This paper proposes and implements a new single-phase magnetless flux switching machine (FSM) for rooftop wind power generation. The key is to integrate an outer-rotor FSM and an inner-rotor FSM with shared stator yoke and stator drum windings. In such a way, this proposed machine can not only realize flux switching function to regulate magnetic flux effectively, but also incorporate the field and armature windings within one stator to reduce the copper losses and improve the overall machine efficiency. Meanwhile, the structure is compact and rotors can be directly driven by blades to capture the wind power. The machine design guidelines from both magnetic and electric aspects are illustrated, the machine characteristics are analyzed by using time-stepping finite-element method, and the system performances are evaluated based on mathematical modeling. Both simulation and prototyping test are conducted to verify the validity of the proposed machine and system.