초록
An ultra light quad-rotor is utilized in various areas for military and commercial purpose. Especially, the airframe shape is designed with various airframe size, weight and purpose. In this paper, the initial airframe shape of the quad-rotor was designed and manufactured. Flight test was conducted for the quad-rotor. The design modification of airframe shape was conducted to meet design requirement. By changing design, weight of airframe structure was reduced and payloads were placed to the best position. By reinforcing ribs and reducing vehicle's legs, the durability of airframe structure was enhanced.