HEREIN the author describes methods and shows instruments, tables, scales and curves used for air navigation. The ground-speed-and-drift meter devised by him and used with such remarkable success in the round-the-world flight with Wiley Post in less than nine days, on which the author was navigator, is illustrated and described.
Much has been accomplished in the last few years in providing methods and equipment for quickly and accurately determining the position and laying the correct course of aircraft, but considerable improvement remains to be made in instruments, particularly sextants.
No one method of navigation can be used under all conditions; a combination of four is necessary to achieve the best results. These four are (a) pilotage, or navigation by landmarks; (b) dead reckoning, or running a course forward from the last definitely known position by the known speed, drift and course of the plane; (c) celestial navigation, or ascertaining position from observations of the sun, moon and stars and correcting the course accordingly; and (d) radio navigation, or following a course by radio signal.
The author describes the several methods and mentions the directional gyro as the most valuable recent development both for blind flying and for maintaining an accurate and steady course under all conditions. If a course could be set and held to an error of 1 deg., and ground-speed and drift were known at all times, no other method of navigation would be needed. The author believes that eventually an automatic ground-speed-and-drift meter will be developed and navigation become more or less mechanical.
Celestial navigation has been made so simple and practical for aerial navigation by new equipment and methods that a line of position of the sun, moon or stars can be laid down in about 3½ min.; and, if precomputed curves are used, in 30 to 40 sec. An example is given of a line of position calculated from tables available for the purpose, and a method of finding the true position of the airplane is followed through. This method, which has been used only by the author and Mrs. Charles A. Lindbergh, has been highly successful.
For night navigation, the author has devised a transparent celluloid chart on which the course is laid down and which, when superimposed on a chart of star curves, enables the navigator to determine and plot a fixed position without any mathematical calculations.
A very satisfactory sextant would result, the author believes, from a combination of the best features of two sextants, one of which is compact and light and has good bubble illumination, while the other reflects the image of the sun in front of the bubble, thus eliminating the need of an astigmatizer.