Beyond the propellers there are two little vertical planes which
can be moved to one side or the other by a control lever in front
of the pilot's seat. These planes or rudders steer the machine
from side to side, answering the same purpose as the rudder of a
boat.

In front of the supporting planes there are two other horizontal
planes, arranged one above the other; these are much smaller than
the main planes, and are known as the ELEVATORS. Their function
is to raise or lower the machine by catching the air at different
angles.

Comparison with a modern biplane, such as may be seen at an
aerodrome on any "exhibition" day, will disclose several marked
differences in construction between the modern type and the
earlier Wright machine, though the central idea is the same.



CHAPTER XXVI
How the Wrights launched their Biplane

Those of us who have seen an aeroplane rise from the ground know
that it runs quickly along for 50 or 60 yards, until sufficient
momentum has been gained for the craft to lift itself into the
air. The Wrights, as stated, fitted their machine with a pair of
launching runners which projected from the under side of the
lower plane like two very long skates, and the method of
launching their craft was quite different from that followed
nowadays.