and these rings are quite sufficient to radiate the heat as
quickly as it is generated.



CHAPTER XXII
The Aeroplane Engine

We have seen that a very important part of the
internal-combustion engine, as used on the motor-car, is the
radiator, which prevents the engine from becoming overheated and
thus ceasing to work. The higher the speed at which the engine
runs the hotter does it become, and the greater the necessity for
an efficient cooling apparatus.

But the motor on an aeroplane has to do much harder work than the
motor used for driving the motor-car, while it maintains a much
higher speed. Thus there is an even greater tendency for it to
become overheated; and the great problem which inventors of
aeroplane engines have had to face is the construction of a light
but powerful engine equipped with some apparatus for keeping it
cool.

Many different forms of aeroplane engines have been invented
during the last few years. Some inventors preferred the radiator
system of cooling the engine, but the tank containing the water,
and the radiator itself, added considerably to the weight of the
motor, and this, of course, was a serious drawback to its
employment.