Insects impress by their agility and their performances in flight. Understanding the aerodynamic mechanisms involved constitutes a considerable challenge for biologists, physicists, but also for engineers responsible for Micro Air Vehicle‘s design, whose principal model remains insects’ flapping flight.
During the last few years, some of the characteristic kinematic patterns allowing us to explain the significant aerodynamic forces generated during flight as well as the underlying fluid dynamics had been unraveled. However, if major elements such as wings kinematics or leading edge vortex production are now partially understood for hovering flight (Walker et al. 2010) as well as for forward flight (Bomphrey et al. 2006), the aerodynamic mechanisms involved during the take-off phase remained unstudied. The substantial lift and power required as well as the involvement of the ground make take-off a particularly interesting manoeuvre to decipher.
The aim of this study is therefore to understand the wing kinematics and vortex production operating during an insect’s take-off and how they could interact with the ground to take advantage of its proximity.
To that end, a detailed kinematic study of an insect during take-off was carried out, completed by an analysis of fluid dynamics during the manoeuvre, intimately related to forces production.
Cabbage white butterflies (Pieris rapae) were selected on the basis of good wing condition wings and strong flight motivation. The experiments were performed at the Research Institute on Insect Biology (Tours University).