Engineers at NASA’s Glenn Research Center are testing a new fan and inlet design - commonly called a propulsor - which could increase aircraft fuel efficiency by four to eight percent more than the advanced engine designs airlines are beginning to use. On today’s jet aircraft, the engines are typically located away from the aircraft’s body to avoid ingesting the layer of slower flowing air that develops along the aircraft’s surfaces, called boundary layer. Aerospace engineers believe they can reduce fuel burn by embedding an aircraft’s engines into these surfaces and ingesting the boundary layer air flow to propel the aircraft through its mission. Boundary layer air flow is highly distorted, and that distortion affects the way the fan performs and operates. These new designs require a stronger fan. The rugged boundary layer ingesting (BLI) inlet-fan combination is the first of its kind ever to be tested. This animation shows an engine fan and inlet ingesting boundary layer air in a wind tunnel.