William J. Claxton - The Mastery of the Air
Whether the engine has two, four, or six cylinders, the car is propelled in a similar way for all the pistons
assist in turning one shaft, called the engine shaft, which runs along the centre of the car to the back axle.
The rapid explosions in the cylinder produce great heat, and the cylinders are kept cool by circulating
water round them. When the water has become very hot it passes through a number of pipes, called the
"radiator", placed in front of the car; the cold air rushing between the coils cools the water, so that it can
be used over and over again.
No water is needed for the engine of a motor cycle. You will notice that the cylinders are enclosed by
wide rings of metal, 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.
But in 1909 there appeared a most ingeniously-constructed engine which was destined to take a very
prominent part in the progress of aviation. This was the famous "Gnome" engine, by means of which
races almost innumerable have been won, and amazing records established.
We have already referred to the engine shaft of the motor-car, which is revolved by the pistons of the
various fixed cylinders. In all aeroplane engines which had appeared before the Gnome the same
principle of construction had been adopted; that is to say, the cylinders were fixed, and the engine shaft
revolved.
But in the Gnome engine the reverse order of things takes place; the shaft is fixed, and the cylinders fly
round it at a tremendous speed. Thus the rapid whirl in the air keeps the engine cool, and cumbersome
tanks and unwieldy radiators can be dispensed with. This arrangement enabled the engine to be made
very light and yet be of greater horse-power than that attained by previously-existing engines.
A further very important characteristic of the rotary-cylinder engine is that no flywheel is used; in a
stationary engine it has been found necessary to have a fly-wheel in addition to the propeller. The
rotary-cylinder engine acts as its own fly-wheel, thus again saving considerable weight.
The new engine astonished experts when they first examined it, and all sorts of disasters to it were
predicted. It was of such revolutionary design that wiseacres shook their heads and said that any pilot
who used it would be constantly in trouble with it. But during the last few years it has passed from one
triumph to another, commencing with a long-distance record established by Henri Farman at Rheims, in
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