Air Weapons: The 70mm Solution

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May 2, 2018: Qatar has ordered 5,000 APKWS II (Advanced Precision Kill Weapons System) laser guided missiles from the United States for $60,000 each. The price includes user training, maintenance and tech support as well as maintenance and testing equipment. These missiles will be used on the 24 AH-64 helicopter gunships Qatar has on order (to be delivered by 2020).

Missiles like APKWS are basically 70mm laser guided rockets. They were developed by taking a 13.6 kg (30 pound) 70mm unguided rocket and adding a laser seeker and moveable fins for guidance. These missiles have a 2.7 kg (six pound) warhead, and a range of about six kilometers when fired from the air. Laser designators on a helicopter, or with troops on the ground, are pointed at the target and the laser seeker in the front of the guided rocket as it homes in on the reflected laser light. 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.

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 figured out how to turn 70mm (2.75 inch) 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 working 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.

Despite the lack of demand, the 70mm missiles eventually found some customers. Back in 2010 the U.S. Marine Corps purchased fifty APKWS II kits for testing. That was followed by an order for kits to convert some of the 100,000 marine 70mm unguided rockets to laser guided ones. In 2013 the marines made their third purchase, for over 20,000 newly manufactured APKWS II missiles. This was the first large purchase of 70mm guided missiles, after a decade of sales efforts by several manufacturers. The marines arm 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. Few fixed wing aircraft can use Hellfire (only the British version of Hellfire, called Brimstone, has been adapted to use on fast moving jets). American jet fighters have demonstrated that using APKWS

There are now several guided versions of the 70mm air-to-surface and surface-to-surface versions. 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.

The guided 70mm rocket is used against targets that doesn't require a larger (49 kg/108 pound), and more expensive (over $100,000), Hellfire missile but still needs some targeting precision. In tests the APKWS hit within a meter (a few feet) of the aiming point, about what other 70mm missiles are capable of. The 70mm missile makes 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.

Orders for 70mm guided missiles were hard to obtain at first because the Hellfire was doing the job and there just wasn't a big demand for a smaller missile. Several smaller missiles have been developed, and one of them, the Griffin, is being used over Pakistan and Afghanistan on American UAV as well as fixed wing gunships (like the AC-130). The smaller Griffin is an alternative to the Hellfire II because it weighs only 16 kg (35 pounds) with a 5.9 kg (13 pound) warhead. Griffin has a pop-out wings, allowing it to glide, and thus has a longer range (15 kilometers) than Hellfire (8,000 meters). UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire. The APKWS was found to be superior to the Griffin because, like Hellfire, it was fast and usually took no more than five seconds to reach the target.