th the corner d. Since the corner
a thus moves upward and the corner h moves downward, that portion of
the rope 19 connected to the corner a will be pulled upward through the
pulley 20 at the corner h, and the pull thus exerted on the rope 19 will
pull the corner b on the other wise of the machine downward and at the
same time pull the corner g at said other side of the machine upward.
This results in a downward movement of the corner b and an upward
movement of the corner c. Thus it results from a lateral movement of the
cradle 18 to the right in Fig. 1 that the lateral margins ad and eh at
one side of the machine are moved from their normal positions in which
they lie in the normal planes of their respective aeroplanes, into
angular relations with said normal planes, each lateral margin on this
side of the machine being raised above said normal plane at its forward
end and depressed below said normal plane at its rear end, said lateral
margins being thus inclined upward and forward. At the same time a
reverse inclination is imparted to the lateral margins bc end fg at the
other side of the machine, their inclination being downward and forward.
These positions are indicated in dotted lines in Fig. 1 of the drawings.
A movement of the cradle 18 in the opposite direction from its normal
position will reverse the angular inclination of the lateral margins of
the aeroplanes in an obvious manner. By reason of this construction it
will be seen that with the particular mode of construction now under
consideration it is possible to move the forward corner of the lateral
edges of the aeroplane on one side of the machine either above or below
the normal planes of the aeroplanes, a reverse movement of the forward
corners of the lateral margins on the other side of the machine
occurring simultaneously. During this operation each aeroplane is
twisted or distorted around a line extending centrally across the same
from the middle of one lateral margin to the middle of the other lateral
margin, the twist due to the moving of the lateral margins to different
angles extending across each aeroplane from side to side, so that each
aeroplane surface is given a helicoidal warp or twist. We prefer this
construction and mode of operation for the reason that it gives a
gradually increasing angle to the body of each aeroplane from the
centre longitudinal line thereof outward to the margin, thus giving a
continuous surface on each side of the mach