Definition
A weight installed in the flight control system of certain aircraft to provide an artificial force on the control column that the pilot must overcome when maneuvering. It increases the stick force required during pitch changes, giving the pilot a sense of the airplane's response to control inputs and helping prevent over-controlling at high speeds.
Plain English
A small weight built into the control system that makes the controls feel heavier, so the pilot has to pull or push with more effort. This added resistance gives the controls a more natural feel and discourages the pilot from moving them too aggressively.
Context Anchor
Seen in aircraft flight control descriptions, maintenance information, and discussions of control feel in larger or more complex airplanes.
Derivation
Named for the way the weight 'bobs' under the influence of gravity and aircraft g-loading. As the airplane pitches or pulls g's, the weight's apparent mass changes, producing a varying force the pilot feels through the control column.
Why Pilots Care
It prevents overly light controls at high speed and helps the airplane feel stable without requiring constant pilot input.
Analogy
It is like adding a weight to a handle so the handle pushes back harder when it is moved suddenly. The weight is there to give your hand useful feedback, not to carry a load.
Intuition Check
Do not read “bob weight” as just any weight in the airplane. Here it means a designed control-system weight that changes the feel of the pitch controls as G force changes.
Example Sentence 1
The bob weight in the elevator control system gave the pilot a noticeable increase in stick force during the pull-up.
Example Sentence 2
At higher airspeeds the bob weight required noticeably more back pressure to hold the nose up.