Partial span inlet guide vane for cross-connected engines

Abstract

A pair of turbofan engines are cross connected such that during normal-mode operation horsepower can be shared by the respective cores, and when one engine core becomes inoperative the fan of that engine can be driven by the turbine of the operative engine to thereby maintain a substantial thrust output. In order to balance the respective thrust outputs, variable inlet guide vanes are controlled to decrease the fan mass flow in the operative engine and increase the fan mass flow in the inoperative engine. The variable inlet guide vanes are so constructed as to only partially span the fan duct so as to not appreciably affect the airflow to the core when the inlet guide vane angle setting is altered to allow the core to thereby retain a high level of supercharging during this operational period of maximum power demand.