Effect of Different Design Parameters On Lift, Thrust and Drag of an Ornithopter

Research in the field of Flapping Wing Micro Air Vehicle (FMAV) is an ongoing quest to master the natural flyers by mechanical means. The field is characterized by unsteady aerodynamics, whose knowledge is still developing. Birds and insects have different methods of producing lift and thrust for hovering and forward flight. Most birds, however, cannot hover. Wing tips of birds follow simple paths in flight, whereas insects have very complicated wing tip paths, for hovering and forward flight, which vary with each species. FMAV based on avian flight is called ‘Ornithopter’ and that based on insect flight is known as ‘Entomopter’. The kinematics of real birds are difficult to be mimicked because of extreme complexities involved and weight limitation of an ornithopter. Simple flapping of wings with suitably chosen parameters, and overall light weight, can produce required lift and thrust. Thus most of the successful ornithopters are designed only with flapping mechanism having flexible membrane wings. The flexibility of the wings causes passive pitching movement during flapping which improves the performance. Flapping frequency, flapping amplitude, incidence angle, flexibility of wings and their geometry are the important design parameters for an ornithopter. In this paper Modified Strip Theory based on blade elemental analysis has been used to develop the aerodynamic model for semi-elliptical wing form. Parametric study has been carried out to show the effect of different parameters on lift, thrust and drag forces for better understanding of ornithopter flight.