The present invention includes a system and method for slowing the rotation of a rotor using, for example, rotor brake system for a rotorcraft comprising: one or more generators connected to a main rotor gearbox; an electric distributed anti-torque system mounted on a tail boom of the rotorcraft comprising two or more electric motors connected to the one or more generators, wherein the two or more electric motors are connected to one or more blades; and wherein a rotation of the rotor is slowed by placing a drive load on the main rotor gearbox with the one or more generators to bleed the mechanical power from rotor into electrical power via the two or more electric motors, wherein the electric distributed anti-torque system generates thrust in opposing directions.

Various implementations described herein are directed to a lubrication system for a gearbox of an aircraft. A lubrication line is coupled to a plurality of jets and/or orifices to provide lubrication to one or more components of the gearbox. A check valve is placed within the lubrication line in a location upstream from the plurality of jets and/or orifices.

According to an aspect, a method of assembling a mandrel includes assembling a plurality of members via interlocking features arranged at opposing edges of each member of the plurality of members to form a compartment, the assembled members having a collective outer surface that conforms to an inner surface of the spar. A support member is inserted into the compartment formed radially inward from the assembled members, the support member making contact with a portion of each member of the plurality of members.

According to an aspect, a method of assembling a mandrel includes assembling a plurality of members via interlocking features arranged at opposing edges of each member of the plurality of members to form a compartment, the assembled members having a collective outer surface that conforms to an inner surface of the spar. A support member is inserted into the compartment formed radially inward from the assembled members, the support member making contact with a portion of each member of the plurality of members.

A rotor blade for a rotary wing aircraft includes a rotor hub including a first flex-beam attachment member and a flex-beam assembly. The flex-beam assembly includes a flex-beam support member having an attachment end and a wrapping end. A first flex-beam includes a first end, a second end and an intermediate portion. The first end of the first flex-beam is connected at the first flex-beam attachment member and the second end of the first flex-beam being connected to the attachment end of the flex-beam support member. A second flex-beam includes first end portion, a second end portion and an intermediate section. The first end portion of the second flex-beam is connected at the first flex-beam attachment member, the second end portion of the second flex-beam being connected at the second flex-beam attachment member and the intermediate section extending about the wrapping end of the flex-beam support member.

A rotor blade for a rotary wing aircraft includes a rotor hub including a first flex-beam attachment member and a flex-beam assembly. The flex-beam assembly includes a flex-beam support member having an attachment end and a wrapping end. A first flex-beam includes a first end, a second end and an intermediate portion. The first end of the first flex-beam is connected at the first flex-beam attachment member and the second end of the first flex-beam being connected to the attachment end of the flex-beam support member. A second flex-beam includes first end portion, a second end portion and an intermediate section. The first end portion of the second flex-beam is connected at the first flex-beam attachment member, the second end portion of the second flex-beam being connected at the second flex-beam attachment member and the intermediate section extending about the wrapping end of the flex-beam support member.

A gear system for a rotary wing aircraft includes a first gear including an inner gear portion having a first pitch and an outer gear portion having a second pitch that is distinct from the first pitch. A second gear includes a third pitch driven at a driving rotational speed. An actuator member is coupled to the second gear while driven at the driving rotational speed. The actuator member shifts the second gear along the first gear to engage with one of the inner gear portion and the outer gear portion to drive the first gear at a first rotational speed and engage with other one of the inner gear portion and the outer gear portion to drive the first gear at a second rotational speed. A controller is operable to control the actuator member to shift the second gear between the inner gear portion and the outer gear portion.

A gear system for a rotary wing aircraft includes a first gear including an inner gear portion having a first pitch and an outer gear portion having a second pitch that is distinct from the first pitch. A second gear includes a third pitch driven at a driving rotational speed. An actuator member is coupled to the second gear while driven at the driving rotational speed. The actuator member shifts the second gear along the first gear to engage with one of the inner gear portion and the outer gear portion to drive the first gear at a first rotational speed and engage with other one of the inner gear portion and the outer gear portion to drive the first gear at a second rotational speed. A controller is operable to control the actuator member to shift the second gear between the inner gear portion and the outer gear portion.

A failsafe multimode clutch assembly is positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling unit having input and output races. The freewheeling unit has a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly must be energized to shift the bypass assembly from the engaged position to a disengaged position. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.

A failsafe multimode clutch assembly is positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling unit having input and output races. The freewheeling unit has a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly must be energized to shift the bypass assembly from the engaged position to a disengaged position. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.