GB539677A - Improvements in aircraft of the helicopter type - Google Patents

Abstract

539,677. Aircraft. OPPERMAN, O. R. March 19, 1940, No. 5046. [Class 4] In aircraft of the helicopter type and wherein the lift is in part effected by the adaptation of the air currents set up by the rotation of the screws to produce aerodynamic re-actions on surfaces disposed in the path of the air currents, the re-action surfaces are formed with annular ridges or steps. In the form shown the supplementary lifting surfaces e, e', are located below a pair of direct lift oppositely rotating airscrews a,a<1> and are provided with annular ridges f, f', or they may be stepped or of louvre form so that the air currents sweeping thereover produce regions of low pressure above them. The airscrews and the supplementary lifting surfaces may be surrounded by open-ended cowlings d, d', part cylindrical and part frustoconical, as shown. Stabilizing wings w, Fig. 3, may be provided to assist horizontal flight, the wings being foldable close against the sides of the fuselage. For this purpose the folding mechanism is driven from one of the motors c<1> of the lifting aircrews through clutches m. The drive is transmitted through bevel gearing k to a shaft j journalled in a swivelling frame h at right angles to a shaft g pivoted in the frame to which the inner end of the wing is attached. The shafts j and g engage through gearing i and the wing is thereby firstly retracted through 90 degrees about a vertical axis. The gearing i is then locked and continued rotation of the shaft j causes the frame h with the shaft g and the wing to rotate through 90 degrees about a horizontal axis ; the duplicate mechanism thus enables both wings to take up the position shown.