An analysis of maximum range cruise including wind effects

In this article the maximum range cruise is analyzed. Wind effects are included in the analysis, taking into account the variation of wind speed with altitude (crosswinds are ignored). The optimal control laws that lead to maximum range are analyzed (unconstrained case); constrained regimes (constant-altitude cruise or constant-Mach cruise) are also analyzed. The maximum range in the optimal regimes (unconstrained and constrained) is studied. The formulation is made for a general aircraft performance model (general drag polar and general specific fuel consumption model), and is particularized for simpler models in order to establish the precise range of validity of some published results. The effects of wind on the optimal control laws and on the maximum range are studied. The accuracy of the incompressible approximation is also studied. Results are presented for a model of a typical twin-engine, wide-body, transport aircraft.