Journal of the United States Artillery, 1919, Vol. 51

Download or read book Journal of the United States Artillery, 1919, Vol. 51 written by Coast Artillery Training Center and published by Forgotten Books. This book was released on 2017-10-20 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Journal of the United States Artillery, 1919, Vol. 51: Published Under Supervision of the Coast Artillery Training Center Staff It is the object of this paper to discuss methods of obtain ing information as to wind movement aloft. Air density is of course an important factor in firing but the methods of obtain ing it are different. The method now used to secure wind aloft data is the observation of small pilot balloons which are allowed to drift freely in the wind. The balloon is inflated with hydrogen and its movements are observed by means of a theodolite as it rises through successive layers. The balloon picks up the horizontal motion of the air practically instantaneously and the drift of the balloon gives the wind in different layers. These balloons are of two sizes; 6 inches and 9 inches in diameter. They are made of rubber and generally of two kinds, red and colorless. On cloudy days, red balloons are more easily observed than colorless ones. The smaller bal loons are distended to a diameter of 20 to 30 inches when inflated. The nine inch balloons are inflated to 30 to 40 inches. They are then released and some of them rise to great heights before bursting. Before inflating, the balloon is weighed. After inflating, the free lift is measured. This is the lifting force of the bal loon exclusive of its own weight. The total lift is the weight of the balloon plus the free lift. Knowing the weight and the free lift of a balloon it is possible to compute its ascensional rate with considerable accuracy. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.