Formation Flight for Aerodynamic Benefit Simulation Development and Validation

The Air Force Research Lab and DARPA have been investigating the challenges and opportunities associated with flying aircraft in formation for aerodynamic benefit. Under the Surfing Aircraft Vortices for Energy (SAVE) concept, aircraft are flown autonomously at longitudinal separations of 3000-8000ft at offsets from the wake sufficient to obtain significant aerodynamic benefit. A baseline C-17 simulation is updated to include the dynamics and the aerodynamic effects of a lead aircraft wake on a trailing aircraft. Details of the wake dynamic and aerodynamic models are provided, including how CFD based models are integrated into a real-time simulation. Flight test data analysis is conducted to extract the actual aerodynamic influences and the results are compared to the CFD based models. The simulation models are updated based on the flight test data and the final results are compared to flight test maneuvers and flight test derived fuel burn measurements.