Variable area fan nozzle with drive system health monitoring

摘要

A nacelle for a turbofan engine includes a variable area fan nozzle (VAFN) and a proximity sensor that is attached to a nacelle forward portion to sense the presence of the VAFN when stowed. The proximity sensor is not attached to the VAFN, thereby enabling the use of a proximity sensor such as linear variable displacement transformer having a relatively compact operational stroke.

主权项

1. A method for monitoring a movable fan nozzle of a turbofan engine, the method comprising:
(a) during a first time period when the fan nozzle is in a stowed position relative to a movable sleeve of the turbofan engine and the movable sleeve is in a forward position relative to a nacelle forward portion of the turbofan engine, using a first proximity sensor to detect the presence of a first portion the fan nozzle, the first proximity sensor being attached to the nacelle forward portion and not attached to the fan nozzle; (b) actuating a fan nozzle drive system operationally coupled with the fan nozzle to move the fan nozzle relative to the sleeve from the stowed position to a deployed position; (c) actuating the fan nozzle drive system to return the fan nozzle from the deployed position to the stowed position; (d) actuating a sleeve drive system operationally coupled with the sleeve to move the sleeve and the fan nozzle relative to the nacelle forward portion, wherein the sleeve moves from a forward position to an aft position relative to the nacelle forward portion; (e) actuating the sleeve drive system to return the sleeve from the aft position to the forward position; (f) during a second time period subsequent to (c) and (e), using the first proximity sensor to detect the presence of the first portion of the fan nozzle; (g) supporting a first member of the first proximity sensor in a fixed position relative to the nacelle forward portion; (h) using motion of the fan nozzle relative to the nacelle forward portion to articulate a second member of the first proximity sensor relative to the first member only during a subset of a total range of relative motion between the fan nozzle and the nacelle forward portion, the subset being less than 25% of the total range of relative motion; and (i) generating a first signal indicative of a position of the second member relative to the first member.