What does «Fuerza G positiva» mean in Spanish?
- If a pilot is subjected to a positive G-force greater than his tolerance limit, he "goes dark", i.e. he can no longer see. This can happen at the exit of a dive. As the aircraft's bow points downward in a near-vertical dive, pilot and aircraft fall to earth, dragged by the force of gravity and the force of the engine. Both are thus subjected to linear acceleration. But when the pilot pulls back on the control stick to send the aircraft suddenly upward, both he and the aircraft are subject to radial acceleration. The pilot's moment of inertia tends to keep him in the original (downward) direction as the plane heads upward. In accordance with Newton's third law of motion, the pilot, who at this moment suffers the effects of a force from the aircraft in the seat-to-head direction, reacts in the head-to-seat direction. The accelerations that cause the pilot to react in this direction are called positive and are measured in terms of positive G. Positive G also occurs in quick curls and turns. Positive G effects are due to the body tissues behaving as if they were heavier than they are. The rider experiences the sensation of being pinned to the seat. Under the effects of positive G-force the blood tends to move toward the feet, with the result that the heart finds it increasingly difficult to send the proper amount of blood to the head. The most noticeable effects of such circulatory difficulty are on the vision, which, as the G-force increases, becomes cloudy, then gray, and finally fades transiently. Individuals tolerate positive G-force very differently. Most can withstand 3.5 G before reaching gray vision, but blindness occurs within 10 s with 5 G. Because the effects of G-force are felt with some delay, blindness may not occur until a few seconds after the movement that causes it. It is typical for blindness to last no more than 20 s and for the pilot to remain conscious during blindness if the G-force is not very intense. However, at 6 or 8 G, unconsciousness may occur.