Airfoil

An airfoil having a leading edge, a trailing edge, an upper surface, a lower surface, a chord-wise axis and a spanwise axis, said airfoil comprising at a chord-wise location on said spanwise axis:

• a. a substantially uninterrupted upper skin member defining said upper surface and a substantially uninterrupted lower skin member defining said lower surface, each of said skin members comprising:
• 1. a first forward surface portion extending rearwardly from said leading edge to a first inflection point;
• 2. a second transisitional surface portion extending rearwardly from said first surface portion at said first inflection point to curve concavely from said chord-wise axis to a second inflection point, each of said second inflection points being located rearwardly from said leading edge at a distance between one-quarter to four-tenths of a chord length of said airfoil at said chord-wise location;
• 3. a third belly surface portion extending rearwardly from said second surface portion at said second inflection point to curve convexly to form an expanded belly portion of said airfoil;
• 4. a fourth trailing edge surface portion extending from said third surface portion to said trailing edge;
• b. each of said upper and lower surfaces being contoured to form a flow pattern where flow along said first and second surface portions is at an average lower velocity, and flow along said third lower surface portion of each surface is at a relatively higher average velocity;
• c. a primary load bearing structure located primarily in the belly section of the airfoil;
• whereby said airfoil is aerodynamically contoured to function effectively aerodynamically, and yet provide relatively greater airfoil thickness at said belly section to enable said primary load carrying structure to have a relatively large height dimension.

An aircraft comprising a central body, and a pair of oppositely extending airfoils, each airfoil having a leading edge, a trailing edge, an upper surface, a lower surface, a chord-wise axis and a spanwise axis, each airfoil having an inboard end and an outboard end, with the inboard end being connected to said body, each airfoil comprising:

• a. a substantially uninterrupted upper skin member defining said upper surface and being aerodynamically contoured to form a flow pattern over the upper surface to produce an upward lift;
• b. a substantially uninterrupted lower skin member defining said lower surface, said lower skin member comprising at the inboard end thereof:
• 1. a first forward lower surface portion extending rearwardly from said leading edge to a first inflection point;
• 2. a second transitional lower surface portion extending rearwardly from said first surface portion at said first inflection point to curve concavely downwardly to a second inflection point, said second inflection point being located rearwardly from said leading edge at a distance between one-quarter to four-tenths of a chord length of said airfoil at said chord-wise location;
• 3. a third belly lower surface portion extending rearwardly from said second lower surface portion at said second inflection point to curve convexly to form a dow-wardly expanded belly section of said airfoil, said belly section diminishing in thickness in an outboard direction;
• 4. a fourth trailing edge lower surface portion extending from said third lower surface portion to said trailing edge;
• c. said lower surface portion being contoured to form a flow pattern where flow along said first and second lower surface portions is at an average lower velocity, and flow along said third lower surface portion is at a relatively higher average velocity, in a manner that relatively greater lifting force is exerted at the first and second lower surface portions, and relatively less lifting force is exerted at the third lower surface portion;
• d. a parimary load bearing structure located primarily in the belly section of the airfoil and diminishing in height in an outboard direction;
• whereby said airfoil is aerodynamically contoured to function effectively aerodynamically, and yet provide realtively greater airfoil thickness at said belly section at the inboard end of each airfoil to enable said primary load carrying structure to have a relatively large height dimension at said inboard end.