Transonic Fan

BNI teamed with Lockheed Martin to work on an unmanned, lighter-than-air vehicle that will maintain a geostationary position at an altitude of 65,000 feet. The vehicle, known as a High Altitude Airship (HAA), is being built by Lockheed Martin and is being funded by the Missile Defense Agency. Specifically, Barber-Nichols designed and┬áproduced the transonic fans that control the vehicle’s internal pressure and cause it to descend. To operate properly at altitude, the fan blade’s tip speed moves in excess of 333 m/s (1,100 ft/s). As gas accelerates through the fan’s converging and diverging blades, it reaches a relative supersonic speed. CFD Analysis drove the fan’s blade design and the sonic barrier was crossed at a point that minimized shock losses.