Definition
A hydraulic actuator with equal piston areas on both sides of the piston, so that the same volume of fluid is required to extend or retract the shaft and the same force is produced in either direction. This is achieved by using a piston rod that passes all the way through the cylinder, exposing equal surface areas to fluid pressure on each stroke.
Plain English
A hydraulic ram that pushes and pulls with the same strength and the same fluid flow, because both sides of the piston have the same working area.
Context Anchor
Seen in aircraft hydraulic system and maintenance descriptions, especially where cylinders move parts such as doors, landing gear, or control surfaces.
Derivation
Balanced here means the two sides are equal -- the piston areas, fluid volumes, and forces match. It does not mean stable or steady; it means matched on both sides.
Why Pilots Care
When an actuator must move a control surface or component the same amount and at the same rate in both directions, a balanced design ensures predictable, symmetrical response without one stroke being faster or stronger than the other.
Analogy
Think of pushing on two equal-size sides of a sliding block. If the same push is applied to either side, the result is about the same amount of movement and force.
Intuition Check
Balanced does not mean the actuator is physically level or centered. Here it means the pressure has equal working area on both sides, so the actuator’s output is about the same in both directions.
Example Sentence 1
The flight control system uses a balanced actuator so the surface moves at the same rate whether commanded up or down.
Example Sentence 2
Balanced actuators in the flap system ensure consistent extension and retraction speeds during approach.