# Comparative Aerodynamic Performance Analysis of Camber Morphing and Conventional Airfoils
## 1 Introduction  
The term morphing is from \"metamorphosis\" and means a change of the form, or nature of a thing, or a person, into a completely different one by natural or supernatural means [1]. In the aerospace and aviation industry, morphing technologies have been adopted to aim for enhanced flight performance by adjusting the aircraft's structure, particularly wing shapes, to optimize flight states and conditions by matching with the corresponding flight mode. If the concept of morphing in wings is broadly defined, control surfaces in conventional aircrafts could also be included; however, morphing wings typically refer to active, continuous, and more substantial changes in the wing structures from its initial design stage. Whereas conventional wing aircrafts manoeuvre and change their flight dynamics by changing the deflection angles of various control surfaces such as flaps, aileron, elevator, rudder, and so on, as well as the wing area by expanding chord lengths, the concept of morphing wing aircraft relies on irregular changes of wing structures including changes in airfoil thickness, camber, span lengths, sweep angles, span bend, and twist as depicted in Figure 1[2]. A major and well-acclaimed aerodynamic benefit of a morphing structure is from its potential to create unusual and substantial shape changes that could satisfy various flight conditions, which a conventional aircraft could not generate. On the basis of these changes one can expect to implement, design, and test morphing wings and equip aircrafts to optimize their flight condition, which could also imply that the morphing aircraft could fly longer, consume less fuel, be more energy effective, and more agile than the same weight conventional ones. One of the important aerodynamic parameters linked to fuel consumption or energy saving could be \(D\), the drag forces exerted on the aircraft during flight, so a reduction in \(D\) should preserve fuel. The aforementioned morphing wings can potentially initiate a larger envelope in flight performance that enables extra residual flight modes of better or smaller \(D\) by continuously altering wing shapes. The different types of morphing along with the geometric parameter that is modified to create the morphing are shown in Figure 1, and amongst them, this paper explores camber change or camber rate morphing. The camber rate of an airfoil (denoted by the first digit in the four-digit NACA airfoil series) describes the convexity of an airfoil between its leading and trailing edges. Continuously changing the camber has benefits in terms of \(L\) distribution, improved manoeuvrability, improved \(L\)/\(D\), expanded flight envelope, and tactical capabilities [1]. A conventional wing with deflecting control surfaces and a morphing wing with varying camber is shown in Figure 2.  
Most of the morphing wing research works focus on either the design and implementation of morphing concepts using selected materials and structures [4; 5; 6; 7; 8; 9; 10; 11], or the  
Figure 1: Categories of morphing types in fixed-wing aircraft. Figure 2: A conventional wing with control surfaces [3] **(a)** and a camber morphing wing (**b**). Control Surfaces: (1) winglet, (2) low-speed aileron, (3) high-speed aileron, (4) flap track fairing, (5) Kruger flaps, (6) slats, (7) three-slotted inner flaps, (8) three-slotted outer flaps, (9) spoilers, (10) spoilers-air brakes. analysis of the structural and aerodynamic performance of suggested morphing concepts and their mechanisms [12; 13; 14; 15]. Researchers have developed camber morphing mechanisms using smart materials [16; 17; 18], corrugated structures [19], multi-unit rib structures [20], vertically slitted rib structures [21], truss elements and runners [22], pressure-actuated cellular structures [23; 24], bio-inspired FishBAC structures [25], monolithic compliant mechanisms [26], or combined form [27] to introduce and validate their effectively working models and design implementation.