Estimation of Vehicle-Level Fuel Burn Benefits of Aircraft Formation Flight

摘要

The present paper investigates the overall aircraft-level impact of formation flight in terms of total drag savings and fuel consumption reductions. The current work is carried out on the basis of an in-house multidisciplinary integrated conceptual aircraft design optimization framework. An aerodynamic method based on potential flow theory is first adapted for the induced drag estimation of aircraft in formation flight. By integrating the formation flight aerodynamic methodology into the in-house aircraft design and optimization platform, the potential drag reduction for arbitrary aircraft configurations in formation can be assessed. For specific flight missions, the fuel burn reduction can be further determined. Through comparing with other simulation and experimental results, the proposed formation flight aerodynamic methods in the present work show very good agreement. A case study on two medium-range passenger aircraft indicates that the trailing aircraft could achieve up to 60% induced drag reduction with optimal longitudinal, lateral, and vertical aircraft separations within formation. The fuel burn savings of the trailing aircraft are calculated to be up to 16% for specific payload and flight range combinations. A reserve fuel study shows that around 2% fuel burn savings would be eroded due to conservative fuel planning in formation flight.