Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Patent
1982-12-28
1984-10-09
Barefoot, Galen L.
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
244 75R, 244219, B64C 348
Patent
active
044757026
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to airfoils, and more particularly to a variable camber leading edge assembly for an airfoil.
BACKGROUND ART
A common way of modifying the lift characteristics of an airfoil for low speed operation is to use leading edge devices which either pivot or slide outwardly from the leading edge of the airfoil to a deployed position. With many such devices, there is a problem that during deployment there is an interruption of smooth airflow over the upper surface of the airfoil. Also, many such devices are not able to be deployed to intermediate positions while maintaining the proper flow of air over the airfoil.
Accordingly, there have appeared in the prior art various devices to vary the shape of the airfoil itself in a manner to vary the camber of the leading edge. Variable camber leading edges are particularly desirable in solving the airfoil stall problem for small, thin, swept-back wings which have good cruise performance, but require high lift devices to make their low speed performance acceptable. However, there is a problem of installing such variable camber leading edge devices on such wings since these thin wings have the least space available in which to house such devices.
Accordingly, it is an object of the present invention to provide a device to vary the camber of an airfoil, and particularly such a device used as a variable camber leading edge assembly. It is a more particular object to provide such an assembly with a flexible upper skin panel which is moved from a cruise position to a more curved high lift position, with the flexible panel having a desired aerodynamic contour throughout its path of travel between the upper cruise position and the downwardly deflected position, with the assembly being relatively compact, and with the major part of the aerodynamic load on the assembly being transmitted into the support structure so as to relieve loading on the drive mechanism of the assembly.
SUMMARY OF THE INVENTION
The present invention relates to apparatus to vary the camber of an airfoil, and more particularly to such apparatus which can advantageously be used as a leading edge assembly. This assembly comprises a main support structure for the airfoil and a moveable nose section at the leading edge of the airfoil. There is an upper skin panel having a rear part connected to said main structure, a forward part connected to the nose section, and an intermediate flexible panel portion extending between the rear part and the forward part.
There is actuating means operatively connected between the nose section and the support structure to move the nose section about a general center of rotation between a first upper position where the flexible panel portion has a lesser degree of curvature and the nose is more horizontally aligned, to a second lower position where the flexible panel portion has a greater degree of curvature and the nose section is aligned in a more downward slant. This is done in a manner so that the curvature of the flexible panel portion increases with movement of the nose section toward its second position.
The actuating mean comprises a cam track connected to one of the support structure and the nose section, and also a cam track contact member connected to the other of the support structure and the nose section. The cam track has a lengthwise axis curved in a generally arcuate path about said general center of rotation. The cam track contact member and the cam track are operatively interconnected to be constrained to move relative to one another along a path generally aligned with the lengthwise axis of the cam track. There is drive means to move the cam track and the cam track contact member relative to one another to move the nose section between its first and second positions.
In the preferred form, the cam track has a forward end connected to the nose section, and the cam track engaging member is connected to the support structure. The cam track contact member engages the cam track at two space locations along the lengthw
REFERENCES:
patent: 1917428 (1933-07-01), Burnelli
patent: 2650047 (1953-08-01), Carhart et al.
patent: 3089666 (1963-05-01), Quenzler
patent: 4131253 (1978-12-01), Zapel
patent: 4171787 (1979-10-01), Zapel
patent: 4247065 (1981-01-01), Grob et al.
Barefoot Galen L.
The Boeing Company
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