m it.

Some designers have provided their water-planes with two floats; others
advocate a single float. The former makes the machine more stable when at
rest on the water, but a great rawback is that the two-float machine is
affected by waves more than a machine fitted with a single float; for
one float may be on the crest of a wave and the other in the dip. This
is not the case with the single-float water-plane, but on the other hand
this type is less stable than the other when at rest.

Sometimes the floats become waterlogged, and so add considerably to the
weight of the machine. Thus in Mr. Hawker's flight round Britain, the
pilot and his passenger had to pump about ten gallons of water out of
one of the floats before the machine could rise properly. Floats are
usually made with watertight compartments, and are composed of several
thin layers of wood, riveted to a wooden framework.

There is another technical question to be considered in the fixing of
the floats, namely, the fore-and-aft balance of the machine in the air.
The propeller of a water-plane has to be set higher than that of a land
aeroplane, so that it may not come into contact with the waves. This
tends to tip the craft forwards, and thus make the nose of the float
dig in the water. To overcome this the float is set well forward of the
centre of gravity, and though this counteracts the thrust when the craft
"taxies" along the waves, it endangers its fore-and-aft stability when
aloft.

CHAPTER XXXV. A Famous British Inventor of the Water-plane

Though Harry Hawker made such a brilliant and gallant attempt to win the
L5000 prize, we must not forget that great credit is due to Mr. Sopwith,
who designed the water-plane, and to Mr. Green, the inventor of the
engine which made such a flight possible, and enabled the pilot to
achieve a feat never before approached in any part of the world.

The life-story of Mr. "Tommy" Sopwith is almost a romance. As a lad
he was intensely interested in mechanics, and we can imagine him
constructing all manner of models, and enquiring the why and the
wherefore of every mechanical toy with which he came into contact.

At the early age of twenty-one he commenced a motor business, but about
this time engineers and mechanics all over the country were becoming
greatly interested in the practical possibilities of aviation. Mr.
Sopwith decided to learn to fly, and in 1910, after continued practice
in a Howard Wright biplan