Practical Flying (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 Excerpt: ...divisions is measured off against the reduced scale (E). If it measures over 6, but under 7, the exact amount can be calibrated by measuring along down the sloping lines. If the exact distance came to 6 on the top row of figures, plus 5 on the vertical row, the measurement would total ABC +.65 of E, so that, taking the length (A) as one unit, any distance can be measured in terms of that unit to two places of decimals. Another type of protractor consists of a square piece of transparent celluloid having a circle marked off in degrees from o to 360 described about its centre, attached to which is a piece of silk thread. At the top and bottom scales in metres and yards are marked off in convenient scales used in Continental maps, i.e., 1/80,000 and 1/100,000. To take a true bearing with this type of protractor, the central point is placed on the spot from which the bearing is to be taken, with the N. and S. line of the protractor corresponding to the true N. and S. of the map. The silken thread leading from the centre is stretched across the protractor and map to the point the bearing of which it is desired to take, and the angle it makes with the true N. and S. line is read off on the arc of the circle. To lay off a course with this protractor, which is graduated in the same way as an aeroplane compass, the centre point is placed over the starting position and the silken thread stretched across the map and protractor, the arc of which it must cut at the desired angle. A pencil line made down the thread will give the desired direction. How to lay the protractor on a map. CHAPTER VIII Preparing for a Cross-country Flight THERE are certain pilots who, when told to fly somewhere, hurry away into the air without proper preliminary study of their course and the co...