Pilot's Handbook of Aeronautical Knowledge

Preface

Acknowledgements

Appendix

Glossary

Index

 The Wind Triangle or Vector Analysis If there is no wind, the aircraft's ground track is the same as the heading and the GS is the same as the true airspeed. This condition rarely exists. A wind triangle, the pilot's version of vector analysis, is the basis of dead reckoning. The wind triangle is a graphic explanation of the effect of wind upon flight GS, heading, and time for any flight can be determined by using the wind triangle. It can be applied to the simplest kind of cross-country flight as well as the most complicated instrument flight The experienced pilot becomes so familiar with the fundamental principles that estimates can be made which are adequate for visual flight without actually drawing the diagrams. The beginning student, however, needs to develop skill in constructing these diagrams as an aid to the complete understanding of wind effect. Either consciously or unconsciously, every good pilot thinks of the flight in terms of wind triangle. If fight is to be made on a course to the east, with a wind blowing from the northeast, the aircraft must be headed somewhat to the north of east to counteract drift. This can be represented by a diagram as shown in Figure 15-19. Each line represents direction and speed. The long blue and white hashed line shows the direction the aircraft is heading, and its length represents the distance the airspeed for 1 hour. The short blue arrow at the right shows the wind direction, and its length represents the wind velocity for 1 hour. The solid yellow line shows the direction of the track or the path of the aircraft as measured over the earth, and its length represents the distance traveled in 1 hour, or the GS. In actual practice, the triangle illustrated in Figure 15-19 is not drawn; instead, construct a similar triangle as shown by the blue, yellow, and black lines in Figure 15-20, which is explained in the following example.
 Figure 15-18. A plotter (A), the computational and wind side of a mechanical flight computer (B), and an electronic flight computer C.

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