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Installation Process Of Bonding Rivets On Cfc Structure Of Fighter Aircraft
Abstract: Fighter aircraft structure is a riveted assembly of no. of metallic and composite components. Electrical bonding is required between the joints of structure to make structure equipotential to avoid current passage and hence electric arc to avoid fire accident. CFC components are not good conductors and outer layer of the CFC component is not a conductor. And hence a special procedure is required where CFC components are joined with another CFC or metallic component. This invention is intended for the process of using bonding rivets on CFC structure joints of aircraft to achieve required electrical bonding for protection of aircraft against lightning and static charges.
Notices, Deadlines & Correspondence
Patent Information
Applicants
HINDUSTAN AERONAUTICS LIMITED
Inventors
1. SHRI. NAVEEN GAJULA
2. SHRI. S. SRINIVASARAO
3. SMT. HEMALATHA J
Specification
DESCRIPTION
TECHNICAL FIELD
The invention describes a process used to achieve required electrical bonding value (less than Olmilliohm) between the Metal to CFC and CFC to CFC structure riveted joints on aircraft in fuel and dry area to protect from lightning.
BACKGROUND OF INVENTION
All structure joints are to be electrically bonded on the aircraft to protect the aircraft from electrical charges developed and protect against lightning. Structure components (Metal & CFC) of the aircraft are usually anodized and/or are painted with epoxy primer to protect from corrosion. Anodic coating and epoxy primer on Metal components and Outer layer & epoxy primer on CFC components are resistant in nature to electrical current and hence direct joining/riveting of CFC to CFC or Metal to CFC will not give required bonding value. A procedure is required to prepare the surface of mating area of the structure component and use of bonding to get required electrical bonding.
SUMMARY OF INVENTION
Structure components to be joined (Metal to CFC and CFC to CFC) have to be prepared by removing existing anodic coating locally and using defined no. of bonding rivets along with conductive sealants to achieve electrical bonding between the joints.
PROCESS DETAIL DESCRIPTION
1. No. of bonding fasteners for Metal/CFC and CFC/CFC:
> Every fifth fastener should be a bonding rivet.
> However at any joint there should be mini mum of two bonding rivets.
> The bonding rivets should be de-anodised before installation.
2. Installation of Bonding fasteners:
In fuel region (Metal/CFC and CFC/CFC):
> After installation of other fasteners as per ADS 9.2, clean the bonding rivet installation area with MEK and remove the interfay sealant completely from the bonding fasteners holes.
> Dip the rivet in conductive sealant PR1764 Class-B and install.
In non-fuel region (Metal/CFC and CFC/CFC): ■
> After installation of other rivets, clean the rivet holes.
> Dry install the bonding rivets and protect with alochrome-1200.
> Protect the rivet with alchrome-1200 on metal to metal joint.
> Protect the rivet head in metal interface region with alchrome-1200 in case of metal to CFC joint.
We claim using of bonding rivets for CFC structural joints and their installation procedure on fighter aircrafts.
Documents
Application Documents
| # | Name | Date |
|---|---|---|
| 1 | 6822-CHE-2014 FORM-5 31-12-2014.pdf | 2014-12-31 |
| 2 | 6822-CHE-2014 FORM-3 31-12-2014.pdf | 2014-12-31 |
| 3 | 6822-CHE-2014 FORM-2 31-12-2014.pdf | 2014-12-31 |
| 4 | 6822-CHE-2014 FORM-1 31-12-2014.pdf | 2014-12-31 |
| 5 | 6822-CHE-2014 DESCRIPTION (COMPLETE) 31-12-2014.pdf | 2014-12-31 |
| 6 | 6822-CHE-2014 CORRESPONDENCE OTHERS 31-12-2014.pdf | 2014-12-31 |
| 7 | 6822-CHE-2014 CLAIMS 31-12-2014.pdf | 2014-12-31 |
| 8 | 6822-CHE-2014 ABSTRACT 31-12-2014.pdf | 2014-12-31 |