Tailwind

Headwind as air or wind movement are referred to which are directed against the direction of movement of an object. An apparent headwind created as wind even in still air by the movement of the object itself In a figurative sense, with headwinds and efforts along several lines that are directed against one's own will, meant.

Importance

Headwind is more detrimental to transport because it decreases due to air resistance, the speed of travel. But sailing ships use the counter- flow of air also for propulsion. In aircraft, a special situation is given. In flight headwind is a hindrance because it reduces the actual speed over ground (English, groundspeed and GS). Here, the true airspeed does not change ( engl. true airspeed, TAS ). When starting and landing on the other hand supports a head wind the lift of an airplane. Therefore, takeoffs and landings are Always place against the prevailing wind direction.

Mathematical Description

The air resistance increases quadratically with the relative speed of the surrounding air. A zero wind with 20 km / h traveling cyclist has to overcome four times the drag force as a traveling at 10 km / h cyclists.

With increasing speed, the air resistance is therefore rapidly higher than the rolling resistance.

Consideration in the navigation

In modern aircraft the expected negative and crosswind is calculated from the relative position of the flight route to be encountered on the way high and low pressure areas - see minimum time route and single Heading Flight. Thus, the fuel consumption and the drift can be taken into account.