364 



AGRICULTURAL ENGINEERING 



made with a larger engine, the difference in the cost of oper- 

 ation would be greater. 



The Type of Engine. The type of engine to select will 

 depend largely on the kind of service required. If the engine 

 is to be placed upon some horse-propelled machine, like the 

 binder, to drive the machinery, a light-weight engine is 

 highly desirable. Lightest weight may be secured by select- 

 ing a high-speed two-stroke cycle engine. The four-stroke 



Fig. 234. 



A gasoline engine used to operate the machinery of a grain 

 binder. 



cycle may be made quite light by introducing high rotative 

 speed and using refinement in construction. Usually, high 

 speed is conducive to increased wear and short life. Modern 

 automobile design has, by improved methods and materials 

 of construction, practically overcome the objections to the 

 high-speed engine. 



