This application is the U.S. national phase of International Application No. PCT/BR2017/000105 filed 1 Sep. 2017, which designated the U.S., the entire contents of which is hereby incorporated by reference.

FIELD

The embodiments disclosed herein relate generally to systems to provide noise abatement for retractable leading edge wing slats of an aircraft wing assembly when the slats are deployed.

BACKGROUND

The noise emitted from an aircraft during take-offs and landings is a significant issue contributing to urban noise pollution in large cities. The aerospace community has been committed since the 1960's to reduce noise levels of commercial aircraft. The maximum noise allowed for an aircraft is regulated by the type certification for the aircraft, for example, the regulations promulgated by PART36 of the Federal Aviation Administration (FAA). These regulatory requirements have imposed more restrictive levels of noise in more recent years.

The progressive introduction of larger and more energy efficient turbofan engines has significantly reduced aircraft engine noise. The non-propulsive part of the airplane (airframe) has however become a major source of noise, mainly during approach and landing phases of flight. One of the most relevant airframe noise source in current aircraft designs are the high-lift devices associated with the aircraft's wings, especially the leading edge devices, such as retractable leading edge wing slats.

There are some prior proposals in the art which are focused on reducing noise generated by leading edge slats, such as those provided by U.S. Pat. Nos. 6,454,219, 8,424,810 and 9,242,720, the entire contents of each being expressly incorporated hereinto by reference. While the proposals in the prior art may be satisfactory for their stated purpose, continual improvements to provide enhanced noise abatement characteristics to retractable leading edge wing slats are still sought.

It is towards providing such improvement to noise abatement characteristics for retractable leading edge wing slats that the embodiments disclosed herein are directed.

SUMMARY

In general, the embodiments disclosed herein relate to noise-abatement systems to provide noise abatement to a wing assembly provided with a forward edge slat when the edge slat is moved from a retracted condition to a deployed condition thereof. The noise-abatement systems will include an elongate shield element (which may have a convex curvature according to certain embodiments) which is unconnected but positionable adjacent to a lower trailing edge of the edge slat along a lengthwise extent thereof, and a support web having a distal end fixed to the shield element and a proximal end capable of fixation to an interior cove surface of the edge slat adjacent an upper trailing edge thereof. In response to movement of the edge slat between the deployed and retracted conditions thereof, the support web will therefore allow movement of the shield element towards and away from the lower trailing edge of the edge slat between an operative position wherein the shield element is positioned adjacent to the lower trailing edge of the edge slat along the lengthwise extent thereof and an inoperative position wherein the edge slat is spaced from the trailing edge of the edge slat and positioned in the cove region thereof, respectively. If desired or necessary (e.g., to reduce weight) a plurality of the webs spaced apart in the lengthwise direction of the lower trailing edge of the slat may be provided.

A spring element may be operatively associated with the web to exert a bias spring force onto the web to move the shield element into the operative position thereof. According to certain embodiments, the spring element is an S-shaped spring leaf element having one end fixed to the proximal end of the web and a distal end attachable to the interior surface of the cove region of the edge slat.

These and other aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.

