"I think that this was one of Grannie's greatest contributions to aviation science"
- Pete Miller (at age 80)

Figure 1.
Figures 2. & 3.
Patented July 2, 1935 2,006,391
Zantford D. Granville, West Springfield, Mass.
Application May 18, 1933, Serial No. 671,603
6 Claims.   (CL 244-12)

      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

of the machine. The flap associated with the wing 5 and the operating means therefor will be described. The corresponding parts associated with wing 4 are substantial duplicates so that one description will suffice for both.

&  nbsp;   The leaf 7 of flap 6 is secured to a longitudinal wing spar 9 by means of hinges 10. The leaf 8 is secured to the leaf 7 by means of hinges 11. Links 12, fixedly secured to the upper surface of leaf 8, normally lie within the wing and extend forward from the leaf 8. Links 13 pivotally supported from fixed brackets 14 form movable pivots for the links 12. A rod 15 which lies within the wing and which is pivoted to the forward end of the link 12, is movable fore and aft to swing the flap between normal and depressed positions. The operation of the flap mechanism through rod 15 is controlled by the pilot through mechanism which will now be described.

      A crank handle 16 is disposed in the fuselage adjacent the pilot's seat for operating the flaps simultaneously and in unison. The crank handle is fast upon a horizontal shaft 17. The shaft also has fast upon it a sprocket 18. The sprocket 18 transmits rotary movement through a chain 19 to a sprocket 20 which is fast upon a screw 21. The screw 21 is universally mounted at one end by means of a ball and socket mounting 22, and is threaded into a sleeve 23. The sleeve 23 telescopes into a sleeve 24. The sleeves 23 and 24 are provided, respectively, with collars 25 and 26, and a coil spring 21 which encircles the sleeve 23 serves normally to force the collars 25 and 26 apart. A cross pin 28 carried by the sleeve 23 is adapted to travel in slots 29 formed in the sleeve 24. The cross pin 28 prevents rotation of the sleeve 23 and limits separation of the collars 25 and 26. The cross pin may, however, travel along the slot 29 whenever the force tending to maintain the flap in normal position, or to urge it toward normal position is great enough to overcome the expanding force of the spring 27.

      The sleeve 24 is provided with an ear 30 whereby it is pivoted to one arm of a lever 31. the lever 21 is mounted upon a horizontal pivot pin 32 and is adapted to be rocked from side to side by operation of the crank 16 and the train of connecting mechanism described. The upper arm of the lever 31 has a link 33 pivoted upon it and the lower arm has a link 34 pivoted upon it. One end of the link 33 is connected through a cable 35. which runs upon a pulley 36, to the upper end of a lever 37 which is fast upon a torque tube 38. The lower link 34 Is connected through a cable 39, which runs upon a pulley 40, to the lower end of the lever 37. The lower end of the lever 37 and the lower end of a parallel crank 41 are pivotally connected to the forward ends of the rods 15 and serve to operate the same.

These flaps were first installed on the 1933 Gee Bee R-2 racer flown by Russell Thaw. Together with a new longer, wider wing they lowered the landing speed of the R-2 from over 100 mph to 65 mph. The flaps were also installed on the unfinished Gee Bee C-8 transport, the 1934 G.M.D. R-6C "Q.E.D." built for Jackie Cochran and "Pete" Miller's 1937 "Time Flies" racer built for Frank Hawks. On February 12, 1934 Z.D. Granville was killed while landing his Model E Sporster at the Spartanburg, SC airport. He was attempting to avoid workers out on the runway when the engine stalled. His U.S. patent for the flap mechanism was finally granted in July 1935, more than a year after his death. His wife, Alta Granville, never obtained her widow's ownership because the legal costs would have been more than she could afford in her job as an office clerk at the Gilbert and Baker industrial plant.