Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Reexamination Certificate
1999-09-07
2001-06-19
Jordan, Charles T. (Department: 3644)
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
C244S213000, C244S212000, C244S215000
Reexamination Certificate
active
06247670
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to devices for introducing perturbations into a flow field near a wing surface or other surface and, in particular, it concerns an active flaperon assembly for delaying or controlling boundary layer separation.
It has been found that mechanical energy (momentum) supplied in the form of perturbations of certain frequencies to the air flow passing over a wing helps to delay boundary layer separation from the surface of the wing, thereby increasing the lift, decreasing drag or otherwise improving the performance which can be obtained from the wing. This principle and various structures for implementing it are described in U.S. Pat. No. 5,209,438 to one of the co-inventors of the present invention. The aforementioned patent is hereby incorporated by reference as if fully set out herein.
While the principle described in the aforementioned patent has been demonstrated to be effective, to the best of the inventors' knowledge, no application of the principle has yet been widely implemented. This may be due to concerns as to the effect of the required wing modifications during normal flight when the perturbations are not required. While the aforementioned patent describes, on a highly schematic level, a number of possible structures for introducing the required perturbations, all of the structures modify existing wing designs to some extent and alter the basic wing profile.
Reference is also made to an unpublished U.S. patent application Ser. No. 09/045,220 to the other co-inventor of the present invention. This application addresses various piezoelectric materials and associated configurations suitable for generating perturbations in the air flow.
There is therefore a need for an active system for generating perturbations in the air flow over a wing which would require little or no modification of a conventional wing structure and which would not affect the air flow when not in use.
SUMMARY OF THE INVENTION
The present invention is an active flaperon assembly for a wing.
According to the teachings of the present invention there is provided, an active flaperon assembly for a wing, the wing including: (a) a main wing portion providing at least one primary lift surface; and (b) a flap hingedly attached to the main wing portion such that the flap can be deployed between a normal position in which the flap provides a flap surface which is substantially a continuation of the primary lift surface and a downwardly deflected position in which the flap surface is inclined downwards relative to the primary lift surface, the active flaperon assembly comprising: (i) a sheet of flexible material deployed near an intersection between the primary lift surface and the flap surface, the sheet being mechanically linked to the flap such that, when the flap assumes the normal position, the sheet is substantially withdrawn from the air flow across the primary lift surface and the flap surface, and when the flap is deflected downwards, the sheet projects into the air flow across the primary lift surface and the flap surface, an extent of projection of the sheet varying as a function of an extent of downward deflection of the flap, and (ii) an actuator associated with the sheet for generating mechanical oscillations in the sheet.
According to a further feature of the present invention, the sheet is mechanically linked to the flap such that at least a part of the sheet moves in an arcuate movement in step with, and about a common axis with, hinged motion of the flap relative to the main wing portion.
According to a further feature of the present invention, the main wing portion has a lower surface, the common axis being substantially at the lower surface.
According to a further feature of the present invention, the main wing portion has a lower surface, the common axis being at a position substantially medial between the primary lift surface and the lower surface.
According to a further feature of the present invention, when the flap assumes the normal position, the sheet assumes a generally curved configuration interposed between the main wing portion and the flap and, when the flap is deflected downwards, a part of the sheet projecting into the air flow is substantially flat.
According to a further feature of the present invention, the sheet is made from metallic material.
According to a further feature of the present invention, the actuator includes piezoelectric material.
According to a further feature of the present invention, the piezoelectric material forms part of a mechanical linkage between the sheet and the flap.
There is also provided, according to the teachings of the present invention, an active flaperon assembly for controlling a fluid flow field near a surface of a body, the active flaperon assembly comprising: (a) at least one rotatable element rotatably mounted relative to the surface about an axis of rotation, the rotatable element having at least one attachment surface located mainly within the body; (b) an elongated opening in the surface adjacent to the rotatable element; (c) a sheet of flexible material deployed within the elongated opening, the sheet being mechanically linked to the at least one attachment surface such that, when the rotatable element is rotated to a first position, the sheet is substantially withdrawn from the fluid flow near the surface, and when the rotatable element is rotated to a second position, the sheet projects into the fluid flow near the surface; and (d) an actuator associated with the sheet for generating mechanical oscillations in the sheet.
According to a further feature of the present invention, the body is a wing, the rotatable element is a flap and the elongated opening is a gap between the flap and a main portion of the wing.
REFERENCES:
patent: 2329177 (1943-09-01), Baker
patent: 2549760 (1951-04-01), Adams
patent: 2635837 (1953-04-01), Grant
patent: 3281095 (1966-10-01), Runge
patent: 3677504 (1972-07-01), Schwarzler
patent: 4015787 (1977-04-01), Maielli et al.
patent: 4120470 (1978-10-01), Whitener
patent: 4845357 (1989-07-01), Brennan
patent: 5096144 (1992-03-01), Fishwick
patent: 5209438 (1993-05-01), Wygnanski
patent: 5545007 (1996-08-01), Martin
patent: 5570859 (1996-11-01), Quandt
patent: 5626312 (1997-05-01), Head
patent: 5697468 (1997-12-01), Russel, Jr. et al.
patent: 5983944 (1999-11-01), Niv
patent: 6105421 (2000-08-01), Yao et al.
patent: 6123296 (2000-09-01), Mangalam
Eliahou-Niv Shaul
Wygnanski Israel
Best Christian M.
Friedman Mark M.
Jordan Charles T.
Ramot University Authority for Applied Research and Industrial D
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