Aeronautics and astronautics – Aircraft sustentation – Sustaining airfoils
Reexamination Certificate
2001-12-27
2004-04-20
Carone, Michael J. (Department: 3641)
Aeronautics and astronautics
Aircraft sustentation
Sustaining airfoils
C244S225000, C244S221000, C244S178000, C244S075100
Reexamination Certificate
active
06722616
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to method and system of lift control of aircraft, and particularly such method and system of lift control of aircraft to generate suitable lift rapidly response to elevators operation.
2. Description of the Related Art
In general, flaps
82
are formed in rear edges of main wings
81
of an airframe
80
of an aircraft, as shown in FIG.
7
. The flaps
82
each normally structure portions of the main wings
81
.
The flaps
82
are operated to rotate at a suitable angle downward to the main wings from a main wing structuring position to a desired operating position, or rotate upward from the operating position in order to return to the position at which they form a general surface with the main wings
81
when the flaps
82
are operated.
An amount of lift acting on the airframe
80
increases when the flaps
82
are rotated in a downward direction, and the lift decreases when the flaps
82
are rotated in an upward direction. Furthermore, an amount of drag force also increases at the same time when the flaps
82
are operated in the downward direction. The flaps
82
are therefore also operated to rotate in the downward direction in cases when it is necessary to brake the aircraft
80
during flight.
Further, elevators
84
are generally mounted to horizontal tail
83
formed in rear portions of the airframe
80
of the aircraft. The elevators
84
are used in order to point a bow
85
in an upward or downward direction, and are installed in order to perform pitching control of the airframe
80
of the aircraft. The bow
85
therefore rises when a pilot in a cockpit pulls a control stick in a direction toward the rear of the airframe, and the bow
85
drops when the pilot pushes the control stick in a direction toward the front of the aircraft. In other words, the elevators
84
are rotated upward by pulling the control stick backward when the bow
85
is to be raised, and the elevators
84
are rotated downward by pushing forward on the control stick when the bow
85
is to be lowered.
Originally, when an aircraft is made to climb or descend, though depending upon speed of its flight, it takes a predetermined time that the airframe
80
actually climbs or descends after the pilot performs elevators operation by the control stick.
The changes of the attitude of actual airframe in pitching direction after a pilot performs elevators operation by the control stick is explained as an example of airframe
80
climbing in order of a state of the airframe
80
in the process of climb referred to figures.
The pilot first pulls the control stick toward the rear of the airframe and operates the elevators
84
to rotate upward, as shown in
FIG. 8
(
1
). Then, for this elevators operation as shown in
FIG. 8
(
2
), a tail portion
86
of the airframe
86
drops, the bow
85
points upward as a result and the attitude of the airframe
80
becomes upward. The angle of attack of the main wings
81
increases in this case, and the lift generated by airflow from the front becomes larger, as shown in
FIG. 8
(
3
). As a result, the airframe
80
climbs as shown in
FIG. 8
(
4
).
In this case the horizontal tail
83
, comprising the elevators
84
of the aircraft, are formed in the tail portion
86
of the airframe. The tail portion
86
of the airframe therefore falls first, and the bow
85
points upward as a result.
Accordingly, when the elevators operation is performed, it takes a predetermined time that the airframe
80
actually climbs or descends after the pilot performs the elevators operation because the aircraft
80
itself has a predetermined length. Further, in order for the airframe
80
to actually begin to climb, one must wait for a predetermined amount of lift to be generated when the bow
85
points upward and the angle of attack of the main wings
81
becomes larger. As a result, it takes a more time.
Therefore although automobiles, for example, are generally structured so that steering is performed in a front end portion of an automobile body by a steering wheel of the front end portion, in comparison time is intrinsically required for the airframe
80
to respond to operations of a rudder upward and downward in the case of aircraft. There is necessity for improvement in the response of the airframe when the elevators operation is performed.
Furthermore, in order to place the aircraft in a landing attitude, procedures such as the following steps relating to aircraft operation are used. Namely, the pilot first operates a throttle lever and descends while increasing or decreasing engine power. Flaps, which are lift control apparatuses mounted to the main wings, are then lowered to a predetermined angle, and the aircraft is decelerated. The elevators of the horizontal tail are then rotated upward by pulling the control stick toward the rear of the aircraft just prior to touchdown, rotating the elevators upward, raising the bow and thereby pulling up the airframe.
Lift is generated in proportion to the square of an airspeed. In this case, at a low speed state during landing, it takes longer time than that in high speed flight until a necessary amount of lift is generated at the main wings after operating the elevators to be upward. The airframe drops greatly during a period until lift is generated, and there are cases in which it is difficult to control the airframe.
It is therefore necessary for a pilot to descend the aircraft by performing the throttle control to increase or decrease the engine power and the raising and lowering operation of the elevators mounted on the horizontal tail during landing. The control of airframe during landing is thus extremely complicated, and this becomes a burden to the pilot in airframe.
Further, when the bow is raised by operating the elevators so as to obtain more lift, the airframe climbs due to the lift generated after a time lag, and there are cases in which an amount of time and distance required for landing is more than necessary.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of, and a system for, lift control of an aircraft in which a necessary amount of lift corresponding to a pilot's operation of elevators can easily be obtained.
Further, another object of the present invention is to provide a method of, and a system for, lift control of an aircraft in which an attitude of an airframe in an upward and downward directions can be controlled by conforming with elevators operation by a pilot.
Furthermore, another object of the present invention is to reduce a load required upon a pilot to control an aircraft during landing, when elevators operation is performed by the pilot during landing, by improving ability of response and performing necessary lift control in association with a lift control apparatus by conforming to elevators operation.
The present invention therefore has a structure in which lift control apparatuses such as flaps and flaperons operate in association when elevators operation is performed by a pilot, thus performing lift control rapidly corresponding to pilot's elevators operation.
Therefore, in accordance with the present invention, lift control apparatuses such as flaps and flaperons operate in association with pilot's elevators operation, and a necessary amount of lift can be obtained without a time lag. As a result, according to the present invention, ability of response of pitching control with elevators of an aircraft can be greatly improved over conventional pitching control.
In particular, although delicate throttle control and elevators operation have been necessary conventionally in order to avoid an airframe from descending during a period from after elevators operation until lift is generated because speed of the airframe is reduced during landing, a necessary amount of lift can be obtained without a time lag when performing elevators operation in accordance with the present invention. Difficulties in pilot's control of the airframe during landing can be reduced,
Carone Michael J.
Oliff & Berridg,e PLC
Semunegus L.
Toyota Jidosha & Kabushiki Kaisha
LandOfFree
Method of lift control of aircraft and system therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of lift control of aircraft and system therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of lift control of aircraft and system therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3275044