A method has been developed to predict the performance of small multirotor vehicles. Using the vehicle geometry, rotor geometry and flight conditions as inputs, the aerodynamic performance is found through an interpolation method using tabulated rotor performance data. The model is able to predict performance in hover and forward flight, and can produce results quickly and easily, making the prediction model a powerful tool. The vehicle performance prediction model also includes a wake interference model that captures the effect of rotors and their shed wakes on others rotors in the vicinity. When compared to flight test data, the method shows good agreement when predicting the angle of attack, rotational velocity and power requirements of the vehicle. The effect of the vehicle orientation on the performance of the vehicle was investigated showing that during fast forward flight, the vehicle requires about 5%
less power in a diamond configuration than in a square configuration.