Wind tunnel high speed powered tests of the ERICA tilt rotor model in S1MA - NICETRIP Project

Within the framework of European research programs, the NICETRIP (Novel Innovative Competitive Effective Tilt Rotor Integrated Project) project aims at building a flying demonstrator of a European civil tilt rotor aircraft. Previous projects like DART, TRISYD, TILTAERO, ADYN and ACT-TILT, studied various aspects of the tilt rotor concept and resulted in the definition of the ERICA (Enhanced Rotorcraft Innovative Concept Achievement) concept. Wind tunnel testing was therefore requested to prove the liability of the ERICA concept with respect to low speed interaction and high speed performances, in order to freeze the general architecture, flight control system and flight control laws and determine the operational performance. The wind tunnel tests have been performed on a 1:5 scaled powered model and covered a wide range of flight envelope points, from low speed helicopter mode to high speed aircraft mode. Two test campaigns have been performed: one low speed test campaign in June and July 2013 in DNW-LLF wind tunnel facility (Netherlands) and one high speed test campaign in May 2014 in ONERA-S1MA wind tunnel facility (France). The present paper aims at presenting the wind tunnel tests performed in the large transonic wind tunnel S1MA on the ERICA tilt rotor concept in conversion and aircraft conditions, with variations of several parameters. In order to assess the performance of the ERICA tilt rotor concept in high speed flight conditions, the full set of data is analysed by aerodynamicists from ONERA and European helicopter industries. The main objectives of the high speed tests were the determination of the aerodynamic interactions and the rotor performance between Mach 0.176 (minimum speed in aircraft configuration) and Mach 0.550 (maximum speed in aircraft configuration). More than 140 data points have been recorded during this test campaign. The model was heavily instrumented and largely remotely controlled, allowing to perform several data points without any mechanical change of model configuration. Trimming points have been performed and variations of collective pitch and movable surfaces like flaps, flaperons, rudder and elevator have been tested. Incidence and sideslip sweeps have also been performed for “blade on” and “blade off” configurations.