| 摘要 |
<p>808,740. Screw propellers helicopter rotors. REIMBERT, M. May 4, 1956 [May 9, 1955; Jan. 25, 1956], No. 13900/56. Classes 4 and 114. [Also in Group XXVI] In a screw propeller or helicopter rotor having an axis of symmetry and blades the tips of which are located at the rear of their roots, any section of the pressure face of a blade in a plane passing through the axis, is a curve, all the tangents to which make with the axis forwardly directed angles of 45 degrees or less. The ship's propeller shown comprises four blades 1 inclined towards the rear from their points of attachment to the hub 2. Any plane through the propeller axis X .. Y and the pressure face of a blade makes a curve such as C1, Fig. 3, of which all the tangents make an angle of 45 degrees or less with the axis X .. Y : as shown the curve is a parabola and the blade ends when the tangent makes an angle of 45 degrees with the axis. The pressure faces of the blades are concave towards the axis their curves forming a logarithmic or other spirals and the tips of the blades lie on a circle concentric with the axis X .. Y. The front and rear outlines of the pressure surfaces of the blade are curves joined to the cylinder of thrust by an arc of a helix. The leading edge of each blade overlaps the trailing edge of the adjacent blade. The hub 2 may be omitted and the blades be attached directly to one another.</p> |
