The duck wing is of course the ancestor of our aircraft designed by the Soviet Union, but now the duck wing design has almost become the exclusive design of China's current warplanes, because our engine technology is not so advanced, we need to rely on this design to make up for the effectiveness of the duck wing is to increase the speed and altitude of the warplanes, the world's other advanced planes do not often use this design, the adoption of the duck wing is greatly for the stealth design has brought difficulties, although China has repeatedly said that it does not affect, but we also have the J-20 as an example of what to do. Difficulty, although our country has repeatedly shouted that does not affect, but we also found that it is constantly changing the specifications and shape of the duck wing, the so-called duck wing is a wing that is different from the main wing of a small wing, previously in the era of the propeller plane in the rear, and now in the front, compared to our planes and other countries aircraft can be seen.