Extremely large sweep amplitude enables high wing loading in giant hovering insects

Abstract

). These capabilities enable the beetle to produce enough lift force to stay airborne with its bulky body (4-10 g). In order to investigate how the sweep amplitude affects the beetle's flight efficiency, we utilized the unsteady blade element model to estimate the power requirements of the same vertical force production for various sweep amplitudes. The results indicate that the sweep amplitude as high as 190 deg is more beneficial for power requirements than the smaller amplitudes, which require higher frequencies resulting in higher inertial powers to produce the same vertical force. Thus, for this large beetle, high sweep amplitude may be a biological strategy for staying airborne. In addition, we thoroughly discussed the effects of input constraints on the outcome by investigating power loadings for variable sweep amplitudes at a constant vertical force, mean wing tip speed, and flapping frequency. Effect of wing surface area was also investigated and discussed to provide useful information for the development of an insect-inspired flapping-wing robot.