Abstract: An actuator for a ram air turbine system includes a piston rod that is cylindrical in shape and centered about a centerline, and stow lock pawls supported by the piston rod and able to move radially. Each of the stow lock pawls has a crown with a crown radius. The actuator further includes a lock bolt extending along the centerline radially within the piston rod and configured to be axially movable within the piston rod between a stowed position and a deployed position. The actuator further includes rollers radially outward from the centerline configured to be guided by the lock bolt and a cylinder having a mating surface with a mating radius. The cylinder is positioned radially outward from the piston rod and configured to be axially movable between the stowed position and the deployed position. A ratio of the crown radius of the stow lock pawls to the mating radius of the cylinder is less than 0.98.

Abstract: A component for use in a ram air turbine actuator includes a lock bolt extending along a centerline with the lock bolt being axially movable between a stowed position and a deployed position and a plurality of rollers that are radially outward from the centerline and guided by the lock bolt. The component also includes a slider radially between at least a portion of the lock bolt and a piston rod with the slider being axially movable between a stop position and the deployed position and up-lock wedges supported by the piston rod. The actuator becomes locked in the stowed position when the lock bolt and slider move axially within the piston rod and a cylinder to position the rollers to push the up-lock wedges radially outward into an aperture and prevent the lock bolt, slider, and cylinder from axial movement.

Abstract: In one aspect, a ram air turbine stall recovery system includes a ram air turbine, a hydraulic pump powered by the ram air turbine with the hydraulic pump having a pump inlet and a pump outlet, an electric generator powered by the ram air turbine, a bypass line that connects the pump outlet to the pump inlet, a bypass valve located on the bypass line between the pump outlet and the pump inlet; and a controller responsive to an input signal that indicates a potential stall condition of the ram air turbine. The controller causes the bypass valve to open to allow a hydraulic fluid to flow through the bypass line in order to reduce a pressure within the hydraulic pump.

Abstract: A combination hub, counterweight and crank arm for a governor assembly in a ram air turbine is has a hub section with a cylindrical orifice, an annular collar section that surround the hub section, a counterweight section that extends out of the annular collar section and a crank arm section that extends out of the annular collar section, with all the sections formed in a single piece steel body.

Abstract: A Ram Air Turbine (RAT) is provided and includes a turbine hub having an end plate and a nose cone attached thereto at trailing and leading ends, respectively, a governor shaft, to which turbine blades are connected, which is coupled to the end plate and supported within the nose cone to be rotatable with the turbine blades about a central axis thereof and axially movable from a first position relative to the turbine hub to a second position relative to the turbine hub and a hub assembly operably coupled to the turbine hub, the governor shaft and the turbine blades whereby the hub assembly biases the governor shaft toward the first position at low rotational speeds such that the turbine blades assume a partial coarse pitch angle, and the second position at high rotational speeds such that the turbine blades assume a fine pitch angle.

Abstract: A ram air turbine assembly includes a preferentially located mass that modifies the resonance frequency of the assembly so that vibration is reduced to desired levels. The example mass can be fixed in a specific location on the ram air turbine or can be deployable once the ram air turbine is moved to an operating position.

Abstract: A combination hub, counterweight and crank arm for a governor assembly in a ram air turbine is a single piece steel body.

Abstract: A ram air turbine assembly includes a governor shaft rotatable about an axis and a stop shaft coupled for rotation with the governor shaft. A rotatable housing portion surrounds at least a portion of the stop shaft. A lock plunger extends through an opening in the rotatable housing portion to prevent rotation of the rotatable housing portion and minimize vibration impact loading when stowed.

Abstract: A flyweight for use in a ram air turbine has a body with a circumferentially enlarged portion extending between flat sides spaced by an angle of between 45 degrees and 150 degrees. A pivot point is defined by a bore at a circumferentially intermediate point in the body, and in a relatively thin inner portion. The relatively thin inner portion extends beyond the pivot point to an end that will be radially inward when the flyweight is mounted in a ram air turbine. A governor, a ram air turbine and a method are also described.

Abstract: A startup assistance apparatus for a fine pitch Ram Air Turbine (RAT) is provided and includes a generator to provide motive power to the RAT when operating in a first mode and to generate electricity from RAT operation when operating in a second mode and a control unit, including a speed sensing unit configured to sense an operating condition of the generator and a controller operably coupled to the generator and configured to control the generator to operate in the first or the second mode based on the sensed operating condition.

Abstract: A Ram Air Turbine (RAT) is provided and includes a turbine hub having an end plate and a nose cone attached thereto at trailing and leading ends, respectively, a governor shaft, to which turbine blades are connected, which is coupled to the end plate and supported within the nose cone to be rotatable with the turbine blades about a central axis thereof and axially movable from a first position relative to the turbine hub to a second position relative to the turbine hub and a hub assembly operably coupled to the turbine hub, the governor shaft and the turbine blades whereby the hub assembly biases the governor shaft toward the first position at low rotational speeds such that the turbine blades assume a partial coarse pitch angle, and the second position at high rotational speeds such that the turbine blades assume a fine pitch angle.

Abstract: A startup assistance apparatus for a fine pitch Ram Air Turbine (RAT) is provided and includes a generator to provide motive power to the RAT when operating in a first mode and to generate electricity from RAT operation when operating in a second mode and a control unit, including a speed sensing unit configured to sense an operating condition of the generator and a controller operably coupled to the generator and configured to control the generator to operate in the first or the second mode based on the sensed operating condition.

Abstract: A method of balancing a ram air turbine that has a turbine shaft with a turbine shaft axis, a rotor attached to the shaft, rotor blades attached to the rotor that move between a fine pitch and coarse pitch position, a spring-loaded governor for controlling the position of the blades that has its springing retained by a stationary outer spring seat and a movable inner yoke plate that slides on the turbine shaft and whose position determines blade pitch, comprises the steps of: pulling the yoke plate toward the spring seat to displace the yoke plate toward the spring seat sufficiently to cause the rotor blades to assume a desired degree of pitch; spinning the turbine shaft at a desired rotational speed; balancing the rotor to minimize vibration of the rotor with the desired rotor blade pitch and turbine shaft speed; and releasing the pull of the yoke plate toward the spring seat.

Abstract: A method of balancing a ram air turbine that has a turbine shaft with a turbine shaft axis, a rotor attached to the shaft, rotor blades attached to the rotor that move between a fine pitch and coarse pitch position, a spring-loaded governor for controlling the position of the blades that has its springing retained by a stationary outer spring seat and a movable inner yoke plate that slides on the turbine shaft and whose position determines blade pitch, comprises the steps of: pulling the yoke plate toward the spring seat to displace the yoke plate toward the spring seat sufficiently to cause the rotor blades to assume a desired degree of pitch; spinning the turbine shaft at a desired rotational speed; balancing the rotor to minimise vibration of the rotor with the desired rotor blade pitch and turbine shaft speed; and releasing the pull of the yoke plate toward the spring seat.

Abstract: A ram air turbine assembly includes a preferentially located mass that modifies the resonance frequency of the assembly so that vibration is reduced to desired levels. The example mass can be fixed in a specific location on the ram air turbine or can be deployable once the ram air turbine is moved to an operating position.

Abstract: An improved ram air turbine (RAT) prevents release of its turbine blades due an over-speed condition by detecting an over-speed condition with a trigger mechanism and rotating the blades to a fixed coarse pitch position with a release mechanism.

Abstract: A ram air turbine (RAT) prevents release of its turbine blades due an over-speed condition by detecting an over-speed condition with a turbine hub-mounted centrifugally operated trigger mechanism and rotating the blades to a fixed coarse pitch position with a release mechanism that responds to the trigger mechanism.

Abstract: A stall recovery system for a ram air turbine (RAT) that supplements the operation of a volume fuse in the hydraulic system of the RAT by sensing a stall condition as the combination of low pressure at less than maximum flow and reducing RAT load torque after the sensed stall so that stall recovery is possible.

Abstract: A control mechanism is provided which feathers the propeller blade pitch during stopping and stores restart energy in the blade pitch governor mechanism. Deceleration to the feathered mode is aided by the airstream. During restart, excess stored energy is used to increase reliability, but is then dissipated mechanically, as by a flywheel mechanism, to maintain low internal impact stresses. More specifically, where single governor spring is used for controlling the pitch of all propeller blades, a braked ball screw device is used to compress that spring during stoppage. Upon restart, the governor spring expands and causes blade pitch change. The ball screw arrangement then dissipates a large portion of the excess energy through torque transmission to mechanical components.

Abstract: An arrangement for mounting a panel on a spacecraft employs a spring sheet which serves to mount one end of the panel to the spacecraft for pivoting the panel with respect to spacecraft and which is capable of storing spring energy for actuating the panel to pivot it from one of a stowed position and a deployed position to the other. In the preferred embodiment, the panel is a radiator for rejecting waste heat into outer space from a dynamic isotope power system of the spacecraft.