Microtecnica SrL (MT) have brought together industry leading expertise to support the design and development of a full scale Active Gurney Flap (AGF) system. The team have a combination of relevant experience in blade actuation across a range of technologies together with significant capabilities in fundamental engineering analysis to support a comprehensive review of potential solutions. The proposal reflected the joint desire of offering a risk managed baseline approach as well as ensuring all potential candidate solutions are assessed as part of the initial development task.
The consortium was lead by MT who provide the technical and programme management and the detail design and manufacture of the wind tunnel and whirl test hardware. MT was supported by Microtecnica Actuation Technologies (MAT), University of Bristol and the “Politecnico di Torino” based in Turin. The team ensured a balance of technical depth together with a commitment and capability to exploit technology for commercial gain.
The objectives of the work plan had been directed to achieving a risk mitigated solution to AGF System in order to develop a product that could be adopted on a production rotorcraft.
The AGF development program followed key deliverables that can be summarised into 4 activities: requirements development, product design, hardware supply testing and evaluation.
The programme had a primary cycle of the 4 activities culminating in the delivery of the first prototype at T0 + 17 months. The cycle had been repeated picking up the lessons from the testing and evaluation with wind tunnel hardware deliveries in T0 +24 months. Output from the wind tunnel testing provided the input for the final hardware (T0 +30 months) for whirl tower testing.
The management of technical risk had been supported by a two tier approach. The primary risk mitigation had been achieved through a balanced approach to analytical and empirical techniques. The consortium used the most advanced predictive engineering tools using finite element techniques for magnetic, stress and thermal analysis. Equally, the electronics and system performance had been extensively analysed before hardware production. Previous experience in fact has shown that the most robust approach was to combine these analysis techniques with small scale breadboard evaluations of elements of the design. These were particularly useful for phenomenon which typically are non-linear in nature such as wear mechanisms and threshold effects like friction.
The consortium had been chosen with a balance of skills and capabilities. The involvement of the University of Bristol was of particular value for both its broad analytical capabilities together with a proven record in rapid prototype and test methods. The involvement of the Politecnico di Torino was in thermal and performance analysis of the actuator, basing on their experience in the specific areas of flight control actuation systems, mechatronics.
Technical risk was underpinned by a choice of technology that can be reconfigured to achieve potential requirements growth. There is intrinsically an element of uncertainty in the final needs of the product. In order to fix this uncertainty, one of the purposes of wind tunnel test was to confirm the operating loads while the aim of the spin rig test was to verify the capability of the system to operate in high centrifugal acceleration environment.
In fact, it should be noted that during the execution of the program, the final Customer, Agusta Westland (AW), had communicated their intention to promote the Active Gurney Flap to an experimental flight program. This caused the responsibility of the Gurney Flap structural parts to be taken by AW. Discussions had been conducted between MT and AW in order to anticipate the demonstration of the actuator performances in high-G environment before the whirl tower test. The spin rig test activities had been then performed to verify the capability of the actuator and its relevant control electronics to operate installed in a representative acceleration environment.