This paper presents a flight model for use in simulating computer generated helicopters. Momentum and energy balance is used to define a rotor thrust envelope. The four basic control inputs take the form of thrust components and the sideslip angle. Time integrations are performed for the three center of mass degrees of freedom only. Six degrees of freedom information is derived for the visual displays. The model can inexpensively function in real time and faster than real time. Validity is demonstrated by comparing model performance predictions with published data.