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Aircraft
Published in Suzanne K. Kearns, Fundamentals of International Aviation, 2018
The heavier-than-air category, however, contains a more diverse collection of aircraft. These include: Aeroplanes – engine-powered, controlled, heavier-than-air machines that derive lift from fixed wings. An aeroplane is what people most often think of when they hear aircraft. Aeroplanes are also called fixed-wing aircraft, distinguishing them from helicopters with rotating wings. Aeroplanes can be configured with wheels to land on the ground (landplanes), with floats to land on water (seaplanes,) or with a combination of floats and wheels that allows them to operate in boThenvironments (amphibians).Rotorcraft – aircraft that have rotating (rotor) blades. Rotor blades can be thought of as spinning wings, with a teardrop cross-sectional shape. When they rotate, they produce a low-pressure area above the rotors resulting in lift. Helicopters incorporate an engine that powers the rotor blades, while gyroplanes have an unpowered rotor blade along with a powered propeller.Ornithopters – aircraft that flap their wings like a bird to achieve lift. These aircraft are mostly experimental and do not play a significant role in civil aviation.Gliders – unpowered aircraft that require assistance (such as from a tow aeroplane) to become airborne. Once airborne, gliders can take advantage of air currents to maintain and even gain altitude.
Aircraft
Published in Suzanne K. Kearns, Fundamentals of International Aviation, 2021
The heavier-than-air category, however, contains a more diverse collection of aircraft: Aeroplanes—engine-powered, controlled, heavier-than-air machines that derive lift from fixed wings. An aeroplane is what people most often think of when they hear aircraft. Aeroplanes are also called fixed-wing aircraft, distinguishing them from helicopters with rotating wings. Aeroplanes can be configured with wheels to land on the ground (landplanes), with floats to land on water (seaplanes), or with a combination of floats and wheels that allows them to operate in both environments (amphibians). Please note that aeroplane is the international spelling of the term, while airplane is the American spelling. To align with ICAO terminology, aeroplane is used within this textbook.Rotorcraft—aircraft that have rotating (rotor) blades. Rotor blades can be thought of as spinning wings, with a teardrop cross-sectional shape. When they rotate, they produce a low-pressure area above the rotors, resulting in lift. Helicopters incorporate an engine that powers the rotor blades, while gyroplanes have an unpowered rotor blade along with a powered propeller.Ornithopters—aircraft that flap their wings like a bird to achieve lift. These aircraft are mostly experimental and do not play a significant role in civil aviation.Gliders—unpowered aircraft that require assistance (such as from a tow aeroplane) to become airborne. Once airborne, gliders can take advantage of air currents to maintain and even gain altitude.
Development of the flapping wing for ornithopters: a numerical modelling
Published in International Journal of Ambient Energy, 2022
S. Mahendran, R. Asokan, Ashutosh Kumar, Vitika Ria, S. Jayadeep
Drones, also called unmanned aerial vehicles (UAVs), are aircrafts that can be either remotely piloted or completely autonomous. UAVs are slowly becoming part of our daily lives. While 20 years ago, they were almost exclusively used by the military, the recent technological advancements made them accessible even to the general public. Nowadays, UAVs are being used in many fields ranging from aerial photography to remote inspection and small drones can be found in hobby stores for less than 150 euro. Micro air vehicles (MAVs) have received significant attraction in the past few years. The application of these drones is meant for border patrol, search-and-rescue and surveillance because of the small size compared to UAV, it is easy to be used for the border performance. These MAV drones are basically categorised into four categories, i.e. fixed wings, flapping wings, rotary wings and vertical take-off and landing. These types of drones are controlled and their performance could be measured, whereas the presence of a human is impossible and more dangerous. MAVs have the ability to optimise and enhance the capability and endurance of the drones. Nowadays, there are so many types of drones that are integrated and used in a wide range of science. The flapping wing mechanism works on because of the conversion of the rotary motion of the motor into the reciprocating motion of the ornithopter. This mechanism is lightweight and simple. Due to the symmetrical wing motion, ornithopter flies straight. The four-bar mechanism is the most common mechanism used in the flapping wing. In the four-bar mechanism, the rotating crankshaft is driven by the motor, the connecting rod pushes the wing up and down. Fortunately, we can modify the mechanism for good stability. Staggered crank outboard wing hinge, dual cranks, transverse shaft are the design modification done for the flapping wing mechanism. MAVs and UAVs are mainly used for low altitude and monitoring of dangerous locations or mappings. Drones are sensitive in accordance with the atmosphere, so the design and the fabrication of drones should have been done accurately. The flapping wing consists of a flexible flapper and it accumulates a mechanism for its own flapping motion. Most of the flapping wings have flexible and light wings as in birds, i.e. flexibility and weight of the wings have an important role in their aerodynamics flow and the stability. Because the new and advanced technologies are used, it is difficult to make the conceptual design and their sizing process bears their total weight. Weight estimation is one of the most important challenges in the conceptual design in it. It is usually a class of UAVs restricted in size. DARPA is originally defined with an MAV as a microdrone of no more than 15 cm. The term, however, was started to be used more broadly and refers to smaller UAVs. Thus, the palm-sized UAVs are sometimes called nano-air vehicles. Most MAVs can perform hovering flight and operate indoors, although this is not a requirement. Their popularity over larger UAVs increases as they are easily portable, more discreet and less dangerous in case of a crash.