Abstract: A torque and/or rotational control apparatus is disclosed in a preferred form of a brake (10) including a plurality of pairs of actuators (18) positioned on opposite sides of a friction disc (16) by spacers (120) having tear shaped cross sections. The pads (32) of the actuators (18) are removably held by a slideable locking pin (70) biased by a spring (80) into an aperture (68) of a backing plate (62) for the pad (32). A notch (64) formed in the pad (32) and the backing plate (62) is slideably received on a rail (66) axially extending from the housing (35) of the actuator (18) to prevent rotation about the locking pin (70). The friction disc (16) includes elongated and shortened fins (42, 43) upstanding between and equally circumferentially spaced intermediate first and second component discs (40, 41). The fins (42, 43) are free of circumferential interconnections to allow air to radially pass freely between the fins (42, 43).

Abstract: A hydraulic spool valve assembly includes a pair of lands spaced apart by a groove, one land comprising a piston face, an adjacent land comprising a hydraulic flow notch, wherein the piston face includes a pair of concentric radially concave concentric. The boundary between the two concave annuli defines a convex split point annulus. The notch is oriented so as to establish a hydraulic fluid flow adapted to impact the split point annulus so as to create inversely directed radial flows across the respective concave annuli. A reverse flow component is thereby established across the groove and back toward the notch to lessen the impact of the force of the hydraulic stream against the split point annulus.