History of aicraft piston engines

11 also in a turbo supercharged version it held the

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Unformatted text preview: his engine was used in the NC flying b oats with a special economical carburetor setting developed at the Washington Navy Yard. The NC-4 was, of course, the first aircraft to cross the A tlantic, 16-27 May 1919.10 T he Liberty was also the first engine to fly n onstop across the American Continent (in the Fokker T-2, 2-3 May 1923, piloted by Kelly and McCready). 11 Also, in a turbo-supercharged version, it held the world's altitude records in 1920, 1921, and 1922, and in 1924 it powered the flight of several Army airplanes around the world. F rom a technical viewpoint, the outstanding airplane engine during W orld War I was undoubtedly the Hispano-Suiza V-8 (figs. 28, 29, and 34c, a nd table 1, p. 88), built first in Barcelona by a Swiss engineer, Marc Birkigt. It was adopted for French fighters in 1915 and used in the Spad (Societe pour Aviation et ses Derives) 7 and 13, perhaps the best fighters of World War I (see fig. 30). T he basic contribution of Birkigt to engine design was the en bloc c ylinder construction with a cast-aluminum water jacket containing steel c ylinder barrels and with enclosed and lubricated valves and valve gear.12 T he success of this engine started a revolution in liquid-cooled engine design which culminated in the Rolls-Royce Kestrel and Merlin, via the Curtiss K -12, C -12, a nd D-12 engines. It was also the prototype for the M ercedes and Junkers engines which were the backbone of the 1940-45 G erman Luftwaffe, together with en-bloc Russian, Japanese, and Italian designs. By 1917 H ispano-Suiza engines were being built in England and t he United States, as well as in France. 33 Figure 30.—An Hispano-Suiza V-8 powered this Spad 7 airplane, used by 27th Squadron, AEF, World War I, 1 917-1918, (Photo A-44832-C) T he only weakness in the early Hispano-Suiza engines, by standards of the time, was a tendency toward exhaust-valve burning. This was due to the fact that the steel cylinder heads were "dry," that is, they did not come directly into contact with the cooling water (see figs. 29 and 34c). T he flat steel head had a tendency to warp and lose contact with the a luminum jacket, which reduced valve cooling and also distorted the valve seats, causing exhaust valves to leak and burn under conditions of severe operation. T he development of this engine was continued in the United States after World War I by the Wright-Martin Company, which in 1919 b ecame the Wright Aeronautical Corporation. One of the most important changes m ade was to eliminate the steel cylinder head and to seat the valves in b ronze inserts pressed into the aluminum heads. This basic improvement set a pattern for the most successful subsequent liquid-cooled engines. I n contrast to the all-forged construction of the Gnome and the modern l arge radial engines, the Hispano-Suiza engine and its descendants were essentially cast-aluminum engines except for the moving parts and the c ylinder barrels. 34 P iston Engines After 1918 I n the period after 1918 h undreds of new engine types appeared. From the t echnical point of view, the period is marked by the following significant d evelopments: Further development of the liquid-cooled engine of the all-cast type, chiefly for military purposes T he development of the air-cooled radial engine to a place of dominance in all but fighter-type mi...
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This document was uploaded on 01/19/2014.

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