John Moss Wathen IV holds a degree in aerospace engineering from Pennsylvania State University. A member of a senior capstone team that designed an unmanned model aircraft, John Wathen IV has a strong interest in aviation.
One of the key components in flight is overcoming the force of gravity. Acceleration in flight is described in terms of “G” or units of force that exceed the force of gravity (1 G). Some military fighter jets reach acceleration in the 9 G range when engaged in a steep turn at high speed.
The effect of Gs on pilots reflects three basic types of acceleration: linear, radial, and angular. Linear acceleration, notated as Gx, is a speed change in a straight line, such as take-off or landing.
Radial acceleration (Gy) reflects a change of direction, such as a sharp turn or pushing into or pulling out of a dive. Aerobatic pilots often encounter radial acceleration.
Pilots encounter angular acceleration (Gz) during climbing turns and spins that apply gravitational force to the body’s vertical axis.
With humans adapted to 1 G life on the earth’s surface, maneuvers that expose pilots to significant acceleration forces can be hazardous. In extreme cases, typically involving Gz forces, the cardiovascular system may not respond fast enough to maintain blood flow to the brain. Unconsciousness can result. For this reason, understanding the safe acceleration thresholds is essential in piloting high-performance aircraft.
