In this paper, we present the mechanical design and control system of a new indoor and outdoor Quad-Tilt-Wing flying robot. The proposed flying robot can achieve vertical takeoff, hovering, and long duration horizontal high-speed flight. All of these flight modes can be achieved by simply changing the angle of the rotors and wings by a tilt mechanism. We present the details on design and prototyping, the attitude control system, and experimental results, including wind-tunnel experiments, full flight tests, and performance tests. The experimental results show that our Quad-Tilt-Wing flying robot successfully achieves full conversion flight: vertical and rapid takeoff, high-speed cruise, and vertical landing. Performance test results show that during horizontal flight, the wings generate lift and effectively reduce energy use compared to a fixed quad rotor architecture. Consequently, the proposed platform combines unique features of multi-rotor and fixed wing systems to achieve long-duration flight with low-energy compared to a conventional multi-rotor UAV.