Tiltrotor aircraft has a tilting proprotor at the tip of wing.The analytical model of dynamic stability for tiltrotor aircraft in forward flight in this paper consists of a cantilever wing and a rotor.The wing withstands vertical bending

chordwise bending and torsional deformations

and the rotor blade is considered to be capable of rigidly withstanding one order flap and lag motions.The aerodynamic loads are gained by quasi-steady flow and thin wing theory.Using the model

the differential equations of motion have been formulated under the condition of high inflow

making it possible to analyze the dynamic stability of tiltrotor aircraft in forward flight.The numerical results are basically consistent with the experimental results obtained by the Bell Helicopter Company

showing that the analytical model is suitable for analyzing the dynamic stability of tiltrotor aircraft in forward flight.