ACES (Advanced Concept Ejection Seat) II Negative Gz Restraint Investigation

摘要

Seven human subjects, and 5th and 95th percentile male manikins were subjected to -Gz conditions on a man-rated centrifuge to test the restraint effectiveness of the ACES II restraint system used on the A-10, F-15, and F-16. The restraint was tested with shoulder straps locked, unlocked, and unlocked with the addition of a tiedown strap connected between the lap belt and the floor. A -1Gz condition was created by inverting the centrifuge cab for 30 seconds. Human subjects were exposed to levels of -1.5 and -2 Gz for 20 and 10 seconds respectively by rotating the centrifuge arm. Manikins were similarly exposed to levels up to -5 Gz. Off-seat displacement was measured directly by a unique spring-loaded transducer mounted in the seat pan. Lap belt and tiedown strap forces, and tracking and ejection task performance were also measured. Average off-seat displacment for the human subjects using the unmodified restraint with shoulder straps unlocked was 3.2, 3.6, and 3.8 centimeters at -1, -1.5, and -2 Gz respectively. With the tiedown strap these figures were reduced to 2.1, 2.6, and 2.7 cm. Corresponding displacements with the shoulder straps locked and no tiedown strap were 2.9, 3.2, and 3.6 cm. Displacement data for the manikins showed similar trends. Tracking performance and ejection delay data were inconclusive. (Author)