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An oscillating aero-wing operating in pitch and plunge in the quasi-steady domain for lift and thrust generation is presented and analyzed. The model may serve as a reference of comparison for sustained forward propulsion of birds, insects and micro air vehicles. It turns out that the propulsive efficiency of the aero-wing cannot be maximized with respect to the Strouhal number since this number is fixed by the drag-to-lift requirements of an overall system. This is in contrast to the liftless propulsion by a hydro-wing in water. The remaining criteria for aero-propulsion are the minimization of the drag-to-lift ratios of the aero-wing and of the overall flight system. Some other current issues of aero-propulsion are discussed for model support and refinement.
aerodynamic propulsion, bio-aerodynamics, flow visualization, propulsive efficiency
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