GB443362A - Improvements in a combined device of a ship's propeller enclosed by a nozzle - Google Patents

Abstract

443,362. Propelling ships. KORT, L., 7, Jakobistrasse, Hanover, Germany. July 19, 1934, No. 21195. Convention date, July 25, 1933. [Class 114] Screw propellers are disposed within tubular nozzles of which the cross sectional areas toward the outlet are constant and toward the inlet increase rapidly. the inlet of the mouth being rounded off with sectional curves of comparatively large radii, and the nozzle is disposed adjacent to the hull which is shaped so as to direct the inflowing stream axially. The propeller placed in the position CB of minimum cross-sectional area in a nozzle from which a flow is directed to an outlet D of equal area and into which it is directed jointly by the shaped hull to the opening and rim of the nozzle the inlet area being greater than the area at B. The outside of the nozzle tapers to an angle 8. In order that the flow is not impeded the sectional form departs from that of a circle in the vicinity of the hull and extends upwardly in the form of lobes. In modifications with twin propellers the hull is extended to form the middle partition, and in some cases the twin nozzles are merged into one at their outlet. Each nozzle may be provided with a flap 2 hinged at 3 whereby the inlet area is adjustable. In other modifications, only a part of the nozzle in the vicinity of the propeller completely surrounds the propeller, the hull itself being arched forwardly at 6 with an edge 7 partly vertical and partly horizontal. In addition there may be a rearwardly extending upper shield with partly vertical and partly horizontal edge walls. In one construction a single engine is used to drive two propeller shafts through gears 17, these shafts begin arranged divergently. The propeller blades are formed of less pitch at their roots and tips than at their middle, and the pitch increases from the leading to the trailing edge.