This paper deals with the fabrication, aerodynamic measurement, and performance evaluation of the corrugated wing patterns on a flapping wing micro air vehicle (FWMAV). The corrugated wing pattern is generally seen in insects. Insect wings with their corrugated topological features give themselves high load-bearing capacity during flapping and hovering. It is believed that appropriate corrugated structures on insect wings enhance aerodynamic performance. A new fabrication process using polydimethylsiloxane (PDMS)-molding and parylene coating was proposed and implemented for a 24 cm-span FWMAV, which is composed of corrugated wing inspired by the dragonfly wing. The fabrication includes the master wing template made by three-dimensional (3D) printing, the PDMS molding process for wing template duplication, and the final parylene coating to obtain corrugated wings. The parylene-C thickness was selected as 40 μm. For comparing the aerodynamic performance, two types of flapping wings were implemented on the FWMAVs: first with a pair of parylene corrugated wings and the other with polyethylene terephthalate (PET) flat membrane (without corrugation) wings. The lift signal was then measured by the load cell in a wind tunnel. Regarding the aerodynamic performance of flapping wings, a systematic performance estimation of finding the cruising conditions and the cruising lift for FWMAVs was investigated through the massive wind tunnel data. The parylene flapping wings with corrugation attained lift coefficients of 7.8-8.0, which the PET flat membrane wing cannot achieve so far.
Journal of Aeronautics, Astronautics and Aviation 53(1), p.83-94