Home | Menu | Poem | Jokes | Games | Biography | Omss বাংলা | Celibrity Video | Dictionary

World Population Day

Information of air missiles

Air-to-Air (A2A) Missiles:

An air-to-air missile (AAM) is a guided missile fired from an aircraft with the purpose of destroying another aircraft or helicopter. It is typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled. Ramjet engines, as used on the MBDA Meteor (currently in development), are emerging as propulsion that will enable future medium-range missiles to maintain higher average speed across their engagement envelope.

Guided missiles operate by detecting their target (usually by radar or infra-red methods, sometimes by laser guidance or optical tracking), and then "homing" in on the target on a collision course. The target is usually destroyed or damaged by means of an explosive warhead, often throwing out fragments to increase the lethal radius, typically detonated by a proximity fuse (or impact fuse if it scores a direct hit).

Note that although the missile may use radar or infra-red guidance to home on the target, this does not necessarily mean that the same means is used by the launching aircraft to detect and track the target before launch. Infra-red guided missiles can be "slaved" to an attack radar in order to find the target and radar-guided missiles can be launched at targets detected visually or via an infra-red search and track (IRST) system, although they may require the attack radar to illuminate the target during part or all of the missile interception itself.

Radar guidance
Radar guidance is normally used for medium or long range missiles, where the infra-red signature of the target would be too faint for an infra-red detector to track. There are two major types of radar-guided missile - active and semi-active.

Active radar(AR)-guided missiles carry their own radar system to detect and track their target. However, the size of the radar antenna is limited by the small diameter of missiles, limiting its range which typically means such missiles have to use another method to get close to the target before turning their radar set on, often inertial guidance).

Semi-active radar (SAR) homing missiles are simpler and more common. They function by detecting the radar energy reflected from the target, the radar energy is emitted from the launch aircraft's own radar signal. However, this means the launch aircraft has to maintain a "lock" on the target (keep illuminating the target aircraft with its' own radar) until the missile makes the interception, limiting the attacking aircraft's ability to maneuver, which may be necessary should threats to the attacking aircraft appear.

An early form of radar guidance was "beam-riding" (BR). In this method the attacking aircraft directed a narrow beam of radar energy at the target. The air-to-air missile was launched into the beam where sensors on the aft of the missile controlled the missile, keeping it within the beam. So long as the beam was kept on the target aircraft, the missile would ride the beam until making the interception. While simple in concept, the difficulty of simultaneously keeping the beam solidly on the target (which couldn't be relied upon to cooperate by flying straight and level), continuing to fly one's own aircraft, all the while keeping an eye out for enemy countermeasures, can be readily appreciated. Although radar beam-riding air-to-air missiles are obsolete, the technology has since evolved toward laser-beam guided air-to-ground munitions, such as laser-guided bombs (LGB). These precision-strike munitions are sometimes called "smart weapons" by the press.

Radar guided missiles can be countered by rapid manoeuvring (which may result in them "breaking lock", or may cause them to overshoot), deploying chaff or using electronic counter-measures.

Infrared guidance
Infrared guided (IR) missiles home on the heat produced by an aircraft. Early infra-red detectors had poor sensitivity, so could only track the hot exhaust pipes of an aircraft. This meant an attacking aircraft had to maneuver to a position behind its' target before it could fire an infra-red guided missile. This also limited the range of the missile as the infra-red signature soon become too small to detect with increasing distance and after launch the missile was playing "catch-up" with its' target.

More modern infra-red guided missiles can detect the heat of an aircraft's skin, warmed by the friction of airflow, in addition to the fainter heat signature of the engine when the aircraft is seen from the side or head-on. This, combined with greater maneuverability, gives them an "all-aspect" capability, and an attacking aircraft no longer had to be behind its target to fire. Although launching from behind the target increases the probability of a hit, the launching aircraft usually has to be closer to the target in a tail-chase engagement.

An aircraft can defend against infra-red missiles by dropping flares that are hotter than the aircraft, so the missile homes in on the brighter, hotter target. Towed decoys and infra-red jammers can also be used. Some large aircraft and many combat helicopters make use of so called "hot brick" infra-red jammers, typically mounted near the engines. Current research is developing laser devices which can spoof or destroy the guidance systems of infra-red guided missiles.

However, the latest missiles such as the ASRAAM use an "imaging" infra-red seeker which "sees" the target ( much like a digital video camera), and can distinguish between an aircraft and a point heat source such as a flare. They also feature a very wide detection angle, so the attacking aircraft does not have to be pointing straight at the target for the missile to lock on. The pilot can use a helmet mounted sight (HMS) and target another aircraft by looking at it, and then firing. This is called "off-bore sight" launch. The Russian Su-27 is equipped with an infrared search and track (IRST) system with laser rangefinder for its HMS-guided missiles.

A recent advancement in missile guidance is electro-optical imaging. The Israeli Python-5 has an electro-optical seeker that scans designated area for targets via optical imaging. Once a target is acquired, the missile will lock-on to it for the kill. Electro-optical seekers can be programmed to target vital area of an aircraft, such as the cockpit. Since it doesn't depend on the target aircraft's heat signature, it can be used against low-heat targets such as UAV's and cruise missiles.

Air-to-air missiles are typically long, thin cylinders in order to reduce their cross section and thus minimize drag at the high speeds at which they travel. At the front is the seeker, either a radar system, radar homer, or infra-red detector. Behind that lies the avionics which control the missile. Typically after that, in the centre of the missile, is the warhead, usually several kilograms of high explosive surrounded by metal that fragments on detonation.

The rear part of the missile contains the propulsion system, usually a rocket of some type. Dual-thrust solid-fuel rockets are common, but some longer-range missiles use liquid-fuel motors that can "throttle" to extend their range and preserve fuel for energy-intensive final manoeuvring. Some solid-fuelled missiles mimic this technique with a second rocket motor which burns during the terminal homing phase. There are missiles in development, such as the MBDA Meteor, that "breathe" air (using a ramjet, similar to a jet engine) in order to extend their range. Modern missiles use "low-smoke" motors - early missiles produced thick smoke trails, which were easily seen by the crew of the target aircraft alerting them to the attack and helping them determine how to evade it.

Missile range
Missiles are often cited with their maximum engagement range, which is very misleading. A missile's effective range is dependent on factors such as altitude, speed, position, and direction of target aircraft. For example the Vympel R-77 has stated range of 100 km. That's only true for a head-on, non-evading target at high altitude. At low altitude, the effective range is reduced by as much as 75%-80% to 20-25 km. If the target is taking evasive action, or in sterm-chase position, the effective range is even further reduced. The effective range of an air-to-air missile is known as the 'no-escape zone', noting the range at which the target can not evade the missile once launched.


Country: USA
Manufacturer: Hughes Missile Systems Division
Date Deployed: 1991
Range: 72 km (Some sources claim 48 km)
Speed: Mach 4
Propulsion: One solid-propellant rocket motor
Guidance: Mid-course inertial navigation and Hughes active radar.
Warhead: 20 kg proximity and impact delay fused blast/fragmentation
Launch Weight: 152 kg
Length: 3.66 m
Diameter: 0.178 m
Fin Span: 0.63 m
Platforms: F-15 Eagle, F-16 Falcon, F/A-18 Hornet, F-4F Phantom, JAS-39 Gripen, Tornado, Sea-Harrier
Remarks: Raytheon is also integrating the AIM-120 on the Eurofighter Typhoon, F/A-22A and Harrier II+

Name: AIM-54A/C Phoenix

Country: USA
Manufacturer: Hughes Missiles Systems
Date Deployed: 1973
Range: 180 km
Speed: Mach 4.3+
Propulsion: One Aerojet Mk 60 Mod 0 or Rocketdyne Mk 47 Mod 0 solid-propellant rocket motor
Guidance: Hughes DSQ-26 system using inertial, semi-active and active radar
Warhead: 59.9 kg Bendix IR and Downey Mk 334 radar proximity and impact delay fused continuous rod blast/fragmentation
Launch Weight: 446.8 kg
Length: 4.01 m
Diameter: 0.38 m
Fin Span: 0.925 m
Platforms: The F-14 Tomcat navy planes

Name: AIM-7F/M Sparrow

Country: USA
Manufacturer: Raytheon Co.
Date Deployed: July 1956
Range: 100 km
Speed: Mach 3.7
Propulsion: One Hercules Mk 58 Mod 0 or Aerojet Mk 65 Mod 0 dual-thrust solid-propellant rocket motor
Guidance: Raytheon Advanced Monopulse Seeker inverse-monopulse semi-active radar homing
Warhead: 39.9 kg proximity and impact delay fused Mk 71 continuous- rod blast/fragmetation
Launch Weight: 228.2 kg
Length: 3.68 m
Diameter: 0.203 m
Fin Span: 1.02 m
Platforms: F-14 Tomcat, F-15 Eagle, F-16 Falcon, F/A-18 Hornet

Name: AIM-9L/M Sidewinder

Country: USA
Manufacturer: Raytheon Co. and Ford Aerospace and Communications Co.
Date Deployed: 1976 for L 1983 for M
Range: 29.03 km
Speed: Mach 2.5
Propulsion: One Thiokol or Bermite Mk 36 Model 7/8 solid-propellant rocket motor or ( later ) One reduced-smoke Thiokol Mk 36 Mod 9 ( TX-683 ) solid-propellant rocket motor
Guidance: DSQ-29 IR homing
Warhead: 10.2 kg Hughes DSU-15/B active laser-fused WDU-17 annular blast/fragmentation
Launch Weight: 85.3 kg
Length: 2.85 m
Diameter: 0.127 m
Fin Span: 0.63 m

Name: Skyflash

Country: UK
Manufacturer: British Aerospace
Date Deployed: 1978
Range: 45 km
Speed: Mach 4
Propulsion: One Aerojet Mk52 Mod 2 or Rocketdyne Mk38 Mod 4 solid-propellant rocket motor
Guidance: Marconi XJ521 monopulse Semi-Active Radar Homing
Warhead: 39.5-kg HE fragmentation with contact, delay action fuses.
Launch Weight: 192.8 kg
Length: 3.68 m
Diameter: 0.203 m
Fin Span: 1.02 m
Platforms: Tornado

Name: AIM-132 ASRAAM

Country: UK, Germany and Norway
Manufacturer: British Aerospace
Date Deployed: 1998 ?
Range: 300 m to 15 km
Speed: Mach 3+
Propulsion: One dual-thrust solid-propellant rocket motor
Guidance: strapdown inertial and Imaging Infrared
Warhead: 10 kg blast/fragmentation
Launch Weight: 100 kg
Length: 2.73 m
Diameter: 0.168 m
Fin Span: 45 cm