An impeller includes a hub, and a plurality of blades supported by the hub, the blades being arranged in at least two blade rows. The impeller has a deployed configuration in which the blades extend away from the hub, and a stored configuration in which at least one of the blades is radially compressed, for example by folding the blade towards the hub. The impeller may also have an operational configuration in which at least some of the blades are deformed from the deployed configuration upon rotation of the impeller when in the deployed configuration. The outer edge of one or more blades may have a winglet, and the base of the blades may have an associated indentation to facilitate folding of the blades.

A fan for a gas turbine engine comprises blades distributed around a hub. The blades include first and second blades, having geometric parameters and/or material properties that differ from each other to frequency mistune the fan. The blades are distributed about the hub with at least one second blade between adjacent first blades. The leading edge of the airfoil of the second blades is disposed axially aft of the corresponding leading edge of the first blades in at least a portion of the blade span.

A fan structure includes a frame body and a fan impeller. The frame body has a base seat and an annular wall. A bearing cup upward extends from a center of the base seat. At least one groove is annularly formed on inner wall face of the annular wall. The fan impeller is pivotally disposed in the bearing cup and has a hub and multiple blades outward extending from the hub. Each blade has an end edge. At least one protrusion section outward protrudes from the end edge into the groove. According to the design of the fan structure, the protrusion section can destroy the production of the vortex of the blade of the conventional fan so as to greatly minify the strength of the vortex. Therefore, the structure of the sound field of the vortex is changed so that the noise of the fan structure is lowered.

To provide a propeller for a boat propulsion apparatus, which propeller is excellent in maintainability including easy assembly and easy disassembly and reliably reduces the impact force caused by colliding with an obstacle and transmitted to the hub and the output shaft of the boat propulsion apparatus. The propeller includes: a shaft sleeve insertably and removably fixed to an output shaft of the boat propulsion apparatus; a plurality of blade components that are individually supported by the shaft sleeve and are arranged at intervals in a rotation direction of the output shaft; and a plurality of dampers disposed in such a manner that each of the plurality of dampers is disposed between adjacent two of the plurality of blade components.

The invention relates to the field of shipbuilding and more specifically to the screw propeller for a pod drive of a vessel, particularly an ice-going vessel, providing movement both ahead and astern in icy conditions where the ice is traversable, while also providing steering for the vessel, and to a pod drive comprising said screw propeller. To reduce the weight, and consequently the cost, of the pod drive, the screw propeller comprises a propeller hub, made so that it can be rigidly attached to the conical tailpiece of the propeller shaft, and screw propeller blades, each comprising a blade foil and a blade flange made in one piece, mounted on the propeller hub. The blade foil passes into the blade flange via a fillet joint forming the weakest portion for the possible destruction of the blade in the cross section of its foil, located immediately adjacent to the fillet joint. The outer surface of the blade flange has a profile, in its meridional cross section, curved inwards towards to the propeller axis, to reduce the distance from said blade foil cross section to the propeller axis.

A marine propeller includes a plurality of blades attached to a hub, with a disk area ratio of approximately 50%, a blade area ratio of approximately 61%, a blade rake angle of approximately 26.5 degrees, a blade skew angle of approximately 0 degrees, and wherein the angle between the chord line at any given radius r on said blades with a line that is parallel to the propeller axis of rotation and intersects the chord line, is equal to tan.sup.1(2Nr/Vo), where N is the rotational speed of the propeller at a selected design condition, Vo is the speed of the water entering the propeller (i.e. the speed of the vessel) at the design condition, and is the angle of attack at the radius r at said design condition, and where a is generally constant across most or all of the span of the blades at the design condition, and where the value of may be selected to be lower near the hub than for the remainder of blade, and where additional camber is provided in the leading edge region, such that leading edge camber line angle of attack is reduced relative to the chord line angle of attack for the overall blade section.

A marine propeller includes a plurality of blades attached to a hub, with a disk area ratio of approximately 50%, a blade area ratio of approximately 61%, a blade rake angle of approximately 26.5 degrees, a blade skew angle of approximately 0 degrees, and wherein the angle between the chord line at any given radius r on said blades with a line that is parallel to the propeller axis of rotation and intersects the chord line, is equal to tan.sup.1(2Nr/Vo), where N is the rotational speed of the propeller at a selected design condition, Vo is the speed of the water entering the propeller (i.e. the speed of the vessel) at the design condition, and is the angle of attack at the radius r at said design condition, and where a is generally constant across most or all of the span of the blades at the design condition, and where the value of may be selected to be lower near the hub than for the remainder of blade, and where additional camber is provided in the leading edge region, such that leading edge camber line angle of attack is reduced relative to the chord line angle of attack for the overall blade section.

A propeller for a water vehicle is provided, comprising a hub and at least two blades, said blades extending outwards from the hub in the radial direction, and the propeller having a uniform blade distribution. The problem addressed by the invention is to provide a propeller for a water vehicle which allows unwanted generation of noise to be efficiently reduced or avoided. According to the invention, the angular distance between the blade tips of two consecutive blades of the propeller varies in relation to the angular distance between the blade tips of two other consecutive blades.

A propeller for a water vehicle is provided, comprising a hub and at least two blades, said blades extending outwards from the hub in the radial direction, and the propeller having a uniform blade distribution. The problem addressed by the invention is to provide a propeller for a water vehicle which allows unwanted generation of noise to be efficiently reduced or avoided. According to the invention, the angular distance between the blade tips of two consecutive blades of the propeller varies in relation to the angular distance between the blade tips of two other consecutive blades.

An apparatus and system for a marine propeller assembly are provided. An aft retention member that may be used with the marine propeller assembly includes a base, an opposing nose and a conic body extending therebetween along a centerline normal to the base. The aft retention member also includes at least one protuberance extending radially away from a surface of the conic body. The protuberance extends axially along a surface of the aft retention member from the base arcuately convergent to a predetermined point between the base and a tip of the nose.