Air-to-air missile
Ramjet engines, as used on the Meteor, are emerging as propulsion that will enable future medium- to long-range missiles to maintain higher average speed across their engagement envelope.
Some modern ones use inertial guidance and/or "mid-course updates" to get the missile close enough to use an active homing sensor.
Le Prieur rockets were sometimes attached to the struts of biplanes and fired electrically, usually against observation balloons, by such early pilots as Albert Ball and A. M.
The US Navy and US Air Force began equipping guided missiles in 1956, deploying the USAF's AIM-4 Falcon and the USN's AIM-7 Sparrow and AIM-9 Sidewinder.
Post-war research led the Royal Air Force to introduce Fairey Fireflash into service in 1957 but their results were unsuccessful.
High casualty rates during the Vietnam War caused the US to reintroduce autocannon and traditional dogfighting tactics but the missile remains the primary weapon in air combat.
[5] Since the late 20th century all-aspect heat-seeking designs can lock-on to a target from various angles, not just from behind, where the heat signature from the engines is strongest.
[6] On the Western side, the Norwegian-American made NASAMS air defense system has been developed for using AIM-9 Sidewinder, IRIS-T and AMRAAM air-to-air missiles to intercept targets.
After a live-fire test occurred in September 2020 off the coasts of Florida, during which it successfully engaged a simulated cruise missile, in 2022 NASAMS was deployed to Ukraine, where for the first time this missile system was used in real combat conditions, and, according to Ukrainian government, was able to shoot down more than 100 aerial targets.
Less commonly, nuclear warheads have been mounted on a small number of air-to-air missile types (such as the AIM-26 Falcon) although these have never been used in combat.
Radar-guided missiles can be countered by rapid maneuvering (which may result in them "breaking lock", or may cause them to overshoot), deploying chaff or using electronic counter-measures.
This meant an attacking aircraft had to maneuver to a position behind its target before it could fire an infra-red guided missile.
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.
Start of the 21st century missiles such as the ASRAAM use an "imaging infrared" 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.
For example, the Russian Su-27 is equipped with an infra-red search and track (IRST) system with laser rangefinder for its HMS-aimed 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.
Missiles are divided into five primary systems (moving forward to aft): seeker, guidance, warhead, motor, and control actuation.
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 maneuvering.
Some solid-fuelled missiles mimic this technique with a second rocket motor which burns during the terminal homing phase.
There are missiles, such as the MBDA Meteor, that "breathe" air (using a ramjet, similar to a jet engine) in order to extend their range.
Nowadays, countries start developing hypersonic air-to-air missile using scramjet engines (such as R-37, or AIM-260 JATM), which not only increases efficiency for BVR battles, but it also makes survival chances of target aircraft drop to nearly zero.
In order to maneuver sufficiently from a poor launch angle at short ranges to hit its target, some missiles use thrust vectoring, which allow the missile to start turning "off the rail", before its motor has accelerated it up to high enough speeds for its small aerodynamic surfaces to be useful.
[10] The second-generation of short-range missiles utilized more effective seekers that were better cooled than its predecessors while being typically "uncaged"; resulting in improved sensitivity to heat signatures, an increase in field of view as well as allowing the possibility of leading a missile within its FOV for an increased probability of kill against a maneuvering target.
Examples include advanced derivatives of the K-13 (missile) and AIM-9 such as K-13M (R-13M, Object 380) or AIM-9D / G / H. This generation introduced much more sensitive seekers that are capable of locking onto the warm heat irradiated by the skins of aircraft from the front or side aspects, as opposed to just the hotter engine nozzle(s) from rear-aspect, allowing for a true all-aspect capability.
[11] Other members of the 4th generation use focal plane arrays to offer greatly improved scanning and countermeasures resistance (especially against flares).
