What is aileron? This is an aerodynamic control tool (roll rudders), which are equipped with conventional aircraft and created according to the "duck" scheme. Ailerons are located on the trailing edge of the wing consoles. They are designed to control the angle of inclination of the "iron birds": at the time of application of the rudder roll deflect in opposite directions, differentially. In order for the plane to lean to the right, the left aileron goes down, and the right aileron goes up, and vice versa.
What is the principle of roll control? Lift is reduced in that part of the wing, which is placed in front of the aileron, raised up. At the part of the wing, which is placed in front of the lowered aileron, the lifting force increases. Thus, a force moment is formed, which modifies the aircraft rotation speed around an axis identical to the longitudinal axis of the machine.
History
Where did the aileron first appear? This amazing device was installed on a monoplane, created in 1902 by innovator Richard Percy from New Zealand. Unfortunately, his car made only very unstable and short flights. The first aircraft to complete a completely coordinated roll using roll rudders was the 14 Bis made by Alberto Santos Dumont. The aerodynamic control used to replace the wing distortion performed by the Wright brothers.
So, we study further the aileron. This device has many advantages. The adjusting surface, which combines the flaps and rudders of the roll, is called flaperon (flaperon). So that the ailerons mimic the function of the flaps released, they are simultaneously lowered down. For long roll control, a simple differential rotation is added to this deviation.
To adjust the tilt of airliners with the above layout, a modified engine thrust vector, gas rudders, spoilers, rudder, transformation of the center of mass of the aircraft, differential displacement of high-altitude rudders and other tricks can also be used.
Side effects
How does aileron work? This is a moody mechanism that has some disadvantages. One of the side effects of its action is a slight yaw in the opposite direction. In other words, when using ailerons to rotate to the right, the plane can slightly move to the left at the moment of an increase in the roll. This effect appears due to the difference in drag between the left and right wing console caused by a change in lift when the ailerons oscillate.
A large drag coefficient is possessed by that wing console, in which the aileron is tilted down. In current control systems of "iron birds" this side effect is reduced by various methods. For example, in order to create a roll, ailerons are also shifted in the opposite direction, but at unequal angles.
Reverse effect
Agree, control of the aircraft requires skill. So, on high-speed cars with a significantly elongated wing, the roll reverse effect can be seen. What does he look like?
If a maneuvering load appears when the aileron located close to the wing tip is deflected, the wing of the aircraft turns out and the angle of attack on it deviates. Such events can smooth out the effect obtained from the aileron shift, and can lead to the opposite result.
For example, if it is necessary to increase the lifting force of a half-wing, the aileron deviates down. Further, the force directed upwards begins to act on the trailing edge of the wing, the wing turns forward, and the angle of attack on it decreases, which reduces the lifting force. In fact, the action of the roll rudders on the wing during reverse is similar to the effect of the trim tabs on them.
One way or another, roll roll rudders were found on many jet aircraft (especially on the Tu-134). By the way, on the Tu-22 due to this effect, the maximum Mach number was reduced to 1.4. In general, pilots have been studying aileron control for a long time. The most common methods for preventing roll rudder reversal are using ailerons-spoilers (spoilers are located near the center of the wing chord and, when released, practically do not cause it to twist) or installing additional ailerons near the center section. If the second option is present, the external (located near the tip) rolls necessary for productive control at low speeds are switched off at high speeds, and the lateral control is carried out due to internal ailerons, which do not reverse due to the impressive stiffness of the wing present in the center section area.
Control systems
Now consider the control of the aircraft. A group of airborne vehicles guaranteeing the adjustment of the movement of "steel birds" is called the control system. Since the pilot is located in the cockpit, and the rudders and ailerons are located on the wings and tail of the aircraft, a constructive connection is established between them. Her responsibilities include ensuring the reliability, ease and effectiveness of controlling the position of the machine.
Of course, with the displacement of the coordinating surfaces, the force affecting them increases. However, this should not lead to an unacceptable increase in voltage on the adjustment levers.
The airplane control mode can be automatic, semi-automatic and manual. If a person with the help of muscular force makes the piloting tools work, then such a control system is called manual (direct regulation of the liner).
Systems with manual administration can be hydromechanical and mechanical. In fact, we found that the wing of an airplane plays an important role in control. On civil aviation machines, two pilots carry out the basic adjustment using kinematic devices that control forces and movements, double command levers, mechanical wiring and control surfaces.
If the pilot controls the machine using mechanisms and devices that provide and improve the quality of the piloting process, the control system is called semi-automatic. Thanks to the automatic system, the pilot only controls a group of self-acting parts, which creates and changes the coordinating forces and factors.
Complex
The basic control of the airliner is a complex of on-board devices and structures, with the help of which the pilot activates adjustment tools that change the flight mode or balance the car in a given mode. This includes rudders, ailerons, and adjustable stabilizer. Elements that guarantee the adjustment of additional control parts (flaps, spoilers, slats) are called wing mechanization or auxiliary control.
The basic coordination system of the liner includes:
- command levers on which the pilot acts by moving them and applying effort to them;
- special mechanisms, executive and automatic devices;
- piloting wiring connecting basic control systems with command levers.
Exercise management
The pilot performs longitudinal control, that is, changes the pitch angle, deflecting the steering column from itself or towards itself. Turning the helm left or right and deflecting the ailerons, the pilot implements lateral control, tilting the car in the right direction. To shift the rudder, the pilot presses the pedals, which are also used to control the front landing gear during the movement of the liner on the ground.
In general, the pilot is the main link in manual and semi-automatic control systems, and flaps, ailerons, and other aircraft parts are just a way to travel. The pilot perceives and processes information about the position of the machine and the rudders, operating overloads, develops a solution and acts on command levers.
Requirements
Basic aircraft control must meet the following requirements:
- When controlling the machine, the movements of the pilot’s legs and arms, necessary for shifting the command levers, must coincide with the natural reflexes of a person that appear while maintaining equilibrium. Moving the command handle in the right direction should cause the movement of the "steel bird" in the same direction.
- The response of the liner to the shift of the command levers should have a slight delay.
- At the moment of rejection of the control tools (rudders, ailerons, etc.), the forces applied to the command handles should increase smoothly: they must be directed to the side opposite to the movement of the handles, and the amount of labor must be coordinated with the flight mode of the machine. The latter helps the pilot get a "sense of control" of the aircraft.
- The rudders must act independently of each other: deviation, for example, elevator can not cause the deviation of the ailerons, and vice versa.
- The angles of displacement of the steering surfaces must ensure the probability of flight of the machine at all required take-off and landing modes.
We hope this article helped you understand the purpose of the ailerons and understand the basic management of "steel birds".