Liftfan Clutch Materials

RCI has developed one JSF clutch friction material system whose performance exceeds by more than 50%, the original JSF design goal for total engagements. This wear life is a factor of 3 to 4 times the current C/C clutch material being used for the STOVL version of JSF (F-35B). The experimental testing performed in Phase I has been done at full scale conditions (full speed and full inertial mass or engagement energy) using a custom built single rotor-single stator clutch test machine. This full scale, full speed, full energy Phase I testing has eliminated the technical risk associated with extrapolating results from lower surface speed subscale test approaches that have previously been used. In addition, RCI has one other friction material system also tested under full scale conditions whose friction behavior (dynamic coefficient of friction) is significantly higher than the current C/C friction material. Higher COF values at high speed engagement conditions can greatly reduce clutch clamp load forces which will extend clutch rotating equipment (bearings, gears, etc.)life. These advancements will be optimized early in Phase II and full up clutch test and demonstration work will be performed at Rolls Royce Corporation, Indianapolis, IN during the second half of the Phase II program. The pay-off for the JSF program in both enhanced STOVL system durability, flight & maintenance operations safety and the reduced cost of ownership is very large-in excess of $70M.