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Wind Theory: "Wind and the Navigator" 1957 USAF Training Film
🕑 Added 2020-11-09 18:50:54 +0000 UTCmore at http://quickfound.net/
Originally a public domain film from the United States Air Force, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://en.wikipedia.org/wiki/Wind_triangle
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
In air navigation, the wind triangle is a graphical representation of the relationship between aircraft motion and wind. It is used extensively in dead reckoning navigation.
The wind triangle is a vector diagram, with three vectors.
The air vector represents the motion of the aircraft through the airmass. It is described by true airspeed and true heading.
The wind vector represents the motion of the airmass over the ground. It is described by wind speed and the inverse of wind direction. Note that by convention wind direction is given as the direction the wind is from. In a vector diagram such as the wind triangle, wind direction must be stated as the direction the wind is blowing to, or 180 degrees different from the convention.
The ground vector represents the motion of the aircraft over the ground. It is described by ground track and ground speed. The ground vector is the resultant of algebraically adding the air vector and the wind vector.
The wind triangle describes the relationships among the quantities used in air navigation. When two of the three vectors, or four of the six components, are known, the remaining quantities can be derived. The three principal types of problems to solve are:
Solve for the ground vector. This type of problem arises when true heading and true airspeed are known by reading the flight instruments and when wind direction and speed are known from either the meteorological forecast or from determination in flight.
Solve for the wind vector. This type of problem arises when determination of heading and true airspeed can be done by reading the flight instruments and ground track and ground speed can be found either by measuring the direction and distance between two established points of the aircraft or by determining the drift angle and ground speed by reference to the ground.
Solve for true heading and ground speed. This type of problem arises during flight planning or during a flight, when there is a need to determine a true heading to fly and a ground speed with which to compute an estimated time of arrival.
The traditional method of solving wind triangle equations is graphical. The known vectors are drawn to scale and in the proper direction on an aeronautical chart, using protractor and dividers. The unknown quantities are read from the chart using the same tools. Alternatively, the E6B flight computer (a circular slide rule with a translucent "wind face" on which to plot the vectors) can be used to graphically solve the wind triangle equations...
https://en.wikipedia.org/wiki/Coriolis_force
In physics, the Coriolis force is an inertial or fictitious force that acts on objects that are in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise (or counterclockwise) rotation, the force acts to the right. Deflection of an object due to the Coriolis force is called the Coriolis effect. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology...
https://en.wikipedia.org/wiki/Geostrophic_wind
The geostrophic flow (/ˌdʒiːəˈstrɒfɪk, ˌdʒiːoʊ-, -ˈstroʊ-/) is the theoretical wind that would result from an exact balance between the Coriolis force and the pressure gradient force. This condition is called geostrophic equilibrium or geostrophic balance (also known as geostrophy). The geostrophic wind is directed parallel to isobars (lines of constant pressure at a given height). This balance seldom holds exactly in nature. The true wind almost always differs from the geostrophic wind due to other forces such as friction from the ground. Thus, the actual wind would equal the geostrophic wind only if there were no friction (e.g. above the Atmospheric boundary layer) and the isobars were perfectly straight. Despite this, much of the atmosphere outside the tropics is close to geostrophic flow much of the time and it is a valuable first approximation. Geostrophic flow in air or water is a zero-frequency inertial wave...
