A study on the dynamic physical performance and physiological protection effect of a combined anti-G measures for two seater pilots

Objective To evaluate the protection effect of combined anti-G prevention for two seater pilots which was composed of a new type oxygen supply system,bladder type anti-G suit and PHP maneuver.Methods Six sets of experiments were carried out on human centrifuge.Two dummies and seven healthy volunteers with individual protection equipment underwent the experiments of:①The dynamic physical performance of anti G equipment.② The static physiological test of combined anti-G prevention.③The +Gz tolerance test when using KT-x anti-G valve and protection suits.④+Gz protection test afforded by pressure breathing for G (PBG).⑤6.5 G for 45 s centrifuge exposure with combined prevention.⑥8.5 G for 15 s centrifuge exposure with combined prevention.The +Gz onset rate was 3 G/s in dynamic performance studies.Results The minimal mask pressure when respectively inspiring (Pmi) under 0.25 MPa and 0.20 MPa air inlet pressure supply was significantly greater than that under 0.16 MPa inlet pressure(P＜0.05).The protection effect of antiG valve and protection suits was (2.11±0.12) G and it was (2.07±0.11) G as with PBG.All subjects completed 6.5 G for 45 s and 8.5 G for 15 s exposures with the combined anti-G prevention.Conclusions The 0.20 MPa air inlet pressure would be adequate for two pilots performing PHP maneuver simultaneously when using PBG.The combined anti-G prevention could provide protection at 6.5 G for 45 s and at 8.5 G for 15 s.The PBG adopted in this combined anti-G prevention would be helpful to prevent the occurrence of discomfort respiratory symptom.Further investigation would be concentrate on determining the proper pre-pressure value which would meet the anti-G as well as comfort requirements. Key words: Gravity suits;  Hypergravity;  Human experimentation Centrifugation;  Anti-G measures