This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
High Flushness Installation of Countersunk Fasteners
Technical Paper
2016-01-2109
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Aerospace structures are typically joined to form larger assemblies using screw lock or swage lock fasteners or rivets. Countersunk fasteners are used widely in the aerospace industry on flying surfaces to reduce excrescence drag and increase aircraft performance. These fasteners are typically installed to a nominal countersink value which leaves them flush to the surface before being locked into position.
The Northern Ireland Technology Centre (NITC) at Queen’s University Belfast has developed and demonstrated two processes which enable high tolerance flush fastening of countersunk fasteners:
- The ‘Flush Install’ process produces countersunk holes based on the specific geometry of each individual fastener;
- The ‘Fettle Flush’ process accurately machines fasteners to match the surrounding surface.
Flushness values well within the allowable tolerances have been demonstrated for both Flush Install and Fettle Flush processes. The Flush Install process uses a physics based, experimentally verified constant ‘ζ’ based on the material types and thickness of the stack being assembled. The Fettle Flush process uses a proprietary toolpath to ensure low machining forces, optimum flushness and excellent surface finish. Both processes were developed by the NITC to TRL4 before transferal to the Manufacturing Technology Centre (MTC) in Coventry for use within a TRL5 application, a Ground Based Demonstrator (GBD) wing at the MTC which further demonstrated the two processes.
Authors
Citation
Morgan, M., McClory, C., Higgins, C., Jin, Y. et al., "High Flushness Installation of Countersunk Fasteners," SAE Technical Paper 2016-01-2109, 2016, https://doi.org/10.4271/2016-01-2109.Also In
References
- Macrotrends LLC Crude Oil Price History http://www.macrotrends.net/1369/crude-oil-price-history-chart 2015
- RITA - Bureau of Transportation Statistics A Decade of Change in Fuel Prices and U.S. Domestic Passenger Aviation Operations U.S. Department of Transportation Report Washington 2012
- Aerospace & Engineering Tools (AET) Ltd. Microstop Countersink Cage Product Brochure UK 2016
- McToal , P. ALCAS wing box root end machining solution - a parallel kinematic approach Presentation at SAE International 2010 Aerospace Manufacturing and Automated Fastening Conference & Exhibition Wichita Kansas 2010