To simulate a realistic plume from a helicopter exhaust, it is sometimes necessary to provide a downwash from the rotor blades. S & C have developed a series of 168 Coanda ringjet ejectors which are fed from the Gnome turboshaft 1 compressor flow. These ejectors allow jets of compressor flow to entrain large quantities of ambient air and turn through 90 degrees, resulting in a large downwash footprint. The rig is mounted on a gantry which can then be placed over the nozzle arrangement under test.
Average downwash velocity 12.52m/s
Max temperature 14.3ºC above ambient (1m below nozzle exit)