Model Reference Adaptive Control (MRAC) technique, which is considered to be an effective tool for the control of unknown dynamical systems behavior, is widely used in practical applications. In principal, a known stable linear model dynamics is taken as a reference model such that its response is tracked by the unknown dynamical system by means of an adaptive control scheme. In this paper, rather than using a linear reference model, we propose a nonlinear reference model to be used in the MRAC of nonlinear plant dynamics. First, a stable nonlinear reference model is formed by using State Dependent Riccati Equation (SDRE) approach. Then an adaptation rule is derived to ensure the convergence of the response of nonlinear plant dynamics to that of the nonlinear reference model. The proposed method is tested experimentally using a 3-DoF helicopter test bed with different parameters and working conditions.