Within the framework of the JTI-Clean Sky (CS) project, and during the first phase of the Low Noise
Configuration Domain of the Green Regional Aircraft – Integrated Technological Demonstration (GRA-ITD, the
preliminary design and technological demonstration of a novel wing flap architecture were addressed. Research
activities were carried out to substantiate the feasibility of morphing concepts enabling flap camber variation in
compliance with the demanding safety requirements applicable to the next generation green regional aircraft, 130-
seats with open rotor configuration.
The driving motivation for the investigation on such a technology was found in the opportunity to replace a
conventional double slotted flap with a single slotted camber-morphing flap assuring similar high lift
performances -in terms of maximum attainable lift coefficient and stall angle- while lowering emitted noise and
system complexity. Studies and tests were limited to a portion of the flap element obtained by slicing the actual
flap geometry with two cutting planes distant 0.8 meters along the wing span.
Further activities were then addressed in order to increase the TRL of the validated architecture within the second
phase of the CS-GRA. Relying upon the already assessed concept, an innovative and more advanced flap device
was designed in order to enable two different morphing modes on the basis of the A/C flight condition / flap
setting:
Mode1, Overall camber morphing to enhance high-lift performances during take-off and landing (flap deployed);
Mode2, Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed)
for load control at high speed.
A true-scale segment of the outer wing flap (4 meters span with a mean chord of 0.9 meters) was selected as
investigation domain for the new architecture in order to duly face the challenges posed by real wing installation.
Advanced and innovative solutions for the adaptive structure, actuation and control systems were duly analyzed
and experimentally validated thus proving the overall device compliance with industrial standards and applicable
airworthiness requirements.
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