Military Spec (Large/Medium)
Calling a Remotely Operated Aerial Vehicle (ROAV), or Remotely Piloted Aerial Vehicle (RPAV) a "drone" is a misnomer unless the aerial vehicle is fully autonomous. The term is, however, so deeply embedded within the public psyche that it is here to stay. Even after fruitless attempts by the aerospace and defence industry to eradicate it, preferring the terms Unmanned Aerial Vehicle (UAV), and Unmanned Aerial Systems (UAS), it continues to endure. This type of drone is most often used for military purposes, however they are also increasingly being used by charities and private sector organisations to effect positive change. Examples include deforestation prevention and anti-poaching. High altitude drones are also being used to monitor the environment. As you will see from the above illustration, drones vary greatly both in size and composition. All those listed above, apart from the AR Parrot (far right), are the product of the aerospace and defence industry.
Semi-Professional Spec (Medium)
Although difficult to accurately categorise, the new breed of battery-powered drones aimed at the consumer and semi-professional market burst onto the scene a few years ago. Unlike military drones that were inspired by aircraft design, these new entrants are a by-product of the consumer electronics industry. Due to economies of scale, they have become increasingly affordable, and are now selling by the million. Although far cheaper and more versatile, they do come with one major limitation compared to their military cousins. As they are not powered by combustion engines, they can only remain airborne for the duration of a single charge. Unlike military drones that are capable of remaining airborne for 6hrs or more, they can only last around 30mins. Some low-volume or custom-built drones are, however, capable of flying for up to two hours. As they are far more expensive than standard "off-the-shelf" models, they tend to be used by professionals for niche applications such as high-value asset inspection, crop monitoring, and industrial land surveying. If air time is more important than the ability to hover, fixed wing drones can be used instead of rotor-drones. As you will see, the consumer-friendly AR Parrot that was dwarfed by the far larger military grade drones, looks far more at home alongside these professional spec drones. This is why the lines are becoming increasingly blurred between professional spec and consumer spec drones.
Consumer Spec (Small)
As with almost every category of drone today, terminology remains very confusing. In our world what we mean by the term "micro drone" is a quad-copter that can be as small as a human hand, and as large as a plate. We think this category of drone has a very bright future, primarily because they are large enough to offer utility, but they're small, light and quiet enough to operate around people, property, and pets. We are therefore convinced that this category of drone will almost certainly become ubiquitous within factories, stores, warehouses, shopping malls, offices, and domestic environments throughout the world. Although they currently suffer greatly from very limited flight time, innovations in battery technology and flight-extending techniques will solve this issue. For example, it may be possible to tether a power supply, or use relay charging, where one drone attaches to a power socket, while another remains airborne. Anything smaller has started to become referred to as nano-sized. For example the makers of the Axis refer to their creation as a "nano drone" as it is almost the size of a human finger nail. This is of course factually incorrect, and will almost certainly lead to further confusion in future. This is because real nano robots are currently being developed that are far, far smaller than the Axis. Please scroll down to find out more.
Research Spec (Nano)
The trend towards miniaturisation continues. Mab is an automated cleaning system, consisting of hundreds of flying micro-robots. It was a concept developed by the winner of an innovation competition run by the Electrolux Design Lab. Although it is unlikely to become commercially available any time soon, it is technologically feasible. Another major technological advancement that's pushing the trend towards miniaturisation even further is nano robotics. Today it's possible to assemble very basic nano-sized machines constructed with components sized from 10 microns (a human hair is around 75 microns) down to a tenth of a micron. Swarms of these nano-sized robots could one day be used to break down nuclear waste, or even cure diseases such as cancer. Proof that little flying robots really are going to change the world!