Abstract: A clutch of the single-plate dry-disc type is structured to include annular friction facings secured to opposite surfaces of a supporting plate of a clutch plate and a plurality of recesses or shallow grooves are defined in the surface of one of the annular friction facings. The shallow grooves extend from the inner periphery of the one annular friction facing and terminate short of the outer periphery thereof.Accelerated air streams are introduced from the exterior through the fly wheel into the plurality of grooves so as to aid in separation of the friction facing of the clutch plate from the engaging surface of a fly wheel as a result of a hydrodynamic force created by the air streams. Furthermore, slots are defined in the surface of the friction facing in addition to the grooves so as to provide discharge passages for powder which has been produced due to wear or attrition of the friction facings.