This invention relates to airplane controls and has for an object to
provide practical and efficient flap mechanism adapted to be set by the pilot to retard
the forward motion of the machine and to increase the lift thereof. This invention resides
more particularly in improvements in the flap construction and in the flap operating means.
In accordance with one feature of the invention, provision is made of a
flap comprising a main leaf hinged to a wing, a secondary leaf hinged to the main leaf and
flap operating means connected to the secondary leaf. A more particular feature of the leaf
construction referred to lies in the combination therewith of operating mechanism adapted to
be housed normally wholly within the wing, and to move the flap structure between a normal
position, in which it is included within the wing boundaries, and a projected position, in
which it is depressed, without subjecting any of the operating parts to excessive strain.
It is a further feature of the invention that the operating train includes
spring means adapted to yield when excessive forces are en-countered. The spring operating
mechanism allows the projected flaps to close automatically to or toward normal position
under excessive lead such as would be encountered if the airplane were put into a steep
dive with the flaps down, or if the pilot opened the throttle to take the air again after
attempting to land. In either case, the increased speed would cause higher pressures on the
flaps which would at least partially overcome the pressure of the spring in the control,
allowing the flaps to close automatically without any attention on the pilot's part. The
flaps would, however, be automatically restored to the original projected positions upon
the restoration of normal pressure. Other objects and advantages will hereinafter appear.
In the drawings forming a part of this specification.
Figure 1 is a fragmentary perspective view
illustrating a portion of a monoplane embodying the present invention;
Figure 2 is a fragmentary sectional plan view
illustrating the flap operating mechanism of Figure 1; and
Figure 3 is a fragmentary transverse sectional
elevation illustrating the mechanism of Figures 1 and 2.
The airplane 1. which is illustrated as of the monoplane type
comprises a fuselage 1, an undercarriage 2, and wings 4 and 5.
Each of the wings 4 and 5 is provided adjacent the fuselage with a flap
6 comprising leaves 7 and 8. The flaps are symmetrically
disposed with reference to the longitudinal, central, vertical plane
