Open Journal of Mechanical Engineering (OJME)2(1) (2017) 04-07 Cite the article: Sagar Mahalingappa Baligidad, Narendra Narayanaswamy, Narayanappa Krishnamurthy (2017). Bio-Inspired Bi- plane Flapping Wing MAV. Open Journal of Mechanical Engineering, 2(1) : 04-07. ARTICLE DETAILS Article History: ABSTRACT The research of micro aerial vehicles (MAVs) is a new field of low-Reynolds-number flow, which attracts much attention in the advanced aeronautical area. Micro air vehicles propelled by flapping wings are gaining interest for certain applications because flapping can provide more agility and maneuverability at low speeds. Flapping wings must deform in certain shapes to produce maximum lift and thrust. In the paper, we discuss an approach we used to design flapping wing Micro Air Vehicles (MAV), which replicating the flying patterns of birds. The development of MAV is complicated, and it involves light weight design, power transmission design, flight controls, low Reynolds number flight, energy supply etc. The main objective of this work is to build an ornithopter with very less wing loading which can be used for surveillance purposes. The weight factor plays an important role and wing loading needs to be as low as possible. An experimental approach adopting trials and error methods was used to fabrication. Finally, four wing MAV is designed for a wingspan of 28cm, total length of 175cm, weight of 14g and it involved a tail rotor for controlling the yawing movements. The prototype, then manufactured, assembled, performed several tests and achieved commendable flight. 1. INTRODUCTION In some insects, vortex is a head before the upstroke begins. Based on a study, another boost in lift occurs at the beginning of the upstroke as the wing passes through the wake of the downstroke [10]. Most insects clap and fling their wings that are rigid for light that generates more lift than conventional beating wings. It can be seen being used in nature by sparrows and some species of fly. Mechanically the clap and fling works by rapidly bringing two wings together beginning with the leading edge. Study showed the leading edges touch and flexible wings will follow in a phenomenon known as feathering [11]. As the wings come together air is pushed out the back-generating thrust, which when angled properly will create lift. Once the wings are together they immediately begin to peel apart allowing air to rush in from the front. This suction also creates thrust, pulling the wings forward. From an outside perspective the air is being circulated around the wings and creates lift. The wing is rapidly moving though air resulting in unsteady flow and vortices forming around the leading edge. These vortices will interact in ways not yet understood with the vortices coming off the edge of the wing creating additional lift. All of these phenomena together are illustrated in Figure 1. Motivated from this study, group decided to develop MAV of clap and fling type wing flapping, which is able to generate required lift than the conventional flapping and group designed a double crank flapping mechanism. This is simplified variant of the complex biological wing. The main objective of this work is to build a small flapping wing vehicle that possesses a wingspan of approximately 28cm and weighs approximately 13g. This vehicle should be capable of vertical takeoff and landing (VTOL) as well as high maneuverability for indoor and outdoor environments. BIO-INSPIRED BI-PLANE FLAPPING WING MAV Sagar Mahalingappa Baligidad 1* , Narendra Narayanaswamy 1 , Narayanappa Krishnamurthy 2 1 CMR Institute of Technology, Bengaluru-560037, India 2 Vijay Vittal Institute of Technology, Bengaluru-560077, India *Corresponding Author E-mail: sagmtech10@gmail.com Open Journal of Mechanical Engineering (OJME) DOI : http://doi.org/10.26480/ojme.01.2017.04.07 KEYWORDS Flapping wing Micro Air Vehicle (MAV), tail rotor, Ornithopter, wing loading etc. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ISSN: 2329-8243 (Print) ISSN: 2329-8235 (Online) CODEN : OJCEB4 Received 12 January 2017 Accepted 10 February 2017 Available online 15 March 2017 In recent years the development and research done on flapping wing Unmanned Micro Air Vehicle, have a wide range of applications like military, surveillance, search-and rescue, etc. But the development of flapping wing MAV has been lagging, due to the complexity of the design and the unsteady aerodynamic forces of flapping wing. Current research interest on developing miniature aerial vehicles (AVs) modeled on the aerodynamics of birds and insects. Many researchers launched AVs demonstrating forward flights have been developed like the Microbat and Delfly [1,2]. Flapping wing aerial vehicles have substantial advantages over traditional vehicles: low noise signature, high efficiency at smaller scales, low Reynolds’s number, survivable and robust. The analysis of flapping wing motions of natural fliers is crucial as they provide clues to design better flying machines at smaller scales [3]. The flapping patterns of flying creatures consist of a flap or stroke and rotation or twisting of the wing which can be divided into two types of flapping wing mechanisms: active and passive. An active mechanism is one in which wing rotation is generated by actively rotating the wing to generate an angle of attack during each stroke [4-8]. A passive mechanism uses aerodynamic drag and the flexibility of the wing to generate wing rotation [9]. MAV can be categories into: Ornithopter (bird-like flapping) and Entomopters (insect- like flapping). The ornithopter is capable of only flying forward whereas the entomopters is able to fly forward and hover as well. In case of birds, it is found that their wing roots and portions of the inner wing behaves like a fixed wing producing most of the lift for flight while the wingtips do the maximum work by flapping. In case of insects, during the down stroke the leading- edge vortex helps in producing lift and in some cases this vortex can spiral out towards the wingtips and in others it remains stationary.