Marcus said:

>now I have a question about human g limitations. Surely once
>somebody is strapped in, in a particular position, the g
>limitations are the same in all cases.

Physiological terms that fighter pilots often use are "red out" and "black out". If the pilot does a high-G maneuver with the centripetal acceleration going from his heart to his head then his visual field will go red before he loses his vision altogether. This is called "red out". If the pilot does a high-G maneuver with the centripetal acceleration going from his head to his heart then his visual field will go black before he loses his vision altogether. This is called "black out". A "black out" usually occurs just before fainting. Really good fighter pilots like Chuck Yaeger used "black outs" to their advantage. If an Me-109 got on Yaeger's tail (6 o'clock), he would take his P-51 into a high G maneuver until he blacked out to being blind but still conscious. Then while blind, he'd do an evasive maneuver to get on the Me-109's "6 o'clock". Typically both he and the German pilot broke out of the high G maneuver at about the same time. Once Yaeger had his vision back, the Me-109 would be right in front of him and he'd blow it out of the sky. Modern fighter planes like the F-16 have a "pelvis up" couch that keeps the pilot's brain closer to his heart. This allows the F-16 pilot to pull much higher Gs before black or red out.

Gary