Research And Optimization Of Aerodynamic Characteristics Of A Tandem Twin-rotor Unmanned Helicopte

In recent years,with the increasing frequency and complexity of natural disasters,higher requirements have been put forward in the field of emergency rescue equipment.Unmanned aerial vehicles have gradually become a new research hotspot in this field due to their strong maneuverability and high flexibility.Due to the technical shortcomings of single functionality,weak load capacity,and poor reliability of existing drone platforms,there is an urgent need for drone platforms with long endurance,high takeoff weight and load capacity,and high reliability.Compared with traditional single rotor drones,tandem drones have greater payload capacity,higher hovering efficiency,and a wider range of allowable center of gravity changes,making them more suitable for large-scale flight missions and long-distance voyages.This article proposes a new type of tandem unmanned helicopter scheme based on the aerodynamic and structural characteristics of existing tandem helicopters,relying on the project,and conducts research on related aerodynamic characteristics.Firstly,based on the existing model parameters and characteristics,the overall parameters of the designed model in this paper were determined by the aerodynamic interference between the two rotors,and the rationality of the relevant parameters was verified.Subsequently,in response to the aerodynamic interference characteristics of twin rotors,the momentum source method was used to analyze the aerodynamic interference characteristics of rotors.The influence of changing the longitudinal and axial spacing of the two rotors on aerodynamic performance was studied.In response to the designed fuselage structure in the project,the aerodynamic shape was designed and its aerodynamic characteristics were analyzed.Drag reduction optimization design was carried out in areas with high pressure gradient,effectively reducing the drag coefficient of the fuselage.A flight dynamics model of the designed aircraft model was established based on the control characteristics of the tandem unmanned aerial vehicle.The aerodynamic interference between the two rotors was simulated by taking into account the inflow ratio of the rotor.Finally,the trim calculation was completed through the equilibrium state equation of the aircraft body.In response to the aerodynamic interference between the rotor and the fuselage,numerical simulations were conducted on the rotor/fuselage flow field under trim conditions using trim values provided by the flight dynamics model.