Deployable Micro UAV
Christopher Jarrette workson Beaverwork’s 2009-2010 project, a UAV for the U.S. Air Force to use in calibrating ground based sensor systems’ antenna patterns.
The vehicle design problem for the second year increased the degree of difficulty. The requirement was to develop a small expendable UAV that could be deployed from a full-scale aircraft at 30,000 ft and autonomously fly a one-hour environmental monitoring mission. The preferred launch platform was a flare dispenser, which required the vehicle to fit into a 2 inch by 2.5 inch by 7 inch cartridge and be capable of tolerating 300g launch loads.
The course took a trajectory similar to its predecessor. In the first semester the students developed and evaluated concepts for vehicle deployment and for testing key performance issues, such as battery capacity in the cold temperatures at high altitude. Because there were no autopilots small enough to fitthe vehicle, working with Lincoln Laboratory and Aurora Flight Sciences, the students designed an autopilot board based on an Aurora design. Again, Lincoln Laboratory and Air Force reviewers participated in the design reviews, and a unique folding wing design was detailed by the end of the semester. During Independent Activities Period, the students built foam and balsa wood glider models. They encountered lateral stability problems, which they fixed by modifying the rear wing design. In the spring semester, the students built a double-size prototype of the aerodynamic configuration and flew it as a radio controlled model to confirm stability and handling qualities. This large-scale prototype allowed testing of autopilot control laws using an off-the-shelf autopilot while the miniature autopilot was in fabrication. The students then built molds, with which they constructed an actual scale prototype with a Kevlar fuselage and carbon wings. This was tested in AeroAstro’s Wright Brothers Wind Tunnel, where they uncovered aerodynamic issues associated with manufacturing tolerances for the very thin wing (laminar separation bubble); a new wing was designed that resolved the issue and yielded a vehicle lift to drag ratio over 10. As a parallel
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AEROASTRO 2011-2012