446 



Popular Science Monthly 



Working drawing showing details of a simple aero ice-racer. This entire machine may be 

 biiilt for less than twenty dollars, if good judgment is used in buying materials 



spring and a small wooden block, as can 

 be seen by referring to the drawings. 

 The bottom edge of the brake should 

 present several rough teeth to the ice. 

 This prevents any sudden catching due 

 to lumps or ridges in the ice. 



The small shields on the top of the 

 body are intended to cut down the re- 

 sistance caused by the bodies of the 

 passengers, and can be constructed of 

 metal or fiber. They are semi-conical 

 in shape as shown, and afford consider- 

 able protection from the cold. 



A motorcycle motor is very well 

 suited for use on a motor ice-racer. 

 These motors can be bought second hand 

 in running condition at most any price 

 from $8.00 up, and ranging in horse 

 power from 3 to 20. The smallest of 

 these weigh only about 40 lbs. complete, 

 and are capable of driving a small ice- 

 racer at considerable speed. 



The speeds possible with the aero- 

 driven ice-boat range very high when 

 the craft in question is properly designed 

 and constructed, and if sufficient power 

 is used. Even the smallest craft should 

 be capable of a speed of a mile a minute 

 when well made, and with a j)owerful 



motor a good machine should attain a 

 speed of nearly 100 miles an hour ; a 

 great deal, however, depends on how 

 well the body is designed and con- 

 structed, and how well the motor runs. 



Having described the aero ice-racer in 

 a general manner, it is next in order to 

 furnish detailed instructions for the con- 

 struction of a simple craft of this type 

 which will give the most satisfactory 

 service, and at the same time require the 

 least eflFort in the making. A machine 

 of this type is therefore described fol- 

 lowing the design in Fig. 1. 



To begin at the bottom and work up. 

 Three wooden runners should be made 

 of clear stock at least \" in thickness. 

 One of these is represented by the lower 

 portion of the rimner shown in Fig. 3. 

 The other two should be similar in shape 

 to the entire runner illustrated in the 

 same figure. The dimensions for these 

 are given in the drawing. The shape 

 can be laid out from the sketch by mark- 

 ing ofif the chief dimensions as indicated 

 and drawing in the curves free hand. 



A V-shaped groo\e •'>;" wide by 3/16" 

 deep is cut along the middle of the bot- 

 tom of these three runners with a miter- 



