In some monoplanes with the inverted _V_ wing arrangement, a dipping
of one wing answers, so to speak, to increase its concavity and thus
to augment the lifting force on that side. The sketch shows the normal
and distorted arrangement of wings: the inner limb being the one bent
down in rounding a curve. An equivalent plan was to change the angle
of inclination of one-half the sail by swinging it about a horizontal
pivot at the center or at the rear edge: some machines have been built
with sails divided in the center. The obvious objection to both of
these plans is that too much mechanism is necessary in order to distort
what amounts to nearly half the whole machine. They remind one of
Charles Lamb's story of the discovery of roast pig.
[Illustration: WING WARPING]
The distinctive feature of the Wright machines lies in the warping
or distorting of the _ends only_ of the main planes. This is made
possible, not by hinging the wings in halves, but by the flexibility
of the framework, which is sufficiently pliable to permit of a
considerable bending without danger. The operator, by pulling on a
stout wire linkage, may tip up (or down) the corners _cc´_ of the sails
at one limb, thus decreasing or increasing the effective surface acted
on by the wind, as the case may require. The only objection is that
the scheme provides one more thing for the aviator to think about and
manipulate.