| 摘要 |
<p>362,198. Screw propellers and fans. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pitts burg, U.S.A.- (Assignees of Schmidt, H. F. ; 85, South Lansdowne Avenue, Lansdowne, Pennsylvania, U.S.A.) Jan. 2, 1931. No. 245. Convention date, Jan. 11, 1930. [Class 114.] A screw propeller blade has straight leading and trailing edges which diverge from their root to tip and the radial cross sections are of substantially uniform thickness with a working surface radially concaved toward the other oppositely disposed surface. Each blade 11 has a diverging leading and trailing edge 12, 13 whereby the tip 14 is substantially greater in length than the root portion 15 and whereby the projected area is a substantial percentage of the disc area. The blade decreases in thickness from the root 15 to the tip 14 and is radially concaved, the decrease in thickness from root to tip is variable and results in a curved taper. In place of a continuous curve the taper may be made up of three straight sided taper sections 17, 18, 19 joined by curves 21, 22 of large radii. Preferably the projected area is about 2/3rds of the disc area and the radial pitch is constant but the axial pitch increases from the leading to the trailing edge. The blades are formed separately with an enlarged root 15 which is secured in a groove in the hub. The hub is formed as a hollow cylinder 10 having an inner boss 34 which is stiffened by discs 35, 36.</p> |
