Within a concept study it is important to be able to evaluate different concepts in early phases. The primary purpose with the project concept studies (KoKoS) is to develop the ability to evaluate concepts for airborne vehicles, mainly for performance and stealth properties. This work describes a framework for flight mechanical concept evaluation. The model is primarily used to study airborne vehicles such as missiles, aircraft and unmanned vehicles. The model is implemented in MATLAB/Simulink. A supersonic missile has been implemented to validate the tool. With this approach, implementation and simulation of different concepts are relatively simple and fast.