AIRCRAFT PROPULSION — TAYLOR 



263 



Figure 8. — Hispano-Suiza" engine, sectional transverse view. 



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 

 fig. 10, S) . The flat steel head had a tendency to warp and lose contact 

 with the aluminum jacket, which reduced valve cooling and also dis- 

 torted the valve seats, causing exhaust valves to leak and bum mider 

 conditions of severe operation. 



The development of this engine was continued in the U.S.A. after 

 World War I by the Wright-Martin Co., which later became the 

 Wright Aeronautical Corporation. One of the most important 

 changes made was to eliminate the steel cylinder head and to seat the 

 valves in bronze inserts pressed into the aluminum heads. This basic 

 improvement set a pattern for the most successful subsequent liquid- 

 cooled engines. 



In contrast to the all-forged construction of the "Gnome" and the 

 modern large radial engines, the "Hispano-Suiza" engine and its 

 descendants were essentially cast-aluminum engines except for the 

 moving parts and the cylinder barrels. 



