Search results
Results from the WOW.Com Content Network
Pilots calculate the Headwind or Tailwind Component and the Crosswind Component of local wind before takeoff. The direction of wind at a runway is measured using a windsock and the speed by an anemometer, often mounted on the same post.
The apparent wind is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. [citation needed]The velocity of the apparent wind is the vector sum of the velocity of the headwind (which is the velocity a moving object would experience in still air) plus the velocity of the true wind.
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.
Pilots can use a use a crosswind component chart to calculate the headwind component and the crosswind component. The red line in this image indicates a 30° angular difference at a 25-knot wind velocity. The headwind is about 22 knots, and the crosswind is about 13 knots. [1]
The wind triangle graphically represents the relationships among velocity vectors used for air navigation. In air navigation, the wind triangle is a graphical representation of the relationship between aircraft motion and wind.
Nomenclature Term described Vector Scalar Variables relating to speed; True wind velocity and speed V T: V T: Boat velocity and speed V B: V B: Apparent wind velocity and speed
The term , where is the speed, and is the fuel consumption rate, is called the specific range (= range per unit mass of fuel; S.I. units: m/kg). The specific range can now be determined as though the airplane is in quasi-steady-state flight.
It is also helpful to calculate the top of descent, or the point at which the pilot would plan to commence the descent for landing. The flight time will depend on both the desired cruising speed of the aircraft, and the wind – a tailwind will shorten flight times, a headwind will increase them.