A rotary wing aircraft comprising: an airframe; a rotor assembly including: a first rotor rotatable about a rotor axis in a first direction; and a second rotor coaxial with the first rotor and rotatable about the rotor axis in a second direction opposite the first direction; and a drive system including: an engine outputting a first torque; a gearbox assembly to reduce the first torque to a second torque and transfer the second torque to the rotor assembly, the gearbox assembly including: an input shaft to input the first torque into the gearbox assembly; an input bevel shaft operably connected to the input shaft to transfer the first torque therethrough; and two gear sets operably connected to the input bevel shaft, each gear set including: a first intermediate idler operably connected to the input bevel shaft, the first intermediate idler and a first output gear disposed at a first intermediate shaft, wherein the first intermediate idler is meshed with a transfer gear disposed at the input bevel shaft; a first output pinion to transfer a second torque acting in the first direction to the first rotor; a first intermediate gear meshed with the first intermediate idler, the first intermediate gear and a second output gear disposed at a second intermediate shaft; and a second output pinion to transfer the second torque acting in the second direction to the second rotor. an airframe; a rotor assembly including: a first rotor rotatable about a rotor axis in a first direction; and a second rotor coaxial with the first rotor and rotatable about the rotor axis in a second direction opposite the first direction; and a first rotor rotatable about a rotor axis in a first direction; and a second rotor coaxial with the first rotor and rotatable about the rotor axis in a second direction opposite the first direction; and a drive system including: an engine outputting a first torque; a gearbox assembly to reduce the first torque to a second torque and transfer the second torque to the rotor assembly, the gearbox assembly including: an input shaft to input the first torque into the gearbox assembly; an input bevel shaft operably connected to the input shaft to transfer the first torque therethrough; and two gear sets operably connected to the input bevel shaft, each gear set including: a first intermediate idler operably connected to the input bevel shaft, the first intermediate idler and a first output gear disposed at a first intermediate shaft, wherein the first intermediate idler is meshed with a transfer gear disposed at the input bevel shaft; a first output pinion to transfer a second torque acting in the first direction to the first rotor; a first intermediate gear meshed with the first intermediate idler, the first intermediate gear and a second output gear disposed at a second intermediate shaft; and a second output pinion to transfer the second torque acting in the second direction to the second rotor. an engine outputting a first torque; a gearbox assembly to reduce the first torque to a second torque and transfer the second torque to the rotor assembly, the gearbox assembly including: an input shaft to input the first torque into the gearbox assembly; an input bevel shaft operably connected to the input shaft to transfer the first torque therethrough; and two gear sets operably connected to the input bevel shaft, each gear set including: an input shaft to input the first torque into the gearbox assembly; an input bevel shaft operably connected to the input shaft to transfer the first torque therethrough; and two gear sets operably connected to the input bevel shaft, each gear set including: a first intermediate idler operably connected to the input bevel shaft, the first intermediate idler and a first output gear disposed at a first intermediate shaft, wherein the first intermediate idler is meshed with a transfer gear disposed at the input bevel shaft; a first output pinion to transfer a second torque acting in the first direction to the first rotor; a first intermediate gear meshed with the first intermediate idler, the first intermediate gear and a second output gear disposed at a second intermediate shaft; and a second output pinion to transfer the second torque acting in the second direction to the second rotor.