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Momentum Theory Calculator

Air Density

\( slug / ft^3 \)

Rotor Radius

\( ft \)

Thrust

\( lb \)

Induced Velocity

36.70

\( ft/s \)

Power

433.8

\( HP \)

Description

This calculator estimates the induced velocity and power consumption of an ideal, hovering helicopter rotor.

Equations

The following equations are used to estimate the induced velocity \( v_i \) and power consumption \( P \) from the input air density \( \rho \), rotor radius \( R \), and thrust \( T \).

\[ A = \pi R^2 \] \[ v_i = \sqrt{T / 2\rho A} \] \[ P = T v_i \]

For more details including the derivation of these equations see our article on momentum theory.

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