초록 ▼

An aircraft turbine engine with a takeoff fan speed and a landing fan speed, the aircraft engine includes a fan duct with a HQ (Herschel-Quincke) acoustic control noise reduction tube. The acoustic control noise reduction tube contains a movable frequency tuner obstruction. The movable frequency tun

An aircraft turbine engine with a takeoff fan speed and a landing fan speed, the aircraft engine includes a fan duct with a HQ (Herschel-Quincke) acoustic control noise reduction tube. The acoustic control noise reduction tube contains a movable frequency tuner obstruction. The movable frequency tuner obstruction is movable within the acoustic control noise reduction tube, with the movable frequency tuner obstruction movable along a fixed tube path length between a first takeoff frequency obstruction tube path location, and a second landing frequency obstruction tube path location, with the frequency tuner obstruction positioned at the first takeoff frequency location with the takeoff speed, and the frequency tuner obstruction positioned at the second landing frequency location with the landing speed to reduce noise.

대표청구항 ▼

The invention claimed is: 1. An aircraft engine, said aircraft engine having a takeoff speed and a landing speed, said aircraft engine including a duct with at least a first acoustic control noise reduction tube, said tube having a tube path between a tube entrance end and a distal tube exit end, sa

The invention claimed is: 1. An aircraft engine, said aircraft engine having a takeoff speed and a landing speed, said aircraft engine including a duct with at least a first acoustic control noise reduction tube, said tube having a tube path between a tube entrance end and a distal tube exit end, said tube having a nonobstructive frequency fno, said tube containing a movable frequency tuner obstruction, said movable frequency tuner obstruction movable along said tube path between a first takeoff frequency obstruction tube path location with a first tube cross-section area, and an at least second landing frequency obstruction tube path location with a second tube cross-section area, said frequency tuner obstruction positioned at said first takeoff frequency location with said takeoff speed, said frequency tuner obstruction positioned at said second landing frequency location with said landing speed with said frequency tuner obstruction having a tuner obstruction cross-section area wherein said tuner obstruction cross-section area is no greater than 99% of said first tube cross-section area and said tuner obstruction cross-section area is no greater than 99% of said second tube cross-section area.