US Patent 9586683 Transitioning an unmanned aerial vehicle to horizontal flight

This disclosure describes a configuration of an unmanned aerial vehicle (UAV) that will facilitate extended flight duration. The UAV may have any number of lifting motors. For example, the UAV may include four lifting motors (also known as a quad-copter), eight lifting motors (octo-copter), etc. Likewise, to improve the efficiency of horizontal flight, the UAV also includes a thrusting motor and propeller assembly that is oriented at approximately ninety degrees to one or more of the lifting motors. When the UAV is moving horizontally, it may be determined if the horizontal airspeed of the UAV exceeds an airspeed threshold. If the horizontal airspeed exceeds the airspeed threshold, the thrusting motor may be engaged and the thrusting propeller will aid in the horizontal propulsion of the UAV.