Patent GB-269620-A (GB)
Title: Improvements in or relating to aircraft
IPC: B64C39/00
Filed: 1925-12-24
Abstract: 269,620. Edwards, A. H. Dec. 24, 1925. Machines supported by rotary propellers; propelling; steering and balancing.-A machine is supported by two rotary propellers on transverse shafts each propeller having blades so feathered about axes parallel to the shaft that the blades automatically rise forwardly from the lowest point of their cycle as the machine moves forwardly. The machine is propelled either by rotating the propeller shafts in the same direction as they automatically rotate or the rotary propellers may be left free and a screw propeller used for forward propulsion. Except in a modification referred to below, each blade starts from the lowest point at zero incidence or at a slight positive incidence which increases during the first quarter of the cycle and then diminishes to zero or a slight positive angle at the highest point. As the blade descends the incidence becomes increasingly negative until level with the propeller shaft and then becomes decreasingly negative until the initial position is reached. The extent of the variation of incidence and the plane of maximum positive and negative incidence may be independently adjusted by hand, the latter in the same or opposite directions on the two sides of the machine. The transverse shafts of the propellers may rotate together as a whole or they may be connected by a balance gear. They may be set at a dihedral angle to give lateral stability. The propellers described have each four aerofoil blades pivoted at their centres of pressure about transverse rods carried by radiating arms and each blade in one form has a sprocket wheel geared by a chain to a sprocket of the same size on a sleeve surrounding the propeller shaft. These sprockets 1<1> - - I<4> are shown in Fig. 6 mounted on separate sleeves, and each sleeve has a lug connected by a link O<4>, Fig. 5, to the end O<3> of a slotted link O which is pivoted at its other end M<2> to a bent lever M. This lever is pivoted at its opposite end N<2> to a projection N' carried by a normally fixed sleeve N, Fig. 6, mounted on a fixed sleeve D surrounding the propeller shaft C, which extends right across the aircraft. The slot in each lever O engages a roller P<2> on a lug P<1> mounted on another normally fixed sleeve P. Each bent lever M has a roller M<1> engaging a groove in a cam J having a toothed ring J<1>, Fig. 6, engaging a bevel wheel K<1> carried by a normally fixed sleeve K, and this wheel engages a toothed ring L<1> on the rotating hub L of the propeller, so that the cam J is driven in the opposite direction to the propeller. The rotation of the cam J causes the levers M to rock and consequently vibrate the levers O about the rollers P<2>, whereupon the links O<4> give a forward and backward motion to the sprockets I<1> - - I<4> to give the propeller blades their appropriate inclinations. By partially rotating the sleeves P the position of the rollers P<2> in the slotted levers O is varied, and consequently the extent of the variation of the incidence of the propeller blades is adjusted, and by partially rotating both of the sleeves P and N the phase of the blade inclinations is adjusted. For this purpose the sleeve N has a toothed ring N<4> geared to a second bevel wheel R<2> on the shaft carried by the ring K, the wheel R<2> being geared to a toothed wheel D<x> on the fixed sleeve D so that movement of the sleeve adjusts the position of the cam J as well as the levers M. The sleeve N has quadrants N<3> moved by cords Q and the sleeve P has quadrants moved by cords Q<1>, these cords being connected to controls as shown in Figs. 8 and 9. Both cords are connected to quad. rants V<1> mounted on a ring V on a drum T secured to a transverse tube R<1> which is moved to effect the simultaneous movement of the sleeves N, P by a lever R. The ring V is capable of being moved around the drum T, to effect opposite adjustments of the propellers on the two sides of the machine, by cords S<4> passed over pulleys T<1>, T<2> and anchored to a quadrant S<x> on a transversely pivoted lever S. This lever is mounted on a sleeve S<3> surrounding the tube R<1> and actuates an elevator at the rear of the machine through a lever S<6> and cords S<5>. Loops Q<x>, Q<xx> in the cables Q<1> are passed over fixed pulleys W<5>, on the side of the fuselage, and around pulleys W<4> on a sliding rod W<3>, the rods on the two sides of the machine being moved, to effect the adjustment of the sleeve P independently of the sleeve N, by arms W<2> on a transverse shaft W<1> moved by a lever W. Fig. 11 shows a modification in which the incidence of the blades is controlled by elevator planes a<1> mounted behind the blades a, these planes a<1> being controlled by cords q connected to the lever a<4> moved by a sliding sleeve l<4> engaged by a lever L<3> pivoted on the arm b of the propeller. The lever l<3> is linked to another lever k moved by a rod m<2> connected to a slide block m<3> in a slotted lever m pivoted at its end m<xx> to the arm b and having a roller m<1> engaging a cam j which can be partially rotated about the fixed sleeve d by cords Q to vary the phase of the feathering movement. The extent of the feathering movement is varied by moving the block m<3> along the slot in the lever m, a link m<x> being carried by a sleeve O<3> rotating with the shaft C and engaged by a sleeve O which can be moved axially by a lever p<4> engaging a groove O<1> in the sleeve O. Where freely rotating propellers are used, the mechanism for cyclically varying the incidence of the blades may be dispensed with, the blades in both forms of propeller being then maintained at a constant inclination. This inclination may be adjusted by rotating the sleeve N corresponding to that shown in Figs. 5 and 6, to which the four sprocket wheels I<1> - - I<4> in this modification would be fixed, or in the form corresponding to Fig. 11 by moving the sleeves O<3>, the levers m being replaced by bell crank levers pivoted at m<xx> and connected tc the rods m<2> and to the links m<x>.