Aerodynamic performance of flexible flapping wings deformed by slack angle

Area of Science:

• Aerodynamics
• Bio-inspired engineering
• Robotics

Background:

• Wing flexibility is essential for flapping wing flight, aiding lightweight construction and payload capacity.
• Existing research on the aerodynamic principles of flexible wings is limited.
• Understanding wing flexibility is key to improving micro-aerial vehicle (MAV) performance.

Purpose of the Study:

• To conduct a parametric study of flexible wings to develop an aerodynamic model.
• To analyze the aerodynamic performance of flexible wings under varying parameters.
• To identify optimal flexible wing designs for flapping-wing MAVs.

Main Methods:

• Quasi-steady aerodynamic modeling was employed.
• Experimental data from 84 flexible wing cases and 19 rigid wing cases were used.
• Parameters varied included the angle of attack at the wing root (αr) and the slack angle (θS).

Main Results:

• Optimal lift generation was observed at an angle of attack exceeding 45°, regardless of the slack angle.
• Coefficient curves were accurately described by a cubed-sine function.
• The developed model demonstrated high accuracy, with errors below 5% for lift, 6% for drag, and 8% for moment.

Conclusions:

• A 5° slack-angled wing is identified as the most suitable for MAV wing design with a simple vein structure.
• A small degree of wing deformation is beneficial for increasing lift, mimicking natural flyers.
• Wing deformation can reduce pitching motion, leading to lower mechanical power consumption and increased wing efficiency.