Evaluation of Navy 9 cst Oil in Bell Helicopter M412 HP Gearboxes

Tests were conducted with 5 and 9 centistoke lubricants in three different helicopter gearboxes, a main transmission, a 42' gearbox and a tailrotor gearbox. The objective of the tests was to observe and measure the difference in the performance of the lubrication systems due to the viscosity difference between the two test lubricants. The 9 centistoke oil has been developed to provide higher component film thickness, increased load carrying capacity and improved corrosion resistance which will provide increased life for drive system gears and bearings.