The development of new innovative rotorcraft vehicles requires strong investments in the field of R&D adopting advanced numerical tools and innovative experimental methodologies. The dynamic stall phenomenon has been the subject of considerable interest in helicopter and aircraft manoeuvrability.
Preliminary results showed that the Active Gurney flap can delay the dynamic stall phenomenon, but further investigations are necessary for a well characterization of these devices. Within this context, in the last twenty years, several facilities have been realised or modified to test oscillating pitching blade/airfoil. However, these facilities are able to cover only a limited 3D “Mach -Reynolds -Reduced frequency” operative envelope respect to the typical flight conditions of helicopters.
The main innovative aspects of the present call regarded, in fact, the wide operative envelope in terms of reduced frequency-Mach number and the integration of such system with an active Gurney flap system installed on the model reproducing several motion laws. Our proposal concerned the design and manufacturing of a 2D airfoil, of an active gurney flap system and of a pitch-oscillating system to perform tests in a large wind tunnel.
The DEMOS project aimed at developing an electromechanical set up for Wind Tunnel test. The system was composed of a pitch oscillating system, an Active Gurney Flap (AGF) system and a balance system.
The baseline design for the pitch oscillating system was composed by a 2D airfoil (c=0.4m) driven by a 1FW3 Siemens torque motor remotely controlled to generate the desired pitch-oscillating motions. From a technical point of view, the pitch-oscillating system had been designed to generate a pitch-oscillating motion of the 2D model with the Sinusoidal, Non-Harmonic and Ramp Law.
In order to study the effectiveness of the Active Gurney Flap (AGF) system in the mitigation of the dynamic stall problem, the 2D pitching oscillating model was equipped with an AGF (maximum protrusion length 1%c) installed on the lower surface of the model at the 95% of model chord.
The baseline configuration for the Active Gurney Flap (AGF) system was composed by a full span T-shape gurney flap driven by two magnetic Linear Motors (Siemens) remotely controlled to generate (during the pitch-oscillating motion of the airfoil) the Sinusoidal Law and Non Harmonic Law.
DEMOS System was instrumented to perform loads measurement, steady and unsteady, using suitable load cells and is also instrumented to perform steady surface pressure measurements.