Development and Investigation of a Flapping Rotor for Micro Air Vehicles
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This thesis describes the concept, design and testing of a micro air vehicle rotor testbed capable of independently controlled blade rotation and powered blade flapping. The design, dubbed the "Flotor", combined the benefits of a conventional MAV helicopter rotor with avian based flapping motion. The Flotor was tested as a conventional rotor, a conventional rotor with powered blade flapping, and a torqueless, freely rotating rotor with powered blade flapping. As a conventional rotor with a maximum figure of merit of 0.5, the results from the Flotor were similar to previously published experiments. With conventional rotation plus powered blade flapping at up to 8 per rotor revolution at a reduced frequency of 0.6, the maximum thrust increased by up to 15% due to delayed stall. The torque required at moderate thrust levels was reduced by up to 30%. The results from a 2-D quasi-steady blade element momentum analysis predicted average rotor loads accurately below 20° collective. As the first attempt at a torqueless flapping MAV rotor, the Flotor was capable of producing thrust and blade loadings comparable to flying animals, but less than current MAVs.