Unmanned air vehicles (UAVs) have undergone massive development over the past 20 or so years, with great changes in size and capabilities. They have acquired weapons (armed UAVs are designated Unmanned Combat Air Vehicles or UCAVs). Stealth UAVs and UCAVs are under development. They have grown greatly in size – the wingspan of the Northrop Grumman RQ-4 Global Hawk is, at 39.9 m, greater than that of a Boeing 737-800 airliner equipped with winglets (35.8 m).

But UAVs have also gotten smaller. First small UAVs came into operational service, then mini-UAVs, which were, in turn, followed by micro-UAVs.
Now, the UK Ministry of Defence (MoD) has revealed that British troops in Afghanistan are using what is believed to be the first nano-UAV to be deployed operationally. The British Army calls it the Black Hornet (it is actually coloured grey, but with black rotor and tail blades). Its manufacturer, Norwegian company Proxdynamics, calls it the PD-100 Personal Reconnaissance System (PRS).
The Black Hornet/PD-100 PRS is a minute helicopter (Proxdynamics refers to it as a nanocopter) UAV. The little aircraft is about 10 cm long and 2.5 cm high and has a mass of 16 g. Its rotor diameter is 12 cm. The “base station” for the nano-UAV is a hand-held device about 20 cm long, 8.5 cm wide and 5 cm high. When not needed, the nanocopter is stored within the base station (which has a liftable flap). The entire system can fit within a soldier’s combat dress pocket.
The base station excludes a display (without a display, the entire system weighs less than 1 kg) but it can be connected with various devices and networks, as required. In British service, photographs released by the MoD show the base station connected with a mini-tablet type device, presumably providing the display. The Black Hornet can be controlled using a small joystick or preprogrammed to fly to specified global positioning system coordinates. It is also fitted with an autopilot. It is powered by a small, rechargeable battery. The manufacturer reports that it has a maximum speed of 10 m/s, an endurance of up to 25 minutes and its digital line-of-sight data link has a range of 1 000 m.
The nano-UAV is fitted with a miniature steerable camera which can supply both video and still images. This camera was developed by UK company Marlborough Communications and the order for the Black Hornet system was placed with the British enterprise. The contract is worth £20-million and covers the supply of 160 “units”.
The miniature aircraft can be flown outdoors or indoors, and is very quiet and difficult to see. The MoD reports that it can function in harsh and windy conditions. Development of the PD-100 PRS commenced in the first half of 2008 and production started in 2012, presumably to meet the British order.
In Afghanistan, the Black Hornet is being used by the Brigade Reconnaissance Force (BRF) of the 4th Mechanised Brigade, which is the British Army contingent of the International Security Assistance Force (a North Atlantic Treaty Organisation mission mandated by the United Nations). A BRF numbers about 150 troops and has the mission of detecting insurgent activity and locating and identifying insurgents, as well as determining the mood and concerns of the local civilian population.
“Black Hornet is definitely adding value, especially considering the lightweight nature of it,” reported BRF Sergeant Christopher Petherbridge. “We use it to look for insurgent firing points and check out exposed areas of ground before crossing, which is a real asset. It is easy to operate and offers amazing capability to the guys on the ground.” Excluding the Black Hornet, the British armed forces currently operate more than 300 UAVs in Afghanistan, including about ten General Atomics MQ-9 Reaper UCAVs.