Why do planes go fast on the runway?

To takeoff, you must generate more lift than the aircraft weighs. If you are flying a fighter with very little wing surface, the speed allows you to generate enough lift with such a small wing. In an airliner, with very large wings, it is the great amount of weight which must be overcome, again requiring high speed.



Planes accelerate rapidly on the runway to generate lift, a physical force that must overcome the plane's weight to achieve flight. According to Bernoulli's principle and Newton's third law, air must move fast enough over the curved surface of the wings to create a pressure difference that "pushes" the plane upward. Most commercial jets need to reach a "rotation speed" (Vr) of approximately 150 to 180 mph (240-290 km/h) to take off. The engines operate at maximum or "flex" power during this phase to reach this speed before the runway ends. Once in the air, the plane continues to climb quickly because air is thinner at higher altitudes, which reduces drag and makes the flight more fuel-efficient for the remainder of the journey.

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While landing, speed is largely affected by the aircrafts current weight, commercial airplanes typically land between 130 and 160 mph (112 to 156 knots).

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Fuel Efficiency and Cost Savings One of the primary reasons for the reduction in flight speed is fuel efficiency. As the cost of aviation fuel has risen over the years, airlines have sought ways to minimize fuel consumption, and flying at slower speeds has proven to be an effective method.

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In jet aircraft, an overspeed results when the axial compressor exceeds its maximal operating rotational speed. This often leads to the mechanical failure of turbine blades, flameout and total destruction of the engine.

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The higher you fly, the more efficient it is The reason planes cruise at high altitudes is that they burn less fuel and can fly faster, as the air is less dense. At 30,000 feet and higher, it is also possible for aircraft to avoid weather systems, making it more comfortable onboard.

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What speed does a Boeing 747 take off at? A fully loaded Boeing 747 'Jumbo Jet' on a normal long haul flight would take off at a speed of around 160 knots which is 184 mph. The calculated take-off speeds vary depending on environmental conditions, runway length and weight.

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The North American X-15 may be the fastest plane in the world, with speeds at 4,520 mph and Mach 5.93. It's an experimental aircraft used and powered by NASA and USAF.

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What speed does a Boeing 747 land at? A 747 'Jumbo Jet' would typically land at a speed of about 145kts-150kts (166mph-172mph), depending on the landing flap setting selected.

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Hard landings can be caused by weather conditions, mechanical problems, overweight aircraft, pilot decision and/or pilot error. The term hard landing usually implies that the pilot still has total or partial control over the aircraft, as opposed to an uncontrolled descent into terrain (a crash).

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Question: Right after takeoff, it often seems that the pilot slows down and the plane drops somewhat. Why is that? I have noticed that it is pretty consistent. Answer: The sensation of slowing down is really one of slowing the rate of acceleration; this is due to reducing the thrust after takeoff to the climb setting.

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Airplane wings are shaped to make air move faster over the top of the wing. When air moves faster, the pressure of the air decreases. So the pressure on the top of the wing is less than the pressure on the bottom of the wing. The difference in pressure creates a force on the wing that lifts the wing up into the air.

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A Boeing 747 has a cross height of 35,105 ft, while the Embraer climbs 190 to 39,370 ft. The Airbus A380 can even fly at 43,097 ft.

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At any given time, there are between 8,000 and 13,000 airplanes in the air. Over 30,000 flights with two million passengers on board take off every single day in the United States alone.

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Mach 10 speed has never been achieved by a manned aircraft, though, so it has never been tested. Mach 10 has, however, been achieved by a spacecraft - on November 16, 2004, NASA launched the X-43A, an air-breathing hypersonic vehicle, and was able to reach real Mach 10 while being pushed into the atmosphere.

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Technically this is the so-called 'stall speed', where air passes over the wings fast enough to sustain altitude, and for small planes this can be less than 50km/h (31mph). But at such low speeds, the aircraft is easily destabilised, and could fail to leave the runway.

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The reason planes cruise at high altitudes is that they burn less fuel and can fly faster, as the air is less dense. At 30,000 feet and higher, it is also possible for aircraft to avoid weather systems, making it more comfortable onboard.

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Most commercial airplanes have a certified maximum altitude of about 40,000 to 45,000 feet. Regardless of its certified maximum altitude, if an airplane flies too high, it may fail in one or more ways. For starters, the engine may suffocate from a lack of oxygen.

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