From: fairfiel@helios.usq.EDU.AU (raymond fairfield)
Subject: Re: Surviving Large Accelerations?
Organization: University of Southern Queensland
Lines: 27

lpham@eis.calstate.edu (Lan Pham) writes:
(in answer to Amruth Laxman
>are you sure 45g is the right number? as far as i know, pilots are
>blackout in dives that exceed 8g - 9g. 45g seems to be out of human
>tolerance. would anybody clarify this please.

>lan

Apart from the fact that you get G in the pull-out, not the dive, that
figure is about right for sustained G, no protection.
The duration of G, it's rate of onset, body position and support aids are
all critical parts of the equation. I remember one note about instrumented
gridiron players recording peaks about 200G. Stapp, the aviation doctor,
either by accident or design, took a short-period 80G in a rocket-sled
decelleration, eye-balls-out against a standard (1950's) harness. It had
to be short, calculate the stopping time, even from 500 - 600mph at that
G. A bang-seat can get up to about 60 G, and you'd better be sitting
straight. Find the book by Martin-Bakers human guinea pig to hear how bad
it can get if the rate of onset is too high. A reclining position and a
good G-suit can keep a pilot functioning at around 12G.

A flotation tank should be a good bet, since you can treat the body as a
fluid, and high-pressure situations are not new. Anyone have any figures?

Ray Fairfield
fairfiel@zeus.usq.edu.au

