Why is air speed called knots?

The term knot dates from the 17th century, when sailors measured the speed of their ship using a device called a “common log.” The common log was a rope with knots at regular intervals, attached to a piece of wood shaped like a slice of pie.

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Why is wind speed called knots?

The term knot dates from the 17th Century, when sailors measured the speed of their ship by the use of a device called a “common log.” This device was a coil of rope with uniformly spaced knots tied in it, attached to a piece of wood shaped like a slice of pie.

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Why do planes use knots instead of mph?

In modern times, a knot is a unit of speed that ties directly into the global latitude and longitude coordinate system. Therefore, in the aviation and nautical worlds, knots are oftentimes used in place of MPH and KPH since they are easier to navigate with.

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What does knots mean in speed?

The term “knot,” in reference to measuring the speed of air and water currents as well as boats and aircrafts, is defined as one nautical mile per hour. A nautical mile is slightly more than a standard mile. 1 nautical mile = 1.15 miles = 1.85 kilometers. 1 knot = 1.15 miles per hour = 1.85 kilometers per hour.

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What does knots mean in aircraft?

Knots is how the speed of aircraft and boats is measured. Both miles per hour and knots is a speed which is the number of units of distance that is covered for a certain amount of time. 1 knot = 1 nautical mile per hour = 6076 feet per hour. 1 mph =1 mile per hour = 5280 feet per hour.

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Why do the Air Force and Navy use NAUTICAL MILES? And What is a KNOT?

36 related questions found

Why do pilots call out 80 knots?

A: The 80-knot call is to ensure that both airspeed indicators are functioning and indicating properly. The rudder is becoming effective at that speed, too.

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How many knots can a 747 go?

It has a pronounced 37.5° wing sweep, allowing a Mach 0.85 (490 kn; 900 km/h) cruise speed, and its heavy weight is supported by four main landing gear legs, each with a four-wheel bogie.

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Why is a knot 47 feet?

The term knot derives from its former use as a length measure on ships' log lines, which were used to measure the speed of a ship through the water. Such a line was marked off at intervals by knots tied in the rope. Each interval, or knot, was about 47 feet (14.3 metres) long.

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How fast is 1 knot in km?

The knot (/nɒt/) is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.151 mph or 0.514 m/s).

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How fast is 21 knots on a ship?

So 21 knots is about 24 miles an hour – and 30 knots is about 34 miles per hour). With large vessels apparently it doesn't matter if the boat is on or under the water – the fastest submarines don't go much above 40 knots – so that's still slower than cars on the motorway.

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Can a plane fly at 100 knots?

For the typical single-engine plane, you'll be able to fly around 140 mph (122 knots). However, some of the more advance single-engine airplanes, like the Pilatus PC-12 NGX, have a top speed of 334 mph (290 knots).

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What is the takeoff speed of a 747 knots?

How Fast Does a 747 Go To Take Off? A typical takeoff speed for a Boeing 747 is around 160 knots (184 mph), depending on the jet's wing flap configuration, the number of passengers aboard, and the weight of their luggage, fuel load, current weather conditions, and other factors.

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How fast is 20 knots an hour?

So, for example, if your cruise ship is traveling at 20 knots (kn), that means it is going 23 miles per hour. What about 10 knots to mph? That's 11.5 mph. And 100 knots to mph: 115.

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Why is a nautical mile longer than a mile?

The nautical mile is longer than a regular mile as it is based on the Earth's coordinates of longitude and latitude, with one nautical mile equal to one minute of latitude. The International Hydrographic Organization use 'M' as the abbreviation for the nautical mile.

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How many knots does a plane need to take off?

Typical takeoff air speeds for jetliners are in the range of 240–285 km/h (130–154 kn; 149–177 mph). Light aircraft, such as a Cessna 150, take off at around 100 km/h (54 kn; 62 mph). Ultralights have even lower takeoff speeds.

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Why do nautical miles exist?

Nautical miles are used to measure the distance traveled through the water. A nautical mile is slightly longer than a mile on land, equaling 1.1508 land-measured (or statute) miles. The nautical mile is based on the Earth's longitude and latitude coordinates, with one nautical mile equaling one minute of latitude.

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Why don't we use nautical miles on land?

Nautical miles (and knots) are used by boats and airplanes, which can travel in straight lines, and use charts with latitude scales (nautical miles) along the margin. Road users don't do either, and thus have no impetus to use nautical miles.

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Why do knots have 28 seconds?

Sailors would put the weighted end in the water, and as the ship clipped along, a reel of the knotted rope would unfurl. If one knot was pulled off every 28 seconds, the ship was traveling at 1 knot. If five knots were being pulled off every 28 seconds, it was traveling at 5 knots, and so forth.

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Why do sailors have so many knots?

Why do sailors use knots? The simple answer is that knots are easier to navigate since, unlike land miles, they are based on the earth's degree of latitudes. One nautical mile is equal to one minute of latitude.

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Why does 747 have a hump?

To make room for the cockpit, and to keep the plane maximally aerodynamic, there had to be a hump. Later versions of the 747 extended the hump farther back and made room for more first-class seats.

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How long can a 747 fly without engines?

For example, with a glide ratio of 15:1, a Boeing 747-200 can glide for 150 kilometres (93 mi; 81 nmi) from a cruising altitude of 10,000 metres (33,000 ft).

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What is the takeoff speed of the A380?

Photo by Mark Harris. Update: The take-off speed of an A380 depends on various factors such as weight, fuel, weather conditions etc. The wheels go up just after V2 (safe take-off speed), at a positive rate of climb. Under typical conditions, it is usually between 150-170 knots (170-195 mph or 275-310 kph).

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