Finding The Actual Speed And Direction Of An Aircraft. A Boeing 747 Jumbo Jet Maintains A Constant Airspeed (2023)

FAQs

What is the actual speed and direction of the 747 relative to the ground? ›

To find the direction, we can use the arctangent function: θ=arctan(650100)≈81.2∘ north of east. So, the actual speed of the 747 relative to the ground is approximately 661.4 mph, and its direction is approximately 81.2 degrees north of east.

A typical takeoff or rotation speed of a Boeing 747-400 model—which was the biggest selling of the 747 variants—is around 160 knots. The Boeing 747-8 Intercontinental, the most recent 747 passenger variant, has a typical cruise speed of Mach 0.86 while flying at an altitude of 35,000 feet, according to Boeing.

The 747 is a four-engined jet aircraft, initially powered by Pratt & Whitney JT9D turbofan engines, then General Electric CF6 and Rolls-Royce RB211 engines for the original variants.

Ground speed can be determined by the vector sum of the aircraft's true airspeed and the current wind speed and direction; a headwind subtracts from the ground speed, while a tailwind adds to it. Winds at other angles to the heading will have components of either headwind or tailwind as well as a crosswind component.

To calculate the speed, divide the distance by the time. Example: A package delivery drone flies 22.5 km in 15 minutes.

The 747 goes from its approximate takeoff speed of 200 mph (89.4 meters per second) to 0 mph in 27 seconds. Using the definition of acceleration, this means the brake-only stopping 747 has acceleration magnitude of 3.31 m/s². So, let's assume that the aircraft starts at 20 mph (8.94 m/s).

Different airplanes will require different speeds to take off. In order for a plane to take off, it must be going fast enough for the wings to generate enough lift to overcome the force of weight. A Boeing 747 under standard conditions must be going 296kph (184 mph) to take off.

I was surprised that despite it's length, the Boeing 747-400 Jumbo Jet has a rotation angle of 10 degrees.

Boeing's first 747 jumbo had much bigger engines which produced about 45,000lbs of thrust. The most recent model, the 747-8, has engines that produce 66,000lbs of thrust.

What is a propulsion system and how is it used to move an aircraft and a spacecraft? ›

A propulsion system is a machine that produces thrust to push an object forward. On airplanes, thrust is usually generated through some application of Newton's third law of action and reaction. A gas, or working fluid, is accelerated by the engine, and the reaction to this acceleration produces a force on the engine.

A propulsion system for an aircraft, which is air-breathing, consists of a mechanical power source (i.e., an engine of some kind) and a propulsor capable of doing work on the air to increase its momentum and so convert this engine power into a propulsive force, e.g., by utilizing a propeller, jet engine, etc., as shown ...

Simply subtract Vx from Vy and add the difference back to Vy, i.e. Vy + (Vy – Vx). For example, if Vx is 64 knots and Vy is 76 knots, the calculation would be 76 – 64 = 12 followed by 76 + 12 = 88. So in this example, Vcc would be 88 knots.

Boeing widebodies

Lufthansa previously bragged that its 747-400 could reach the highest altitude in its fleet, with a maximum service ceiling of 44,947 ft (13,610 m). The German flag carrier also flies the modern 747-8, which has a service ceiling of 43,100 ft (13,137 m).

At takeoff, the average speed of a commercial airplane is anywhere between 160 and 180 mph (140 to 156 knots).

Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.

The average velocity of an object moving in a constant direction is calculated with the formula: velocity = distance time . The SI unit for velocity is m/s, plus the direction the object is traveling.

The vector addition of airspeed and wind speed gives the ground speed of an aircraft: v_g = √(v_a² + v_w² - (2v_av_w cos θ). Thus, for a given airspeed, the ground speed becomes greater than airspeed when the angle between airspeed and wind speed is lower.

To find the distance flown in a given time, multiply GS by time. The distance flown in 1 hour 45 minutes at a GS of 120 knots is 120 × 1.75 or 210 NM. To find the GS, divide the distance flown by the time required. If an aircraft flies 270 NM in 3 hours, the GS is 270 ÷ 3 = 90 knots.

At 10,300 m (34,000 ft) cabin pressure was 843 hPa and changed 8 hPa for every 300 m (1000 ft) change in aircraft altitude (r(2) = 0.993; P < 0.001). Lowest cabin pressure was 792 hPa at 12 200 m (40,000 ft) but during only 2% of flight time was cabin pressure less than 800 hPa.

How to calculate acceleration? ›

Acceleration (a) is the change in velocity (Δv) over the change in time (Δt), represented by the equation a = Δv/Δt. This allows you to measure how fast velocity changes in meters per second squared (m/s^2).

The chart notes that if a Boeing 747-400 had an operational landing weight of 475,000 lbs (215,456 kg) and wanted to land at a runway located at sea level, then the suggested runway length would be a little over 1,500 meters, or roughly 5,000 feet.

Planes accelerate between 115 mph and 160 mph (185 km/h – 257 km/h or 100 -140 knots) on the runway. But, the exact acceleration depends on the plane's model, outside temperature, and other factors. Generally speaking, commercial planes require the most acceleration to take off, while small planes require the least.

Here are the rotation rules: 90° clockwise rotation: (x,y) becomes (y,-x) 90° counterclockwise rotation: (x,y) becomes (-y,x) 180° clockwise and counterclockwise rotation: (x, y) becomes (-x,-y)

If we know the distance flown and the altitude change, we can calculate the glide angle using trigonometry. The tangent (tan) of the glide angle (a) is equal to the change in height (h) divided by the distance flown (d).

The angle of rotation between the two points or vertices is the number of central angles times the measure of a single central angle: angle of rotation =m×α = m × α .

Thrust Calculation

The net thrust (F_N) of an engine is given by: F N = ( m ˙ a i r + m ˙ f u e l ) v e − m ˙ a i r v. Most types of jet engine have an air intake, which provides the bulk of the fluid exiting the exhaust.

The 747-100, for instance, was tested up to Mach 0.99, almost breaking the sound barrier. Other 747s, such as Air Force One, have approached the sound barrier but never crossed it. As such, it's unclear if we will ever know if Evergreen's 747-100 really went supersonic.

There are two general types of jet propulsion air-breathing and nonair-breathing engines.

What is the difference between propulsion and thrust? ›

Thrust provides the forward motion needed to sustain lift and counteract drag. It is also used to accelerate, gain altitude, and sometimes to maneuver. Propulsion is the act of moving or pushing an object forward.

The most widely used form of propulsion system for modern aircraft is the gas turbine engine. Turbine engines come in a variety of forms.

Jet engines, which are also called gas turbines, work by sucking air into the front of the engine using a fan. From there, the engine compresses the air, mixes fuel with it, ignites the fuel/air mixture, and shoots it out the back of the engine, creating thrust.

The turbine blades are cooled by engine bleed air. Air from the compressor stages of the engine is bled and fed to the blades to cool them. There are holes drilled on the blades through which the air is passed. In early jet engines, only Low Pressure (LP) air is passed through the blades.

The velocity of the plane with respect to the ground is equal to the velocity of the plane with respect to the air plus the velocity of the air with respect to the ground.

Ground speed is the actual speed that an aircraft travels over the ground and is also referred to as "shadow speed." Ground speed combines the aircraft's airspeed and the wind speed relative to the aircraft's direction of flight.

Airspeed is the vector difference between the ground speed and the wind speed. On a perfectly still day, the airspeed is equal to the ground speed. But if the wind is blowing in the same direction that the aircraft is moving, the airspeed will be less than the ground speed.

Ground speed: It is the time one takes to cover a certain distance over the ground. For example, at cruise altitude, aeroplanes might have a ground speed of 300–600 knots (555-1,110 kmph). However, the wind can alter the speed at which the aircraft passes over the ground.

From the aircraft, we can not directly measure the wind speed, but must compute the wind speed from the ground speed and airspeed. Wind speed is the vector difference between the airspeed and the ground speed. On a perfectly still day the wind speed is zero and the airspeed is equal to the ground speed.

The equation for speed is simple: distance divided by time. You take the distance traveled (for example 3 meters), and divide it by the time (three seconds) to get the speed (one meter per second).

What is the vertical speed of a 747 descent? ›

This means you should begin your descent 105 nautical miles from your destination, maintaining a speed of 250 KIAS (about 45 percent N1) and a descent rate of 1,500 to 2,000 feet per minute, with thrust set at idle.

Indicated Airspeed is the speed shown on the airspeed indicator. Calibrated Airspeed is indicated airspeed corrected for position installation error. Equivalent Airspeed is calibrated airspeed corrected for compressibility. True Airspeed is equivalent airspeed corrected for temperature and pressure altitude.

A very simple rule of thumb is to add 2% to the calibrated airspeed for every 1000 ft of altitude.

Indicated Airspeed and True Airspeed

The speed indicated on an ASI is known as the Indicated Airspeed (IAS). It is the speed of the aircraft relative to the body of air through which it is flying.

It is the vector sum of the velocity v_PT of the passenger relative to the train and the velocity v_TG of the train relative to the ground:v_PG = v_PT+v_TG. Each velocity symbol in Equation 3.7 contains a two-letter subscript.

Absolute altitude refers to the actual distance the aircraft is flying in relation to the ground and is expressed in “feet above ground level.” This type of altitude is generally determined using a radar altimeter, which measures how long it takes radar signals to reach the ground and reflect up to the plane.