In time of helicopter flight rotor blades produce significant vibration and noise as a result of variations in rotor blade aerodynamic loads with blade azimuth angle. For this reason future helicopters need to be improved with respect to environmental and public acceptance. The active twist control of helicopter rotor blades by an application of embedded piezo–composite actuators leads to significant vibration and noise reduction without the need for complex mechanisms in the rotating systems. For the design of a rotor blade with active twist, a new design methodology was developed. This methodology is based on the new 3D finite element model, planning of experiments and response surface technique to obtain high piezoelectric actuation forces and displacements with the minimal actuator weight and energy applied. To investigate an active twist of the helicopter rotor blade, the structural static analysis with thermal load using 3D finite element model was developed by finite element software ANSYS. An optimisation problem for the optimum placement of MFC actuators in the helicopter rotor blade was formulated based on the results of parametric study of the rotor blades with C– and D– spars in model scale and taking into account the producer’s requirements. Optimisation results were obtained for two rotor blades with C– and D– spars in model and full scales and with two possible applications of the MFC actuators. Results shows that D-spar is more effective than C-spar in terms of minimal distance between location of centre of gravity and elastic axis, but the obtained maximal torsion angles are practically the same for both rotor blades. Torsion angle obtained from the finite element simulation of helicopter rotor blades was successfully validated by experimental value to confirm the modelling accuracy. Design Tool was produced using the methodology developed for the optimum placement of actuators in the helicopter rotor blades. Designer can find compromise between necessary solutions using optimal results obtained or applying the developed Design Tool.