ine, which has a gradually
increasing or decreasing angle of incidence from the centre of the
machine to either side. We wish it to be understood, however, that our
invention is not limited to this particular construction, since any
construction whereby the angular relations of the lateral margins of
the aeroplanes may be varied in opposite directions with respect to
the normal planes of said aeroplanes comes within the scope of our
invention. Furthermore, it should be understood that while the lateral
margins of the aeroplanes move to different angular positions with
respect to or above and below the normal planes of said aeroplanes,
it does not necessarily follow that these movements bring the opposite
lateral edges to different angles respectively above and below a
horizontal plane since the normal planes of the bodies of the aeroplanes
are inclined to the horizontal when the machine is in flight, said
inclination being downward from front to rear, and while the forward
corners on one side of the machine may be depressed below the
normal planes of the bodies of the aeroplanes said depression is not
necessarily sufficient to carry them below the horizontal planes passing
through the rear corners on that side. Moreover, although we prefer to
so construct the apparatus that the movements of the lateral margins
on the opposite sides of the machine are equal in extent and opposite m
direction, yet our invention is not limited to a construction producing
this result, since it may be desirable under certain circumstances
to move the lateral margins on one side of the machine just described
without moving the lateral margins on the other side of the machine to
an equal extent in the opposite direction. Turning now to the purpose of
this provision for moving the lateral margins of the aeroplanes in the
manner described, it should be premised that owing to various conditions
of wind pressure and other causes the body of the machine is apt to
become unbalanced laterally, one side tending to sink and the other side
tending to rise, the machine turning around its central longitudinal
axis. The provision which we have just described enables the operator
to meet this difficulty and preserve the lateral balance of the machine.
Assuming that for some cause that side of the machine which lies to
the left of the observer in Figs. 1 and 2 has shown a tendency to drop
downward, a movement of the cradle 18 to the right of said figures, as