no combining gearbox
Well not the same one in the Wessex perhaps.
The Boeing Vertol 107-II is a large twin-turbine engined Air Transport category helicopter of all-metal semi-monococque stressed-skin construction. It has tandem 3-bladed fully articulated rotorheads with partially-overlapping blades, which are synchronised by a mix box, forward and aft transmissions and interconnecting drive shafts.
Also known as Combining Gearbox as in the Chinook which has a similar design.