Small-scale Aeroelastic Rotor Simulation, Design and Fabrication

Abstract

Efficient, small-scale fixed-pitch rotor blades are essential for miniature rotorcraft. Extremely thin blade sections are required for highly efficient rotor performance that leads to acceptable mission endurance. Such rotor blades are difficult to manufacture from sufficiently rigid material to avoid significant torsional deformation in operating conditions. In practice, it is necessary to trade-off manufacturing simplicity and mechanical rigidity of a blade design against aerodynamic performance. This paper presents a design methodology for this problem, based on development of a simulator for steady-state rotor performance along with a search algorithm to find the ideal taper and twist geometry for a specified motor torque. The approach is demonstrated on the design of rotors for a small scale quad-rotor unmanned aerial vehicle under development at the Australian National University. Experimental thrust tests indicate good correspondence with theoretical predications. Nomenclature A Rotor disc area, m2 AoA Angle of Attack, rad c Blade chord, m cd Non-dimensional drag coefficient cl Non-dimensional lift coefficient cm Non-dimensional moment coefficient