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Anonymous users2024-02-06The reason why the machine is able to fly in the sky is the result of the interaction of four forces.
The four forces are:
The thrust of the engine.
The resistance of the air.
The plane's own gravity.
The lift of the air.
The aircraft takes off by the thrust of the engine to generate speed, and the speed generates lift through the shape change of the wings, the thrust is greater than the drag, and the lift is greater than the gravity, so that the aircraft can take off and climb high. When the aircraft climbs to the cruising altitude, the small throttle is closed, which is called level flight, at this time, the lift is equal to gravity, and the thrust is equal to the drag, that is, the constant speed flight.
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Anonymous users2024-02-05An airplane can fly thanks to its wings and engines. When the airplane is moving, the air above the wing is fast, and the air under the wing is slow, so that an upward lift is generated, and the plane will fly smoothly into the sky. In addition, the engine in the aircraft is connected to the propeller, and the propeller rotates to drive the airflow, and the aircraft can fly in the sky for a long time.
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Anonymous users2024-02-04At such a fast speed, you can get a lot of airflow, and the supporting force generated is enough to make the plane fly in the sky.
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Anonymous users2024-02-03Airplanes are heavier-than-air aircraft, so they need to expend their own power to gain lift. And the ** of lift is the effect of air on the wing in flight.
The upper surface of the wing is curved and the lower surface is flat, so when the wing is in relative motion to the air, the air flowing through the upper surface travels a distance (s1) in the same time (t) than the air flowing through the lower surface (s2), so the relative velocity of the air on the upper surface is faster than the air on the lower surface (v1 = s1 t> v2 = s2 t1). According to Panulli's theorem – "The pressure exerted by a fluid on the surrounding matter is inversely proportional to the relative velocity of the fluid." ", so the pressure exerted by the air on the upper surface on the wing f1 is less than that on the lower surface f2 .
The resultant force of f1, f2 must be upward, which creates a lift force.
From the principle of the wing, we can also understand how the propeller works. The propeller is like a vertical wing, with the bump facing forward and the smooth facing backward. The resultant force of the pressure as it rotates forward, pushing the propeller forward, thus driving the aircraft forward.
Of course, the propeller is not simply raised and smooth, but has a complex curved surface structure. Older propellers were fixed shapes, while later designs were designed with relative angles that could be changed to improve propeller performance.
Flying requires power to move the aircraft forward, and more importantly, for the aircraft to gain lift. Early airplanes were usually powered by piston engines, and four-stroke piston engines were the mainstay. The principle of this type of engine is shown in the figure, which is mainly to inhale air, ignite and expand after mixing with fuel, drive the piston to reciprocate, and then convert it into the rotary output of the drive shaft
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Anonymous users2024-02-02Because the plane has wings, there are engines.
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