452 



FARM MOTORS 



adhere to the ground th'e best. In nearly all cases this 

 is not true, since the lug which is sharp is very apt to cut 

 through the earth, while one which is dull or round and 

 does not have such penetrating effect will pack the earth 

 down and thus make more resistance for itself while 

 passing through the earth. Nearly every engine builder 

 has a style of lug of his own. Fig. 338 shows a new 

 style of traction wheel which seems to be giving very 

 good results. The more weight that can be put on to 

 the drive wheels of an engine the better it will adhere 

 to the ground, providing the surface is firm enough to 

 support the load. This makes the matter of location of 



the main axles upon the 

 boiler an important factor. 

 When the boiler is rear- 

 mounted it is obvious that 

 more of the weight is 

 thrown upon the front 

 wheels, which act as a 

 guide, than when the 

 boiler is side-mounted. 

 Hence one would be led to 

 believe that the side-mounted traction engine will have 

 better tractive power than the rear-mounted. It is also in- 

 dicative of better tractive power when the pivot of the 

 front axle is as far ahead as possible. For this reason 

 some builders are now attaching a frame to the boiler 

 and crowding the front trucks ahead. Fig. 336 is an illus- 

 tration of this type of mounting. 



591. Width of tires. Where traction engines such as 

 are used for harvesting and threshing grain simultane- 

 ously are used for plow work or in the field an excep- 

 tionally wide tire is required. If an engine is to be used 

 for this work exclusively the wheels are made with the 



FIG. 336 



