NEGATIVE INCREMENT OF LIFT COEFFICIENT AT SMALL ANGLES OF ATTACK OF SYMMETRICAL AIRFOIL FOR UAVs

Abstract

The main features of the aerodynamics of small-sized unmanned aerial vehicles, appearing in flight modes at maximum range and duration and distinguishing this class of aircraft from large-sized vehicles, are currently attracting increased attention. This is due to the increasing use and intensity of application of this class of aircraft. Negative increment of the lift coefficient at low angles of attack, although not quite a common phenomenon, but this behavior of profile characteristics can lead to a significant change in the stability and controllability characteristics of aircraft using such profiles in the design of all-turn rudders, or other surfaces. This can significantly complicate control system algorithms and require the installation of additional sensors. In this paper, based on laboratory experiments, we analyze how the shape of the tail part of the airfoil affects the variation of the lift coefficient at low angles of attack.