A Test Rig to Assess the Effectiveness of Drag Reduction Devices on a Heavy-Class Helicopter

The present paper describes the experimental activity carried out to evaluate the effectiveness of the CFD-based shape optimisation of several components of a common helicopter platform of the heavy-weight class. The considered geometry is basically the same of the model tested in the frame of thè GO AHE AD project. The comprehensive wind tunnel campaign includes both the original helicopter configuration and the optimised version to assess the optimisation effectiveness by comparison. The optimised components included different hub-cap configurations, a set of fairings for the blade-stubs attachments and the sponsons. Moreover, the effects on drag reduction produced by an array of vortex generators positioned on the back-ramp were investigated. Different measurement techniques were employed as loads and moments measurements, steady and unsteady pressure surveys and stereo particle image vclocimetry. The performed measurements confirm a overall drag reduction of about 6% at cruise attitude for the optimised configuration.