Military technology: When it comes to unmanned aircraft, lots of small drones are cheaper, and in some ways better, than a few big ones

THE future of air power is likely to be unmanned. It may also be surprisingly small. Reapers and Predators grab the headlines, but such big, well-known drones are already outnumbered by small, cheap and capable aircraft.

One good example is the RQ-11B Raven, made by AeroVironment of Monrovia, California, and widely used by America's armed forces. It looks like a model aircraft. When disassembled it fits into a backpack. Launching it is a matter of snapping the parts together and throwing it into the air, whence it is carried aloft by an electric propeller. It weighs two kilograms. The American army's entire annual purchase of almost 1,300 Ravens is thus lighter than a single fully armed Reaper. Pilots might dismiss Ravens as radio-controlled toys, but they are popular with soldiers. More are being rushed to Afghanistan.

At its simplest, a Raven acts as a flying pair of binoculars that can look over the next hill, or escort a convoy from above. Being small and quiet, it can get close to targets unobserved, for a good look. Unlike bigger drones, whose limited numbers mean that officers in the field are in constant competition for their services, Ravens are abundant and thus generally available to provide instant video imagery, day or night. Special display software overlays the images they send back on a map to produce a moving picture of what is going on on the ground. An operator can thus call down artillery fire with lethal precision without having to see the target directly. For extra accuracy, Raven can also mark targets with a laser illuminator.

Another reason for Raven's popularity is that it is easy to use. The controlling hardware is a tablet computer with buttons on the side, rather like a portable games console, and most people can get the hang of it in a couple of days. Predators, by contrast, were originally flown by real, albeit ground-based, pilots—and, though high demand for operators has led to a new rapid-training course for groundlings, it still takes 22 weeks to complete. Ravens are now being upgraded to use a communications system that provides enough bandwidth for 40 of them to fly in the same area, instead of the current four.

The American army has experimented with turning the drones into miniature bombers, capable of delivering a grenade-sized weapon, to destroy a small vehicle or take out the occupants of a particular room with high precision and little collateral damage. For greater punch, AeroVironment has a prototype version of a lethal drone called Switchblade. This resembles Raven, but is a flying bomb, packed with explosives. Its guidance software enables it to lock on to and follow a rapidly moving target.

At the moment, Ravens cost around $56,000 each, and economies of scale should bring this down. By contrast, machines like the Predator cost at least $5m, and another $5,000 an hour to fly. From the army's point of view, small is definitely beautiful.