AGM-114 Hellfire is a
helicopter-based heavy anti-armor
missile used by United States
Army and
Navy. The first generation of Hellfire currently being used is deployed on
AH-64 Apaches and and
AH-1 Super Cobra helicopters.
There are four major revisions to the missile:
- AGM-114A Basic Hellfire is the original Hellfire. More than 30,000 were purcahsed from the manufacturer (Martin Marietta and Rockwell International) since 1982. They are no longer purchased by the army. The current stock is used in live fire trainning.
- AGM-114B Navy Hellfire is mostly in use by the Navy. The difference between the "A" and "B" revisions is the presence of the electronic arm/safety device required for the use on the ship.
- AGM-114C Hellfire has an improved semiactive laser seeker, lower trajectory and a low smoke motor. The visibility is also increased compared to the "A" revision.
- AGM-114F Interim Hellfire features two warheads to defeat reactive armor. The domestic production by Rockwell was completely in January, 1994. Apparently there's further production of this modification for foreign markets.
- AGM-114K Hellfire II provides a number of significant improvements over all the other modifications. Dual warheads are now standard. The missile is more protected against electro-optical tampering. There's a semi-active laser seeker and programmable auto-pilot (both allowing for improved target re-acquisition). Hellfire 2 also solves the "laser obscurant/bascatter problem".
There are two engagement modes: remote and autonomous. In autonomous mode, Hellfire missile is fired from an aircraft and is subsequently controlled by that aircraft until final delivery. In the remote mode, the aircraft serves as a launch platform for the missile. The target is designated by a soldier on the ground or another aircraft who then guide the missile to the intended destination. Remote delivery has an advantage of allowing the delivery vehicle to stay out of combat zone - increasing the survivability. Remote deployment requires larger cooperation between the parties.
In addition to the aforementioned methods of engagements there are four methods of delivery. These are primarily controlled by three factors: distance to the target, visibility, and terrain conditions. In all the Hellfire modifications up to AGM-114K if the laser guidance is lost, so is the missile. Only AGM-114K has target re-aquisition mechanisms after the target is lost.
The delivery methods are as follows:
- Lock on before launch: In this mode, the missile laser seeker locks on to the laser energy reflected from the target. This guarantees that the target has been acquired prioer to the launch. The downside to this is the fact that the aircraft must attain a much higher altitude therefore exposing itself.
- Lock on after launch: This delivery allows the aircraft to stay lower, therefore avoiding much threat. The missile's trajectory will also be much lower. On the other hand, this method doesn't guarantee target acquisition which may result in a wasted missile.
- The last two methods are Lock on after launch - high and Lock on after launch - low. These methods allow the aircraft to fire a missile when hidden behind an obstacle (such as a mountain). After launch, the missile will clear the obstacle (not higher than 1,000 ft) providing that the vehicle is 1,500 ft away. The major disadvantage of this deploments is the fact that the missile may break the cloud cover therefore losing the target lock. The "low" mode of Lock After Launch deploment can then be used to minimize the altitude of the hellfire trajectory.
http://www.fas.org/man/dod-101/sys/missile/agm-114.htm