Trains, Boats & Planes | 21 March 2017How Do Drones Fly? Share article facebook twitter google pinterest Drones, or multicopters, are radio controlled aircraft (RC). In Adam Juniper’s book, The Complete Guide to Drones, he explains how drones fly by first comparing them to traditional aircraft: the lift that keeps a traditional plane aloft comes from the air flowing over its carefully crafted shape, meaning forward momentum is essential; multicopters are a lot more flexible. Only the propeller blades need to be aerodynamically shaped, with control achieved through subtle changes to the speed of their rotation. The Complete Guide to Drones The curved shape of an airplane’s wing smashes into the air as it hits it. The upward curve means the shape is more disruptive of the air above the wing, pushing it away and effectively lowering the air pressure above the wing in comparison to that below where the shape remains flat and air is unimpeded. Once the difference in pressure above and below the wing is enough, the higher pressure below has the effect of pushing the wing upward. Of course, this only works when the wing is moving forward fast enough for it to create the necessary lift, which is why long runways are needed for takeoff. With helicopters, a similar curve is applied to blades rotating above the cockpit, which is why they are often called “rotary wing aircraft.” The angle of helicopter blades can be adjusted, and the tail rotor can be sped up or slowed to turn the cockpit, a little like the rudder on a plane. However, the tail rotor has another function; without it there would be nothing to stop the cockpit spinning out of control with the blades. DIRECTIONAL CONTROLWere the computer in charge, there would be no real reason for a ‘copter to have a designated front, but for more natural piloting (and often because of camera positioning) multicopters will have a clearly marked forward direction. The DJI Phantom pictured here uses red marking stripes and colored LED lights. Most multicopters eschew such complicated mechanics in favor of making very fast alterations to the rotation speed of an even number of matching propellers. Common prop arrangements are shown below, but they’re far from the only options. The biggest advantage of having an even number of propellers is that their opposing rotations very easily eliminate the natural effect of torque rotation that would otherwise cause the craft to spin (this is the same reason Leonard da Vinci’s helicopter would never have flown, even with a motor replacing the “four strong men” he suggested). Rather than achieving control through complicated surfaces, the multicopter simply adjusts the speed of its props to lean into the pilot’s chosen direction or to temporarily take advantage of the torque effect to make turns. By taking tilt readings from on-board gyroscopes (often called “6-axis gyro”) and directional readings from a compass, the computer can ensure that the right amount of thrust is applied by each rotor. Opposing rotors / The Complete Guide to Drones OPPOSING ROTORS In general, featuring an even number of rotors that rotate in opposing directions avoids the torque effect that would otherwise cause a multicopter to spin out of control. However, there are some exceptions to this rule, as shown later in the book. Hover / The Complete Guide to Drones HOVER A stable hover is achieved when the craft’s thrust is being directed downward. All things being equal, the props will be rotating at the same speed. Directional flight / The Complete Guide to Drones DIRECTIONAL FLIGHT Directional flight is achieved by pushing the craft forward. To begin movement, the copter will lean into the direction of travel and hold this angle to maintain forward momentum. Rotation / The Complete Guide to Drones ROTATION A multicopter can rotate around its central axis while hovering by increasing the speed of motors in the appropriate direction. From a user’s perspective you simply need to move the yaw control left or right. Buy from an Online Retailer US: —————————– Welcome to the world of drones! The Complete Guide to Drones will show you everything you could ever want to know about buying and flying your first drones. From getting to grips with the jargon you’ll need to speak to other flyers, to how you can design and build your own drone with advanced features like live video feedback and programmable autopilot. You’ll even learn how to read a sectional chart (that’s a pilot’s map-see, you’re learning already!) This book is your gateway to the fun (and the learning) that awaits, and it’ll keep you safe in the skies too. Adam Juniper has been flying drones and model helicopters for years, and enjoys nothing more than sharing those skills or the videos he captures. He is active in the community — his YouTube videos have been seen by thousands of fellow pilots. He has authored several books including My Story: Easy Digital Tools (9780762108893) and Photoshop Elements (9781904344230). He’s also worked as a book publisher and professional video producer (with a book on the subject to his name), and has written for numerous digital creativity magazine. Share article facebook twitter google pinterest If you have any comments on this article please contact us or get in touch via social media.