Cobham partnership
Reaching the fifth anniversary in 2009, the environmental test partnership between TRaC and Cobham plc's Flight Refuelling Ltd, has proven to be a remarkable success for both parties, and has become TRaC’s benchmark for excellence in environmental test partnerships. Based on a truly collaborative approach, with TRaC adding more value to Cobham’s development and verification processes, the net benefits of this partnership have yielded annual savings in excess of 25% on vibration and shock testing.
Cobham's Dorset facility is the market leader for air refuelling, providing innovative fourth generation solutions to defence customers around the world. With a heritage in air refuelling spanning 70 years and over 1,000 systems delivered to date, Cobham provides a nose to tail refuelling capability, encompassing state of the art refuelling systems and integration. Specialising in wingtip to wingtip solutions, Cobham offers weapon systems integration including safety critical interface electronics, pneumatic technologies and advanced lightweight designs for air to air and air to ground weapons. In 2004, as one of the largest users of vibration and shock testing facilities across the UK, Cobham's Wimborne site required a flexible, cost effective supplier to meet their increasing reliance on external test house availability.
An in-house environmental test facility was initially considered, but would have consumed a considerable proportion of the capital expenditure budget on a non-core speciality, coupled with the specialist vibration skill-set required to run the facility and the intricacies of quality accreditation. Utilising their core competencies, TRaC intervened to offer a novel environmental test outsourcing solution.
TRaCs solution was to invest in the creation of a complete vibration test facility on Cobham's Wimborne site, offering total control of development, pre-qualification and full qualification test planning. Taking entire responsibility for capital expenditure, engineer recruitment, UKAS accreditation, maintenance and the day-to-day running of this new test laboratory, TRaC was able to integrate into Cobham's Wimborne operations and provide a seamless solution as if the facility was an internal department.
TRaC equipped the new facility with vibration, shock, and climatic test capabilities, including a 160kN-thrust LDS 984 electromagnetic shaker with combo slip-table, an LDS 875, and a range of M&P controller. Damon Close, one of TRaC’s most experienced vibration test engineers, was placed in the role of Test Laboratory Manager. Damon’s responsibilities include the hands-on management of testing at Cobham's Wimborne site, and he provides a single point of contact for all environmental requirements, ranging from fixture design to building bespoke vibration and fatigue test solutions. Working in unison at the early stages of development has allowed TRaC and Cobham to manage the problems that can affect qualification programmes, such as programme delays, facility availability and unbudgeted spend. Flexible working arrangements are key to the success of this partnership, with overtime availability built into the contract from the start to handle those eventualities where late evening and weekend testing is required to meet demanding schedules. This flexibility is enhanced with the support of TRaC’s field-based "TRaC on-Call" environmental test engineers.
One of the technically challenging aspects of Cobham's vibration testing is the physical size and mounting configuration of the equipment under test, where hardware can be in excess of 5m long, 1m in diameter and weighing up to 650kg. The off-centered mass and inherent large overturning moments characteristic of refuelling probes is not conducive to straight-forward vibration test set-ups. The dynamic behaviour of the test item in response to vibration excitation is an issue which not only requires careful deliberation by Cobham during the design phase, but requires significant consideration by TRaC prior to and during testing. To overcome these difficulties, TRaC initially design, model and analyse bespoke fabricated aluminium alloy fixtures to replicate in-service mounting. These fixtures need to be designed with sufficient structural rigidity to overcome the large bending moments and the effects of the vibration regime itself, however, designed sufficiently light-weight such that the vibration capacity of the shaker is not compromised. Secondly, horizontal-axis testing is performed on a 9 bearing guided slip-table, specified by TRaC at the investment phase, which is capable of reacting the high over-turning moments associated with test hardware of this size.
Beyond the day-to-day operations, the laboratory is supported by TRaC's Warwick facility for all aspects of quality, maintenance and calibration. The laboratory draws upon TRaC's in-house maintenance team to plan and action preventative maintenance, with breakdown cover assured within 24 hours of notification.
Ensuring integrity and competence throughout, the Wimborne laboratory is accredited by UKAS to ISO/IEC 17025:2005, and the facility undergoes a comprehensive independent audit annually. This provides Cobham with the further benefit of impartial, independently accredited test quality standards with global recognition.
Further benefits to Cobham include preferential access to the wider range of environmental test services from TRaC's UKAS accredited and CAA recognised test laboratory in Warwick. In all, TRaC has successfully supported Cobham on over 20 development and qualification programmes for aerospace applications at various sites.
