r horse-power. This meant that while a pre-war
engine of 100 horse-power would weigh some 400 lbs., the 1918 engine
developing three times the power would have less than double the weight.
The result of this improvement was that a scout aeroplane at the time
of the Armistice would have 1 horse-power for every 8 lbs. of weight
lifted, compared with the 20 or 25 lbs. of its 1914 predecessors. This
produced a considerable increase in the rate of climb, a good postwar
machine being able to reach 10,000 feet in about 5 minutes and 20,000
feet in under half an hour. The loading per square foot was also
considerably increased; this being rendered possible both by improvement
in the design of wing sections and by more scientific construction
giving increased strength. It will be remembered that in the machine
of the very early period each square foot of surface had only to lift
a weight of some 1 1/2 to 2 lbs., which by 1914 had been increased to
about 4 lbs. By 1918 aeroplanes habitually had a loading of 8 lbs. or
more per square foot of area; which resulted in great increase in speed.
Although a speed of 126 miles per hour had been attained by a specially
designed racing machine over a short distance in 1914, the average at
that period little exceeded, if at all, 100 miles per hour; whereas in
1918 speeds of 130 miles per hour had become a commonplace, and shortly
afterwards a speed of over 166 miles an hour was achieved.

In another direction, also, that of size, great developments were made.
Before the War a few machines fitted with more than one engine had been
built (the first being a triple Gnome-engined biplane built by Messrs
Short Bros. at Eastchurch in 1913), but none of large size had been
successfully produced, the total weight probably in no case exceeding
about 2 tons. In 1916, however, the twin engine Handley-Page biplane
was produced, to be followed by others both in this country and abroad,
which represented a very great increase in size and, consequently,
load-carrying capacity. By the end of the War period several types were
in existence weighing a total of 10 tons when fully loaded, of which
some 4 tons or more represented 'useful load' available for crew,
fuel, and bombs or passengers. This was attained through very careful
attention to detailed design, which showed that the material could be
employed more efficiently as size increased, and was also due to the
fact that a large machine was not liable to be