Solar-powered drones are equipped with wings that possess typical characteristics of low wing loading

high flexibility

and high aspect ratio. As the main load-bearing structure of the wing

the wing spar has very strict requirements on its load capacity and weight. The key technical issues in the research of solar-powered drone spar structures were how to improve the load efficiency of the spar structure

achieve a comprehensive balance between load capacity and weight

and realize the integrated design and manufacturing of large-scale composite material spars. This paper proposes a fast structural configuration selection and optimization design method for the composite material spar design of solarpowered drones. This method determines the design parameters by calculating the load capacity of the spar cross-section

and considers the ply symmetry

strain constraint

and stability constraint at the same time. It can avoid building a fullscale finite element model and performing iterative calculations at the scheme stage

thus improving the  esign efficiency of the spar structure. Secondly

for the large-scale composite material tubular spar structure

a dedicated molding method is proposed

which realizes the integrated manufacturing of the spar and ensures the quality of the molded parts

providing a reference for the manufacturing process of similar large-scale composite material structures. Finally

a static test of a 2 m-scale tubular spar is carried out

and the strain results of the typical cross-section are within 10% error of the design results

verifying the applicability of this fast optimization design method.