Experimental Aerodynamic Comparison of Active Camber Morphing and Trailing-Edge Flaps

Abstract

Unlike hinged flaps (e.g. ailerons, elevator and rudder), camber morphing devices vary camber distribution in a smooth and continuous way, resulting in aerodynamic efficiency improvements due to the absence sharp changes in airfoil camber. One such camber morphing concept, the Fish Bone Active Camber (FishBAC) device, has shown significant aerodynamic benefits when compared to a flap. In this work, a quasi-2D wind tunnel test was performed to investigate the aerodynamic performance of a FishBAC device and compare it to a trailing edge plain flap. A combination of quasi-steady force balance and wake rake pressure measurements were used to determine aerodynamic force coefficients. These measurements are complemented

Design, Manufacture and Wind Tunnel Test of a Modular FishBAC Wing with Novel 3D Printed Skins

“…A maximum ∆C L ≈ 0.55 is observed in the linear region of the lift curve (i.e., for angles of attack of less than α < 10 • ), whereas a ∆C L ≈ 0.40 is observed at around stall. Additionally, it is seen that the point of minimum drag does shift with increasing camber deflections, which is consistent with the results observed by [24]. However, it is worth noting that these drag coefficient results vary significantly with the angle of attack, which is not expected in a 2D wind tunnel test.…”

“…However, it is worth noting that these drag coefficient results vary significantly with the angle of attack, which is not expected in a 2D wind tunnel test. Two-dimensional drag coefficients should remain relatively unchanged with increasing pitch angle (at a given camber deflection) when the flow is attached (i.e., in the linear region of the lift curve), and then "spike" as the flow starts to separate and stall (see [24] for example). These drag results suggest the presence of 3D effects that standard wind tunnel corrections ( [33]) cannot correct.…”

“…The second generation of FishBAC devices was designed and manufactured around incorporating carbon fibre-reinforced composite to the spine (Figure 2), which presents significantly improved material properties when compared to 3D-printed plastics, and also allows for stiffness tailoring by exploiting variations in the fibre angle [23]. This generation of FishBAC devices was useful to further study the aerodynamic behaviour of the FishBAC by conducting comprehensive wind tunnel experiments that showed the clear aerodynamic benefits that this morphing device has when compared to a hinged trailing-edge flap of similar dimensions [24]. However, one clear disadvantage of using a carbon fibre laminate for the spine is that the stringers have to be bonded to the spine, which increases the time and complexity of the manufacturing process, as well as the part count.…”

Effects of an Unsteady Morphing Wing with Seamless Side-Edge Transition on Aerodynamic Performance

“…This results in a consistently higher efficiency for the wing equipped with a morphing flap over a large range of angles of attack, resulting in a maximum of 40% enhanced L/D at AoA = 14 • . This result is also consistent with published numerical work, where up to 18% gains in aerodynamic efficiency was achieved for a similar morphing configuration[32] and an over 50% improvement in (L/D) was obtained for a quasi-2D FishBAC experimental study[33].…”

“…This is supported by a further study which compared the same morphing concept with a traditional unsealed configuration using both CFD and experimental methods, and results showed that up to 18% gains in aerodynamic efficiency is achievable [32]. Most recently, Rivero et al [33] performed a quasi-2D wind-tunnel test to investigate the aerodynamic performance of a FishBAC morphing flap and compare it with a hinged flap configuration. Experimental results showed that the quasi-2D morphing flap was able to produce an over 50% improvement in the lift-to-drag ratio (L/D) at moderate to high lift coefficients where the flap device is significantly deflected, and an at least 16% higher lift-to-drag ratio at all lift coefficients, even for the lowest deflection values (~10 • ).…”