Expert: Paul Soderman - 12/11/2008

Question
What determines (mathematically) G force felt by the pilot in the cockpit of an aircraft in a turn?

Answer
The G force is caused by the centrifugal force induced by the aircraft moving in a turn.  The force F is computed as:

F = m V^2/R

where  m is the pilot's mass, V is his velocity, and R is the radius to the center of the turn.

Technically, centrifugal force is not really a true force acting over a distance R but a reaction to a change in inertia.  The pilot wants to go in a straight line, the airplane turns and induces a G force on him.  But the reaction  feels like a force pushing him, so calling it a force or reaction is not important.  He gets squashed in either case.
Paul