I am working on a project where we are using ducted fans and just recently we were testing to effect of some bellmouth inlets we made for the ducts. At full throttle the thrust for the fans with no bellmouth inlet was approximately 8.8 lbs and with the inlet the thrust was approximately 10.5 lbs. This is the kind of result we expected but for each test we went to full throttle and the power consumed went down when we added the inlets even though we were at the same throttle setting. I would have expected that by going to the same throttle setting we would supply the same amount of power each time and just get more thrust for an equal amount of power. But we saw thrust increase and power consumption decrease for the same throttle setting. Does anyone know why this is?