A Polymorphing Wing Capable of Span Extension and Variable Pitch

Abstract

This paper presents the development of a novel polymorphing wing capable of Active Span morphing And Passive Pitching (ASAPP) for small UAVs. The span of an ASAPP wing can be actively extended by up to 25% to enhance aerodynamic efficiency, whilst its pitch near the wingtip can be passively adjusted to alleviate gust loads. To integrate these two morphing mechanisms into one single wing design, each side of the wing is split into two segments (e.g., inboard and outboard segments). The inboard segment is used for span extension whilst the outboard segment is used for passive pitch. The inboard segment consists of a main spar that can translate in the spanwise direction. Flexible skin is used to cover the inboard segment and maintain its aerodynamic shape. The skin transfers the aerodynamic loads to the main spar through a number of ribs that can slide on the main spar through linear plain bearings. A linear actuator located within the fuselage is used for span morphing. The inboard and outboard segments are connected by an overlapping spar surrounded by a torsional spring. The overlapping spar is located ahead of the aerodynamic center of the outboard segment to facilitate passive pitch. The aero-structural design, analysis, and sizing of the ASAPP wing are detailed here. The study shows that the ASAPP wing can be superior to the baseline wing (without morphing) in terms of aerodynamic efficiency, especially when the deformation of the flexible skin is minimal. Moreover, the passive pitching near the wingtip can reduce the root loads significantly, minimizing the weight penalty usually associated with morphing.

Material Extrusion Additive Manufacturing of the Composite UAV Used for Search-and-Rescue Missions

“…For the UAV models, produced by material extrusion, the aerodynamic performances were determined by testing in the wind tunnel [47][48][49]. The manufacturing of morphing wing models [50][51][52][53] lends itself very well to the additive manufacturing process by material extrusion, since the components are manufactured in the shortest time and at low costs. Currently, the use of composite filaments, with short [54][55][56] or continuous fibers [57,58], employed in the 3D-printing process represents an intensively researched field with applications in aerospace.…”

Numerical Investigation and Optimization of a Morphing Airfoil Designed for Lower Reynolds Number

“…Additional interesting solutions proposing more profound (three-dimensional, 3D) shape changes (including active span and pitch varieties) can also be seen in [14][15][16][17]. In addition to being used to enhance aerodynamic performance, morphing wings can also be used for other purposes, e.g., to maximize the area being exposed to sunlight, which is extremely important for high-altitude solar-powered aircraft [18].…”

Impacts of Tapered Wingtip on Lateral-Directional Stability Coefficients of a Morphing Fixed-wing UAV

“…Their design provided an enhancement of up to 24% in aerodynamic performance for both subsonic and hypersonic flight regimes (Liu et al, 2022). Parancheerivilakkathil et al proposed a multiple morphing application that includes an active wing span increment and passively wing pitch angle alteration and provided improvement in aerodynamic performance and bending moment (Parancheerivilakkathil et al, 2022). RQ-7a Shadow unmanned aerial vehicle is redesigned with a camber morphing airfoil by Jo and Majid and they obtained aerodynamic performance improvement of up to 60% (Jo and Majid, 2023).…”