We present the results of experimental study of the influence of width of circular samples of wound organo- and carbon-plastics on the moduli of elasticity and stress limits. We reveal a significant dependence of the circular modulus of elasticity and stress limits on the width of circular sample and on the angle of reinforcement. We present the methods for studies of samples loaded by concentrated forces and forces distributed along the generatrix, by internal pressure, and by axial force. Our purpose is to determine the mechanical properties of wound composites.