`v_o = sqrt(2*( P_T - P_S )/ 1.2041 )`

Enter a value for all fields

The Air Speed calculator computes the air speed of an aircraft based on the static local atmospheric pressure (P_S), the total pressure (P_T) and the density of air (`rho`).

INSTRUCTIONS: Choose units and enter the following:

• (P_T) Total Pressure measured by a pilot tube
• (P_S) Total Static local atmospheric pressure
• (ρ) Density of Air

Air Speed (V₀): The calculator returns the velocity in meters per second.  However this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The formula used in this calculator is the basis for airspeed measurement on aircraft which relies on reading the pressure at a pitot tube device mounted on the external surfaces of the aircraft.

This equation is derived from Bernoulli's equation's proposition that the total energy in the air flowing past the pitot tube is the sum of the potential energy due to air pressure and the kinetic energy due to motion of the air.

`E_Tot` = `E_"Potential"` + `E_"Kinetic"`

This translates to `P_"Total" = P_"Static" + 1/2*rho*V^2`

Solving for V gives us the formula used for Air Speed in this calculator:

 `V = sqrt( (2*(P_"Total" - P_"Static"))/rho)`

where:

• V = Air Speed
• P_Total = Total Pressure Measured by a Pilot Tube (a pressure measurement instrument used to measure fluid flow velocity)
• P_Static = Total Static Local Atmospheric Pressure
• ρ = Density of Air