Evaluation of a Proposed F-4 Ejection Seat Cushion by +Gz Impact Tests.

Abstract : During 1986 to 1987, approximately 45 human impact experiments were accomplished on a vertical deceleration tower to evaluate the influence of three separate seat cushions on the human biodynamic response during positive vertical (+ Gz) impact accelerations that simulated the catapult phase of ejection. The human subjects were exposed to the following three seat cushions at a peak impact level of 10 G: (1) the standard operational F-4 ejection seat cushion, (2) the standard operational ACES II ejection seat cushion, and (3) a proposed F-4 ejection seat cushion composed of ConformTM foam. Principle measurements that were collected and analyzed included seat pan loads, head accelerations, and chest accelerations. Test results showed that the current operational F-4 seat cushion produced greater biodynamic responses (in terms of parameter magnitudes) during vertical acceleration than either the proposed F-4 seat cushion or the ACES II seat cushion.