This paper describes 5-axis centralized feedback control system for a single-rotor helicopter. Optimal control theory is directly applied to 25-state Multiple-Input Multiple-Output (MIMO) analytical linear model of a small-scale unmanned helicopter without decoupling the motion dynamics. The linear Kalman filter is also designed for an estimation of the blade flapping and lagging angl... https://yeswellneses.shop/product-category/dedorant/