S92 SELF-SCAVENGING TRANSMISSION SUMP

One of the challenges faced in designing the S92 Helicopter Main Transmission was packaging a unit with 25% more power into an existing envelope. Part of the solution was to design the lower portion of the gearbox to forcibly evacuate oil, thereby eliminating the need for a gravity-drain sump and scavenge pump. The gearbox planetary carrier is used as the impeller of a crude oil pump to scavenge oil from itself and pump it to a separate reservoir. Extensive use of 3D modeling was used to design the components as part of the concurrent engineering approach. Testing of the concept was accomplished using 1/2-scale prototype parts made using stereo-lithography. The 3D models were also used by the casting supplier for pattern creation.