Definition
The pressure exerted by a moving fluid (such as air) due to its motion. It is calculated as one-half the air density multiplied by the velocity squared (q = ½ρV²), and represents the kinetic energy contained in a moving airstream that can be converted into force on an object in that airstream.
Plain English
The push that moving air exerts on something it flows against. The faster the air moves, the harder it pushes. This pushing force is what creates lift on a wing and drag on the airplane.
Context Anchor
Seen in airspeed system, aerodynamics, and aircraft load discussions, especially when explaining how airflow creates forces on wings and surfaces.
Derivation
From Greek dynamis, meaning 'power' or 'force.' Dynamic pressure is the pressure that exists because of motion — as opposed to static pressure, which exists whether the air is moving or not. The symbol q is the standard engineering shorthand used in aerodynamic equations.
Why Pilots Care
It determines the aerodynamic forces of lift and drag that govern aircraft performance, stall speeds, and structural loads.
Analogy
If you hold your hand out of a car window, the push you feel from the moving air is like dynamic pressure. As the car goes faster, the push on your hand increases quickly.
Grounding Statement
Stick your hand out of a car window at 30 mph, then at 60 mph. The much stronger push you feel at the higher speed is dynamic pressure in action.
Intuition Check
Dynamic pressure does not mean changing pressure in a general sense. Here it means the specific pressure created by air moving relative to the aircraft.
Example Sentence 1
The airspeed indicator works by comparing dynamic pressure from the pitot tube against static pressure from the static port.
Example Sentence 2
Maintenance checks focus on areas where high dynamic pressure during flight places extra stress on the airframe.