Definition
A force acting on a rotating propeller blade that tries to twist the blade toward a higher pitch angle (a coarser, more steeply angled blade). It arises because the blade's center of pressure — the point where aerodynamic lift effectively acts — is located ahead of the blade's pitch-change axis (the axis the blade rotates around when its pitch is changed). The lift acting forward of that axis produces a twisting moment that pushes the blade toward higher pitch.
Plain English
When a propeller is producing thrust, the air pushing on each blade tries to twist that blade so it takes a bigger 'bite' of the air. This happens because the push from the air lands a little ahead of the line the blade pivots around, so it ends up rotating the blade toward a steeper angle.
Context Anchor
Seen in propeller and powerplant maintenance discussions, especially when explaining the forces acting on constant-speed propeller blades.
Derivation
Aerodynamic comes from Greek 'aer' (air) and 'dynamis' (power or force) — literally 'force from moving air.' Twisting describes the rotational push on the blade about its own long axis. Together: a force from the air that tries to rotate the blade around its pitch axis.
Why Pilots Care
Constant-speed propeller mechanisms must counteract ATF along with centrifugal twisting force to hold selected RPM; understanding it aids troubleshooting and safe operation.
Analogy
It is like wind pushing unevenly on a weather vane and making it turn, except here the airflow is trying to twist a propeller blade instead of turning a vane.
Intuition Check
Do not read twisting force as the whole propeller twisting off the airplane. Here it means each propeller blade is being twisted around its own long axis by the airflow.
Example Sentence 1
Aerodynamic twisting force tends to drive the propeller blades toward higher pitch during normal operation.
Example Sentence 2
The constant-speed governor supplies oil pressure to overcome both centrifugal and aerodynamic twisting forces and maintain the selected RPM.