Miniature trailing-edge effectors for rotorcraft performance enhancement

The performance effects of a miniature trailing-edge effectors, or MiTEs, mounted at the trailing edge of a rotor blade have been explored using blade-element theory. MiTEs are a derivative of the Gurney flap, which is a lift enhancement device with a height of one to five percent of the airfoil chord, and is mounted normal to the airfoil surface. Compared to the clean airfoil, the maximum lift coefficient is increased by much as 30 percent using a Gurney flap that is two percent of chord in height and located on the lower surface at the trailing edge. MiTEs are best described as a deployable Gurney flap, and can be used to actively control the loading on a helicopter rotor blade for enhanced performance, vibration control, etc. The MiTEs would be segmented in the spanwise direction and deploy around the azimuth as needed. MiTEs are an attractive option for rotorcraft because the actuation requirement to deploy these devices at the high frequencies is minimal. The potential to increase the rotor performance is considered, where the MiTEs are deployed on the retreating side of the rotor disk to increase the maximum lift. These studies show up to 20-percent gains in the maximum flight speed, 16- percent increases in the maximum lift-to-drag ratio, and a 10-percent increase in potential thrust.