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Natural Laminar Flow Solution for the Interface between SA HTP Leading Edge and Torsion Box

IP.com Disclosure Number: IPCOM000248192D
Publication Date: 2016-Nov-07
Document File: 6 page(s) / 430K

Publishing Venue

The IP.com Prior Art Database

Abstract

Natural Laminar Flow HTP project provides a promising Single Aisle HTP surface modification that reduces the total drag during the flight by using an optimum aerodynamic surface. Such solution requires a structural and manufacturing modification of the current HTP, since gaps and protuberances are not allowed. As a consequence, the LE/Box interface screw heads must be covered by a GFRP cover. After analyzing several solutions, the preferred one consists of a local Leading Edge flange thickness reduction while maintaining structural performance, achieved by embedding a Titanium sheet into the LE flange's composite laminate

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Natural Laminar Flow Solution for the Interface between SA HTP Leading Edge and Torsion Box

October 2016

Natural Laminar Flow Solution for the Interface between SA HTP Leading Edge and Torsion Box


1. Technical field and domain for the Defensive Publication

This Defensive Publication belongs to the technical fields and domains presented in

Table 1:

Technical Field

Technical Domains

2. Abstract

Natural Laminar Flow HTP project provides a promising Single Aisle HTP surface modification that reduces the total drag during the flight by using an optimum aerodynamic surface. Such solution requires a structural and manufacturing modification of the current HTP, since gaps and protuberances are not allowed. As a consequence, the LE/Box interface screw heads must be covered by a GFRP cover. After analyzing several solutions, the preferred one consists of a local Leading Edge flange thickness reduction while maintaining structural performance, achieved by embedding a Titanium sheet into the LE flange's composite laminate. See Figure 1.

GFRP Cover

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DEFENSIVE PUBLICATION

Group

OPD-A/C DESIGN & COMPONENT INTEGRATION (Overall Physical Design)

Domain Empennage / Wing

Subdomain A320 Horizontal Tail Plane Leading Edge

Structures

Table 1. Technical field and domains for the invention

Embedded Titanium Sheet

Figure 1. Embedded Titanium Schema

1


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Natural Laminar Flow Solution for the Interface between SA HTP Leading Edge and Torsion Box

October 2016


3. Location and context

Generalities

Leading Edges of Single Aisle HTP Aircraft lifting surfaces with Natural Laminar Flow requirements constitute a key development for the future years.

Laminar Flow reduces friction drag and implementation on HTP would potentially lead to up to 2% of A/C Friction drag reduction. See Figure 2.

Figure 2. Components contribution to friction drag

Single Aisle HTP/VTP Natural Laminar Flow

Close to the aircraft skin, the flow is, in most of the cases, turbulent due to several aspects:


a) Laminar Flow is unstable with respect to small perturbations.

b) Surface imperfections may cause early transition to turbulence.

The current existing methods to reach laminarity are Natural Laminar Flow and Laminar Flow Control. This Defensive Publication focuses on the first one. Natural Laminar Flow (NLF) is obtained by a profile that produces a progressive pressure drop (for example: favourable gradient) resulting in flow acceleration and a delay in transition to approximately the point of minimum pressure.

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DEFENSIVE PUBLICATION

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Natural Laminar Flow Solution for the Interface between SA HTP Leading Edge and Torsion Box

October 2016

For Single Aisle HTP Leading Edge Natural Laminar Flow environment, four main topics (Figure 3) must be taken into account:

1. Anti-erosion plate bonded on top of theoretical aerodynamic profile results in a...