Page:Popular Science Monthly Volume 88.djvu/472

 How to Build an Aero Ice-Racer

���By R. U. Clark

��A small and simple ice-racer, which should attain speeds of from sixty to one hundred miles an hour, according to the power of the engine used

ILLUSTRATED accounts of several motor - driven ice - boats have ap- peared for some time past in differ- ent publications. The machines depicted have been more or less alike, and prac- tically all have born a close resemblance to an ordinary sled fitted with a motor. In many cases these vehicles have been greatly overpowered, for although some of them have attained to speeds as high as eighty miles an hour, they have ac- complished this with considerable waste of power, principally because of their faulty design, both as regards body shape and propelling mechanism.

In designing any high speed vehicle the body and all the external parts should approximate a pure streamline form as nearly as possible. This fact has been thoroughly demonstrated dur- ing the past few years in the case of the aeroplane, and during the past season has been forcibly illustrated at the auto races. In the case of the motor-driven ice-boat, the necessity of a streamline body is far more apparent when it is considered that more than 95% of the tractile power is consumed in overcom- ing the resistance of the wind where traction is secured by direct aerial drive.

In addition to being essential to high

��speed, a closed-in ice-boat body affords a very necessary protection from the cold and wind, which alone would be reason enough for constructing such a vehicle along these lines. It therefore seems strange that, in spite of these facts, people should think a wooden cross equipped with runners and a motor, a fit apology for a motor ice- boat, but this is probably due to the fact that the advantages of closed-in con- struction are not fully realized, and con- sequently the builder does not care to take the time to build a decent body.

A motor ice-boat to be worth while should combine the following features : Strength, lightness, cheapness, proper streamline form, complete protection from the wind, and abo\e all ease of construction. Fortunately it is a very simple matter to design and build such a body, as will be at once apparent after a glance at the illustrations submitted herewith. As will be noticed from these sketches there are two possible seating arrangements which allow of simple streamline body construction. The ma- chine depicted in Fig. \, with the motor at the rear, is designed primarily for use as a single jiassenger machine, in which case the body need not be over five feet long, by about twenty inches

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