Airfoil with bicambered surface

An airfoil having a profile, a chord, a leading edge, a trailing edge, a significant span, means defining a lower surface, means defining an upper surface, said profile expanding in thickness from said leading edge to a maximum thickness located at a predetermined point in front of midpoint of said chord, thereafter contracting in thickness reaching a minimum thickness at a predetermined point along said chord, thereafter expanding in thickness to a second maximum thickness located at a predetermined point behind midpoint of said chord, thereafter contracting in thickness to said trailing edge where said surfaces conjoin, said means defining an upper surface being bicambered in contour and constructed with a forward raised ridge and a rear raised ridge comprising alternating favorable pressure gradient means and adverse pressure gradient means to produce substantially attached flow, reattachment of flow, relaminarization of flow and delay of trailing wake separation on said upper surface, said means defining a lower surface being bicambered in contour and constructed with a forward raised ridge and a rear raised ridge comprising alternating favorable pressure gradient means and adverse pressure gradient means to achieve increased pressure behind midpoint of said chord.

A stable, high efficiency, high angle-of-attack airfoil comprising a significant span, a leading edge, a trailing edge, means defining a bicambered upper surface, means defining a lower surface, a chord comprising a straight line extending from said leading edge to said trailing edge, said means defining upper and lower surfaces conjoined at said leading edge and at said trailing edge, a profile expanding in thickness from said leading edge to a maximum thickness located in front of midpoint of said chord, thereafter contracting in thickness reaching a minimum thickness at a predetermined point along said chord, thereafter expanding in thickness to a second maximum thickness located behind midpoint of said chord, thereafter contracting in thickness to said trailing edge where said surfaces conjoin, said means defining a lower surface being bicambered in contour and constructed with a forward raised ridge and a rear raised ridge comprising alternating favorable pressure gradient means and adverse pressure gradient means to achieve increased pressure behind midpoint of said chord.