Lift distribution of washout twist morphing MAV wing

Abstract

Micro Air Vehicle, or also commonly known as MAV, is a miniature aircraft that has been gaining interest in the industry. MAV is defined as a flying platform with 15cm wingspan and operates at a speed of around 10m/s. Recently, MAV has been exposed with the latest development and link towards the biologically-inspired designs such as morphing wing. Twist morphing wing is one of the latest MAV wing design developments. The application of Twist Morphing (TM) on MAV wing has been previously known to produce better aerodynamic performance. Previous study in washin TM wing has shown a promising possibility of generating higher lift force. Despite the benevolent performance exhibited by the washin TM wing, the lift distribution for the washout type of TM MAV is relatively unknown and still open to be explored. This is probably due to the lack of experimental test rig to produce the washout twist morphing motion on the MAV wing. Therefore, this research aims to produce a special test rig for washout TM wing that is compatible for wind tunnel experimental testing. By using the special test rig, the experimental investigation on the lift performance of washout TM MAV wing can be done. Based on the wing deformation results, it clearly shows that the proposed test rig is capable to produce up to 19.5mm tip deflection at the morphing point, which is also resulting in a significant morphing motion. Higher morphing force induces larger morphing motion. Based on the lift distribution results, they show that the morphing motion has significantly affected the overall lift distribution on the MAV wing. The morphing motion on TM wing has produced at least 17.6% and 5.33% lower CL and CLmax magnitude, respectively, with the membrane wing especially at the pre-stall region. However, the TM wing is still able to maintain the stall angle similar to the baseline wing at αstall= 31°. By maintaining high αstall value with lower CL and CLmax magnitude, TM wing produces more agility for the MAV maneuverability that will be useful for indoor mission or obstacle avoidance flight.

Structural Deformation Analysis on Morphing Mav Wing

“…The strong agreement between the simulation and experimental results is highlighted by the low relative error, which holds true even when the morphing forces are increased. [17] and the present works…”

“…The wing displacement, normalized by the wing chord value (c= 0.15m) is calculated based on equation (1) which is taken from N.I. Ismail [17]. All the washout TM wings had considered the aerodynamic and morphing loads for the wing displacement since both of these factors contributed to the total wing deformations.…”

“…Each wing, whose physical properties and configurations are given in Table 1, has 1 mm thickness membrane skin component stretched about a frame, except the rigid wing. The inclusion of membrane skin onto the wing skeleton would permit gross deformation in wing shape in response to the subjected morphing forces [17]. Polymethyl methacrylate (also known as Perspex [18]) and silicone rubber [19] are utilized for the wing skeleton and membrane skin of the wings, respectively.…”

“…Based on experimental study conducted by N.I. Ismail et al [17], Table 3 provides a comparison between experimentally measured wing tip deformations and those obtained through simulation for different morphing force levels (1N, 3N, and 5N). The relative error quantifies the difference between the experimental and simulated results as a percentage of the experimental value [25].…”

Computational Aerodynamics Study on Neo-Ptero Micro Unmanned Aerial Vehicle

“…As α increases beyond its stall angle (α = 18°), a sudden drop in CL trend, in which the magnitude of CL drastically deteriorates at a rate of ˗ 3% for every 2° angle of attack increment, occurs. Here, one can presume that the stall phenomenon with a significant drag increase has overwhelmed Neo-Ptero's lift distribution 23) .…”