One of the more daunting tasks of designing a multirotor unmanned aerial vehicle (UAV) is the selection of a propulsion system that will provide desired performance. Rigorous methods for selecting these drive components, that is, the motors, propellers, and batteries for electric UAVs are not readily available. Currently, many UAV designs are based on legacy selections or limited and at times incorrect manufacturer data. These design methods are either simplistic or lacking in analysis and validation of component selection. Proper propulsion system design should address the mission requirements for which the vehicle is being designed. A proper design methodology is the best chance that the designer has to create a new vehicle that will be mission-capable. This paper attempts to satisfy the need for more thorough method of propulsion component selection. The paper is written also to document the popular online drive system validation tool due to numerous requests. This tool is one example implementation of the methodologies described by this paper.