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IJMERR 2023 Vol.12(3): 175-183
DOI: 10.18178/ijmerr.12.3.175-183

Effects of the Butterfly Forewing Flap-and-twist Motion on the Generation of Thrust and Lift

Kamonrat Tangudomkit and Pruittikorn Smithmaitrie*
Department of Mechanical and Mechatronics Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, Thailand
*Correspondence: pruittikorn.s@psu.ac.th (P. S.)

Manuscript received September 23, 2022; revised November 8, 2022; accepted December 24, 2022.

Abstract—A butterfly is a unique flying insect that can fly at a low flapping frequency of 10-15 Hz. Therefore, it consumes little energy while flying. However, the mechanism of low-frequency wing beat has not been thoroughly explained. In this work, it was found that the synchronized flap-and-twist motion enhances the positive lift during both upstroke and downstroke. Models of butterfly forewings were made and tested to investigate the effects of flapping and twisting motions on the generation of thrust and lift. The active flapping and passive twisting mechanisms are proposed. Different ranges of flapping and twisting angles of the wings were investigated. The experimental result shows that the large symmetric twist angle [-75°, 75°] has a unique 3-cycle repetition of flapping force, which generates positive lift in a range of 0-0.06 N most of the time, with strong thrust fluctuations in a range of ±0.10 N. This synchronized flapping and twisting motion with positive lift generation is one explanation for butterfly flight in nature and reveals how butterflies can lift themselves with such a low flapping frequency.

Keywords—flapping wing, butterfly robot, aerodynamics, wing synchronous motion

Cite: Kamonrat Tangudomkit and Pruittikorn Smithmaitrie, "Effects of the Butterfly Forewing Flap-and-twist Motion on the Generation of Thrust and Lift," International Journal of Mechanical Engineering and Robotics Research, Vol. 12, No. 3, pp. 175-183, May 2023. 

Copyright © 2023 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is non-commercial and no modifications or adaptations are made.