Fiberglass is an alloy or mixture material as a composite material that has mild, easily formed, and inexpensive characteristic properties. In this study using a mechanical testing method that aims to determine the properties of the material in savonius windmill blades, the method of testing carried out in this study is tensile testing and impact testing on savonius windmill blades that are hand lay up. Based on the tensile test, the average tensile strength obtained by random fiberglass composite and woven roving 200gr 2 layers were 49.52 Mpa with an average modulus of elasticity of 21,88 Gpa. For the charphy impact test, the average impact strength is 0.035 joule / mm2 with absorbed energy of 0.7046 joule.