AIM-120 AMRAAM

AIM-120 AMRAAM 

The AIM-120 AMRAAM  is an American medium-range air-to-air missile (from 75 to 160  km depending on the version) , equipped with an active radar guidance system . He is nicknamed Slammer by American pilots.
The AMRAAM is the world's most popular beyond-visual-range missile , with more than 14,000 produced for the United States Air Force , United States Navy and 33 international customers in 2008. AMRAAM was used in several engagements and is credited with ten aerial victories. Now over 30 years old in its design, the AMRAAM is scheduled to be replaced by the newer AIM-260 JATM , in the mid-2020s to provide better performance and capabilities to defeat electronic jamming.

System Specifications

• Missile type:      Medium range air-to-air missile
• Builder:              Hughes / Raytheon
• Unit cost:      US$ 386,000 
• Deployment:      September 1991
• Features:
• Engines:              solid fuel rocket
• Launch mass:     152kg  _
• Length:               3.66m  _
• Diameter:       0.178m  _
• wingspan:       0.526m  _
• Speed:               Mach 4 (4,900 km/h; 3,000 mph)
• Operational
• range:                   AIM-120A/B: 50–70km
•                               AIM-120C: 50–120km
•                               AIM-120D: 50–180+ km
• Payload :              18 kg of WDU-41/B fragmentation explosive (23 kg AIM-120A/B)
• Guidance:       active radar , inertial guidance
• Launch platform:

                         F-4 ,F-14 , F-15,F-16,F/A-18,F-22,F-35,Eurofighter Typhoon ,Saab JAS 39 Gripen &

        NASAMS for ground platform

Development 

In the late 1970s, disappointed with the AIM-7 Sparrow , the United States Air Force (combining the United States Air Force and air components of the United States Navy and United States Marine Corps ) decided to initiate development of a new missile, which this time does not expose its launcher and, therefore, which is able to guide itself. Furthermore, this independence of the missile should make it easier to engage several targets. In 1979, Hughes Aircraft and Raytheon were selected to develop the YAIM-120 AMRAAM missile, in 1981, Hughes Aircraft won the contract, the first flight test took place indecember 1981. A year earlier many NATO air forces had joined the program. In February 1982, the first AIM-120 was fired from an F-16 , but it was not untilseptember 1987that a first shot is made at supersonic speed. Numerous technical and political difficulties delayed the program and caused budget overruns. The first pre-production units were delivered inoctober 1988, but it is only inSeptember 1991that it was declared operational

Improvements

 In 1994 the first copies of the AIM-120B version were delivered. This differs from the initial AIM-120A version by a new WGU-41/B guidance system containing reprogrammable EPROM modules and a new processor. In 1996, a new version was born, the AIM-120C. The first noticeable difference is the change in the fins. These are shortened to be carried in the cargo bay of the F-22, it nevertheless remains suitable for all other vectors already qualified for the AIM-120A and AIM-120B versions. It is also equipped with a new WGU-44/B guidance system. The standard AIM-120C is divided into several sub-versions including, in particular, the C4 and C5 versions. The first is equipped with a new warhead WDU-41/B, the second is further improved by a larger rocket engine (WPU-16/B) and a shorter control section due to the miniaturization of electronics embarked. Deliveries of these new versions began inJuly 2000. The next version, named C6, features a new detonator. The C7 version, the development of which began in 1998, aims to replace the AIM-54 Phoenix missile , which was retired onSeptember 30, 2004. The program having slipped slightly, the C7 entered operational service only at the end of 2007, while its predecessor is retired, resulting in a temporary “hole” in the capabilities of the American armed forceS.

Long range version 

The development of the AIM-120D is, inJanuary 2016, well advanced. Production of the first prototypes began in 2006. This new version is equipped with a data link with the launcher, an INS navigation system readjusted by GPS , and an extended firing envelope. The unit cost exceeds one million dollars . It keeps the same envelope as the AIM-120C and the Radar of its seeker remains of the passive mechanical type unlike the new generation Radar such as the METEOR which uses radar with active antenna , it operates in the X  band .

All versions combined, approximately 17,500 AIM-120s were produced inJune 2015.

In 2019, the United States Armed Forces are scheduled to purchase their last batch of AIM-120s in 2026, with the latter theoretically to be replaced by the AIM-260 JATM. 

Ground-to-air development 

A Norwegian NASAMS launch vehicle.

In view of the quality of this missile, it was decided to extrapolate a surface-to-air version of air defense designed by the Norwegian company Kongsberg Defense & Aerospace . The designation MIM-120A is sometimes used, but is not official. The first to be equipped with it were the Norwegians, with the NASAMS system , which carries 6 weapons. It has been operational since 1995. This system and an improved version, the NASAMS II, were ordered, in 2009, for Spain , Finland and the Netherlands .

The United States are developing two versions, the SLAMRAAM, mounted on Hummer for the US Army , and the CLAWS for the US Marine Corps , also mounted on Hummer . In addition, tests were carried out on modified MIM-23 Hawk missile launchers. The SLAMRAAM should enter service in 2008 and replace some of the Avenger systems , considered too "light", and the aging MIM-23 Hawk .

Guidance 

The first third of the missile is made up of the guidance system. First, there is the antenna, under a conical dome. Behind it are placed the batteries that power the system, then the guidance electronics itself. The missile is a "fire and forget" type, which means that once the missile is fired, it is completely autonomous. When fired, the aircraft's weapon system transmits the coordinates of the target to the missile. These coordinates usually come from the launcher's radar , but can also be provided by an infrared detection system , from another aircraft equipped with a data link, or even from an AWACS. The missile then calculates an intercept trajectory, and heads towards the point of impact thanks to inertial guidance ( INS ). However, if the firing aircraft continues to illuminate the target using its radar, the missile trajectory is updated. Some air forces did not express the wish to have this update option, thus, the Royal Air Force found that without this update, the effectiveness of the AIM-120 was lower than that of the BAe Sky Flash which it replaces.

Once the target comes within range of its radar, the missile switches to active guidance. The seeker springs into action, finds the target and locks onto it. NATO airmen nickname this mode Pitbull because it no longer drops its target. If the missile is fired at close range, it goes directly into active mode and is therefore very effective.

Warhead 

The warhead consists of 23  kg of fragmentation explosive for the AIM-120A and AIM-120B versions, called WDU-33/B. The AIM-120C version is equipped with the WDU-41/B  warhead made up of 18 kg of fragmentation explosive .

Propulsion 

The AIM-120A and the AIM-120B are equipped with a solid-fuel rocket engine allowing them to reach the range of 75  km and the speed of Mach 4. The AIM-120C as for him, has a larger engine to reach 110  km . Little information is available on this engine, whose official name is WPU-6/B for the AIM-120A/B versions and WPU-16/B for the AIM-120C.

Releases

• YAIM-120A: Initial program for an active-guided medium-range missile;
• AIM-120A: First version;
• AIM-120B: WGU-41/B guidance system;
• AIM-120C: Shortened ailerons, WGU-44/B guidance;
• AIM-120C4: Warhead WDU-41/B;
• AIM-120C5: WDU-41/B warhead, WPU-16/B propulsion, 110  km range;
• AIM-120C6: New trigger system;
• AIM-120C7: Improved range and guidance, testing completed in 2007;
• AIM-120D: In-flight GPS updating , data link, extended firing envelope, initial operational capability inApril 2015 ;
• "MIM-120A": Ground-to-air version used in the Norwegian NASAAM, CLAWS and American SLAMRAAM systems.

Vectors

The AIM-120 AMRAAM in a surface-to-air defense mount.

• AV-8B Harrier II
• F-4 Phantom ( Germany only)
• Eurofighter Typhoon
• F-16 Fighting Falcon (all versions)
• Panavia Tornado
• F/A-18 Hornet (all versions)
• F-14 Tomcat (trials only)
• F-15 Eagle (C, I and S versions only)
• F-22 Raptor
• F-35 Lightning 
• Saab JAS 39 Gripen
• NASAMS ground platform