Mechanism wing МЕХАНИЗМ КРЫЛА САМОЛЕТА Wing aircraft

Mechanism wing МЕХАНИЗМ КРЫЛА САМОЛЕТА

Wing aircraft The wing is a key part of the aircraft structure, it creates a lift force: the airfoil is arranged so that the console is a plane divides the incoming airflow. Above the upper edge of the wing, a region of low pressure at the same time under the bottom an area of high pressure, wing 'pushed' up, and the plane climbs.

Straight wing Прямое крыло The main advantage is its forward wing high lift coefficient even at small angles of attack. This can significantly increase the specific load on the wing, and thus reduce size and weight , without fear of significant increase in take-off and landing speeds. This type of wing used in the subsonic and transonic aircraft with jet engines. Another advantage is the direct wing manufacturability , allowing cheaper production. The downside, of predetermining the unsuitability of such a wing in flight speeds of sound , is the sharp increase in the coefficient of drag in excess of the critical Mach number.

High lift system Механизация крыла Modern aircraft - the best example of what has been said. Specifically for our theme this example - the mechanization of the wing. Many of those who flew passenger airliners, and sat by the window near the wing saw before takeoff (or landing) wing like "crushes". From the back edge of the "crawl" the new plane, gently curving downwards. And when the run after landing on the upper surface of the wing is raised something like a near vertical plates. It also has elements of the wing. In this case, I mentioned the flaps and spoilers.

The main part of the wing The elements of the wing, by which they can actively influence on the lift and delay stall on takeoff and landing, can be attributed shields, flaps, slats. Shields Elements of mechanization krylanaibolee often used in the past because of the simplicity of the design. They can be simple and drawers. Simple plates - a control surface which in the retracted position closely adjacent to the rear surface of the lower wing. In the event of such a shield between him and the top surface of the wing of a zone of a vacuum. Therefore, the upper boundary layer in this zone as it is sucked. It draws its separation at high angles. This increases the speed of flow over the wing and consequently the pressure falls.

Slats The next element of the wing - the slats. To expand the capabilities of the aircraft flying at high angles of attack (and therefore at a lower rate), that is, as they say "tighten stall" and were designed slats. You've probably seen the planes after leaving the band does not smoothly rise up and do it intensely, rather abruptly his nose. This is just a plane with the applicable slats. The fact that the critical angle of attack. increased their use at 10 º -15 º. According to the construction and operation to the slats like the slotted flaps, only set, of course, on the leading edge of the wing.

Flaps Simple flap increases the lift by increasing camber. This increases the pressure on the lower wing surface. Retractable flaps also increases the wing area , which also increases its loadbearing properties. More effective in this planeschelevoy flap. The slit in it tapers and the air passing through it accelerates. He then interacts with the boundary layer , and accelerates it, preventing it from tearing and increasing lift. Such slots in the flap planes is advanced from one to three and the total increase in lift when the application reaches 90%.

The wing can be divided into three parts, the left and right half-plane, tsentroplan. Fyuzelyazh can be made carriers. (For example in airplanes PAKFA T-50, F-35, Su-27), the halfplane, in turn, are divided by the influx of the wing (if any), in some cases, the ears (what's this? ) And ending ->. Often there is an expression of the "wings", but it is mistaken with respect to the monoplane, as it consists of two half-planes.

Principle of operation The lifting force of the wing is created due to the difference of air pressures at the lower and upper surfaces. Air pressure also depends on the velocity distribution of air flow near these surfaces. One common explanation is the principle of the wing shock model of Newton : air particles collide with the lower surface of the wing, standing at an angle to the flow , the elastic bounce down (" downwash ") soglasnotretemu Newton's law , pushing the wing up. This simplified model takes into account the law of conservation of momentum, but completely neglects the flow around the upper surface of the wing , so that it gives an understated amount of lift.

Another common , but the occurrence of wrong pattern lift due to the pressure difference of the upper and lower sides of the profile arising according to Bernoulli's law [ 1] on the lower wing surface air flow rate is lower than the upper , so the lift of the wing is directed upwards. Usually considered a wing with flat - convex shape : flat bottom surface , the top - arched. The incoming flow is divided into two wing parts - upper and lower - in this case , due to the convexity of the wing , the upper part of the stream must pass a longer path than the lower. To ensure the continuity of the flow rate of air over the wing must be greater than underneath it, from which it follows that pressure on the upper side of the airfoil lower than the bottom , this pressure difference is caused by the lifting force. However, this model does not explain the occurrence of lift on the lenticular symmetrical or concave- convex profiles , when the flows above and below are the same distance.

To address these shortcomings, N. E Zhukovsky introduced the concept of circulation flow rate, and in 1904 he formulated theorem of Zhukovsky. The circulation speed allows to consider downwash and get much more accurate results in the calculations.

Flap (top to bottom): 1) The maximum efficiency (climb, level flight, reduced) 2) The largest area of the wing (take-off) 3) Most lift, high resistance (approach) 4) The greatest resistance, reduced lift (after landing)

One of the main drawbacks of the above explanation is that they do not consider viscosity of the air, i. e. the transfer of energy and momentum between the individual layers of the stream (which is the cause circulation). Significant impact on the wing may have the ground, "reflecting" the flow disturbance caused by the unit, and returning some of the momentum back (ground effect).

Also, in the above explanation does not reveal the mechanism of energy transfer from the wing to the thread that is doing work by the wing. Although the upper part of the air flow does have an increased rate , the geometric path length has nothing to do with it - this is caused by the interaction of layers of fixed and moving air and the upper surface of the wing. The flow of air along the upper surface of the next wing , "sticks" to it and tends to follow along the surface even after the inflection point of the profile ( Coanda effect ). Thanks to the progressive movement , a wing does work on this part of the acceleration of flow.

In fact, the flow around the wing is very complex three- dimensional non-linear and often non-stationary, the process. The lifting force of the wing depending on its area, the profile shape in plan, and the angle of attack, speed and flux density (Mach number), and a number of other factors.

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