the area where the wheel contacts the blade is so narrow that the edge will look flat. i sharpen kitchen knives all the time for friends where i live and for my own and they cut great. the edge is more or less a v edge which you control the angle you want to put on the knife. if you hold the blade high on the wheel (around the 12:00 position) the way i sharpen you end up with a thin and extremely sharp edge. hold it low (below the 1:00 position or lower) you get a more durable edge but the lower you go the less likely it is to become shaving sharp. i dont understand what you mean by cutting in air.