This paper examines closed-loop dynamic soaring by small autonomous aircraft. Wind field estimation, trajectory planning, and path-following control are integrated into a system to enable dynamic soaring. The control architecture is described, performance of components of the architecture is assessed in Monte Carlo simulation, and the trajectory constraints imposed by existing hardware are described. Hardware in the loop simulation using a Piccolo SL autopilot module are used to examine the feasibility of dynamic soaring in the shear layer behind a ridge, and the limitations of the system are described. Results show that even with imperfect path following dynamic soaring is possible with currently existing hardware. The effect of turbulence is assessed through the addition of Dryden turbulence in the simulation environment.