Elastomeric riblets

Abstract

An array of aerodynamic riblets incorporates a high elongation elastomeric layer having spaced tips and optionally a protective cladding. The elastomeric layer may be adhered to an aerodynamic surface directly or as an appliqué in combination with one or more of an adhesive layer, one or more supporting polymer layers and a metal foil layer.

Description

REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. patent application Ser. No. 12 / 566,927 entitled Elastomeric Riblets filed on Sep. 25, 2009 by inventors Diane C. Rawlings and Alan G. Burg, the disclosure of which is incorporated herein by reference. This application is copending with U.S. patent application Ser. No. 14 / 051,271 entitled Rigid Tipped Riblets filed on Oct. 10, 2013, U.S. patent application Ser. No. 14 / 070,183 entitled Amorphous Metal Riblets filed on Nov. 1, 2013 and U.S. patent application Ser. No. 14 / 105,027 entitled Shape Memory Riblets filed on Dec. 12, 2013, all having a common assignee with the present application, the disclosures of which are incorporated herein by reference.BACKGROUND INFORMATION[0002]1. Field[0003]Embodiments of the disclosure relate generally to the field of surface geometries for aerodynamic improvements to aircraft or surfaces having a flow interface and more particularly to embodiments and fabrication methods...

AI Technical Summary

Benefits of technology

[0011]In a further alternative methods for web processing, the complimentary tool is a roll-to-roll tool and a polymer layer, a metallic layer or a combination of polymer and metallic layers, such as an LSA, is deposited intermediate the adhesive layer and the elastomeric layer. A thin film coating or modification of the riblet exterior surface for decorative appearance and / or to provide electrical conductivity / resistance (to mitigate static charging), UV reflectivity or absorption (to improve long term durability in high solar / high altitude environments) and / or to reduce transport across the surface to improved oxidation and / or fluid resistance may be sputtered (or otherwise deposited) onto the complimentary tool prior to deposition of the high elongation elastomeric layer or deposited onto the high elongation elastomeric layer after removal from the complimentary tool. In modifications to these methods, ion implantation or chemical surface modification my be to form a layer or modified surface on the riblets.

Problems solved by technology

However in service use such as on an aircraft aerodynamic surface, polymers are relatively soft thus reducing the durability of the surface.

Existing solutions with polymeric tips may readily deform hundreds of percent with fingernail pressure and may be unrecoverable since the thermoplastic polymer (fluoropolymers such as THV or FEP for example) has “yielded” or the thermoset (structural epoxy for example) has fractured at relatively low strain.

Such structures may be undesirable in normal service use on an aircraft or other vehicle.

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