Avian whiffling-inspired gaps provide an alternative method for roll control.

Area of Science:

• Aerospace Engineering
• Bio-inspired Design
• Fluid Dynamics

Background:

• Avian whiffling involves inverted flight with wing gaps, potentially aiding maneuverability.
• This biological mechanism has aerodynamic parallels to uncrewed aerial vehicle (UAV) control surfaces like spoilers and ailerons.
• Whiffling has not yet been directly applied to aerodynamic design for UAVs.

Purpose of the Study:

• To investigate if trailing edge wing gaps, inspired by bird whiffling, can serve as an effective control mechanism for UAVs.
• To evaluate the potential of these gaps for rapid descent and banking control.
• To compare the performance of gapped wings against traditional spoilers and ailerons.

Main Methods:

• Wind tunnel testing of 3D printed wings with variable trailing edge gaps.
• Comparison of lift and rolling moment coefficients with traditional spoilers and ailerons.
• Analytical estimation of actuation force and work for gaps, spoilers, and ailerons.

Main Results:

• Gapped wings showed reduced lift compared to spoilers but required more work.
• At high angles of attack, gapped wings generated rolling moment coefficients comparable to significant aileron deflections.
• Actuation force and work for gapped wings were substantially lower than for ailerons.

Conclusions:

• Whiffling-inspired wing gaps are not optimal for rapid descent compared to spoilers.
• Gapped wings offer a viable, energy-efficient alternative to ailerons for roll control in UAVs.
• This bio-inspired approach presents a novel control mechanism for small, energy-constrained fixed-wing UAVs.