**2.2 An optimal main helicopter rotor projection model obtained by viscous effects and unsteady lift simulation**

This subchapter presents a model of airfoil which allows obtaining a method for optimal main helicopter rotor projection by viscous effect and unsteady lift simulation through algorithm and set of program entireties, applicable to ideological and main project of helicopter rotor. Numerical analysis considerations in this paper can be applied, on basis of a real rotors theoretical consideration, with sufficient accuracy in analysis and constructive realizations of helicopter rotor in real conditions. The method for unsteady viscous flow simulations by inviscid techniques is developed. This allows the to define such optimal conception model of aerodynamic rotor projection which is corresponding to rotor behavior in real condition and with sufficiently quality from the aspect of engineer use.
