RCAirDesign allows a builder to estimate important metrics relevant to the success or failure of a design or build project for model aviation. Measurements of weight and length can be entered in a mixture of units and easily translated to different units as desired. Two worksheets allow a specialized mixed-unit breakdown of components of an airplanes overall weight, and wing area by segments. The important metrics of wing loading, thrust to weight ratio, and power loading are instantly evaluated with the entered data. Entirely different sets of measurements can be saved, named, recalled and edited as different models. Users can set up a default model customized for their own needs.