The low reliability of attitude measurement is due to nonlinear vibration of complex transmission system with multiple axes and meshed gears that are characteristics of unmanned helicopter. Therefore, by using a prototype unmanned helicopter with coaxial rotor and ducted fan configuration, a longitudinal and lateral adaptive control strategy without attitude feedback is proposed, which includes augmented control based on model reference adaptive decoupling control, acceleration control based on adaptive pole assignment and longitudinal and lateral displacement control based on dominant pole assignable PD control. Automatic flight by a planned route is achieved. Flight test results show that the cross-track error is small when the flight velocity of unmanned helicopter changes significantly. The proposed control strategy not only provides satisfied results but also useful insight about sensorless control of unmanned helicopter.