Going with the flow

Advanced balances, pressure-sensitive paint, and wind-tunnel testing streamline aircraft aerodynamics.

Balances to measure lift and drag forces on wind-tunnel models have systematically improved over the last couple decades, particularly when they are machined from a single piece of metal so they are less subject to hysteresis, but nothing has done more to revolutionize aerodynamic testing than pink-colored pressure-sensitive paint (PSP).

“Historically, models would have discrete point measurements of pressure, which are expensive to do because orifices have to be drilled in the model and plastic tubes run out to the equipment,” said Stephen Smith, Senior Research Engineer in the Experimental Aerophysics Branch at NASA Ames Research Center (ARC). “Data acquisition was slow and you only got data values at those discrete points.”