Torque

Relationship between force F, torque τ, linear momentum p, and angular momentum L in a system which has rotation constrained in one plane only (forces and moments due to gravity and friction not considered).

Torque, moment or moment of force is the tendency of a force to rotate an object about an axis, fulcrum or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist.

Loosely speaking, torque is a measure of the turning force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque (turning force) that loosens or tightens the nut or bolt.

The symbol for torque is typically τ, the Greek letter tau. When it is called moment, it is commonly denoted M.

The magnitude of torque depends on three quantities: the force applied, the length of the lever arm connecting the axis to the point of force application and the angle between the force vector and the lever arm. The length of the lever arm is particularly important; choosing this length appropriately lies behind the operation of levers, pulleys, gears and most other simple machines involving a mechanical advantage.

As applied to model aircraft, torque refers to the twisting power of a propeller or the rotors of a helicopter. The physics regarding such variances as the length of the propeller blades, e.g., the lever arms, remains the same. The pitch of the blades has a direct bearing on torque as well.

The SI unit for torque is the newton meter (N·m).

This page uses content from the English Wikipedia. The original article was at Torque. The list of authors can be seen in the page history. As with EFlightWiki, the text of Wikipedia is available under the GNU Free Documentation License.