WP3

This WP deals with the planning and the carrying out of wind tunnel tests aimed to produce a comprehensive set of data about the fundamental effects of Active Gurney Flaps on main rotor performances. The rotor tests were divided in two different campaigns. In the first one, a set of passive blades were designed, produced and tested on the whirl tower provided by GRC1 in the large wind tunnel of Politecnico di Milano. These passive blades were tested to evaluate the effectiveness of different size passive Gurney flaps and to check and adjust the PIV setup waiting for the active blade set. In fact, these tests showed that also small Gurney with a relatively limitated radial extension (from 60% to 70% of the blade) and located at the 90% of the chord showed apparent increases in blade lift. Thus, they demonstrated to be useful for blade dynamic control. The second campaign concerned the tests on the active blades equipped with active Gurney flaps system. This specific campaign enabled to gather a large amount of information about the effects of different Gurney flap actuation laws on blade performance. The tests results can be considered very interesting and will be useful to address the full-scale tests on a real helicopter that will be the last step of the investigation on active rotor blades in the frame of GRC1 program. Indeed, the tests demonstrated that a significant increase in rotor efficiency can be achieved by means of active Gurney flap.