Stall Speed Calculator

This stall speed calculator helps determine the stall speed of an aircraft based on critical factors such as aircraft weight, wing area, airspeed, altitude, and environmental conditions.

About the Author: Created by Fotios Angelakis, MSc in Mechanical Engineering, with 5+ years of experience in data analytics and energy engineering. Learn more about the author's qualifications and experience.

Temperature:

Altitude:

Barometric Pressure:

Wing Area:

Aircraft Weight:

Max Lift Coefficient (C_L):

How to calculate stall speed by using this calculator.

Steps to Calculate Stall Speed

Enter the weight of the aircraft and select the appropriate unit (kg, g, or oz).
Provide the wing area and select the unit (m², in², or dm²).
Input the aircraft's maximum lift coefficient (C_L) based on the aircraft type.
Enter the altitude of your location (in meters or feet).
Input the barometric pressure at your location (in Pa, mbar, or inHg).
Input the temperature at your location (in Celsius or Fahrenheit).
Click "Calculate Stall Speed" to get the stall speed in m/s, km/h, and mph.
The calculator will also determine if the aircraft is in a stall condition and indicate the required recovery speed.

Key Factors in Stall Speed Calculation

The stall speed formula depends on several key variables, including:

Aircraft Weight: The force due to gravity acting on the aircraft.
Wing Area: The surface area of the aircraft's wings.
Lift Coefficient (C_L): The maximum coefficient of lift for the aircraft.
Air Density: Affected by altitude, temperature, and pressure, this determines the air's resistance.
Airspeed (U_∞): The free-stream velocity of the air over the wings.

Stall Speed Equations

The stall speed (V_s) is calculated using the following formula:

1. Stall Speed Formula

The general formula for stall speed is:

V_s = √((2 * W) / (ρ * S * C_L))

Where:

V_s = Stall speed (m/s)
W = Weight of the aircraft (N)
ρ = Air density (kg/m³)
S = Wing area (m²)
C_L = Maximum lift coefficient (dimensionless)

2. Adjustments for Air Density

Air density (ρ) can be calculated using the barometric pressure, temperature, and altitude, with the formula:

ρ = P / (R * T)

Where:

P = Barometric pressure (Pa)
R = Specific gas constant for air (287.05 J/kg·K)
T = Temperature in Kelvin (K)

3. Load Factor

If the aircraft is turning, the load factor (n) affects the stall speed, and the stall speed in a turn (V_s) is given by:

V_s = V_s0 * √n

Where:

V_s0 = Stall speed at level flight (m/s)
n = Load factor (dimensionless, typically between 1 to 2 in turns)

Note: This stall speed calculator is specifically designed to calculate the stall speed in level flight or turning conditions based on the inputs provided.

Why Stall Speed is Important

The stall speed is a critical parameter for pilots. Flying below this speed can result in a loss of lift and a potential stall, which is dangerous. The stall speed increases with higher weight, lower wing area, and higher load factors (turning). By calculating the stall speed in real-time with this aircraft stall speed calculator, you can assess the minimum safe flying speed for your aircraft in different flight conditions.

Common Aircraft Stall Speed Ranges

Aircraft	Stall Speed (V_s in m/s)
Cessna 172	50.0
Piper Cub	35.0
Beechcraft Bonanza	57.0
Mooney M20	45.0
Airbus A320	120.0

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