Doesn't fit, HWD. The reduction in lift in the descent is only drag x sin (angle of descent). Sin (angle of descent) is, for small angles, approximately tan (angle of descent) which is in fact the reciprocal of the glide ratio. For example for a PA-28 this would be about 1/11 of the drag. Since lift is in that case 11 times drag (as lift to drag ratio is also the glide ratio), you are only losing 1/121 of lift. I think. Never tried this calculation before, but it seems sound. Anyone find a flaw?