Case Study 2-Free Style

BNI successfully designed and manufactured the transonic fans and associated permanent magnet motors for an unmanned, lighter-than-air vehicle known as a High Altitude Airship (HAA). The HAA will maintain a geostationary position at an altitude of 65,000 feet and the transonic fans control the vehicles internal pressure and cause it to descend when necessary. The motor is more than 95% efficient across a 2:1 speed range. The motor design challenge was further magnified by the allowable form factor dictated by the fan hub diameter and by heat.