Compared with fixed-wing aircraft, what are the advantages of variable-swept wings
The needs of airplanes are different. In order to increase the flight speed, you must choose wings with a large sweep angle and a small aspect ratio to reduce the shock wave resistance of the aircraft. However, the lift of this type of wing is small at subsonic speeds. The induced resistance is large and the efficiency is not high.
Ordinary airplanes can only choose the swept angle of the wings at a certain angle. This is a compromise solution that takes into account both high-speed and low-speed performance. However, it can only be sparse in everything.
From the perspective of aerodynamics, to meet the aircraft's requirements for supersonic flight, subsonic cruise, and short moment takeoff and landing at the same time, it is best to make the wings swept back and use different sweep angles to adapt to different flights. status.
This is the basic design idea of the variable swept wing, which allows the wing to rotate back and forth to change the swept angle, so that the aircraft can take into account the aerodynamic requirements of high-speed and low-speed flight at the same time, and expand the range of flight speed.
Specifically, when the plane takes off, landing or needs to fly at a low speed, turn the wings forward to reduce the sweep angle to improve the low-speed flight performance of the aircraft and shorten the take-off and roll-off distance; and when the aircraft needs to fly at a high speed Turn the wing backward to increase the sweep angle to reduce the flight resistance and improve the high-speed flight performance of the aircraft.
Therefore, the variable-swept wing technology can solve the contradiction between high and low speeds of supersonic aircraft and improve take-off and landing performance.
Now, all kinds of dazzling maneuvers are made with the wings extended, hovering faster, and turning can be compared with the previous propeller aircraft.
Then, the wing suddenly turned to the back, as if an eagle suddenly preyed, and when it swooped down, the eagle would retract its wings, just so flamboyant, it began to make a high-speed pass through the field. Yes, this action immediately made everyone applaud.
(You readers can greatly imagine the appearance of the two wings turning to the back at the same time to complete the sweep. This action can be said to be the most handsome, and it is also the most classic scene in the hearts of every Tomcat fan.)
High speed pass!
The huge Tomcat fighter is like a flying lock mark. From one side of the runway, it flies to the other side by brushing the ground. The swept back of the wings makes its body look more coordinated. Almost parallel to the horizontal tail, the high-speed performance in this case is quite powerful.
Moore closed his eyes, he didn't want to look any more.
He knew that this time he would lose.
Although he knows about cheating, he can no longer talk about it. Kissinger's meaning just now is very obvious. No matter which one is sold, it is good for the US government. In the case that Congress does not provide funds, Foreign arms sales are the best way. Dismantling each other will not be allowed.
The other party must have gotten off the oil, but I don't know what method it is. I have been paying attention to it, and I haven't noticed that the other party has used a pumping truck. Now, it's too late to say anything. This business is a cheap navy!
When he closed his eyes, he missed a more exciting shot.
If you only do the prescribed actions, of course, you can't fully show the heroic attitude of the Tomcat fighter. Nathan's smooth movements are not yet over.
Pass at low speed.
For jet fighters, high-speed flight is the first consideration. When high-speed flight is taken care of, the low-speed capability is insufficient. That is to say, when the speed is low to a certain level, the aircraft will directly stall and crash because the speed is too low. .
The lower the minimum speed, it means that the aircraft's low-speed capability is very powerful, and it will be effective when dealing with some low-speed aircraft, such as helicopters or propeller aircraft.
The wing sweep angle of the Tomcat fighter is computer-controlled, and the appropriate sweep angle is selected according to the speed. However, humans can also intervene. Nathan skillfully toggles the switch during each maneuver. The wing was manually controlled in the fully extended position.
At this time, the Tomcat fighter was only one meter above the ground, and it was making a low-speed pass over the airport runway. When the F-15 fighter was just doing it, it was still 3 meters high.
At this time, the aircraft's altimeter completely loses its function, and it relies on the pilot's own feeling to fly. A little carelessness will cause serious consequences.
Nathan is sure.
When the plane flew to the middle, which was directly in front of the stands erected in the distance, Nathan suddenly turned on the afterburner and began to climb rapidly. While holding the joystick in his arms, he turned the rudder on the left. Push to the bottom.
If he did not fix the wing, he would start turning backwards at this time, and now, the wing is still in the unfolded state. In this astonishingly tight turn and climb, the surface of the wing suddenly rises up. White mist.
This white mist quickly evaporates from the wings and the rear fuselage, surrounding the entire rear fuselage, as if entering a fairyland. As the plane climbs, this white mist also rises with the plane. Formed a beautiful scene.
"Wow!" There was a sigh of astonishment at the scene. This picture is simply too beautiful, even in the sky of lofty ambition, there is no such lens, only the shape of a shock wave cloud breaking through the sound barrier of an airplane.
When the aircraft breaks through the sound barrier, a sharp cone-shaped cloud will appear. The nose of the aircraft passes through the head of the pointed cone. The pointed cone is shrouded in the center of the aircraft fuselage, which looks quite beautiful.
But now, unlike the pointed cone, these white mists are all pulled out by the fuselage itself, which looks even more exaggerated and has a sensational visual effect.
At this time, Brown had gotten off the F-15 fighter jet. He was standing at the end of the runway, looking at this magnificent scene. From his perspective, the sunset was behind the plane's fuselage, and the entire fuselage was soaring with fog and clouds. This action is really shocking.
Why didn't I think that I could still do this! He was already jealous in his heart.
The principle is not difficult.
This can also be called a shock cloud cluster, but it does not appear when it crosses the sound barrier. As long as the air humidity reaches a certain condition, the shock wave generated by the high-speed relative movement of the air when the aircraft reaches a certain flight speed can precipitate such a foggy cloud cluster.
To be specific, when the wing is making this sharp turn and rising, a large area of low pressure appears on the wing. According to the ideal gas state equation, when the pressure decreases, the temperature will decrease accordingly.
The Mirama base is near the sea, and the air humidity is high. When the temperature drops, the water vapor in the air will condense, forming a beautiful large white mist in the low pressure area of the wing!
This action was quite shocking, and it gave everyone present a very strong intuitive impression. I played with the clever Nathan. Of course, he hasn't finished the performance yet, and there are still good-looking things behind. (End of this chapter)