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Aviation History
1919
1919 - 1472.PDF
AIRSHIP ENGINEERING PROGRESS IN THE UNITED STATES By J. C. HUNSAKER, Eng. D., Commander, Construction Corps, U.S. Navy (Continued from page 1456.) C Class Airships AFTER the completion of the B class ships, there was an almost complete stop to airship work in the United States, and an improved single-engine type which was designed in the winter of 1917-18 was not built. The reason for this was a discouraging report from abroad as to the effectiveness of airships on anti-submarine patrols. But the conclusions drawn from airship operations abroad in the bad winter weather proved to be premature, and as the good weather of the spring of 1918 permitted English and French airships to operate more freely, it became apparent that we should proceed immediately with a larger and faster type. Using this time all of the practical experience gained at home with B class ships and detailed information from abroad with regard to British, French and Italian airships, the Bureau of Construction and Repair undertook to take a step in advance and to design a ship of maximum performance. Full use was made of all available sources of information. In the initial stages of the design, the data regarding the performance of British airships, obtained from the British Admiralty through Lieut.-Comdr. P. L. Teed, R.N.V.R.— attached to the office of the British Naval Attache at Wash ington—-was especially helpful. Experience showed the advantages of high speed to cope with winds, great endurance to follow convoys long distances, and a duplicated power plant to lessen chances of complete breakdown at sea. The C class was designed with these ends in view. To obtain high speed, a new form of envelope and a car of very low resistance were developed from wind tunnel experi ments. The speed was to be obtained by a combination of high power with the utmost refinement in design to keep down resistance. Twin engines were used, giving a total of 250 b.h.p. The actual speed on trial was 60 m.p.h., making probably the fastest airship of its size ever built. The principal dimensions and characteristics of the C 5, as weighed off before her start for Newfoundland, were as follows:— Length Diameter Volume Purity .. 98-6 per cent Temperature 65 ° Fahr. Barometer .. 30 ins. 7,940 lbs. ^•Total lift J 192 ft. 41 ft. 9 ins. 182,000 cub. 12,700 lbs. ft. . . . . . . or . or . . 1,015 lbs. . 3,250 lbs. 120 lbs. 25 lbs. 250 lbs. 15 lbs. 85 lbs. olb. 4,760 lbs. 2,150 miles. 1,540 miles. Weight empty Weight carried— Crew (six men) . . Fuel Oil Navigating equipment Radio Food Water for drinking Ballast ., Useful load Endurance at 45 m.p.h., 47 hours, Endurance at 55 m.p.h.., 28 hours, During 1918 contracts were placed with Goodyear and Goodrich for 30 airships, the cars to be supplied from the Burgess Co., Marblehead, Mass. After the Armistice contracts were reduced to 15 ships. C 1, the first ship, was completed in September, 1918, and on October 22, 1918, flew 400 miles from Akron to Washington in 8f hours. It flew over the Navy Department building, and landed at Anacostia to permit an inspection by officers of the department. It then proceeded to Rockaway, Long Island. Later in the year, the C 1 was ordered to Key West, and flew down the coast, stopping at intermediate air stations. The C 5 on May 14, 1919, flew from Montauk to New foundland with six men in 25 hours 50 mins., a distance of 1,022 nautical miles on char4 without stop. This flight will remain for a long time as 1 notable achievement. The distance actually flown (not being in a straight line) was about 1,200 nautical miles, or very nearly the distance from Newfoundland to the Azores. The C 5 was unfortunately lost at Newfoundland in a gale while moored out in a field, and was, therefore, unable to attempt the Transatlantic flight, which was within her designed endurance. The power plant of the C I consists of twin Hispano-Suiza engines fitted with propellers to hold the engine down to 125 b.h.p. This is done to increase reliability, and because the envelope pressure is not sufficient for speeds over 60 m.p.h. The C 5 had twin Union 120 b.h.p. engines. Each engine has an electric self-starter and the usual equipment. The tanks are arranged in the rear of the car under the centre of buoyancy of the envelope, so that balance is not The U.S. Navy C-2 twin-engine dirigible, with experimental horseshoe patch suspension H74
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