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Military


Xianglong - Wing

Xianglong / Flying Dragon HALE UAV"Xianglong" UAV biggest feature is that it has taken a rare wing layout, which in the history of Chinese aircraft design is a bold breakthrough. With the front wing, the rear wing of the two pairs of wings, and the front and rear wing connected to form a diamond-shaped frame. The front wing wing is connected to the front fuselage and swept and wagged the winged winglets ; the wing wing is connected to the top of the vertical tail, swept forward and underneath the reverse angle; the rear wing wing is at 70-90 connected together. Xianglong UAV compared with the conventional aircraft, even the wing aircraft with strong structure, anti-crash ability, anti-chatter ability, flight resistance is small, far range and other advantages.

"Xianglong" the biggest feature is the use of the wing layout. From the aerodynamic performance point of view, compared to the traditional long flight aircraft used in the large aspect ratio wing, connecting wing layout has a light weight, stiffness, induced resistance is small, high lift coefficient advantages. In the case of pneumatically equivalent, the wing structure is lighter than the conventional layout by 1/10 to 1/5, and the vertical deformation of the wingtip is only half of the conventional layout. In addition, the machine also uses the "Global Hawk" did not use the winglets, which also often help reduce cruise resistance, reduce fuel consumption, improve flight time.

In the early 1970s, NASA produced a small wing technology certification machine with this novel aerodynamic layout of the test. The wing concept is mainly to sweep the wing, the tail swept forward, both through the vertical stabilizer or direct rigid connection, the connection point can be in the middle of the wing can also be at the end of the wing. The design of the rhombus wing is mainly consistent with the wing sweep angle and the wing sweep angle. The aerodynamic layout of the wing is a kind of advanced aerodynamic layout which is suitable for high sag capacity and high structure efficiency. It is characterized by its special high natural attitude recovery ability and good aerodynamic stability. High profile recovery comes mainly from the front and rear of the layout of the good interference, because the tail to swept the wing and connected, and the connection point closer, the tail than the normal layout of the aircraft to be much larger, and from the wing near, by the machine Wing under the wash gas flow greater impact.

Under the wash stream it can reduce the tail's real air angle of attack, so when the front of the wing up to the stall angle of attack, the tail under the influence of the underflow is still in the normal state of lift; wing lost after the lift, Or normal, which gives the aircraft a strong natural bow recovery torque, let it quickly return to normal flight attitude. As the tail swept forward, its angle of attack stall range itself than the swept wing before the wing wide, superimposed the role of the flow, the aircraft flying high angle of attack natural recovery angle is quite wide, it is difficult to enter the stall state. These advantages have an invaluable role in simplifying the design of aircraft control systems .

There is also a benefit in the wing layout - high lift ratio. "Global Hawk" with a simple high aspect ratio than the straight wing, relying on more than 36 large aspect ratio in exchange for high lift ratio. But the straight wing is not suitable for high subsonic flight, "Global Hawk" flight speed can only reach 650 km / h or so. We know the altitude thin air, the height of 19,000 m sea level air density is only 8.4%, to fly it increased speed, or increases the wing area, wing loading is reduced.

The wing area of the wing layout is larger than the simple normal layout, and the wing load is light. In addition, the wing layout, especially the diamond-shaped wing of the wing will use the swept wing. The wing sweep can reduce the high sub-sonic wave resistance, so it can fly faster, flying faster also means that it can use a smaller wing and higher wing load. Small wings and high wing loads can greatly reduce aircraft resistance, or that the same wing and wing load can fly higher. The lift coefficient of the wing layout is lower than that of the ordinary straight wing, but because of the mutual interference can reduce the induced resistance, the actual resistance coefficient of the wing layout is also very low, the total lift resistance ratio is still quite high, very suitable for high altitude and high speed Flight mission requirements.

In addition, the wing layout there are some special controls on the ability, such as can be very convenient to achieve direct force control, this feature is still useful for the reconnaissance aircraft. The aircraft can control the flight path without changing the attitude, which is helpful to reduce the interference of the image caused by the change of attitude due to the change of attitude. The advantages of the wing layout There is also a very important aspect, that is, the natural advantages of the structure - the traditional wing is the use of beam bearing force, this structure, especially for the large aspect ratio wing elasticity caused by the material Aircraft wing deformation will affect the actual flight performance.

"Global Hawk" relies on superior strength of the material technology and technology to obtain a high aspect ratio wing, with the maximum load from the ground take off, the wing up to the curvature of up to 1.5 meters. And the wings of the wing before and after the wing of the ingenious design of the traditional wing of the force structure has undergone tremendous changes, the structure of the anti-twist wing because of the two have a considerable height difference between the wing and become a closed with a large The thickness of the structural support frame, which makes the wing rigid and elastic control requirements greatly reduced. At the same time, due to the force structure is more reasonable and stable, it can greatly reduce the weight of the aircraft structure, for improving the high altitude flight capability and flight time has a very important significance.



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Page last modified: 18-07-2019 18:36:29 ZULU