After 4.2 hours of flight while cruising at 8,000 ft, the right aileron control system 'Otellier fitting disconnected. The pilot said that the aileron trail position in the airstream caused the glider to enter a spiral dive to the right which could not be stopped by left aileron or rudder. The pilot bailed out about 1,000 ft AGL. The glider was assembled on 5/30/92 in accordance with the flight and maintenance manual. The glider was then flown for 4.6 hours and parked overnight. The pilot said he lubed the male ball fitting prior to assembly as instructed in the manual and cleaned and lubed the slide lock plate with WD-40. The fitting manufacturer's safety maintenance information (not available to pilots) requires the ball and socket fittings to be lubed at each assembly, but cautions against allowing lubricants on the slide lock plate because the slide 'may lose its nonreversibility' and cause the fitting to disconnect. The glider maintenance and flight manual does not caution against lubricants on the slide lock plate.