Hi Everybody I understand why a U-Tail has an increase in horizontal effective aspect ratio and can be 5% smaller than a conventional tail. Basically because of the chastity belts the endplates represent. What I dont understand is why an all moving tail can be sized 10-15% smaller than a conventional tail according to Raymer. Could anybody shed some light on this? What about an all moving U-tail? Could it be 15% smaller? How do these effects affect the calculations/parameter?