Study of Synchronized Multirotor Micro Air Vehicle Aerodynamics

Multi-rotor systems, such as coaxial and tandem rotors, can be regarded as a next-generation rotor system for full-scale helicopters as well as micro air vehicles (MAVs). Much research is being done to make them more efficient due to their widespread application from defense to drone delivery systems. Since the lower rotor operates in the wake of the upper rotor in both coaxial and tandem rotor configuration, its efficiency gets compromised. For such multi-rotor systems, synchronizing the rotor with a specific phase difference between them, such that the lower rotor gets minimally affected by the upper rotor wake, can lead to a more efficient design. A prescribed wake model was implemented to predict the performance of synchronized and non-synchronized coaxial and tandem rotors. The results show a noticeable effect on the overall performance due to the synchronization of the rotors, especially in the case of co-rotating coaxial arrangement. This has an important implication that synchronizing MAV rotors could be a key to better efficiency and compact design.