Spring-Loaded Wings


Long Title: Development of a Passively Actuated Flow Control Mechanism for Micro-Air Vehicles

 

Passive flow control refers to mechanisms or methods that change a flow in a beneficial way, without directly adding any energy to the flow. Two examples of this are dimples on golf balls or spoilers on sports cars. While at Oregon State University, a numerical flow simulation of micro-air vehicles (think drones and hobby planes) demonstrated that that a spring-loaded trailing edge could, in some cases, increase the lift to drag ratio during flight. The numerical model featured a flat plate with a trailing edge that could flap, but whenever it would flap away from its resting position, there would be a restoring force proportional to the angular displacement. Our job was to turn this numerical model into a real experiment.

The difficulty in this project was designing something that matched the numerical model, could be built with our very small budget, and was very small. The entire spring and calibration system had to fit within the a wing that was 4 mm thin! It was great design-on-a-budget experience, and we even had to weld together some custom tools of our own in order to fabricate the model. Experimental results confirmed those anticipated by the simulations and have been published in the Journal of Fluids and Structures (2015), which may be accessed by clicking here.

 

Macro shot of final version of the spring-loaded wing