Abstract: An embodiment of the present invention provides an aircraft that includes a fuselage and a rotatable wing disposed above the fuselage. At least one cross-wing driveshaft is disposed within the wing and is driven in rotation by a drive system connected to first and second engines that are located at respective sides of the fuselage beneath the wing. The drive system is so configured that one or both of the first engine and the second engine can drive the at least one cross-wing driveshaft in the event of failure of an engine.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: An embodiment of the present invention provides an aircraft that includes a fuselage and a rotatable wing disposed above the fuselage. At least one cross-wing driveshaft is disposed within the wing and is driven in rotation by a drive system connected to first and second engines that are located at respective sides of the fuselage beneath the wing. The drive system is so configured that one or both of the first engine and the second engine can drive the at least one cross-wing driveshaft in the event of failure of an engine.

Abstract: An embodiment of the present invention provides an aircraft that includes a fuselage and a rotatable wing disposed above the fuselage. At least one cross-wing driveshaft is disposed within the wing and is driven in rotation by a drive system connected to first and second engines that are located at respective sides of the fuselage beneath the wing. The drive system is so configured that one or both of the first engine and the second engine can drive the at least one cross-wing driveshaft in the event of failure of an engine.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: A variable-speed gearbox for a tiltrotor with fixed engine and rotating proprotor includes an input shaft coupled to the respective fixed engine, an output shaft coupled to the respective proprotor; a high-speed clutch integrated into a high-speed gear train, the high-speed gear train having an input coupled to the input shaft and an output coupled to the output shaft; and a low-speed clutch integrated into a low-speed gear train, the low-speed gear train having an input coupled to the input shaft and an output coupled to the output shaft. The high-speed clutch and the low-speed clutch can be freewheeling clutches capable of disconnecting the output and the input of the respective gear train of the high and low-speed gear trains in an overrunning condition when the output rotates faster than the input of the respective gear train. The low-speed clutch can be permanently engaged. In accordance to some embodiments the variable-speed gearboxes may include an accessory drive.

Abstract: An embodiment of the present invention provides an aircraft that includes a fuselage and a rotatable wing disposed above the fuselage. At least one cross-wing driveshaft is disposed within the wing and is driven in rotation by a drive system connected to first and second engines that are located at respective sides of the fuselage beneath the wing. The drive system is so configured that one or both of the first engine and the second engine can drive the at least one cross-wing driveshaft in the event of failure of an engine.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: A variable-speed gearbox for a tiltrotor with fixed engine and rotating proprotor includes an input shaft coupled to the respective fixed engine, an output shaft coupled to the respective proprotor; a high-speed clutch integrated into a high-speed gear train, the high-speed gear train having an input coupled to the input shaft and an output coupled to the output shaft; and a low-speed clutch integrated into a low-speed gear train, the low-speed gear train having an input coupled to the input shaft and an output coupled to the output shaft. The high-speed clutch and the low-speed clutch can be freewheeling clutches capable of disconnecting the output and the input of the respective gear train of the high and low-speed gear trains in an overrunning condition when the output rotates faster than the input of the respective gear train. The low-speed clutch can be permanently engaged. In accordance to some embodiments the variable-speed gearboxes may include an accessory drive.

Abstract: A method of modifying a workpiece includes providing a workpiece, determining a load stress profile associated with a load condition, the load stress profile comprising a load stress greater than a material stress limit of the workpiece, determining a residual stress profile, the residual stress profile comprising a residual stress less than the material stress limit of the workpiece, and providing the workpiece with the residual stress profile, wherein a sum of the load stress and the residual stress is less than the material stress limit of the workpiece.

Abstract: An apparatus includes a first shaft member including a first material and having a first shaft axis, a first distal end having a first diameter, and a first proximate end, and a second shaft member including a second material different from the first material, and having a second shaft axis, a second proximate end having a second diameter, and a second distal end. A joint permanently affixes the first distal end of the first shaft member to the second proximate end of the second shaft member such that the first shaft axis is aligned with the second shaft axis, where the first distal end substantially abuts the second proximate end, and wherein the first diameter is substantially identical to the second diameter. The second shaft member protrudes through a housing, the housing including a seal sealing against an outer diameter of the second shaft member.

Abstract: A method of modifying a workpiece includes providing a workpiece, determining a load stress profile associated with a load condition, the load stress profile comprising a load stress greater than a material stress limit of the workpiece, determining a residual stress profile, the residual stress profile comprising a residual stress less than the material stress limit of the workpiece, and providing the workpiece with the residual stress profile, wherein a sum of the load stress and the residual stress is less than the material stress limit of the workpiece.

Abstract: A method of modifying a workpiece includes providing a workpiece, determining a load stress profile associated with a load condition, the load stress profile comprising a load stress greater than a material stress limit of the workpiece, determining a residual stress profile, the residual stress profile comprising a residual stress less than the material stress limit of the workpiece, and providing the workpiece with the residual stress profile, wherein a sum of the load stress and the residual stress is less than the material stress limit of the workpiece.

Abstract: A bimetallic shaft for use in gearbox applications wherein the member of shaft that protrudes from the gearbox is designed and constructed from a corrosion-resistant metallic compound to prevent corrosion and wear to exposed shaft material. A gearbox comprising a bimetallic shaft having a corrosion-resistant material on the portion of the bimetallic shaft that protrudes from a gearbox housing, wherein a gearbox shaft seal radially surrounds the bimetallic shaft. A method of providing a bimetallic gearbox shaft comprising: a first shaft member comprising a non-corrosion-resistant material and having a first shaft axis, a second shaft member comprising a corrosion-resistant material and having a second shaft axis, and a joint that permanently affixes the first shaft member to the second shaft member such that the first shaft axis is aligned with the second shaft axis.

Abstract: A bimetallic shaft for use in gearbox applications wherein the member of shaft that protrudes from the gearbox is designed and constructed from a corrosion-resistant metallic compound to prevent corrosion and wear to exposed shaft material. A gearbox comprising a bimetallic shaft having a corrosion-resistant material on the portion of the bimetallic shaft that protrudes from a gearbox housing, wherein a gearbox shaft seal radially surrounds the bimetallic shaft. A method of providing a bimetallic gearbox shaft comprising: a first shaft member comprising a non-corrosion-resistant material and having a first shaft axis, a second shaft member comprising a corrosion-resistant material and having a second shaft axis, and a joint that permanently affixes the first shaft member to the second shaft member such that the first shaft axis is aligned with the second shaft axis.