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UAV and Drone
UAV is an acronym for “Unmanned Aerial Vehicle,” an example of which is a drone. A drone is basically an aircraft without a human pilot on board. Nowadays, the drone market is exceedingly expanding. In this regard, a survey suggested that the drone market will encounter an annual growth rate of 9.6 percent, making almost 70 billion dollars around the world, between 2018 and 2023. There are several different types of drones out there in the market- a few of them are just prototypes, while most of them are already in practice. The categorization of drones depends on a specific basis, for instance, drones use for photography, drones utilized for aerial mapping and drones utilized for surveillance, etc. However, aerial platforms serve as a basis for the best categorization of drones. There are four major types of drones depending upon the kind of aerial platform used;
1. Multi-Rotor Drones
2. Fixed-wing Drones
3. Single Rotor Drones
4. Fixed-wing Hybrid VTOL
One of the most common types of drones utilized by professionals and hobbyists alike is a multi-rotor drone. These types of drones are most commonly utilized for most common applications, for instance, aerial video surveillance and aerial photography, etc. Various categories of products are commercially available in this category- say multi-rotor drones for technical purposes such as aerial view photography, and there are also several versions available for recreational purposes such as leisure flying and amateur drone racing. Among all four types of drones which are categorized based on an aerial platform, multi-rotor drones are the simplest to produce and are the cheapest option available to date.
Further classification of multi-rotor drones depends upon the number of rotors on the platform viz;
• Tricopter: A multi-rotor drone having three rotors.
• Quadcopter: A multi-rotor drone having four rotors.
• Hexacopter: A multi-rotor drone having six rotors.
• Octocopter: A multi-rotor drone having eight rotors.
Among these types of multi-rotor drones, quadcopters are widely used and the most popular variant.
Being relatively cheaper and easier to manufacture, multi-rotor drones have a lot of cons too. Out of all the cons, the prime one being limited flying time, speed, and limited endurance. Multi rotor drones are unfit for long and large-scale projects such as long-range aerial mapping or surveillance. The main problem of multi-copters is that they have to spend a large portion of their energy (commonly coming through a battery source) in fighting against gravity and stabilizing themselves in the space or air. Nowadays, most of the multirotor drones are capable of flying up to 20-30 minutes.
Fixed-wing drones are contrary to multi-rotor drones in manufacturing and design. Like regular airplanes, fixed-wing drones also use a ‘wing.’ Unlike multi-rotor drones, fix wing drones do not spend energy to combat gravity or to stay afloat on the air. However, they advance on their specific set course or as commanded by the guide control (commonly a remote device operated by a human being) until unless their source of energy allows. Generally, fixed-wing drones possess an average flying time of a few hours. Drones powered by gas engines can fly up to 16 hours or higher.
Considering their higher fuel efficiency and flying time, fixed-wing drones are suitable for long-distance operations such as mapping or surveillance. However, keeping in view that fixed-wing drones are not able to stand still on the air, hence they cannot be used for aerial photography. Higher costs and training on flying skills are the significant downsides of fixed-wing drones. A runway or a catapult launcher is required to land and set a fixed-wing drone in the air. In contrast, multi-rotor drones are cheaper and require no training in flying skills.
Single Rotor Drones
Single rotor drones possess a very close similarity in structure and design to actual helicopters. In contrast to a multi-rotor drone, single rotor drone harbors just one big-sized rotor and one small rotor on the tail side of the drone to control its heading. In terms of efficiency, single rotor drones are way more efficient than multi-rotor drones variants. They, along with being powered by gas engines, also delivers higher flying times. In terms of aerodynamics, lesser the number of rotors lesser will be the rotation of an object, and this is the reason why quadcopters are more stable than octocopters. Keeping in view the above discussion, it is clear that single rotor drones are way more efficient than multi-rotor drones.
However, single rotor drones offer much higher complexity and operational risks. They are also much expensive than other versions of drones. The large-sized rotor blade of a single rotor drone can prove to be fatal in case of an accident if the drone is not carefully used or get involves in an accident. In contrast, multi-rotor drones due to their small rotor blades have never been involved in any fatal or lethal accident. Like fixed-wing drones, they also demand specialized training to fly them.
Fixed-wing Hybrid VTOL
As the name pointers, fixed-wing hybrid VTOL combines the advantages of both fixed-wing drones and that of rotor based models with a fixed-wing model providing a higher flying time and that of rotor based models providing hover. The concept of a fixed-wing hybrid model did not gain much success since its invention around the 1960s. However, as soon as new generation sensors are introducing, such as gyros and accelerometer, this model of fixed-wing hybrid got some new direction and life.
THE hybrid VTOL model is an amalgam of automation and manual gliding. In order to lift the drone up into the air from the ground, a vertical lift is utilized. Moreover, to keep the drone stabilized in the air, gyros and accelerometer work in automated mode (autopilot mode). A programmed or a remote-based manual control is utilized the guide a drone in the desired direction or course. Some variants of this fixed-wing hybrid VTOL model are available commercially. However, the most popular is the one being used in Amazon commercials for the prime delivery service of Amazon.