| dc.description.abstract | Small multirotor Unmanned Aerial Vehicles (UAVs) have the last decades become popular in many areas because of their simple design, low cost, and ease of use. Multirotor UAVs are simple to operate because of their Vertical Take-Off and Landing (VTOL) capacity and ability to hover in place. Because of this, a multirotor is often preferred, even though it has a very limited endurance compared to a fixed-wing UAV. A fixed-wing UAV takes advantage of the moving air to produce lift more efficiently than a multirotor UAV but cannot hover and requires a larger area for take-off and landing, increasing the complexity of the operation. Different fixed-wings designs with VTOL capacity have been developed. A traditional VTOL UAV combines the operating mode of a multirotor and a fixed-wing UAV and has to transition mid-flight between the different modes. Research also provides an alternative approach: the Lift-Augmented Quadcopter (LAQ), a multirotor UAV with a set of wings that provides partial lift during transit to reduce the motors’ workload and improve the UAV’s efficiency without transitioning to a fixed-wing operation mode. This thesis aimed to explore the LAQ as a UAV design and investigate if this design could be more beneficial than a traditional multirotor UAV in terms of flight efficiency. A theoretical analysis has been conducted, presenting a hypothesis that a LAQ could drastically reduce the power consumption compared to a quadcopter at certain speeds. A prototype was designed based on the configuration from the analysis, and a series of flight experiments were conducted. The flight experiments were used to evaluate the design and to compare the results with the theoretical analysis. Two different wing configurations were tested: a statically mounted wing fixed to the fuselage and an actuated wing with a fixed Angle Of Attack (AoA) relative to the airflow. Both wing configurations resulted in a power reduction of 50% compared to a traditional quadcopter, doubling the possible flight time at the most optimal flight speed of 8 m/s. The different wing configurations had advantages and disadvantages, affecting the aerodynamic properties of the UAV and having particular concerns that must be addressed when designing and building a LAQ. This thesis proposes different design considerations for further optimization of the LAQ for future research. | eng |