May 30, 2012: A 70mm air-to-ground missile, the APKWS II (Advanced Precision Kill Weapons System) was recently tested, successfully, with an armor piercing warhead. The M282 warhead is a shaped charged type explosive that can penetrate the armor of most armored vehicles (except tanks) and also thick masonry or concrete walls. Most 70mm missiles of this type have explosive warheads. But there are times when you have to knock down thick walls to get at your target.

Earlier this year the U.S. Marine Corps sent the first APKWS II (a laser guided 70mm/2.75 inch rockets) to Afghanistan for use on its helicopters. A year ago the marines bought about a hundred APKWS II kits, to convert some of their 100,000 70mm unguided rockets to laser guided ones (that can hit stationary and moving targets). The marines then successfully test fired over 80 of these guided 70mm rockets from their AH-1W helicopter gunships and several other helicopters that are frequently equipped to fire the unguided 70mm rockets. Since the guided rockets proved successful more kits were purchased, making this the first real sale for 70mm guided rockets.

After more than a decade of development effort, by several different companies, there are now several guided versions of the 70mm air-to-ground rocket but very few sales. 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 of a package, at a weight and price the customer would accept. The price of the new guided 70mm missiles is about a third of what a 227 kg GPS guided smart bomb costs and a fifth of what a 49 kg laser guided Hellfire missile goes for.

The guided 70mm rocket is to be used against targets that don't require a larger (49 kg/108 pound) and more expensive (over $100,000) Hellfire missile but still need some targeting precision. In tests the APKWS hit within a meter (a few feet) of the aiming point, and the other 70mm missiles are just as accurate. This is pretty standard for laser guided weapons. GPS guidance brings the bomb to within 5-10 meters of the target.

The 70mm missile makes an excellent weapon for UAVs, especially since you can carry more of them. The launcher for these missiles is built to replace the one for Hellfire but carries four 70mm missiles.

All these 70mm rockets are basically 13.6 kg (30 pound) 70mm rockets with a laser seeker, a 2.7 kg (six pound) warhead, and a range of about six kilometers. 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 70mm missile homes in on the reflected laser light.

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), but 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 can go over 10 kilometers.

Orders for 70mm guided missiles were hard to get 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 in Afghanistan and Pakistan. The smaller Griffin is an alternative to the heavier Hellfire II and its 9 kg (20 pounds) warhead and range of 8,000 meters. Griffin weighs only 16 kg (35 pounds) with a 5.9 kg (13 pound) warhead. Griffin has pop-out wings, allowing it to glide, and thus has a longer range (15 kilometers) than Hellfire. UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire.

The marines believe that a mini-Hellfire, in the form of their APKWS II, has a role on the battlefield and are using it in combat. The APKWS is a lot cheaper than Hellfire or Griffin and for the marines, cheaper is seen as better.