我們要根據大型飛機模型的不同用途去選擇不同的翼型。翼型很多，好幾千種。但歸納起來，飛機的翼型大致分為三種。

We need to select different airfoils according to different uses of large aircraft models. There are many kinds of airfoils. But to sum up, there are roughly three types of aircraft airfoils.

一是平凸翼型，這種翼型的特點是升力大，尤其是低速飛行時。不過，阻力中庸，且不太適合倒飛。這種翼型主要應用在練習機和像真機上。二是雙凸翼型。其中雙凸對稱翼型的特點是在有一定迎角下產生升力，零度迎角時不產生升力。飛機在正飛和到飛時的機頭俯仰變化不大。

One is the planoconvex airfoil, which is characterized by high lift, especially at low speed. However, the resistance is moderate and is not suitable for inverted flight. This kind of airfoil is mainly used in training machines and video cameras. The second is the biconvex airfoil. The characteristic of the biconvex symmetric airfoil is that it produces lift at a certain angle of attack and does not produce lift at zero angle of attack. The nose pitch of the aircraft does not change much when it is flying and when it is arriving.

這種翼型主要應用在特技機上。三是凹凸翼型。這種翼型升力較大，尤其是在慢速時升力表現較其它翼型優異，但阻力也較大。這種翼型主要應用在滑翔機上和特種飛機上。另外，機翼的厚度也是有講究的。同一個翼型，厚度大的低速升力大，不過阻力也較大。厚度小的低速升力小，不過阻力也較小。實際上就選用翼型而言，它是一個比較復雜、技術含量較高的問題。其基本確定思路是：根據飛行高度、翼弦、飛行速度等參數來確定該飛機所需的雷諾數，再根據相應的雷諾數和您的機型找出合適的翼型。還有，很多真飛機的翼型并不能直接用于模型飛機，等等。這個問題在這就不詳述了。

This airfoil is mainly used in aerobatics. The third is concave and convex airfoil. The lift of this airfoil is large, especially at slow speed, which is superior to other airfoils, but the drag is also large. This airfoil is mainly used in gliders and special aircraft. In addition, the thickness of the wing is also exquisite. For the same airfoil, the lift at low speed with large thickness is large, but the drag is also large. The low-speed lift with small thickness is small, but the resistance is also small. In fact, the selection of airfoil is a relatively complex and technical problem. The basic idea is to determine the required Reynolds number of the aircraft according to the flight height, wing chord, flight speed and other parameters, and then find the appropriate airfoil according to the corresponding Reynolds number and your model. Also, many real aircraft airfoils cannot be directly used for model aircraft, and so on. This problem will not be detailed here.

機翼常見的形狀又分為：矩形翼、后掠翼、三角翼和紡錘翼（橢圓翼）。

The common shapes of wings are divided into rectangular wing, swept wing, delta wing and spindle wing (oval wing).

矩形翼結構簡單，制作容易，但是重量較大，適合于低速飛行。后掠翼從翼根到翼梢有漸變，結構復雜，制作也有一定難度。后掠的另一個作用是能在機翼安裝角為0度時，產生上反1-2度的上反效果。

The rectangular wing is simple in structure and easy to make, but it is heavy and suitable for low speed flight. The swept wing has a gradual change from the wing root to the wing tip, and its structure is complex, so it is also difficult to make. Another function of the sweep back is to produce an up-reflection effect of 1-2 degrees when the wing installation angle is 0 degrees.

三角翼制作復雜，翼尖的攻角不好做準確，翼根受力大，根部要做特別加強。這種機翼主要用在高速飛機上。

The manufacturing of delta wing is complex, the attack angle of wing tip is not easy to be accurate, and the force on wing root is large, so the root should be specially strengthened. This kind of wing is mainly used in high-speed aircraft.

紡錘翼的受力比較均勻，制作難度也不小，這種機翼主要用在像真機上。翼梢的處理。

Spindle wings are uniformly stressed and difficult to make. This kind of wing is mainly used in video cameras. Treatment of wing tip.

由于機翼下面的壓力大于機翼上面的壓力，在翼梢處，從下到上就形成了渦流，這種渦流在翼梢處產生誘導阻力，使升力和發動機功率都會受到損失。為了減少翼梢渦流的影響，人們采取改變翼梢形狀的辦法來它。更多相關飛機模型的事項就來我們網站http://snakedoctor.net咨詢吧！

Since the pressure below the wing is greater than the pressure above the wing, vortex is formed at the wing tip from bottom to top. This vortex produces induced drag at the wing tip, causing loss of lift and engine power. In order to reduce the influence of wingtip vortex, people take the method of changing the shape of wingtip to solve it. For more matters related to aircraft model, please visit our website http://snakedoctor.net Ask!