Combination primary and fan air thrust reversal control systems for long

Abstract

Combination primary and fan air thrust reversal control systems for long duct fan jet engines are disclosed. In one form, the system spoils and expands primary air and, then, allows the spoiled, expanded air to exit from the fan air duct exhaust nozzle while directing fan air in a thrust reversal direction out cascade vanes circumferentially located in the aft portion of the engine nacelle. In other forms, the system directs unequal pressure fan air and primary air through separate thrust reversal ducting and out cascade vanes circumferentially located in the engine nacelle. In equal pressure fan air and primary air systems, the air may be mixed in ducting prior to being emitted from common cascade vanes, or may be maintained separate prior to emission. In still other forms, the primary air is pre-exhausted through separate nozzles located in the primary duct wall, and a portion is then exhausted through the nacelle cascade vanes. In all systems, circumferential cascade vanes are radially located in the rear portion of the engine nacelle and are exposed by rearwardly translating the aft portion of the nacelle, which forms the fan air duct exhaust nozzle. As the fan air duct exhaust nozzle is translated rearwardly, fan air duct blocker doors and, depending on the system, primary air duct blocker doors are positioned to divert the jets for thrust reversing. As an alternative to a primary air duct blocker door, the primary air duct exhaust nozzle is translated rearwardly to contact the exhaust cone or plug and, thereby, valve off the primary air duct. In this case, the fan and primary exhaust nozzles are translated rearwardly as unit.