Improving the aerodynamic design is certainly what can lead to the most significant improvements in term of performance and efficiency. For instance, reducing drag lowers losses while in flight, and consequently the drone will be able to fly faster or further. But it’s not only about efficiency as efforts can also be made to increase the maneuverability or to understand any transitional flight phase. Furthermore, knowing the aerodynamic model is a prerequisite to implementing model-based control systems.
Our current setup allows for the characterisation of drones with 1.2m wingspan or smaller. We use a robotic arm to move and position (and pivot) the drone in the test section. A set of multi-axis load cells are available to measure the aerodynamic forces and moments. For 1.2m wingspan drones, the flow speed can be tuned between 1m/s and 12m/s with turbulence intensity below 1%. Higher speed can be reached at the cost of a slight turbulence increase or by contracting the flow to a smaller test section.
On demand, the tests can be fully automatized in order maximize the quantity of results that can be obtained per test session. This is particularly useful for extensive measurement campaigns.
Measurement of local wind profile is made possible by the use of ProCap. This tool combines a multi-hole pressure probe with the motion tracking camera system and allows quick and accurate capture of any velocity vector field. Live interpolated measurements are displayed on a TV screen in the test section, which makes this flow characterization method very intuitive and interactive.