Drone Design

Look, up in the sky. It's a bird! It's a plane! No, it's a drone! Formally called as Unmanned Aerial Vehicle (UAV), these flying gadgets which are more popularly called as drones are getting very popular. Drones are an airborne system or an aircraft operated remotely by a human operator or autonomously by an onboard computer. If you are from India and a cricket fan, you should be quite familiar with drones by now. The Indian aviation regulator DGCA and the Civil Aviation Ministry have given conditional permissions to the Board of Control for Cricket in India (BCCI) for aerial filming of cricket matches since 2021. It makes watching the sport more exciting as the drone is able to hover above the playground, and show any sport from hitherto impossible angles. The use of drones is a part of the objective of the government of India, which is looking to promote their commercial use in the country.

Uses of Drones
Of course, cricket and other sports are just an example where drones are finding use. There are various other fields where drones are proving to be quite useful. One of the main advantages of a drone is that they are airborne, small, and can be operated relatively easily. Since they offer six degrees of freedom, drones are better placed to manoeuvre in remote places, and at locations which are otherwise inaccessible.

What is meant by 6 degrees of freedom?
Degrees of freedom are the ways airborne objects (and other bodies) are able to move through space. Six degrees of freedom (6 DoF) refer to the specific number of axes that a rigid body is able to freely move in 3D. As far as drones are concerned, the three standard degrees of freedom include their ability to move up/down, left/right and forward/back. In addition, drones can also roll (move on X axis), pitch (move on Y axis) and roll (move on the Z axis). Remember, move ON an axis is different from move ALONG an axis.

Here are only a few instances where drones prove useful:

• Weather forecasting: Drones are extremely useful in keeping an eye on developing weather conditions in real-time, and supply remote imagery and storm data to assist with life-saving measures. In countries like India, where monsoons are becoming increasingly unpredictable, they can help protect loss of life and property damage with advanced warning.
• Farming: Drones are an inexpensive way of surveying large farmland areas. Fitted with proper sensors, they can accurately capture crop data that farmers can use to increase their harvest.
• Military: Since they are unmanned and smallish, drones are playing an increasing crucial role in protecting hostile borders by providing real-time images of enemy movements. Since they are relatively unaffected by harsh climatic conditions, drones are a safe and effective way for providing military intelligence.
• Medical Aid: Drones are one of the easiest ways of providing emergency medical aid to stranded people. Suppose there is a flood and there is an urgent need to provide medicines across a river. Drones can handle this task quite easily.
• Monitor Offshore Oil Rigs: Offshore mining of black gold is an engineering marvel. Drones monitor the oil rig platform especially near the water surface, where manual inspection can prove to be extremely dangerous.
• Scientific Surveying: UAVs can aid scientists and archeologists in surveying intractable terrain. Antarctica, Siberia, the arid deserts of Middle East, and the dense forests of some rain forests are extremely inhospitable and almost uninhabitable. The use of drones has made monitoring them a comparatively easy task for scientists and geologists.

These are but a few instances where drones are useful in real-life examples. As drone technology gets more sophisticated, they will find more uses – in delivering packages, measuring air quality, photographing deep sea water fish, and so on. Drones are increasingly being used in news broadcasting, film making, and other walks of life. And yes, since basic drones are quite affordable, they are proving quite popular with people who use it for recreational purpose - drone racing is getting popular with amateurs.

Types of Drones Drones can be classified in various ways - based on the blades they have, based on their use, based on their size, based on their readiness to be airborne, etc. For the purpose of this article, we will classify them based on their blades.

• Single Rotor Drones: These are one of the most basic types of drones. Quintessentially unmanned helicopters, they have a single main rotor and an anti-torque device.  They can generate thrust much more efficiently than multi-rotor drones and are particularly suited for longer flight times.
• Multi Rotor Drones: Multi rotor drones are the most common types of drones that have 3 rotors (tricopter), 4 rotors (quadcopter), 6 rotors (hexacopter) or 8 rotors (octocopter). Multi rotor drones are the most popular drones with both professionals and hobbyists. They are used for aerial photography, video surveillance etc. They typically have low payload capacity.
• Fixed-wing drones: As the name implies, these have fixed wings like the traditional aero plane. They don’t have vertical take-off ability and cannot hover. However, since they only need energy to propel forward and not hover, they are very energy efficient and faster moving than rotating drones.
• Hybrid Drones: Hybrid models combine fixed-wing drones with vertical lift rotors. They have the ability to take-off vertically and then move forward with the help of fixed wings. This makes them versatile and ideal for commercial applications.

Looking Under the Hood
The different types of drones serve different purposes. No drone is better than the other. If a drone performs sophisticated tasks and is able to move adroitly, it is more expensive to build than a basic drone. Designing a drone for a specific task is quite an assiduous task and an engineering challenge, as there are various factors at play in drone design. Are tricopters better than quadcopters? How safe are drones with a single rotor? How much weight can a commercial drone safely carry? How to increase the thrust and range of drones? Does the drone comply with the safety norms prescribed by the aviation authorities of the country where it is to be used? There is no easy answer to all these questions, and is the reason why world leaders in engineering software like Altair have developed programs that help companies come up with better drone design. Indeed, drone design is an exciting challenge for companies that provide engineering software services, and we will cover it in detail in another article. Stay tuned!