
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- Published: 06 Sep 2009
- Uploaded: 20 Jul 2011
- Author: jaglavaksoldier
Is missile | yes |
---|---|
Name | AIM-9 Sidewinder |
Caption | An AIM-9 is affixed to an F/A-18 Hornet. |
Origin | United States |
Type | Short-range air-to-air missile |
Manufacturer | NammoRaytheon CompanyFord AerospaceLoral Corp. |
Unit cost | |
Production date | September 1953 |
Service | 1956 (AIM-9B) – present |
Engine | Solid-fuel rocket |
Weight | |
Length | |
Diameter | |
Wingspan | |
Speed | Mach 2.5 |
Vehicle range | |
Filling | annular blast-frag |
Filling weight | |
Guidance | Infrared homing |
Detonation | Magnetic influence (old models)Active infrared (AIM-9L onwards) |
Launch platform | Aircraft, helicopter gunships |
The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft and recently, certain gunship helicopters. Variants and upgrades remain in active service with many air forces after five decades. When a Sidewinder missile is being launched, NATO pilots use the brevity code Fox Two in radio communication, as with all "heat-seeking" missiles.
The Sidewinder is the most widely used missile in the West, with more than 110,000 missiles produced for the U.S. and 27 other nations, of which perhaps one percent have been used in combat. It has been built under license by some other nations including Sweden. The AIM-9 is one of the oldest, least expensive, and most successful air-to-air missiles, with an estimated 270 kills worldwide to date.
The missile was designed to be simple to upgrade. It has been said that the design goals for the original Sidewinder were to produce a reliable and effective missile with the "electronic complexity of a table model radio and the mechanical complexity of a washing machine"—goals which were well accomplished in the early missiles. The United States Navy hosted a 50th anniversary celebration of its existence in 2002. Boeing won a contract in March 2010 to support Sidewinder operations through 2055, guaranteeing that the weapons system will remain in operation until at least that date. Air Force Spokeswoman Stephanie Powell noted that due to its relative low cost, versatility, and reliability it is "very possible that the Sidewinder will remain in Air Force inventories through the late 21st century."
The name sidewinder refers to a venomous rattlesnake of the same name, which uses infrared sensory organs to hunt warm-blooded prey.
drone at China Lake, 1957.]] The Sidewinder toke inspiration from the earlier WW II German Enzian, and incorporated a number of innovations that greatly improved its performance. The first innovation was to replace the "steering" mirror with a forward-facing mirror rotating around a shaft pointed out the front of the missile. The detector was mounted in front of the mirror. When the long axis of the mirror, the missile axis and the line of sight to the target all fell in the same plane, the reflected rays from the target reached the detector (provided the target was not very far off axis). Therefore, the angle of the mirror at the instant of detection estimated the direction of the target in the roll axis of the missile.
The yaw/pitch direction of the target depended on how far to the outer edge of the mirror the target was. If the target was further off axis, the rays reaching the detector would be reflected from the outer edge of the mirror. If the target was closer on axis, the rays would be reflected from closer to the centre of the mirror. Rotating on a fixed shaft, the mirror's linear speed was higher at the outer edge. Therefore if a target was further off-axis its "flash" in the detector occurred for a briefer time, or longer if it was closer to the center. The off-axis angle could then be estimated by the duration of the reflected pulse of infrared.
The Sidewinder also included a dramatically improved guidance algorithm. The Enzian attempted to fly directly at its target, feeding the direction of the telescope into the control system as it if were a joystick. This meant the missile always flew directly at its target, and under most conditions would end up behind it, "chasing" it down. This meant that the missile had to have enough of a speed advantage over its target that it did not run out of fuel during the interception.
The Sidewinder is not guided on the actual position recorded by the detector, but on the change in position since the last sighting. So if the target remained at 5 degrees left between two rotations of the mirror, the electronics would not output any signal to the control system. Consider a missile fired at right angles to its target; if the missile is flying at the same speed as the target it should "lead" it by 45 degrees, flying to an impact point far in front of where the target was when it was fired. If the missile is traveling four times the speed of the target, it should follow an angle about 11 degrees in front. In either case, the missile should keep that angle all the way to interception, which means that the angle that the target makes against the detector is constant. It was this constant angle that the Sidewinder attempted to maintain. This "proportional pursuit" system is very easy to implement, yet it offers high-performance lead calculation almost for free and can respond to changes in the target's flight path, which is much more efficient and makes the missile "lead" the target.
However this system also requires the missile to have a fixed roll axis orientation. If the missile spins at all, the timing based on the speed of rotation of the mirror is no longer accurate. Correcting for this spin would normally require some sort of sensor to tell which way is "down" and then adding controls to correct it. Instead, small control surfaces were placed at the rear of the missile with spinning disks on their outer surface; these are known as rollerons. Airflow over the disk spins them to a high speed. If the missile starts to roll, the gyroscopic force of the disk drives the control surface into the airflow, cancelling the motion. Thus the Sidewinder team replaced a potentially complex control system with a simple mechanical solution.
A prototype Sidewinder, the XAAM-N-7 (later AIM-9A), was first fired successfully in September 1953. The initial production version, designated AAM-N-7 (later AIM-9B), entered operational use in 1956, and has been improved upon steadily since.
The Sidewinder subsequently evolved through a series of upgraded versions with newer, more sensitive seekers with various types of cooling and various propulsion, fuse, and warhead improvements. Although each of those versions had various seeker, cooling, and fusing differences, all but one shared infrared homing. The exception was the U.S. Navy AAM-N-7 Sidewinder IB (later AIM-9C), a Sidewinder with a semi-active radar homing seeker head developed for the F-8 Crusader. Only about 1,000 of these weapons were produced, many of which were later rebuilt as the AGM-122 Sidearm anti-radiation missile.
The Navy Sidewinder design progression went from the early production B model to the D model that was used extensively in Vietnam. The G and H models followed with new forward canard design improving ACM performance and expanded acquisition modes and improved envelopes. The "Hotel" model followed shortly after the "Golf" and featured a solid state design that improved reliability in the carrier environment where shock from catapult launches and arrested landings had a deteriorating effect on the earlier vacuum tube designs. The Ault report had a strong impact on Sidewinder design, manufacture, and handling.
The next major advance in IR Sidewinder development was the AIM-9L ("Lima") model, introduced in 1978. This was the first "all-aspect" Sidewinder with the ability to attack from all directions, including head-on, which had a dramatic effect on close in combat tactics. Its first combat use was by the United Kingdom during the 1982 Falklands War, the "Lima" reportedly achieved a kill ratio of around 80%, a dramatic improvement over the 10-15% levels of earlier versions scoring 17 and 2 shared kills against Argentine aircraft. On that same year but over Lebanon's Bekaa Valley, 51 out of the 55 Syrian-flown MiGs shot down were hit by Israeli Air Force Sidewinders.
In both combat uses of AIM-9L, the opponents had not developed any tactics for the evasion of a head-on missile shot of this kind, making them more vulnerable. The AIM-9L was also the first Sidewinder that was a joint variant used by both the US Navy and Air Force since the AIM-9B. The "Lima" was distinguished from earlier Sidewinder variants by its double delta forward canard configuration and natural metal finish of the guidance and control section. The Lima was also built under license in Europe by a team headed by Diehl BGT Defence. There are a number of "Lima" variants in operational service at present. First developed was the 9L Tactical, which is an upgraded version of the basic 9L missile. Next was the 9L Genetic, which has increased infra-red counter counter measures (IRCCM); this upgrade consisted of a removable module in the Guidance Control Section (GCS) which provided flare-rejection capability. Next came the 9L(I), which had its IRCCM module hardwired into the GCS, providing improved countermeasures as well as an upgraded seeker system. Diehl BGT also markets the AIM-9L(I)-1 which again upgrades the 9L(I)GCS and is considered an operational equivalent to the initially "US only" AIM-9M.
The subsequent AIM-9M ("Mike") has the all-aspect capability of the L model while providing all-around higher performance. The M model has improved capability against infrared countermeasures, enhanced background discrimination capability, and a reduced-smoke rocket motor. These modifications increase its ability to locate and lock-on to a target and decrease the chance of missile detection. Deliveries of the initial AIM-9M-1 began in 1982. The only changes from the AIM-9L to the AIM-9M were related to the Guidance Control Section (GCS). Several models were introduced in pairs with even numbers designating Navy versions and odd for USAF: AIM-9M-2/3, AIM-9M-4/5, and AIM-9M-6/7 which was rushed to the Persian Gulf area during Desert Shield to address specific threats expected to be present. The AIM-9M-8/9 incorporated replacement of five circuit cards and the related parentboard to update infrared counter counter measures (IRCCM) capability to improve 9M capability against the latest threat IRCM. The first AIM-9M-8/9 modifications, fielded in 1995, involved deskinning the guidance section and substitution of circuit cards at the depot level, which is labor intensive and expensive—as well as removing missiles from inventory during the upgrade period. The AIM-9X concept is to use reprogrammable software to permit upgrades without disassembly.
China Lake developed an improved compressed carriage control configuration titled BOA. ("Compressed carriage" missiles have smaller control surfaces to allow more missiles to fit in a given space. The surfaces may be permanently "clipped", or may fold out when the missile is launched.)
The BOA design reduced size of control surfaces, eliminating the rollerons, and returned to simple forward-canard design. Although the Navy and Air Force had jointly developed and procured AIM-9L/M, BOA was a Navy-only effort supported by internal China Lake Independent Research & Development (IR&D;) funding. Meanwhile, the Air Force was pursuing a parallel effort to develop a compressed carriage version of Sidewinder, called Boxoffice, for the F-22. The Joint Chiefs of Staff directed that the services collaborate on AIM-9X, which ended these separate efforts. The results of BOA and Boxoffice were provided to the industry teams competing for AIM-9X, and elements of both can be found in the AIM-9X design.
F/A-18C and shot-down a QF-4 Drone]]
For a brief period in the late '80s, an ASRAAM effort led by a European consortium was in play under a MOA with the United States in which AMRAAM development would be led by the US and ASRAAM by the Europeans. The UK working with the aft end of the ASRAAM and Germany developing the seeker (Germany had first hand experience improving the Sidewinder seeker of the AIM-9J/AIM-9F). By 1990, technical and funding issues had stymied ASRAAM and the problem appeared stalled, so in light of the threat of AA-11 and improved IRCM, the US embarked on determining requirements for AIM-9X as a counter to both the AA-11 and improving the IRCM features. The first draft of the requirement was ready by 1991 and the primary competitors were Raytheon and Hughes. Later, the UK resolved to revive the ASRAAM development and selected Hughes to provide the seeker technology in the form of a high off-boresight capable Focal Plane Array. However, the UK did not choose to improve the turning kinematic capability of ASRAAM to compete with AA-11. As part of the AIM-9X program, the US conducted a foreign cooperative test of the ASRAAM seeker to evaluate its potential, and an advanced version featuring improved kinematics was proposed as part of the AIM-9X competition. In the end, the Hughes-evolved Sidewinder design, featuring virtually the same British funded seeker as used by ASRAAM, was selected as the winner.
The AIM-9X Sidewinder, developed by Raytheon engineers, entered service in November 2003 with the USAF (lead platform is the F-15C; the USN lead platform is the F/A-18C) and is a substantial upgrade to the Sidewinder family featuring an imaging infrared focal plane array (FPA) seeker with claimed 90° off-boresight capability, compatibility with helmet-mounted displays such as the new U.S. Joint Helmet Mounted Cueing System, and a totally new three-dimensional thrust-vectoring control (TVC) system providing increased turn capability over traditional control surfaces. Utilizing the JHMCS, a pilot can point the AIM-9X missile's seeker and "lock on" by simply looking at a target, thereby increasing air combat effectiveness. It retains the same rocket motor, fuze and warhead of the 9-"Mike", but its lower drag gives it improved range and speed. AIM-9X also includes an internal cooling system, eliminating the need for use of launch-rail nitrogen bottles (U.S. Navy and Marines) or internal argon bottle (USAF). It also features an electronic safe and arm device similar to the AMRAAM, allowing reduction in minimum range and reprogrammable InfraRed Counter Counter Measures (IRCCM) capability that coupled with the FPA provide improved look down into clutter and performance against the latest IRCM. Though not part of the original requirement, AIM-9X demonstrated potential for a Lock-on After Launch capability, allowing for possible internal use for the F-35, F-22 Raptor and even in a submarine launched configuration for use against ASW platforms. Combined with the Joint Helmet Mounted Cueing System this delivers combined kill ratios exceeding 50:1 against nonhigh-off-boresight equipped fighters.
As of September 2008, Raytheon has delivered 3,000 AIM-9X missiles to the armed services and has begun testing the Block II version of the missile. The Block II adds Lock-on After Launch capability with a datalink, so the missile can be launched first and then directed to its target afterwards by an aircraft with the proper equipment for 360 degree engagements, such as the F-35 and F-22.
The AIM-9 is made up of a number of different components manufactured by different companies, including Aerojet and Raytheon. The missile is divided into four main sections: guidance, target detector, warhead, and rocket motor.
The Guidance and Control Unit (GCU) contains most of the electronics and mechanics that enable the missile to function. At the very front is the IR seeker head utilizing the rotating reticle, mirror, and five CdS cells or “pan and scan” focal-plane array (AIM-9X), electric motor, and armature, all protruding into a glass dome. Directly behind this are the electronics that gather data, interpret signals, and generate the control signals that steer the missile. An umbilical on the side of the GCU attaches to the launcher, which detaches from the missile at launch. To cool the seeker head, a 5,000 psi (35 MPa) argon bottle (TMU-72/B or A/B) is carried internally in Air Force AIM-9L/M variants while the Navy uses a rail mounted nitrogen bottle. The AIM-9X model contains a Stirling cryo-engine to cool the seeker elements. Two electric servos power the canards to steer the missile (except AIM-9X). At the back of the GCU is a gas grain generator or thermal battery (AIM-9X) to provide electrical power. The AIM-9X features High-Off-Boresight capability; together with JHMCS (Joint Helmet Mounted Cueing System), this missile is capable of locking on to a target that is in its field of regard said to be up to 90 degrees off boresight. The AIM-9X has several unique design features including built-in-test to aid in maintenance and reliability, an electronic safe and arm device, an additional digital umbilical similar to the AMRAAM and jet vane control.
Next is a target detector with four IR emitters and detectors that detect if the target is moving farther away. When it detects this action taking place, it sends a signal to the Warhead Safe and Arm device to detonate the warhead. Versions older than the AIM-9L featured an influence fuze that relied on the target's magnetic field as input. Current trends in shielded wires and non-magnetic metals in aircraft construction rendered this obsolete.
drone, 1974.]]
The AIM-9H model contained a 25-pound () expanding rod-blast fragmentary warhead. All other models up to the AIM-9M contained a 22-pound () annular blast fragmentary warhead. The missile's warhead rods can break rotor blades (an immediately fatal event for any helicopter).
Recent models of the AIM-9 are configured with an annular blast fragmentation warhead, the WDU-17B by Argotech Corporation. The case is made of spirally wound spring steel filled with 8 pounds () of PBXN-3 explosive. The warhead features a safe/arm device requiring five seconds at 20 g () acceleration before the fuze is armed, giving a minimum range of approximately 2.5 kilometers.
The Mk36 solid propellant rocket motor provides propulsion for the missile. A reduced smoke propellant makes it difficult for a target to see and avoid the missile. This section also features the launch lugs used to hold the missile to the rail of the missile launcher. The forward of the three lugs has two contact buttons that electrically activate the motor igniter. The fins provide stability from an aerodynamic point of view, but it is the "rollerons" at the end of the wings providing gyroscopic precession that prevents the serpentine motion that gave the Sidewinder its name in the early days. The wings and fins of the AIM-9X are much smaller to accommodate one in each side bay of the F-22 Raptor as originally planned, AIM-9X control surfaces are reversed from earlier Sidewinders with the control section located in the rear, while the wings up front provide stability. The AIM-9X also features vectored thrust or jet vane control to increase maneuverability and accuracy, with four vanes inside the exhaust that move as the fins move. The last upgrade to the missile motor on the AIM-9X is the addition of a wire harness that allows communication between the guidance section and the control section, as well as a new 1760 bus to connect the guidance section with the launcher’s digital umbilical.
, 1971.]]
Please note that this list is not exhaustive.
Category:Cold War air-to-air missiles of the United States Category:Vietnam War guided missiles Category:Gulf War guided missiles Category:Kosovo War guided missiles Category:Iraq War guided missiles Category:Raytheon products Category:Air-to-air missiles of Germany Category:Swedish Air Force guided missiles Category:Modern weapons of Germany Category:Luftwaffe guided missiles Category:Royal Canadian Air Force & Canadian Forces Air Command guided missiles Category:Falklands War guided missiles
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