Drift meter

This article is about the aircraft instrument for measuring wind speeds. For the World War I bombsight, see Drift Sight.
Douglas DC-6B drift meter in Finnish Aviation Museum

A drift meter, also drift indicator and drift sight, is an optical device used to improve dead reckoning for aircraft navigation. It consists of a small telescope extended vertically through the bottom of the aircraft with the eyepiece inside the fuselage at the navigator's station. A reticle, normally consisting of spaced parallel lines, is rotated until objects on the ground are seen to be moving parallel to the lines. The angle of the reticle then indicates the aircraft's drift angle due to winds aloft, and can be used to calculate the ground speed.

References

This article is issued from Wikipedia - version of the Thursday, June 21, 2012. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.