Achieving atmospheric flight on Mars is challenging due to the low density of the Martian atmosphere. Aerodynamic forces are proportional to the atmospheric density, which limits the use of conventional aircraft designs on Mars. Here, we show using numerical simulations that a flapping wing robot can fly on Mars via bioinspired dynamic scaling. Trimmed, hovering flight is possible in a simulated Martian environment when dynamic similarity with insects on earth is achieved by preserving the relevant dimensionless parameters while scaling up the wings three to four times its normal size. The analysis is performed using a well-validated 2D Navier-Stokes equation solver, coupled to a 3D flight dynamics model to simulate free flight. The majority of power required is due to the inertia of the wing because of the ultra-low density. The inertial flap power can be substantially reduced through the use of a torsional spring. The minimum total power consumption is 188 W kg when the torsional spring is driven at its natural frequency.

Wing-wake interaction is a characteristic nonlinear flow feature that can enhance unsteady lift in flapping flight. However, the effects of wing-wake interaction on the flight dynamics of hover are inadequately understood. We use a well-validated 2D Navier-Stokes equation solver and a quasi-steady model to investigate the role of wing-wake interaction on the hover stability of a fruit fly scale flapping flyer. The Navier-Stokes equations capture wing-wake interaction, whereas the quasi-steady models do not. Both aerodynamic models are tightly coupled to a flight dynamic model, which includes the effects of wing mass. The flapping amplitude, stroke plane angle, and flapping offset angle are adjusted in free flight for various wing rotations to achieve hover equilibrium. We present stability results for 152 simulations which consider different kinematics involving the pitch amplitude and pitch axis as well as the duration and timing of pitch rotation. The stability of all studied motions was qualitatively similar, with an unstable oscillatory mode present in each case. Wing-wake interaction has a destabilizing effect on the longitudinal stability, which cannot be predicted by a quasi-steady model. Wing-wake interaction increases the tendency of the flapping flyer to pitch up in the presence of a horizontal velocity perturbation, which further destabilizes the unstable oscillatory mode of hovering flight dynamics.

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Traditional methods for grading and returning corrected homework to students do not require the student to determine how they erred, learn how to avoid repeat errors, or revise and improve their work. Educators know that multiple focused reviews of material are often required for learning analytically difficult material. Even when educators provide detailed feedback and corrections, many students look at the grade on a homework assignment without review and put it away until exam study time. The result is a missed opportunity for the student to more fully understand details they have yet to master, and the time the instructor spent making corrections is wasted.In the self-evaluation and revision method for student homework students complete their homework and submit an electronic copy. A solution is then given to students who mark and correct their work, give their original work a grade, and submit the self-evaluated and reviewed work. This system applies a direct principle for good undergraduate engineering practice: it provides prompt feedback and it also applies three indirect principles by developing cooperation among students, encouraging active learning, and communicating high expectations.The purpose of this study is to investigate the effect of the self-evaluation and revision homework system on student learning and attitude for three mechanical engineering courses at the United States Military Academy (USMA) at West Point, NY. A fourth-year course on vibration engineering across five semesters that has implemented the system over several years (n=49, 34, 37, 43, 16 students), a fourth-year course on control systems across a single year (n=34) and a third-year course on rigid body dynamics across one semester (n=38) are included in the study. The students in the courses were surveyed multiple times during the semester to determine if there had been any changes in their attitude toward the method within a semester and between courses.

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