Design, Characterization and Initial Testing of a Vertical Stabilizer Common Research Model for Aircraft Ground Icing Testing

Under contract to Transport Canada (TC) and with joint funding support from the Federal Aviation Administration (FAA), a vertical stabilizer common research model (VS-CRM) has been designed and built by the National Research Council of Canada (NRC). This model is a realistic, scaled representation of modern vertical stabilizer designs without being specific to a particular aircraft. The model was installed and tested in the NRC 3 m × 6 m Icing Wind Tunnel in late 2021/early 2022. Testing was led by APS Aviation Inc., with support from NRC and NASA, in order to observe the anti-icing fluids flow-off behavior with and without freezing or frozen precipitation during simulated take-off velocity profiles. The model dry-air aerodynamic properties were characterized using flow visualization tufts and boundary layer rakes. Using this data, a target baseline configuration was selected with a yaw angle equal to 0° and rudder deflection angle equal to -10°. Testing with fluids and precipitation showed that some amount of fluid and contamination was present at the end of each run, with the amount dependent on the fluid type, contamination type, air temperature, run profile and model configuration. The tests with snow and freezing rain showed that exposure of the model to the full holdover time resulted in adhered contamination to the model surface, as the fluid flowed down and off the model due to the near-vertical orientation of the model surface. Other test profiles included dynamic motion of the model to simulate one-engine inoperative conditions, as well as non-standard applications to better understand the fluid behaviour over the model surface. The analysis also includes fluid thickness measurements after fluid application, after precipitation application, and at the end of a simulated take-off run. The results from this research campaign have been presented to the SAE G12 Aerodynamics Working Group, and further testing with the VS-CRM was completed in early 2023.