This paper studies an effective lag damping prediction method for a fl
exible flap-lag-torsional hingeless rotor model and correlation with t
he experimental data for a four-bladed rotor. The ONERA dynamic stall
models of lift, drag, and pitching moment for each aerodynamic airfoil
element and an advanced three-dimensional finite state wake model are
used. The nonlinear equations of motion are represented in terms of s
tate variables with 4 x 10 structural state variables. Eight aerodynam
ic elements for each rotor blade and at least eight wake harmonics are
employed, The aerodynamic and wake state variables are 4 x 48 and 45,
respectively. A numerical simulation technique is applied to determin
e the transient response of the hingeless rotor model and to predict t
he lag damping. Numerical investigations indicate that the present the
oretical/numerical method improves the correlation of the theoretical
and experimental results compared to an earlier eigenvalue, perturbati
on analysis.