A ceiling fan including a retention system and method of redundantly retaining a ceiling fan can include a ceiling fan motor assembly including a hollow motor shaft at least partially surrounded by a motor housing. A retainer plate is provided at the bottom of the motor housing including an opening. A retainer rod extends through the opening in the retainer plate and secures to the retainer plate. A support cable couples to the retainer rod to suspend the retainer plate from a structure, wherein the retainer plate is configured to redundantly retainer the ceiling fan.

Propulsion assembly comprising: an inner casing (13); an outer casing (3); an inter-duct casing (15) delimiting a primary duct (12) between the inner casing (13) and an outer wall (14), and a secondary duct (16) between the outer casing (3) and an outer wall (17); a fan capable of generating an air flow (24) circulating from downstream to upstream in the secondary duct (16); the assembly further comprising: at least one duct (27) for bleeding air from said flow (24), this bleed duct (27) comprising an inlet port (28) in the outer wall (17) and an outlet port (29) in the inner wall (14); an outer flap (30) movable between an open position and a closed position of the inlet port (28); an inner flap (31) movable between an open position and a closed position of the outlet port (29).

A ceiling fan assembly having a motor assembly with a rotating blade hub, and at least one fan blade mounted to the rotating blade hub with a blade span defined between a tip and a root, and defining an airfoil cross section including a rounded leading edge and a v-shaped trailing edge defining a chord therebetween. The blade comprising a pressure side surface and a suction side surface extending between the leading and trailing edges and including a hollow interior and including a tip opening at the tip and a root opening at the root for accessing the hollow interior. The at least one fan blade includes a thickness to chord ratio of less than about 15%.

An airfoil arrangement for a gas turbine engine may include a clearance device using a shape memory alloy movable to provide clearance between an airfoil and one or more other components of the gas turbine engine. The clearance device may be formed as part of a fan blade. The arrangement may be configured to reduce overall weight and dimensions of the gas turbine engine.

A system and method for providing feedback for an aircraft-bladed rotor about a longitudinal axis and having an adjustable blade pitch angle. At least one position marker is provided at the rotor, extends along an axial direction, from a first end to a second end, and has varying magnetic permeability from the first end to the second end. At least one sensor is coupled to the rotor and configured for producing, as the rotor rotates about the longitudinal axis, at least one sensor signal in response to detecting passage of the at least one position marker. A control unit is communicatively coupled to the at least one sensor and configured to generate a feedback signal indicative of the blade pitch angle in response to the at least one sensor signal received from the at least one sensor.

A device and a method for adjusting stirring blades on a stirring blade receptacle of a stirrer, wherein the stirring blades can be fixed with a stirring blade axis in receiving bores, which are arranged transversely to an axis of rotation and are a part of the stirring blade receptacle, at intended predetermined angle of attack relative to a virtual plane that is arranged transversely to the axis of rotation of the stirrer. An associated device body is provided with a receiving element for receiving the stirring blade receptacle with unfixed stirring blades. A stop is arranged on the device body for each lower face, which faces the receiving element and is a part of the stirring blades, outside the respective stirring blade axis. Each respective stirring blade is then brought into abutment against its associated stop, to place it into the predetermined angle of attack.

A device and a method for adjusting stirring blades on a stirring blade receptacle of a stirrer, wherein the stirring blades can be fixed with a stirring blade axis in receiving bores, which are arranged transversely to an axis of rotation and are a part of the stirring blade receptacle, at intended predetermined angle of attack relative to a virtual plane that is arranged transversely to the axis of rotation of the stirrer. An associated device body is provided with a receiving element for receiving the stirring blade receptacle with unfixed stirring blades. A stop is arranged on the device body for each lower face, which faces the receiving element and is a part of the stirring blades, outside the respective stirring blade axis. Each respective stirring blade is then brought into abutment against its associated stop, to place it into the predetermined angle of attack.

Methods and apparatus to retain a rotor blade are disclosed herein. An example apparatus includes a rotor blade coupled to a rotatable hub of an engine system. The rotor blade includes a root, a flange and a blade. The root and the flange are disposed inside a cowling, and the blade is disposed outside of the cowling. The example apparatus also includes a retainer disposed inside the cowling adjacent the flange. The flange is to engage the retainer to retain the rotor blade with the engine system.

Methods and apparatus to retain a rotor blade are disclosed herein. An example apparatus includes a rotor blade coupled to a rotatable hub of an engine system. The rotor blade includes a root, a flange and a blade. The root and the flange are disposed inside a cowling, and the blade is disposed outside of the cowling. The example apparatus also includes a retainer disposed inside the cowling adjacent the flange. The flange is to engage the retainer to retain the rotor blade with the engine system.

A ceiling fan and a fan set are provided. The fan set includes an upper fixed plate, a lower fixed plate, and a plurality of fan blades. The upper fixed plate has a plurality of first through holes that are in a ring-shaped arrangement, and the lower fixed plate has a plurality of second through holes that are in a ring-shaped arrangement. The quantity of the second through holes is equal to the quantity of the first through holes, and the positions of the second through holes respectively correspond to the positions of the first through hole. Each of the fan blades has an assembly portion, a blade portion, and three fasteners. The fasteners pass through the first through holes and the second through holes such that each of the fan blades is fastened between the upper fixed plate and the lower fixed plate.