This month we completed the wind tunnel testing of VA-X4.

Wind tunnels are hollow tubes with powerful fans at one end which create an airflow inside the tunnel. The model inside the tunnel remains stationary whilst the rapid airflow simulates the aircraft moving through the air at high speed. There are sensors and instruments inside the tunnel and model that provide engineers with hard data, and windows to observe experiments visually.

The testing allows us to place the aircraft at varying angles of attack and sideslip conditions. We can also change the aircraft configuration quickly; add or remove the landing gear, deflect a control surface etc. to simulate many different conditions.

Various types of instrumentation are used to determine the forces on the model. Flow visualization techniques are also used to provide diagnostic information, these can include free stream smoke, tufts, or surface oil flow.

The tests allow us to generate a lot of data quickly, thousands of data points a day. These large datasets are required by the flight dynamics, performance and flight control law teams, they enable the team to validate their computer simulations and to assess the vehicle aerodynamic static stability, aerodynamic performance and control surface power.

We are pleased to confirm that the testing was successful and allows us to progress to the next stage of our programme.