GB2512020A

GB2512020A - A method of preventing the formation of ice on an aircraft

Info

Publication number: GB2512020A
Application number: GB1222315.2A
Authority: GB
Inventors: Russell Older
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2012-12-11
Filing date: 2012-12-11
Publication date: 2014-09-24
Also published as: GB201222315D0

Abstract

A system for preventing the formation of ice on an aircraft wing 1 includes an electrically heated metallic element 2. The wing leading edge is formed from a non-metallic fibre-reinforced composite material with a metallic mesh 2 embedded or bonded to it. The primary function of the mesh is to act to dissipate energy created in the event of a lightning strike. An electrical system 3 includes a power supply 4, wires 5 and connectors 6 for connection to the mesh. The system also includes multi-point power switching units 7 together with surge protection and fuses 8.

Description

A METHOD OF PREVENTING THE FORMATION OF ICE ON AN

AIRCRAFT

Introduction

The present invention relates to a method of preventing the formation of ice on an aircraft, particularly an aircraft wing. More specifically, it relates to a method of preventing the formation of ice on a non-metallic composite part ofan aircraft, such as a wing, which is provided with a metallic element for the purpose of protecting it from damage caused by lightening strikes. The invention also provides a system for rn preventing the formation of ice on such a wing and, to an aircraft equipped with such a system.

Background

Tt is known to provide an aircraft wing with a system to prevent the formation of ice.

is Typicafly, this has taken the form of bleeding hot air from the engines and pumping it onto the wing to warm it. However, this reduces engine efficiency.

It has more recently become common for aircraft wings to be formed from a fibre reinforced composite material, such as carbon-fibre. However, unlike a metallic wing, a fibre reinforced wing must be provided with protection against lightening strikes. This usually takes the form of some kind of metallic element that may be in the form of a mesh, such as expanded copper, bonded to the outside surface of the fibre composite or otherwise incorporated or embedded within the composite in order to create a Faraday cage that acts as a shield against lightening strikes.

The present invention seeks to provide an improved method and system for preventing the formation of ice on an aircraft wing that is formed from a composite material and which is already provided with a metallic element for the purposes of protecting it against lightening strikes.

Summary of the Invention

According to the invention, there is provided a method of preventing the formation of ice on part of an aircraft, such as a wing, that comprises a non-metallic composite body incorporating a metallic element that dissipates energy caused by a lightening strike, 3s the method including heating said element by supplying a current thereto to prevent ice formation. By heating the same element that is already incorporated into the aircraft wing and used to protect the aircraft wing against damage that would otherwise be caused by a lightening strikes, an extremely efficient and light weight solution to problem of ice formation is provided.

tn a preferred embodiment, the heating element is connected to a switched power source. For example, an engine driven generator may be provided. The power source is switched so that it will be operated only when necessary, i.e. when the temperature is such that ice formation on the wings may occur. The switching may be automatic, in the o sense that it will be activated when the temperature drops below a preselected temperature or, it may be operative only when triggered by a switch in the cockpit. Tt can be deactivated during flight, for example, when so that the metallic element will fulfil its function of protecting the wing against lightening strikes in the normal way.

The method preferab'y includes the step of connecting the element to a switched power source via a fused connection and/or a surge protector. This ensures that, in the event of a lightening stnke, the fuse will b'ow thereby preventing damage to the power source and other componentry. Several fuse connectors may be provided and may be arranged so that, in the event that one fuse blows following one or more lightening strikes, the ice 00 20 protection system will continue to operate via other fused connectors, i.e. one or more leve's of redundency will be incorporated into the system.

According to the invention, there is also provided a system for preventing the formation of ice on part of an aircraft, such as a wing, that comprises a non-metallic composite body having a metallic element bonded thereto to dissipate energy caused by a lightening strike, the system comprising a power source connected to said element, said power source being operable to supply a current to said element to heat it.

Prcfcrably, thc systcm also comprises a fuscd connector and/or surgc protector connecting the power source to said element. Multip'e fused connectors and/or surge protectors maybe provided as redundant back-ups in the event that a fuse b'ows or a surge protector is triggered, so that the system will remain operational and, the metallic element will continue to offer protection against lightening strikes.

tn a preferred embodiment, wires extend from the power source, the wires having connectors to connect them to said element.

The connectors may compris a tab having a s&der lining, the tab being folded around a portion of the element and heated to a temperature sufficient to melt the solder and secure it to the element. The tab maybe formed from the same metaflic material as the metallic element.

In a preferred embodiment, the metallic element is a mesh. Most preferaNy, it is an expanded copper foil.

jo According to the invention, there is also provided an aircraft incorporating the system according to the invention. The metallic mesh maybe incorporated or bonded into the wing of such an aircraft.

Brief Description of the Drawings

Figure lisa perspective view of a fibre reinforced leading edge of an aircraft wing with an embedded metallic element; Figure 2 is a perspective view of a tab and wire for connecting a power source to the metallic element shown in Figure 1; and Figure 3 is a diagram to show the redundant and surge protected electrical connection 00 20 between a power source and the metallic element.

Detailed Description of the Preferred Embodiments

Referring now to Figure 1 of the drawings, there is shown a leading edge of an aircraft wing 1 formed from a non-metallic fibre-reinforced composite material which is provided with a metallic mesh 2 embedded, bonded or otherwise attached to a portion of the wing i. The primaly function of the metallic mesh 2 is to act as a Faraday cage to conduct electricity from a lightening strike away thereby preventing localised damage to the composite structure.

An electrical system 3 is aho provided and includes a power supply 4 which is connected to the metaflic mesh 2 via wires 5 and connectors 6. To prevent a surge of electricity caused by a Ughtening strike flowing back into the system, the power supply 4 is connected to the metaflic mesh 2 via multi-point switching units 7 and a surge protection and fuse box 8.

To connect the metaflic mesh 2 to the electncal system 3, the connectors 6 may comprise a square or rectangular tab 9 (see Figure 2) that may be made from the same metallic material as the mesh 2 that is attached to the end of each wire 5. Each tab 9 can have a solder lining ioso that, once it has been folded over an edge of the metaflic mesh 2 and heated to melt the solder 10, a secure connection between the tab 9 and the mesh 2 is obtained.

The fuse and/or surge protection 8 is provided with redundancy by providing multiple switches that divert current flow away from fuses that have been damaged as a result of o a lightening strike. A redundancy system is shown in Figure 3. Tn normal operation, current wou'd flow in and across the metaflic mesh 2 so as to heat it up and prevent the build up of ice on the leading edge 1. In the event of a lightening strike, a large current would flow back down both the positive and negative wires. To prevent damage to the electrical system, inline fuses or surge protectors 8 would blow. To enable the system to continue to operate, multiple pairs of fuses and/or surge protectors are provided, together with means for switching between them in the event that one pair becomes damaged. As shown in Figure 3, there are three pairs of fuses na, rib, tic. Each pair of 00 switches ha, rib, hic is connected to the wires 5 via a switch a, 7b so that, in the event that one fuse blows, current can be re-routed via one of the remaining two fuses.

Although reference is made to an aircraft wing, it will be appreciated that this is taken to include within its scope wing leading and/or trailing edge devices, which may also be provided with a metallic element for the purposes of protection against lightening strike and ice build up. Other parts of an aircraft structure may also be protected from both lightening strike and ice formation in the same way.

Although reference is primarily made to a metallic element in the form of a mesh, it is also envisaged that the metallic element can also be formed as a result of applying an aluminium metal spray onto the wing or othcr composite part of the aircraft structurc to provide it with Ughtening protection. The principle would remain the same, except that the tab connector would not be required as it would be possible to solder directly on to the sprayed surface.

It will be appreciated that the foregoing description is given by way of example only and that modifications may be made to the support assembly of the present invention without departing from the scope of the appended claims.

Claims

Claims 1. A method of preventing the formation of ice on pare of an aircraft that comprises a non-metallic composite body incorporating a metallic element that dissipates energy caused by a lightening strike, the method including heating said element by supplying a current thereto to prevent ice formation.
2. A method according to claim 1, comprising the step of heating said element by connecting it to a switched power source.
3. A method according to claim 2, comprising the step of connecting the element to a switched power source via a fused connection and/or a surge protector.
4. A system for preventing the formation of ice on pait of an aircraft that comprises a non-metallic composite body having a metallic element bonded thereto to dissipate energy caused by a Ughtening strike, the system comprising a power source connected to said element, said power source being operable to supply a current to said element to generate heat.

00 20
5. A system according to claim 4, comprising a fused connector and/or surge protector connecting the power source to said element.
6. A system according to claim 5, comprising wires extending from the power source and connectors at the end of said wires to connect them to said element.
7. A system according to claim 6, wherein said connectors comprise a tab having a solder lining, the tab being folded around a portion of the element and heated to a temperature sufficient to mel the solder and secure it to the e'ement.
8. A system according to any of claims 4 to 7, wherein said metaflic element is a mesh.
9. A system according to claim 8, wherein said mesh is expanded copper foil.
10. An aircraft incorporating the system of any of claims 4 to 9.
11. An aircraft according to claim 10, wherein the metallic element is incorporated into an aircraft wing. aD