The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (C.sub.L) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

A disclosed method reduces a wave drag on an airfoil traveling at a speed. At least a portion of the airfoil is configured to be selectively moveable between a first position and a second position. The first position is a neutral position, and the second position generates a shock wave near to the leading edge of the airfoil. The method includes the steps of maintaining the airfoil in the first position when the speed is less than a first limit and moving the airfoil to the second position when the speed is greater than a first limit.

[Object] To provide a wing achieving reduction of friction drag and easy to design and also easy to manufacture and an aircraft including such a wing. [Solving Means] A wing 1 is typically used as a main wing of an aircraft 100. The wing 1 is a swept-back wing having a swept-back angle A. The wing 1 is configured such that a surface pressure (pressure distribution (Cp)) on an upper surface of a vicinity of a leading edge 11 in a fluid increases from a wing root 17 to a wing tip 15. A cross-flow component of an external streamline of a surface of the wing 1 is reduced in the vicinity of the leading edge 11, and boundary layer transition is not easily induced in the vicinity of the leading edge 11. With this, friction drag caused by cross-flow instability can be reduced.

[Object] To provide a transonic airfoil capable of reducing pressure drag more than before, a wing having such an airfoil, and an aircraft including such a wing.

[Solving Means] An airfoil 11 has a shape in which a pressure coefficient Cp of a static pressure in a chord direction of a leading edge 12 of the airfoil 11 is 0.04 or less at z/c=0.015 (where z represents a coordinate in a direction perpendicular to an airflow direction within a plane that forms an airfoil, with a leading edge being as a reference (an upper wing surface direction is positive, and a lower wing surface direction is negative), and c represents a chord length). Thus, a pressure distribution has a sharp rise, which can decrease pressure drag.

The invention relates to airfoils, called jn1431-265 and 1413-362, which operate intelligently by adjusting the variable aerodynamics thereof, not only through the attack and sine angle, but also through the effect of scale (air speed), which, when combined, improve the efficiency of the wings configured therewith by up to 30%, cause the wings to experience a predictable stall and also rapidly recover therefrom, and also making the wings configured therewith more efficient at low speed, which reduces the need to use flaps or slats (high lift devices), and, in the event that flaps or slats are used, increase the effect of said airfoils even more. On the other hand, at an increased speed, the aerodynamic variables also adjust by up to a third of the value thereof (the angle of attack remaining unchanged), causing the wing to also be very stable at high speed conditions.

The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (C.sub.L) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

The invention relates to airfoils, called jn1431-265 and 1413-362, which operate intelligently by adjusting the variable aerodynamics thereof, not only through the attack and sine angle, but also through the effect of scale (air speed), which, when combined, improve the efficiency of the wings configured therewith by up to 30%, cause the wings to experience a predictable stall and also rapidly recover therefrom, and also making the wings configured therewith more efficient at low speed, which reduces the need to use flaps or slats (high lift devices), and, in the event that flaps or slats are used, increase the effect of said airfoils even more. On the other hand, at an increased speed, the aerodynamic variables also adjust by up to a third of the value thereof (the angle of attack remaining unchanged), causing the wing to also be very stable at high speed conditions.

The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (C.sub.L) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

A wing includes: an inner end configured to be coupled to a fuselage of an aircraft; an inboard section extending from the inner end; a fixed leading edge of the inboard section having a drooped contour positioned along at least a portion thereof; and an outboard section extending from the inboard section.

Methods, apparatus, and articles of manufacture to monitor a shock wave proximate a surface of an aircraft are disclosed. An example apparatus includes a first camera at a first location on an aircraft to capture a first image of a surface of the aircraft during a first time period, and capture a second image of the surface during a second time period, a second camera at a second location to capture a third image of the surface during the first time period, and capture a fourth image of the surface during the second time period. The example apparatus further includes a position calculator to identify a first position of a shock wave based on the first and third images, and a second position based on the second and fourth images, and calculate a difference between the first and the second positions, and a command generator to generate a command to control at least one of an actuator and a control surface based on the difference.