Counter Rotating Turbine with Reversing Reduction Gearbox

A gas turbine engine, wherein the gas turbine engine defines a longitudinal direction, a radial direction, and a circumferential direction, and a forward end and an aft end along the longitudinal direction, the gas turbine engine comprising:

• a turbine section comprising a first rotating component and a second rotating component along the longitudinal direction, and a first rotor and a second rotor;
• wherein the first rotating component is connected to the first rotor, the first rotating component including a first shroud comprising a plurality of first shroud airfoils extended from the first shroud along the radial direction and one or more connecting airfoils;
• and
• wherein the second rotating component is connected to the second rotor, the second rotating component including a second shroud defining a plurality of second shroud airfoils extended from the second shroud along the radial direction;
• a gearbox comprising an input gear and an output gear, wherein the second rotor is coupled to the input gear of the gearbox;
• a driveshaft extended in the longitudinal direction, wherein the driveshaft is connected to the output gear of the gearbox, and wherein the first rotor is coupled to the driveshaft;
• and
• an oil supply comprising one or more supply lines for providing a supply oil flow to the gearbox and one or more scavenge lines for removing a scavenged oil flow from the gearbox,
• wherein the one or more supply lines define a total internal cross-sectional area between about 0.2 inches squared and 1.4 inches squared;
• and
• wherein the one or more scavenge lines define a total internal cross-sectional area between about 0.9 inches squared and 6 inches squared.

A gas turbine engine, wherein the gas turbine engine defines a longitudinal direction, a radial direction, and a circumferential direction, and a forward end and an aft end along the longitudinal direction, the gas turbine engine comprising:

• a turbine section comprising a first rotating component and a second rotating component along the longitudinal direction together forming at least in part a turbine of the turbine section, and a first rotor and a second rotor;
• wherein the first rotating component is connected to the first rotor, the first rotating component including a first shroud comprising a plurality of first shroud airfoils extended from the first shroud along the radial direction and one or more connecting airfoils;
• wherein the second rotating component is connected to the second rotor, the second rotating component including a second shroud defining a plurality of second shroud airfoils extended from the second shroud along the radial direction;
• and
• wherein the turbine has an axial length L and N number of stages, wherein an average axial spacing dx separating each of a plurality of adjacent first shroud and second shroud airfoils is related to N and L by L(A/(N−1))<dx<L(B/(N−1)), where A is between 0.05 and 0.15 and B is between 0.25 and 0.40;
• a gearbox comprising an input gear and an output gear, wherein the second rotor is coupled to the input gear of the gearbox;
• and
• a driveshaft extended in the longitudinal direction, wherein the driveshaft is connected to the output gear of the gearbox, and wherein the first rotor is coupled to the driveshaft.