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Drones in Agriculture
Published in K. R. Krishna, Agricultural Drones, 2018
There are few other criteria that could be adopted to classify drones. According to Gogarty and Robinson (2012), modern drones could be classified as micro, small, medium and large. On the basis of the altitude and endurance considered together, they are referred as medium-altitude long endurance (MALE) or high-altitude long endurance (HALE) drones. Generally, drones for military surveillance, scouting and bombing are MALE or HALE types, because they have to travel long distances and high altitudes without detection, and return to barracks after completing the tasks. It seems drones such as Global Hawk and Predator could easily travel for 7500 miles from the launch site, identify the target, drop bombs and return. All these aspects are accomplished at the push of buttons and on the iPad or a computer screen (Gale Encyclopaedia of Espionage and, intelligence, 2014). On the contrary, agricultural drones are usually micro or small, low-altitude or very low-altitude types. They have short endurance of around 30 min to 2 h. They are lightweight machines.
Poison pill or cure-all?
Published in Kristin Bergtora Sandvik, Maria Gabrielsen Jumbert, The Good Drone, 2016
Kristoffer Lidén, Kristin Bergtora Sandvik
Compared to satellites, drones can provide more detailed and immediately available footage, and change flight paths according to need. The oldest and most prevalent use of medium altitude and long endurance (MALE) drones is for surveillance (the monitoring of behaviour and activities over a large part of the battlefield) and reconnaissance (the process of getting information about enemy forces or positions, including target selection) to improve situational awareness in combat, and military strategic decision-making. The first use of drones for intelligence, surveillance and reconnaissance (ISR) that may in some way be termed a PoC use, was the US deployment of the Gnat 750, a predecessor to the Predator, over Bosnia in 1994 (The Economist2012). Since then, the use of larger and more sophisticated high altitude long endurance (HALE) (Global Hawk by Northrop Grumman) and MALE drones like the Heron (IAI) or the Predator (General Atomics) for ISR have become commonplace in conflict. Handheld micro and nano drones such as Raven B (Aerovironment) and Black Hornet (Prox Dynamics) are also increasingly common in combat. These function as “binoculars in the air” to enhance force protection and combat effectiveness. Non-state armed groups have also acquired surveillance drones, including the Hezbollah, Hamas and the Islamic State (Zwijnenburg, 2014).
Autonomous Vehicles for Infrastructure Inspection Applications
Published in Diego Galar, Uday Kumar, Dammika Seneviratne, Robots, Drones, UAVs and UGVs for Operation and Maintenance, 2020
Diego Galar, Uday Kumar, Dammika Seneviratne
The following classifications, which can vary with national legal restrictions, can be taken into account when selecting a UAV for thermal imaging (Krawczyk, Mazur, Sasin, & Stokłosa, 2015): NAVs (nano air vehicles): Usually used in swarms of UAVs for radar confusion for ultra-short range surveillance. All sensors, including cameras, propulsion system, and control subsystems, need to be small (Austin, 2010).Micro UAVs: Have a close range, are portable, can be hand launched, and fly at very low altitude. Payload weight is less than 2 kg. Takeoff weight is less than 5 kg. Total power is lower than 100 W. Total time less than 1 h (Dalamagkidis, Valavanis, & Piegl, 2008).Mini UAVs: Have a close range and fly at low altitudes. Payload weight is 1–3 kg. Takeoff weight is less than 20 kg. Total power is less than 10 kW. Total time is shorter than 2 h (Dalamagkidis, Valavanis, & Piegl, 2008).Regular/small UAVs: Have medium range, medium altitude. These include launch systems. Payload weight is less than 150 kg. Takeoff weight is less than 400 kg. Total power is 10–50 kW. Total time less than 6 h.MALE (medium-altitude long-endurance) UAVs: Perform long flights at medium altitudes (Dalamagkidis, Valavanis, & Piegl, 2008).HALE (high-altitude long-endurance) UAVs: Perform long flights at high altitudes. Total flight time is 24–48 h (Dalamagkidis, Valavanis, & Piegl, 2008).
Development of surrogate models for the prediction of the flow around an aircraft propeller
Published in International Journal of Sustainable Energy, 2018
Christina Salpigidou, Dimitris Misirlis, Zinon Vlahostergios, Kyros Yakinthos
The accurate prediction of the flow development around rotating aerodynamic bodies such as compressor/turbine blades and propellers is very important for the precise design and optimisation of aircraft engines and propulsion systems or energy harvesting components such as wind-turbines and hydro-turbines. The present work is mainly focusing on the aerodynamic performance calculation of a fixed propeller used for the propulsion of light-weight aircrafts and medium altitude long endurance unmanned aerial vehicles (UAVs). The propeller operation significantly disturbs the fluid flow, especially near the fuselage, and introduces three-dimensional phenomena that can alter its aerodynamic characteristics, which have a straight-forward impact on its performance. As a result, an accurate prediction of the complicated 3D flow phenomena is of great importance for a proper assessment and optimisation of the whole aircraft aerodynamic characteristics.
Crashworthiness study of UCAV’s main landing gear using explicit dynamics
Published in International Journal of Crashworthiness, 2022
Raees Fida Swati, Muhammad AsfandYar Amjad, Muhammad Talha, Hassan Elahi, H. R. Hamdani, Abid Ali Khan, S. R. Qureshi
The advent of unmanned combat aerial vehicle has completely revolutionized modern warfare. This has led to rapid advancements in this domain in the last decade alone. From low-speed piston-driven medium altitude long endurance to jet-powered high-speed high altitude and long endurance unmanned combat aerial vehicle to becoming hallmark feature of next generation of fighters. The design requirements for each of these alone create a myriad of challenges for designing landing gear. As these are all stealth unmanned combat aerial vehicles, they will have an internal weapon’s bay. This will restrict the size of a landing gear. Furthermore, the main landing gear would have to as light weight as possible to increase endurance and payload capacity [1–3]. Jet-powered unmanned combat aerial vehicles will have a higher landing velocity meaning higher impact energy that would have to be absorbed and dissipated by the main landing gear [1–5]. These factors all compounded together increases the risk of failure in landing gear and decreases their crash worthiness under high velocity impact. Data released by Office of Aerospace Medicine Washington, US Department of Transportation indicates that 47% of crashes in military drones [6], were during landing. Further breakdown of these data showed that these failures were because cost saving was prioritized leading to low reliability and durability of components. The main landing gear would have to be more durable and crash worth and maximum take-off weight will be higher while keeping the costs low [4,7]. All these problems need to be addressed and the main landing gear optimized for topology, shape and size.
On the application of drones: a progress report in mining operations
Published in International Journal of Mining, Reclamation and Environment, 2021
Khadija Omar Said, Moshood Onifade, Joseph Muchiri Githiria, Jibril Abdulsalam, Michael Oluwatosin Bodunrin, Bekir Genc, Oluwagbenga Johnson, Jide Muili Akande
Drones greatly differ in specification based on both the design and task resulting in development of various classification systems based on different parameters [3]. Watts et al. [15] classified UAVs as for educational research, defence, or leisure based on their design such as flying endurance, dimensions, and abilities. These classes include HALE (High Altitude, Long Endurance), MALE (Medium Altitude, Long Endurance), LALE (Low Altitude, Long Endurance), LASE (Low Altitude, Short-Endurance), NAVs (Nano Air Vehicles), MAVs (Micro or Miniature Air Vehicles), and VTOL (Vertical Take-Off & Landing) or HTOL (Horizontal Take-off & Landing).