Air Weapons: 66 Years Later

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October 20, 2019: The lightweight, laser-guided APKWS (Advanced Precision Kill Weapons System) missile has finally gone into mass production. The manufacturer (BAE) received a $2.7 billion order to fill demand through 2025 from American (army, marines and air force) as well as a growing number of foreign customers which currently includes Britain, Iraq, Lebanon, Netherlands, Jordan, Afghanistan, Tunisia, Philippines and Australia. This order also includes kits for upgrading unguided 70mm (2.75 inch) rockets with a guidance system that turns them into APKWS.

Many users have had APKWS since 2012 and fired thousands in combat and report a hit rate of over 90 percent. APKWS first became available to troop use in 2010 and was slow to catch on. But as more users tried it, liked it and ordered more the demand reached the point where a full, long term, mass production contract made sense, if only to avoid shortages and to keep the price low.

The fact that APKWS was cheap and four of them cost as much as one Hellfire is a major attraction. The more capable Brimstone cost at least 50 percent more than Hellfire but APKWS had many of the features that made Brimstone attractive, like being used on fast-moving (jet fighter) aircraft. APKWS was very attractive to nations with much smaller defense budgets but in need of laser-guided missiles.

APKWS are basically 70mm unguided rockets with a laser guidance kit attached. Normally each APKWS weighs 15 kg (32 pounds), with a guidance system attached. The guidance system consists of a laser light seeker and moveable fins, battery and microprocessor to guide the rocket to the reflected laser light the laser designator is bouncing off the target. These 70mm rockets usually have a 2.7 kg (six pound) warhead, and a range of about 10 kilometers when fired from a fixed-wing aircraft or helicopter.

Adding laser guidance to 70mm rockets seemed like an obvious concept but it took many years to develop a reliable system. The 2.75 inch (70mm) rockets were developed during World War II, as an air-to-air weapon for use against heavy bomber formations. The Germans had developed a similar and very successful weapon (the R4M). Before long it was noted that neither the Japanese nor the Germans had any heavy bombers, so the U.S. 70mm rocket was switched to air-to-ground use. Actually, the 70mm rocket was retained for air-to-air use into the 1950s, but it was never successful in that role. The 70mm rocket became very popular in the 1960s when it was discovered that the weapon worked very well when launched from multiple (7 or 19 tube) launchers mounted on helicopters. The 108-138m cm (42-55 inch) long rockets could be fired singly or in salvoes and gave helicopter pilots some airborne artillery for supporting troops on the ground. There are many variations in terms of warheads and rocket motors. Some versions could go over 10 kilometers.

Since the 1990s several firms have spent years trying to figure out how to turn 70mm unguided rockets into laser-guided missiles. Most were designed to use existing the Hellfire missile fire control system. Several successful designs entered service by 2010. The APKWS began as a 2002 effort by an American firm, which could not get it to work. British firm BAE took it over and got it to work by 2007 and partnered with the American firm to sell it. APKWS, like its competitors, was built to be compatible with existing laser designators, and aircraft equipped to use Hellfire missiles. For helicopters, APKWS could also be adapted to use 7 or 19 tube launchers long employed for the unguided rockets. The big advantage of all these 70mm missiles is that it is one fourth the weight of a Hellfire, and one fourth the cost. That means AH-64s burn less fuel carrying them, and APKWS is as effective as a Hellfire in, for example, destroying the hundreds of small armed boats Iran plans to use in any war with the Arab states on the west coast of the Persian Gulf. But there are already many similar weapons available for this and few nations want to add what they consider a redundant weapon system.

This weight advantage made ground use attractive for specialized troops, like Special Forces. But before anyone would even consider a ground-to-ground 70mm guided missile, there had to be evidence that the air-to-ground version worked. The 70mm missiles eventually found some customers. In 2010 the U.S. Marine Corps tested APKWS II on their helicopter gunships and were so impressed that they bought many more. The marines armed their AH-1W helicopter gunships with the guided 70mm rockets and in 2012 marine AH-1Ws have fired over a hundred APKWS II in Afghanistan and none of them missed.

APKWS was adapted for use from a number of helicopters as well as fixed-wing aircraft like the A-10, F-16, AV-8B, CN-235 gunship and A-29. APKWS has been exported to Iraq, Lebanon and Jordan and was used in 2017-18 in the fight against ISIL (Islamic State in Iraq and the Levant) in Iraq. There are now a growing number of 70mm air-to-surface and surface-to-surface versions in production or development.

Developing a guided 70mm rocket took so long because the manufacturers underestimated the technical difficulties of getting the laser seeker and flight control mechanisms into that small a package at a weight and price the customer could afford. The price of the new 70mm missile is now about $30,000 each. This is typical for these weapons and about a third less than a smart bomb and less than a third of what a Hellfire missile costs. Tests have shown that the ground-based 70mm missile is reliable, thanks to over a decade of development and combat use of the air-to-ground version.

In tests, the APKWS hit within a meter (a few feet) of the aiming point and has proved an excellent weapon for UAVs, especially since you can carry more of them. The launcher for carrying these missiles is designed to replace the one for Hellfire but can carry four missiles instead of one. UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire.

Another reason for putting APKWS into mass production is because there is now demand for it by ground forces. Actually the demand has been around for a while. First proposed back in 2006, an American firm has finally put together a lightweight, vehicle-based system, using the APKWS II. Called Fletcher, it consists of vehicle-based launchers. The largest of these  can hold 23 missiles. A more attractive version uses a four-tube launcher weighing 13.6 kg (30 pounds) empty. This launcher is two meters (78 inches) long and 30cm x 30cm (11.8 inches). Fletcher uses one of the smaller (lighter) rocket motors and warheads, thus each APKWS used by Fletcher weighs 11.3 kg (25 pounds). A Fletcher launcher with four rockets weighs 59 kg (130 pounds). The compact and lightweight Fletcher launcher can be mounted on any vehicle that normally mounts a heavy (12.7mm) machine-gun or RWS (Remote Weapons Station). This version of Fletcher are being marketed to special operations forces that use many lighter off-road vehicles. For example, DAGOR is a two ton light truck that can carry 1.4 tons or nine troops. It can be carried inside a CH-47 or slung under a UH-60 helicopter. DAGOR can also be dropped via parachute and be ready to roll within two minutes of reaching the ground. Vehicles like DAGOR and even lighter ATVs (all-terrain vehicles) are popular with special operations troops and Fletcher was designed to provide these forces as well as regular infantry with lightweight laser-guided missile systems. Potential buyers showed an interest in a larger launcher, so the 23 tube launcher was offered as well. Fletcher can use slightly heavier APKWS rockets that have a longer range but that won’t happen until users indicate a need for it. The current surface-to-surface APKWS range is 5,000 meters. APKWS has always been able to use laser designators on a helicopter, or with troops on the ground. The laser seeker can actually see reflected laser light out to 14 kilometers but the rocket motor in most 70mm laser-guided rockets is only effective at between five and ten kilometers. Fletcher was first announced in 2017 and available for service by early 2019.

Adapting aircraft weapons for ground use is not unusual. The United States has adapted heat-seeking (Sidewinder) and radar-guided (AMRAAM) air-to-air missiles for use on anti-aircraft ground vehicles. It is rare to adapt air-to-ground missiles for use on ground vehicles but Fletcher came along at the same time that Brimstone, the British version of Hellfire, was also adapted for surface-to-surface use. Brimstone has a longer range (12 kilometers), a more capable guidance system that can work without laser guidance and is a lot more expensive. Fletcher is more effective (lighter, cheaper and more compact) for ground troops who encounter armored vehicles and want to deal with this threat right away while they can see it, and before the armored vehicles see them.