In 2001, BAE Systems and Thales were awarded the contract to develop and assess the technology required for a fourth generation electro-optic targeting system. This technical demonstrator programme (TDP), code named JOANNA â€“ JOint Airbourne NavigatioN and Attack â€“ aims to demonstrate the in-flight use of new techniques to allow laser targeting from greater stand-off ranges, and to reduce pilot workload
CTI and Lomond Castings (formerly Johnstone Castings) produced one-offs for the main structural casting components of the flying technology demonstrator. CTIâ€™s involvement included design support to aid castability, working closely with BAE Systems design engineers, and the production of three aluminium castings â€“ the Forward and Rear Outer Structures and the Outer Gimbal, to Class 1 Grade B.
The two parts of the outer structure, with an envelope of 0.5m x 0.5m x 1.2m each, were produced using CTIâ€™s PatternlessÂ® Process, and the third casting involved the use of a new rapid prototyping technology for sand moulds.
From BAE Systems CAD models of each part, CTIâ€™s design engineers modelled the gating and feeding systems required and generated the cutter paths for the machining of two large sand moulds for the Forward and Rear Outer Structures. Both parts were produced to Class 1 Grade B within a 10-week period.
For the Gimbal, CTIâ€™s engineers modelled the gating and feeding system, and the sand mould and cores were produced by the new rapid prototyping technology, which is now fully operational at CTI. The mould was assembled and poured, and the casting finished, heat treated, inspected and delivered to Class 1 Grade B, all within eight working days of CTI receiving the BAE Systems CAD file. Lomond Castings made two smaller components to Class 1 Grade C to complete the assembly.
CTI utilised the services of a number of local subcontractors for the finishing of the castings. Shot blasting was performed by Broadblast Ltd, non-destructive testing by NDT Ltd, heat treatment by Alloy Heat Treatment and tensile testing by Bodycote Ltd. All of these organisations are based in Sheffield, with the exception of the Dudley-based Alloy Heat Treatment.
Computer generated models of the three parts produced for the JOANNA project (l-r: Forward Outer Structure, Rear Outer Structure, Outer Gimbal)
Rear Outer Structure aluminium casting produced by CTIâ€™s PatternlessÂ® Process
Commenting on the project, Tom Little of BAE Systems said, â€œThanks to the capability of the technologies used and the experience and knowledge of their engineers, CTI, working closely with the BAE Systems design team, were able to support an extremely tight manufacturing timescale and produce acceptable â€˜flight worthyâ€™ castings on the first iteration, reducing both cost and lead-timeâ€.
With the successful development of this targeting system, BAE Systems envisage significant sales over the next 20 years, helping to secure the future of their highly skilled workforce.