The Cordova daily times., 1919-06-20
FRIDAY, JUNE 20, 1919.
ENGINEERING A FLIGHT

Admiral Peary methodically planned his attack upon the North Pole. Elk perimentally he tried out his conclu- sions. He carefully selected his com panions, and insured both them and himself to the hardships of arctic travel The food and transportation problems were fully worked out. In the light of the careful and thorough preparatory work the result was foregone conclusion. Shackleton and Amundsen also won by similar methods.
 The flying men of the Navy set their goal upon the other side of the At lantic. They also took up their task in much the same way as the naval constructor undertakes the design of a battleship. The flight problem had many ramifcations, but the two most important were the men and the ma chine. Both were developed, the one by preliminary training upon the smaller hydroplanes and other out of the experience gained in the progress sive design and building of larger and larger plans. The plane which was finally developed, the NC class, repre- sents the combined efforts of many en- gineers and the experience of many flyers. A few of the characteristics of the plane are worth comment.
 The weight of the plane without load is 15,1O0 pounds; and, with it's maxi mum load, 2S,O0O pounds; the weight of gasoline, oil men and provisions being 13,100 pounds. The weight of the plan is 53.5 per cent of the con- bined weight of plane and load. To appreciate this better, the weight of a steel ore car of 50 tons capacity is about "A per cent of the combined weight of load and car. The plane carries O.S6 of it's unloaded weight, the ore 8 times it's own weight. In other words the plane requires 3.5 times as much material in it's construc- tion for an equivalent carrying weight.
 A steel ore car does not receive gentle treatment over the roadbeds and at the speeds that are reached in modnern traffic, but the strains which 1t must meet are proportionally less than for the plane travelling at speed of 80 knots. Nevertheless the plane is not subjected to the shocks, except at landing, that the ore car must meet The large surplus of material as compared with the ore car on the basis of weight-carrying capacity is undoubtedly required on account of the peculiar conditions under which the plane must operate. The com parison becomes less striking when we consider that the plane must carry its own motive power, whereas the car is only containing vessel
 The total area of the wings, banking planes, estabilizers and rudders is 2,981.6 square feet. The weight when fully loaded is 9.45 pounds per square foot of surface; and when gasoline and oil are exhausted the weight is 5.46 pounds per square foot. The aggre- gate power of the four motors is given as 16000 horsepower or an equivalent of O.536 horsepower per square foot of surface. The fully loaded weight is equivalent to 17.62 pounds per horse- power, and the weight, less gasoline and oil, is 1922 pounds per horsepower. Thus the plane at the end of its flight has much less weight to sustain and greater power per unit of weight. It is perhaps not difficult to see why planes of this size have considerable difficulty in rising at the beginning of a long flight.
 At the beginning of the flight, of the total weight the machine made up 53.5, the gasoline 39. and the oil 3.2, and the men and supplies AZ per cent. At the end of the flight. when the gasoline and oil are exhausted, the machine constitutes 92.6 and the men and sup piles "A per cent of the total weight. Thus the plane Is somewhat similar to the man who packs his grub upon his back on long trip Each day makes the load lighter. The plane. however, lightens its load at the rate of over 700 pounds per hour of flight. The man on foot lightens his pack at