Seasprite Oil Out Transmission Testing

This paper describes oil out testing of the upgraded Kaman SH-2G Seasprite helicopter drive system components which was performed under Navy contract in May and June of 1992. These tests subjected the Kaman-designed engine-mounted nose gearbox (NGB) and input/accessory gearbox (IAGB) to evaluation for drive system survivability after loss of lubrication with the objective of satisfying a 30 minute continued operation requirement. The tests were successful and this success is attributed to several design features incorporated in the gearboxes during development of the upgraded drive system. These features include increased gear backlash to accommodate thermal growth, high hot hardness gear and bearing materials, which maintain hardness at elevated temperatures and an auxiliary lubrication system which delivers a minimum of 40 percent of the gearbox normal operating oil requirements during emergency lubrication conditions. Maximum stable temperatures recorded during testing were 370° F in the IAGB and 431° F in the NGB. The auxiliary systems operated on approximately one and two quarts of oil for the NGB and IAGB, respectively. The tests were suspended after 60 minutes of operation and subsequent teardown inspections showed no indications of distress. No evidence of scoring or wear was found and parts continue to be viable ground test assets.