On August 15, The Eastern Theater Command of the People's Liberation Army of China announced a video of a fighter jet overlooking Penghu Islands . In addition to arousing heated discussion, the video also caused controversy, that is, how far is the fighter jet from the Penghu Islands?
First, let's look at the picture of the fighter overlooking the Penghu Islands
Penghu Island consists of Xiyu Island and Penghu main island and Baisha Island and Hujing Island on both sides. See the picture below
Now we know that the picture overlooking the plane includes Xiyu Island and Penghu main island. The following figure is roughly marked
However, due to the perspective of the picture above, the length of Xiyu Island and Penghu main island is similar, but it is not actually the case. Moreover, the perspective of the aircraft is not a frontal perspective. As shown in the figure below, the angle of
is replaced with a frontal perspective. The figure below is
Through the perspective angle, according to the perspective relationship, the actual position of the aircraft is probably located at the vertex of a triangle with the connection length of the main island of Penghu, Hujing Island and Baisha at this perspective.
The following figure is
Penghu main island, Baisha and Hujing Island are connected for about 23 kilometers, and the Xiyu Island is about 12 kilometers. According to the ratio in the photo, the distance between the aircraft and the Xiyu Island and the Penghu main island can be roughly measured and estimated.
After measurement, the fighter's distance from the main island of Penghu is between 15-16 kilometers, while the distance from Xiyu is about 9 kilometers.
What does this mean?
Take J-10 as an example. The flight speed at high altitude is two Mach per hour and the low altitude is 1.2, that is, 1470 kilometers. Even if we calculate it based on the subsonic speed 900 kilometers, it takes 15 kilometers to take 1 minute, 9 kilometers to take 36 seconds. What can we do in 36 seconds? How many steps can we run? The missile doesn’t have time to take off.