The human body does allow partial blackouts, it can take them, but it is very difficult on the body. As you may know, for every G you pull, Your body weight is doubled, so if you weigh 150 pounds normally, when you get to 2 Gs, the force of gravity makes your body feel like it weighs 300pounds, at 3 Gs 450, 5 Gs 600 etc....
The following is an exerpt from a study done by the FAA about G effects on pilots:
4. G'S AND THEIR PHYSIOLOGICAL EFFECTS. A G may be thought of
as the force or "pull" of gravity upon a body. On the earth,
this pull causes the body to have a certain weight. When an
elevator, car, or airplane accelerates, slows down, or changes
direction, objects and occupants appear to move, be thrown, or
centrifuged (they experience an acceleration) in the opposite
direction. These changes, occurring in speeding up
(acceleration) or slowing down (deceleration), may be referred to
as G's. For example, consider a pullup from a dive as
illustrated in Figure 1. The amount of G experienced by the
pilot depends on how vigorously the pilot pulls back on the
controls and how readily the aircraft responds. Assume, however,
that the pilot "pulls" +4G's; if the pilot were on scales, he or
she would appear to weigh four times his or her usual weight.
The G's in this case are designated with a positive (+) number
because of their direction. Now, imagine a pushover at the start
of a dive (Figure 2). The aircraft changes direction in such a
way that the pilot tends to be thrown upward and outward. The
pilot may have the sensation of weightlessness; indeed, if the
pilot were on scales, he or she would weigh less. The notation
used would be in a negative (-) numbers because of the direction
of the acceleration in relation to the axes of the body.
For the rest of the study, go to
http://www1.faa.gov/avr/afs/ac91-61.txtAs for in AH the G effects do not effect anything except the visual screen as it may turn black in a hard turn and red in a dive. You do maintain control of the aircraft, even when you cant see. What i do if i go into a blackout, is predict where the ground is and try to pull up into the air, then wait for the blackout to go away, or i hit autopilot for it to correct me if im over a flat ground. From my experience no matter how hard i pull on the stick, the G effects do not damage/hurt the pilot in any way, just make the screen go black or red.
