Abstract:A detailed investigation including a low-speed flow study is presented on the development of ultra-light dragonfly mimetic flying robots with a focus on the dragonfly's remarkable gliding capability. It is revealed that the dragonfly's corrugated wing structure and cruciform configuration provide superior flying characteristics for fixed wing robots in low Reynolds number flight. It was also found that the dragonfly configuration has additional merit in its compatibility with propellers or high lift devices. This combination with such classic aero-engineering makes possible robots with broader flight envelope than conventional fixed-wing flying robots.

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Electroacoustical constants (, , and dij) of calcium aluminate silicate Ca2Al2SiO7 piezoelectric single crystals, which have the tetragonal structure with the point group , were evaluated. The normalized first-order temperature coefficients of all the constants were determined between −30 and 120 °C at 10 kHz frequency, e.g., for and were 69.3 and 87.6, and for d14 and d36 were −338.4 and 552.4 ppm/°C, respectively. The Rayleigh surface acoustic wave (SAW) velocities for the fundamental X- and Z-cuts of the crystals were theoretically calculated. The results were supported by the SAW velocities measured for the Z-cut of the crystal, proving the accuracy of the electroacoustic constants determined in this study.

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