Recent robotic research has led to different architectural approaches that support enactment of automatically synthesized discrete event controllers from user specifications over low-level continuous variable controllers. Simulation of these hybrid control approaches to robotics can be a useful validation tool for robot users and architecture designers, but presents the key challenge of working with discrete and continuous representations of the robot, its environment and its mission plans. In this work we address this challenge showcasing a unified DEVS-based hybrid simulation platform. We model and simulate the hybrid robotic software architecture of a fixed-wing UAV, including the full stack of controllers involved: discrete, hybrid and continuous. We validate the approach experimentally on a typical UAV mapping mission and show that with our unified approach we are able to achieve simulation speed-ups up to one order of magnitude above our previous Software In The Loop simulation setup.