Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Reexamination Certificate
1999-05-25
2001-12-11
Eldred, J. Woodrow (Department: 3644)
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
C244S210000, C244S211000, C244S214000, C244S215000, C244S216000, C244S217000
Reexamination Certificate
active
06328265
ABSTRACT:
BACKGROUND-TECHNICAL FIELD
This invention relates to the means for extra lift production and regulation thereof on an aircraft wing.
BACKGROUND-DESCRIPTION OF PRIOR ART
For the extra lift production at low speeds, the prior art is using movable slabs that are used on the front portion of wing for the control of boundary layer over an upper camber surface of wing at higher attack angles. For complex slabs trajectories, there has been used various complex and bulky mechanisms disposed in the front portion of wing as it is the case in the following patents:
The U.S. Pat. No. 4,360,176 disclosed a track member mechanism, while the U.S. Pat. No. 4,399,970 disclosed a combination of a track member and a lever mechanism.
The U.S. Pat. No. 3,941,334 and the U.S. Pat. No. 4,427,168 show the deformation and lowering of the entire front portion of wing with the simultaneous extraction of slabs and formation of a slot.
The U.S. Pat. No. 3,897,029 discloses a formation of two successive slots on the front portion of wing using a pair of slabs.
All the solutions that use movable slabs require fairly large space within the front portion of wing for placement of very complex and bulky mechanisms, and the practical application on fighter airplanes with thin airfoils is limited. Additionally, these mechanisms are adding up extra weight to the overall weight of an aircraft.
On the fighter airplanes that have wings with thin airfoils and sharp leading edge, it is not possible in reality to apply any of the solutions with movable slabs and therefore, completely movable front portion of wing without slots is used instead. In this situation, the aircraft wing can not be set to attack angles high enough for the extra lift production due to inability to control the boundary layer over the upper camber surface of wing.
For the production of extra lift on a trailing edge of wing, the prior art is using different design solutions of flaps with one or two slots disposed in front of flaps for the control of the boundary layer over an upper surface of flaps. For this purpose, there have been used different complex mechanisms for both making complex flaps' trajectories and synchronized motion of segments that form slots in front of flaps as it is the case in the following patents:
The U.S. Pat. No. 4,447,028 discloses a relatively simple mechanism for making a complex motion with the simultaneous extraction and lowering of flaps that have their pivotal locations situated under a lower surface of wing.
The U.S. Pat. Nos. 3,987,983 and 4,172,575 disclose mechanisms for deflection of the segments of flaps, which form two successive convergent slots for the control of the boundary layer over an upper surface of flap segments.
The disadvantages of all the formerly mentioned technical solutions of the prior art for flaps are such that very complex mechanisms are used, which require significant additional space out of contour of wing for their placement in order to make convergent slots with high convergence ratio and air flux capacity. On the other hand, by applying simple mechanisms, convergent slots can not be formed with air flux capacity high enough for efficient boundary layer control.
For the lift regulation and roll control of the aircraft, the prior art has been using maneuvering surfaces aileron and flaperon that are pivoted synchronically on the left and right wing in the opposite direction.
By using rotational movement of ailerons and flaperons, small movements of the actuating means cause augmented and rapid changes in the airflow on the wing surface due to change in camber and the attack angle of a wing airfoil providing high efficiency of roll control at higher speed of the aircraft.
A problem arises at low speed and higher attack angles of the aircraft where it is not possible to control the boundary layer over the upper camber surface of wing, which results in significantly lower efficiency of roll control.
In order to increase the efficiency of the roll control at low speeds of flight and in the landing phase on the fighter airplanes, prior art is using inboard flaperons in addition to outboard ailerons/flaperons, which results in the significant loss of extra lift on the aircraft wing.
The following patents tried to solve the problems of the roll control at low speed in different ways:
In the U.S. Pat. No. 4,015,787, it is disclosed that segment
13
is automatically deflected with the deflection of flaperon
14
creating a convergent slot for the control of the boundary layer over an upper camber surface of flaperon
14
. However, this technical solution can not be used as the outboard aileron at high speed of flight.
In the U.S. Pat. No. 4,705,236, it is disclosed outboard ailerons without slots, which are used at higher speed of flight for roll control. By extracting the outboard aileron by means of track member at low speed of flight, slots are formed for the control of boundary layer over an upper camber surface of the aileron but without the possibility for the regulation of slot size and convergence simultaneously with the deflection of aileron in the maneuvering phase. In addition, this solution requires significant space for the placement of the regulating mechanism and actuating means out of wing contour.
The U.S. Pat. No. 3,921,942 discloses an application of the outboard ailerons without slots at high speed of flight and with slots at low speed of flight. However, the practical application of this solution faces significant difficulties due to problems regarding required rigidity on real constructions.
For the simultaneous yaw and roll maneuver at higher speeds, the prior art has been using maneuvering surface spoiler, which is functioning on the principle of loss of airlift and increase in drag only on one wing and it is not used for the stabilization of the aircraft and sharp yaw and roll maneuvers at low speeds.
BRIEF SUMMARY OF THE INVENTION
My slot forming segments and slot changing spoilers are used for the production and regulation of the extra lift on the aircraft wing. Accordingly, besides the objects and advantages of the patents described above in my patent application, several objects of my slot forming segments and slot changing spoilers are:
1. to provide for efficiency of maneuvering surfaces for roll control that are simultaneously used for extra lift production at low speeds and in the landing phase of the aircraft without significant loss of lift on the wings;
2. to provide for the regulation of drag on both wings during roll control when maneuvering surfaces are deployed for extra lift production;
3. to provide for a significant enlargement of the wings' surface area and increase in their camber for extra lift production at low speed and in the landing phase of the aircraft;
4. to provide for the efficient control of the boundary layer over the entire upper camber surface of wing when leading and trailing edge are deflected downwardly and the entire wing is set under a high attack angle especially on fighter airplanes with thin airfoils that have a sharp front portion of wing where solutions of the prior art for slabs can not be used;
5. to provide for the low drag and optimal deployment of the wings' maneuvering surfaces for the efficient maneuver at high speeds.
Further objects and advantages of my slot forming segments and slot changing spoilers are to provide for low weight of the aircraft, simple production, low cost, and a possibility for their implementation on the existing structures of the aircraft wings. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
Although the description contains many specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.
Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
REFERENCES:
patent: 2772058 (1956-11-01), Grant
patent: 31120
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