Retractable nozzle fairing system for aeroplane center boost engine

Abstract

A retractable/deployable nozzle fairing for use with a center boost engine on a jet propelled aircraft having the capability of aerodynamically fairing the center boost engine's exhaust nozzle and reducing the diameter of the empennage outlet when deployed so as to minimize the base drag characteristics of the empennage body structure when the center boost engine is shut down. More particularly, an exhaust nozzle retractable/deployable fairing for use with aircraft of the type commonly employing multiple main power plants and an auxiliary center boost engine of the type which is commonly used only: (i) during take-off; (ii) during air refueling operations, and/or (iii), under certain emergency operating conditions; and, wherein the retractable/deployable fairing member is formed of flexible sheet material that is fabricated into a truncated generally conical nozzle configuration--i.e., it is fabricated in the deployed condition constituting the 'zero stressed' state--having a parting line along the fairing keel line. Suitable actuators attached to the empennage body frames are provided for shifting the fairing member between its fully deployed truncated conical position (a 'zero stressed' state) and its fully retracted position in which the fairing parts along its keel line as it is moved into a retracted position surrounding the upper portion of the exhaust nozzle, at which point the retracted nozzle fairing is fully stressed. In use, when the fairing is retracted, it is expanded around the nozzle; and, when it is deployed, it is shifted rearwardly to form a truncated conical extension of the nozzle, thus reducing the diameter of the empennage outlet and, consequently, reducing the base drag characteristics of the empennage body structure.