In a plane disposed at a small angle, A, as in
Fig. 26, the center of pressure is nearer the forward
end of the plane than with a greater positive
angle of incidence, as in Fig. 27, and when
the plane is in a normal flying angle, it is at the
center, or at a point midway between the margins.

PLANE MONSTROSITIES.--Growing out of the idea
that the wing in nature must be faithfully copied,
it is believed by many that a plane with a
pronounced thickness at its forward margin is one
of the secrets of bird flight.

Accordingly certain inventors have designed
types of wings which are shown in Figs. 28 and
29.

_Fig. 28 Changing centers of Pressures._

_Fig 29. Bird-wing structures._

Both of these types have pronounced bulges,
designed to "split" the air, forgetting, apparently,
that in other parts of the machine every effort is
made to prevent head resistance.

THE BIRD WING STRUCTURE.--The advocates of
such construction maintain that the forward edge
of the plane must forcibly drive the air column
apart, because the bird wing is so made, and that