Cruise Velocity Calculator

How to Use the Calculator

1. Enter the engine power of your vehicle in horsepower (HP).
2. Input the air density in kg/m³. This value can vary depending on altitude and temperature. At sea level and 15°C, the air density is approximately 1.225 kg/m³.
3. Provide the drag coefficient of your vehicle. This is a dimensionless number that depends on the shape of the vehicle. A typical value for a car is between 0.3 and 0.4.
4. Enter the frontal area of your vehicle in square meters (m²). This is the area of the vehicle that faces forward and is perpendicular to the direction of motion.
5. Click the "Calculate" button to compute the cruise velocity.

Understanding the Results

The calculator provides the cruise velocity in meters per second (m/s), kilometers per hour (km/h), and miles per hour (mph). This is the speed at which the vehicle can maintain a steady speed while consuming a relatively constant amount of fuel.

Working Principle

The cruise velocity is calculated based on the balance between the engine power and the aerodynamic drag force. The formula used is derived from the principle that at cruise speed, the engine power is equal to the aerodynamic drag force.

The aerodynamic drag force (F_d) is given by the formula:

F_d = 0.5 * ρ * C_d * A * V²

Where:

• F_d = Aerodynamic drag force (N)
• ρ = Air density (kg/m³)
• C_d = Drag coefficient
• A = Frontal area (m²)
• V = Velocity (m/s)

Rearranging this formula to solve for velocity (V), we get:

V = √(2 * P / (ρ * C_d * A))

Where P is the engine power in watts.