Application of the Boundary Layer Data System on a Laminar Flow Swept Wing Model In Flight

Two versions of a small, self-contained device developed specifically to measure boundary layer characteristics – collectively referred to as the Boundary Layer Data System – were applied in a flight test of a 30-degree laminar flow swept wing test article. The devices were used to provide local boundary layer measurements in conjunction with surface pressure and infrared image measurements for an Air Force Research Laboratorysponsored test of Northrop Grumman’s SensorCraft wing design. The model was carried aloft by Scaled Composites’ White Knight aircraft. The flight altitudes of over 40,000 ft, Mach numbers above 0.5, and local dynamic pressures up to 150 psf are the highest values yet for application of the devices. Two different configurations of the Boundary Layer Data System were flown: a device with a stage to position a traversing pressure probe, and a version of the device with a stationary surface Preston tube. The devices weigh less than a pound and are completely self-contained, meaning that they have their own internal power and memory. The devices attach to the test surface with double-sided structural adhesive tape and thus require no mechanical penetration of the test surface, making them a flexible tool for flight testing. This paper describes the devices, their use on the flight test, and presents some sample results.