The simplified performance analysis and initial configuration design are required for the successful development of UAV during the conceptual design, in which empirical formulas and trend equations are utilized for the UAV performance analysis. In the conceptual design phase various UAV configurations may be considered, however, it is very inefficient and unnecessary to consider all configurations for the conceptual design. In this study, the database for the fixed wing UAVs whose MTOW is between 50kg and 1,500kg was also constructed for the selection of configuration frequently used. The parametric analyses were performed for major performance parameters, and trend equations were developed through regression analyses for these individual performance parameters.