Case Study - IP8 Bleed Valve Duct, Exhaust Air Flow Reconfiguration


The Rolls Royce Trent 800 engine contains three bleed valve duct attenuators positioned at discrete angles round the intermediate pressure compressor.

The bleed valve duct has a dual function within the engine; initially to supply noise reduction and finally to vector the bleed efflux into the bypass duct.


Through sustained operation of the engine, it had been acknowledged that there was scope to further optimise the design of the component to improve its operational performance.

Therefore an extensive redesign of the IP8 bleed valve duct to moderate the effects of its exhaust air flow was employed, which consisted of several permutations to the functional configuration.


  • We proposed an alternative method of manufacture; this entailed CNC machining one of the major design characteristics contrasted against the current Laser Drilling process.
  • We were able to offer an internal manufacturing solution leading to cost savings, reduction in lead-time and improved metallurgical properties.
  • Extensive internal process trials were conducted with technical support from a dependable tooling specialist.
  • Further refinement and validation of the manufacturing method was completed.


By implementing the revised manufacturing method the following results were achieved:

  • Reduction of identified process lead-time by 48%
  • Identified process cost saving of 52%
  • Condensed delivery schedules through Concurrent Engineering for each redesign
  • Method of manufacture has proven very robust with no quality issues to date