The gun hydraulic drive unit is a 42 horsepower fixed displacement motor sized to achieve a 6,000 round per minute gun firing rate at all flight loading conditions. The gun port door is mechanized such that is opened to provide an exit path out of the aircraft for the projectiles. It is activated when the pilot squeezes the trigger on the control stick (the first detent) in the cockpit. The door opens to 90 degrees and is activated in milliseconds. When the trigger is released by the pilot (or the last round switch engaged), the door is commanded to close. It takes several seconds for the door to close completely. The door is an aid to the F-22's stealth characteristics, and it helps the aircraft's aerodynamics by reducing drag. The gun port is a steel casting that is located under the port door. It is used to protect the aircraft and its structure from gun muzzle blast by deflecting projectiles up and away from the aircraft surface. If a misfire occurs in the one-half portion of the gun port, it is designed to capture the projectile.

The gun gas purge system consists of an actuated purge door that opens at the same time as the gun port door. The purge door, located on the fuselage side near the gun breech, forces outside air (ram air) into the aircraft when opened and a static screened vent (on the top of the fuselage) allows gun gas (which is mostly hydrogen, and as such, explosive) and ram air to exit overboard. When the trigger is released by the pilot (or the last round switch is engaged), the door is commanded to close M61A2 20-mm Gun System for F-22.

F-22 Carriage Capability

The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission.

There are two basic external configurations for the F-22: Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks. Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations. An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration.

The LAU-128/A rail launcher is the standard rail launcher used today on the F-15 and can carry either of the missiles used on the F-22, AIM-120 AMRAAM or AIM-9 Sidewinder. However, both missiles carried on the fire missile adapter configuration for F-22 must be the same type for aircraft weight and balance considerations. The 600-gallon fuel tanks are similar to the same external tanks that are used on the current F-15 Eagle. However, a new tank is being developed that has baffles in it to prevent the fuel from sloshing. This gives the tank better center of gravity control, which allows for safe jettisoning of the tanks. The BRU-47/A rack is not the same type of rack that is used internally on the F-22 to carry the GBU-32 1,000-pound class Joint Direct Attack Munition (JDAM), although they are similar and both are currently in use. However, there are no plans to carry JDAM externally on F-22. The BRU-47 will only be used to hold the external fuel tanks.

The pylon itself is designed for minimal impact on aircraft performance. If it becomes necessary for the pilot to jettison the external stores, the entire pylon is jettisoned along with the tank or missile launch rails. The pylon has an aft pivot, so when the stores are jettisoned, the forward attach point is released first, the pylon rotates on the pivot, and then the aft pivot is released. This motion allows the pylon, along with the tank or launch rail to clear the aircraft when it is released into the slipstream.



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