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Bats fly with astounding agility, maneuverability and efficiency. Their flight mechanics are completely different from those of insects and birds and characterized by several unique aeromechanical features including: (1) complex three-dimensional articulated wing structures, (2) flexible wing skeletons, (3) anisotropic, highly elastic wing membrane skins and (4) a network of shear stress sensors distributed over the wing surface. Over the three years of this project we have developed new tools and experimental systems for the study of bat flight. We have documented and quantified key aspects of bat flight behavior and of the mechanical properties of bat wing materials, and investigated key aspects of how the construction of the bat wing enables superior flight performance. Key findings include quantification of the complex but highly intercorrelated motions of the many joints of the bat wing, and delineation of possible wing joint motion combinations that can reproduce full 3D complexity with a simplified control scheme, and description of the complex wakes formed by bats during flight.

MIT has developed the technology for micro-gas turbine generators. These are millimeter- to centimeter-size heat engines fabricated with semiconductor industry micromachining techniques (MEMS), ultimately capable of producing 10-100 W of power in less than a cubic centimeter. Applications include compact power sources offering energy and power densities an order of magnitude better than current battery technology; propulsion for small air vehicles; and a variety of microblowers, compressors, and heat pumps. The work was divided into 8 microscale disciplinary areas: (1) engine systems design, (2) turbomachinery fluid dynamics, (3) combustion, (4) structures, (5) bearings, (6) electromechanics, (7) silicon fabrication technology, and (8) microfabrication of high temperature materials and structures. Advances in the disciplinary technologies enabled the design and construction of a proof-of-principle 'demo engine'. This 20 mm square by 4 mm thick simple cycle gas turbine is designed to produce about 11 grams of thrust or 17 watts of shaft power. The design turbine inlet temperature is 1600 K and the rotational speed is 1.2M rpm. At the conclusion of this MURI, the first engines had been built and were just beginning testing. A companion microturbogenerator is a few months behind the gas turbine., Original contains color plates: All DTIC reproductions will be in black and white.