In some embodiments, a rotorcraft includes a fuselage, a tailboom, a drive system and a variable thrust cross-flow fan system. The cross-flow fan system includes a cross-flow fan assembly that is mechanically coupled to a drive shaft and operable to rotate with the drive shaft about a longitudinal axis. The cross-flow fan assembly includes first and second driver plates having a plurality of blades rotatably mounted therebetween. The blades are disposed radially outwardly from the longitudinal axis and have a generally circular path of travel when the cross-flow fan assembly rotates about the longitudinal axis. The blades are moveable between a plurality of pitch angle configurations. A control assembly is coupled to the blades. The control assembly is operable to change the pitch angle configuration of the blades to generate variable thrust at a substantially constant rotational speed of the cross-flow fan assembly.

An ultrashort nacelle configuration employs a fan cowl having an exit plane and a serrated trailing edge. A variable pitch fan is housed within the fan cowl. The variable pitch fan has a reverse thrust position inducing a reverse flow through the exit plane and into the fan cowl. The serrated trailing edge forms a plurality of vortex generators configured to induce vortices in the reverse flow.

A blower assembly for advancing the flow of air in an air flow device at a selected one of a plurality of air flow rates is provided. The blower assembly includes a blower housing defining a body thereof and a wall of the blower housing moveably secured to the body, a blower wheel rotatably mounted to the blower housing and a motor for rotating the blower wheel at a selected one of a plurality of rotational speeds. The blower assembly further includes a motion device secured to the body and to the wall. The motion device moves the wall relative to the body to a selected one of a plurality of distinct wall positions. The motor rotates the blower wheel at a selected one of a plurality of rotational speeds. A controller calculates optimum wall position and rotational speed to provide for minimal energy usage rate.

A gas turbine engine includes a fan having a plurality of fan blades configured to rotate about a central axis of the gas turbine engine. Each fan blade is configured to pivot about a pitch axis that extends radially away from the central axis to vary a pitch of the fan blade.

A fan for a gas turbine engine is disclosed. The fan includes a fan disk and a plurality of fan blades coupled to the fan disk. The fan disk is adapted for rotation about a central axis. The fan blades are coupled to the fan disk for rotation therewith about the central axis.

A turbomachinery engine can include a fan assembly with a plurality of variable pitch fan blades. The fan blades are configured such that they define a first VPF parameter and a second VPF parameter. The first VPF parameter is within a range of 0.10 to 0.40 and is defined as the hub-to-tip radius ratio divided by the fan pressure ratio. The second VPF parameter is within a range of 1-30 lbf/in.sup.2 and is defined as the bearing spanwise force divided by the fan area. In certain examples, the turbomachinery engine further includes a pitch change mechanism, a vane assembly, a core engine, and a gearbox.

A turbofan gas turbine engine according to the present disclosure includes an engine core, a variable pitch fan, and a fan flow bifurcation with a flow path splitter ring that divides a bypass duct from an engine core inlet. The variable pitch fan is driven by the engine core and has movable fan blades that are reconfigurable to provide forward or reverse thrust. The fan flow bifurcation is arranged between the variable pitch fan and the engine core and is configured to interact with air flow when the fan blades are set to forward or reverse thrust.

Pre-assembled blade (20) for fans (10) for cooling the coolant contained inside the radiator (1) of operating machines and/or vehicles, comprising a blade body (20a) rigidly connected to an axial shank (21), a part of which situated radially on the outside of the blade body is in the form of a cylindrical pin (21b); wherein the shank (21) has a part axially on the outside of the blade body in the form of a cylindrical pin (21b), holes (21c) with internal female threading being formed inside the pin (21b); and in that the blade (20) comprises a blade flange (22) comprising. a hollow cylindrical body (22a), the opposite end bases of which comprise respectively: a flat edge (22b) provided with through-holes (22c). an inset annular seat (22d); a disk (23) provided with through-holes (23a) and an eccentric recess (23d) for stably containing with friction a pin (24) which is also eccentric, for rotationally actuating the blade about its axis; screws (25) designed to pass through the through-holes (23a) in the disk (23) and mate with the female thread of the holes (21c) in the pin (21b) in order to fix relative to each other the disk (23), flange (22) and pin (21b), thus ensuring a definite angular alignment of the blade relative to the pin (24) during pre-assembly.

A hub for a propeller having variable-pitch blades for a turbomachine with longitudinal rotation axis, including a plurality of blade platforms, each one being designed to receive a blade root, the platforms being distributed around the annular outer periphery of the hub concentrically with the longitudinal rotation axis, wherein each blade platform has the general geometric shape of a spherical cap, and wherein, between two adjacent blade platforms around the longitudinal rotation axis, the transverse dimension, in particular the diameter, of the hub can vary axially and radially.

A ducted fan module with variable-pitch blades for a turbo engine includes a rotor carrying a plurality of blades, a stationary casing and a pitch changing and control system for adjusting and controlling the setting of the blades. The rotor includes a central shaft and a blade support ring surrounding the central shaft, a front end of the ring that is connected to a front end of the central shaft, so as to create a rearward-opening annular space between the ring and the shaft. The annular space of the rotor housing the blade changing and control system and the central shaft are guided by a first bearing mounted in a stationary casing behind the ring. The fan has a tubular part connected to the stationary casing and extending into the annular space in front of the first bearing and carrying at least a first complementary bearing for guiding the shaft.