Abstract: A curvilinear plate for a heat exchanger is provided. The curvilinear plate can include an inner plate defining a plurality of first grooves and an outer plate defining a plurality of second grooves. The outer plate is attached to the inner plate with the plurality of first grooves and the plurality of second grooves substantially aligned to define a plurality of channels therebetween. Each channel extends from a first opening on a first portion of a first end of the curvilinear plate to a second opening on a second portion of the first end. A method is also generally provided for forming a curvilinear plate.

Abstract: A transduct segment, that can include a main tube extending from a first end to a second end and defining a hollow passageway therethrough, a lower platform attached to an outer surface of the main tube on first side of an aperture defined within the main tube, and an upper platform attached to the outer surface of the main tube on second side of the aperture that is opposite of the first side, is provided. The upper platform is integral with the lower platform to define a supply channel therebetween, and the supply channel is in fluid communication with the hollow passageway of the main tube through the aperture defined by the main tube. The lower platform and the upper platform define an interface defining a plurality of channels in fluid communication with the hollow passageway defined by the main tube.

Abstract: Methods of cooling a hot fluid in an annular duct of a gas turbine engine are provided. The method can include directing the hot fluid through a plurality of cooling channels that are radially layered within the annular duct to define a heat transfer area, and passing a cooling fluid through the annular duct such that the cooling fluid passes between the radially layered cooling channels. Additionally or alternatively, the method can include passing the hot fluid into a first inner radial tube, through a plurality of cooling channels defined within a plurality of curvilinear plates that are radially layered within the annular duct, and into a second inner radial tube; and passing a cooling fluid through the annular duct.

Abstract: An annular heat exchanger for a gas turbine engine is provided. The annular heat exchanger can include a first annular ring comprising a first main tube defined by a plurality of transduct segments; a second annular ring comprising a second main tube defined by a plurality of transduct segments and a curvilinear plate defining at least one channel therein that is in fluid communication with a transduct segment of the first main tube and a transduct segment of the second main tube.

Abstract: A curvilinear plate for a heat exchanger is provided. The curvilinear plate can include an inner plate defining a plurality of first grooves and an outer plate defining a plurality of second grooves. The outer plate is attached to the inner plate with the plurality of first grooves and the plurality of second grooves substantially aligned to define a plurality of channels therebetween. Each channel extends from a first opening on a first portion of a first end of the curvilinear plate to a second opening on a second portion of the first end. A method is also generally provided for forming a curvilinear plate.

Abstract: A transduct segment, that can include a main tube extending from a first end to a second end and defining a hollow passageway therethrough, a lower platform attached to an outer surface of the main tube on first side of an aperture defined within the main tube, and an upper platform attached to the outer surface of the main tube on second side of the aperture that is opposite of the first side, is provided. The upper platform is integral with the lower platform to define a supply channel therebetween, and the supply channel is in fluid communication with the hollow passageway of the main tube through the aperture defined by the main tube. The lower platform and the upper platform define an interface defining a plurality of channels in fluid communication with the hollow passageway defined by the main tube.

Abstract: Methods of cooling a hot fluid in an annular duct of a gas turbine engine are provided. The method can include directing the hot fluid through a plurality of cooling channels that are radially layered within the annular duct to define a heat transfer area, and passing a cooling fluid through the annular duct such that the cooling fluid passes between the radially layered cooling channels. Additionally or alternatively, the method can include passing the hot fluid into a first inner radial tube, through a plurality of cooling channels defined within a plurality of curvilinear plates that are radially layered within the annular duct, and into a second inner radial tube; and passing a cooling fluid through the annular duct.

Abstract: An annular heat exchanger for a gas turbine engine is provided. The annular heat exchanger can include a first annular ring comprising a first main tube defined by a plurality of transduct segments; a second annular ring comprising a second main tube defined by a plurality of transduct segments and a curvilinear plate defining at least one channel therein that is in fluid communication with a transduct segment of the first main tube and a transduct segment of the second main tube.

Abstract: Spaced apart counter-rotatable forward and aft rows of forward and aft propellers are mounted on forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators on the frames are operable for controlling pitch of the propellers. A hydraulic fluid supply outboard of the frames is connected to forward and aft rotary unions which are operable for transferring hydraulic fluid between forward and aft union stators to forward and aft union rotors mounted within the forward and aft rotary unions. The forward union rotor is operable to transfer the hydraulic fluid from the forward rotary union to the aft pitch change actuators and the aft union rotor is operable to transfer the hydraulic fluid from the aft rotary unions to the forward pitch change actuators. The forward and aft rotatable frames counter-rotatably mounted on a structural frame located forward or aft of the propellers.

Abstract: Axially spaced apart counter-rotatable forward and aft rows of forward and aft propellers mounted on forward and aft rotatable frames includes a flowpath passing through the forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators mounted on the aft rotatable frames are connected to and operable for controlling and setting pitch of the aft propellers. The pitch change actuators are mounted radially inwardly of the flowpath in a one to one ratio with forward and aft rotatable struts extending radially across the flowpath. One or more rotatable shafts extend through one or more of the rotatable struts and connect one or more of the pitch change actuators to one or more of the propellers. The pitch change actuators may be ganged together by unison rings having ring teeth engaging gear teeth on gears connected to the pitch change actuators or connected to the rotatable shafts.

Abstract: Axially spaced apart counter-rotatable forward and aft rows of forward and aft propellers mounted on forward and aft rotatable frames includes a flowpath passing through the forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators mounted on the aft rotatable frames are connected to and operable for controlling and setting pitch of the aft propellers. The pitch change actuators are mounted radially inwardly of the flowpath in a one to one ratio with forward and aft rotatable struts extending radially across the flowpath. One or more rotatable shafts extend through one or more of the rotatable struts and connect one or more of the pitch change actuators to one or more of the propellers. The pitch change actuators may be ganged together by unison rings having ring teeth engaging gear teeth on gears connected to the pitch change actuators or connected to the rotatable shafts.

Abstract: Spaced apart counter-rotatable forward and aft rows of forward and aft propellers are mounted on forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators on the frames are operable for controlling pitch of the propellers. A hydraulic fluid supply outboard of the frames is connected to forward and aft rotary unions which are operable for transferring hydraulic fluid between forward and aft union stators to forward and aft union rotors mounted within the forward and aft rotary unions. The forward union rotor is operable to transfer the hydraulic fluid from the forward rotary union to the aft pitch change actuators and the aft union rotor is operable to transfer the hydraulic fluid from the aft rotary unions to the forward pitch change actuators. The forward and aft rotatable frames counter-rotatably mounted on a structural frame located forward or aft of the propellers.