Full Vehicle Helios Model Performance Correlation with SB1 Defiant Flight Test

Full vehicle CREATE-AV™ Helios model has been developed for SB>1 Defiant®, a Joint-Multi-Role Technology Demonstrator (JMRTD) designed by the Sikorsky-Boeing team utilizing compound design with coaxial rotor and propulsor. The full vehicle model includes coupling with RCAS for elastic blade deformation as well as full vehicle trim in steady level flight condition. The purpose of current study is to assess performance prediction capability of the developed Helios modeling approach for such a complex non-traditional design by correlating with flight test data. To minimize uncertainty in flight test data reduction, correlations were made with the data that were directly measured or requiring minimal derivation. The Helios model showed generally very good correlation in power, component forces, rotor and propulsor efficiencies for wide range of flight test conditions. The model also showed very good correlation in performance sensitivity to trim state and rotor RPM, which demonstrates the modeling approach can be used to find optimal flight trim condition. Significance of geometric details and its aerodynamic interference such as shaft modeling has been demonstrated. Impact of measurement uncertainty to data correlation was also demonstrated.