wedges forwardly with sufficient speed to compel
momentum to maintain it in flight. To do so requires
but a small amount of energy. The head
resistance of the bird formation is reduced to a
minimum, and at such high speeds the angle of
incidence of the wings is very small, requiring but
little aid to maintain it in horizontal flight.



CHAPTER II

PRINCIPLES OF AEROPLANE FLIGHT


FROM the foregoing chapter, while it may be
rightly inferred that power is the true secret of
aeroplane flight, it is desirable to point out certain
other things which must be considered.

SPEED AS ONE OF THE ELEMENTS--Every boy,
probably, has at some time or other thrown small
flat stones, called "skippers." He has noticed
that if they are particularly thin, and large in
diameter, that there is a peculiar sailing motion,
and that they move through the air in an undulating
or wave-like path.

Two things contribute to this motion; one is the
size of the skipper, relative to its weight, and the