On the use of sweeping jets to trim and control a tailless aircraft model

Active Flow Control (AFC) was incorporated into the SACCON model in order to trim it in pitch. The combination of AFC and control-surface deflection enables the model to be stable and controllable. The trim requirements can be predicted and implemented provided one realizes that AFC is no less important than other parameters changing the aerodynamic characteristics of a wing. This implies that AFC should be treated concomitantly with other design parameters because it introduces many new options. The most important outcome of this exercise implies that the traditional boundary layer approach with prescribed pressure gradients should no longer be used when AFC is to be implemented. This concept is proven by way of examples associated with the SACCON model that can be trimmed either by large deflection of flaps or by AFC. A right combination of both parameters may require a minimal input of AFC (e.g. 2 actuators) in conjunction with a small flap deflection. Thus far, the actuator array positioned close to the flap hinge proved to be most effective but this result may not be universal. The tests were carried out at low speeds (Mach number < 0.2) and Reynolds numbers based on the outer panel chord of the model that approached 10⁶.