Anti-G suit pressure-how much is just right?

The early development of anti-G suits and G-valves is reviewed, as well as contemporary research on advanced anti-G protection systems. The classic works of E. Wood, G. Hallenbeck, and others in the 1940s resulted in the basic anti-G-suit and inflation schedules still in use in the USAF. The standard mechanical G-valve senses the Gz level and regulates G-suit pressure in at a linear rate of 1.5 psi/Gz. Currently, numerous anti-G valves utilizing modern control techniques are under development. Microprocessors are being advocated to monitor the aircraft status and thereby control the G-suit inflation. It is possible that additional inputs such as onset rate, anticipated peak Gz, seat-back angle, time at G, individual variability, comfort, and the pilot´s physiologic status should also be considered in determining the optimum anti-G-suit inflation parameters. A nonlinear anti-G-suit inflation rate, pre-inflation, and sequential or pulsating pressure schedules could also be utilized by new concept valves, and may result in techniques to provide improved protection to the pilot against G-induced loss of consciousness