Abstract: The present invention includes a rotorcraft drive system, method, and aircraft comprising a fixed engine; a rotating spindle that rotates a proprotor gearbox and rotor pylon between a hover and forward flight position, wherein the rotating spindle rotates about a rotation bearings on two inboard ribs of a wing member; and an interconnect drive shaft connected to the fixed engine, wherein the interconnect drive shaft passes through an aft cove of the wing member and connects to the engine via a forward-aft drive shaft, wherein the forward-aft drive shaft is connected to the proprotor gearbox to provide power to a proprotor.