@article{soltmann_hall_2017, title={Power-Required Flight Testing of Unmanned Aerial Systems Using Non-Steady-State Flight}, volume={54}, ISSN={["1533-3868"]}, DOI={10.2514/1.c033982}, abstractNote={Power-required flight testing has traditionally been done using the classic power independent of weight, velocity independent of weight method. This method is well suited for manned aircraft but has some shortcomings when applied to unmanned systems that are remotely piloted and/or operating on small test ranges. Maximum-likelihood estimation was used to identify the lift and drag models of two test aircraft using data acquired through acceleration and deceleration runs. The calculated power-required data were reduced using the classic technique to remove weight and air density effects. Flight-test data were collected using a Raspberry Pi single-board computer because of its low cost, weight, and good performance. Data points using the classic flight-test method were also collected for comparison against the dynamic method. Because of the small test range used, a third of all points collected using the classic method had to be eliminated because of assumption violations. The flight-test results show good ...}, number={3}, journal={JOURNAL OF AIRCRAFT}, author={Soltmann, Lars M. and Hall, Charles E., Jr.}, year={2017}, month={May}, pages={1162–1171} }
 @article{heinzen_hall_gopalarathnam_2015, title={Development and Testing of a Passive Variable-Pitch Propeller}, volume={52}, ISSN={0021-8669 1533-3868}, url={http://dx.doi.org/10.2514/1.C032595}, DOI={10.2514/1.c032595}, abstractNote={A novel approach to passive propeller blade pitch variation is investigated. To effect passive pitch changes, the propeller blades are allowed to pivot freely about a radial axis, and aerodynamic pitching moments are tailored to give favorable blade pitch angles over a wide range of advance ratios. Computational modeling of the system indicated that a large expansion of the efficient operating envelope is possible, compared to a fixed-pitch propeller. Wind-tunnel experiments corroborated the computational results and demonstrated that the propeller maintained near-peak efficiency by passively adjusting blade pitch angles by over 15 deg to the match changing advance ratio. The passive variable-pitch propeller was then successfully demonstrated in flight on an unmanned aerial vehicle. Using tailored aerodynamics in place of active control allows this performance improvement to be realized at a fraction of the weight and complexity of a traditionally actuated variable-pitch propeller. The concept enables the...}, number={3}, journal={Journal of Aircraft}, publisher={American Institute of Aeronautics and Astronautics (AIAA)}, author={Heinzen, Stearns B. and Hall, Charles E., Jr. and Gopalarathnam, Ashok}, year={2015}, month={May}, pages={748–763} }
 @article{southwell_hall_burke_2013, title={Correlation of population density to designated urban areas}, volume={10}, number={1}, journal={Journal of Aerospace Information Systems}, author={Southwell, J. T. and Hall, C. E. and Burke, D. A.}, year={2013}, pages={40–46} }
 @article{burke_hall_cook_2011, title={System-Level Airworthiness Tool}, volume={48}, ISSN={["0021-8669"]}, DOI={10.2514/1.c031022}, abstractNote={One of the pillars of aviation safety is assuring sound engineering practices through airworthiness certification. As unmanned aircraft systems grow in popularity, the need for airworthiness standards and verification methods tailored for unmanned aircraft systems becomes critical.While airworthiness practices for large unmanned aircraft systemsmay be similar to manned aircraft, it is clear that small unmanned aircraft systems require a paradigm shift from the airworthiness practices of manned aircraft. Although small in comparison with manned aircraft these aircraft are not merely remote-controlled toys. Small unmanned aircraft systems may be complex aircraft flying in the national airspace system over populated areas for extended durations and beyond line of sight of the operators. A comprehensive systems engineering framework for certifying small unmanned aircraft systems at the system level is needed. This work presents a point-based tool that evaluates small unmanned aircraft systems by rewarding good engineering practices in design, analysis, and testing. The requirements scale with vehicle size and operational area, while allowing flexibility for new technologies and unique configurations.}, number={3}, journal={JOURNAL OF AIRCRAFT}, author={Burke, David A. and Hall, Charles E., Jr. and Cook, Stephen P.}, year={2011}, pages={777–785} }
 @article{cox_gopalarathnam_hall_2010, title={Flight Test of Stable Automated Cruise Flap for an Adaptive Wing Aircraft}, volume={47}, ISSN={0021-8669 1533-3868}, url={http://dx.doi.org/10.2514/1.46789}, DOI={10.2514/1.46789}, abstractNote={0p-optimization function was effective in producing pressure differentials that would have reduced drag. The effectivenessoftheC 0 p-maintenancefunctioncouldnotbedeterminedbecauseoflargesample-to-samplevariations in measured C 0 p values. It remains unknown whether this high-frequency content actually represented rapidly varying pressures on the airfoil surface or if it was the result of noise in the measurement system.}, number={4}, journal={Journal of Aircraft}, publisher={American Institute of Aeronautics and Astronautics (AIAA)}, author={Cox, Craig and Gopalarathnam, Ashok and Hall, Charles E., Jr.}, year={2010}, month={Jul}, pages={1178–1188} }
 @article{cox_gopalarathnam_hall_2009, title={Development of Stable Automated Cruise Flap for an Aircraft with Adaptive Wing}, volume={46}, ISSN={0021-8669 1533-3868}, url={http://dx.doi.org/10.2514/1.38684}, DOI={10.2514/1.38684}, abstractNote={Cruise flaps are devices designed to minimize drag, and previous research has explored using a wing-based pressure differential to automate them. Different presentations of the pressure-differential data tend to lead to the development of different types of controllers for automated cruise flaps. A presentation used by previous researchers led to an unstable drag-minimizing controller, whereas a presentation used in this research leads to a stable controller that implements multiple functions. Techniques previously used for high Reynolds number natural-laminar-flow airfoils are modified for use with the low Reynolds number SD7037 planned for future flight testing. The results of rigid-aircraft simulations are presented, showing the effectiveness of the multifunction controller, which is able to simultaneously reduce drag and alleviate the effects of vertical gusts.}, number={1}, journal={Journal of Aircraft}, publisher={American Institute of Aeronautics and Astronautics (AIAA)}, author={Cox, Craig and Gopalarathnam, Ashok and Hall, Charles E., Jr.}, year={2009}, month={Jan}, pages={301–311} }