TRANSITION PHASE ANALYSIS OF A QUADCOPTER BIPLANE TAILSITTER UAV USING COMPUTATIONAL FLUID DYNAMICS Undergraduate Thesis Submitted as a Partial Fulfillment for the Degree of Sarjana Teknik from Institut Teknologi Bandung Author Wahyu Widhi Dyatmika 13618116 Advisors: 1. Ema Amalia, S.T., M.T. 2. Dr. Firman Hartono, S.T., M.T. UNDERGRADUATE PROGRAM IN AEROSPACE ENGINEERING FACULTY OF MECHANICAL AND AEROSPACE ENGINEERING INSTITUT TEKNOLOGI BANDUNG 2022 2 UNDERGRADUATE THESIS TRANSITION PHASE ANALYSIS OF A QUADCOPTER BIPLANE TAILSITTER UAV USING COMPUTATIONAL FLUID DYNAMICS By: Wahyu Widhi Dyatmika Student Number: 13618116 Bandung, 3 August 2022 Approving, Advisor 1 Advisor 2 Ema Amalia, S.T., M.T. NIP. 197410271998032001 Dr. Firman Hartono, S.T., M.T. NIP. 197703082008011008 3 ABSTRACT Several large corporations begin to use unmanned aerial vehicles (UAVs) to deliver items to their customers, especially for last-mile deliveries. UAV is preferred for last-mile cargo delivery because of its reachability and accessibility. Tailsitter is a novel UAV configuration that can be used for the last-mile delivery of cargo. This configuration enables the aircraft to land on its tail, take off in rotary-wing mode, and then switch to the fixed-wing mode for cruising. In the transition phase, in which the aircraft changes from fixed-wing to rotary-wing lets the aircraft into a stall condition. Thus, understanding the stall performance, as well as the propeller and wing interaction during stall, is critical for creating the optimum tailsitter design. However, the stall performance of an aircraft is difficult to obtain because of the unpredictability of the flow. In this research, the performance of a quadcopter biplane tailsitter during the transition phase is analyzed. Two different analysis is used for gathering data. First, the freestream and propeller rotational velocities are obtained in an analytical model using the force equilibrium equation.