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Helicopter Hover Power Calculator

Air Density

\( slug / ft^3 \)

Main Rotor Radius

\( ft \)

Helicopter Gross Weight

\( lb \)

Figure of Merit (typically 0.65)

\( - \)

Power

756.2

\( HP \)

Main Rotor Induced Velocity

37.07

\( ft/s \)

Description

This calculator estimates the power consumption of a hovering helicopter rotor.

Equations

The following equations are used to estimate the power consumption \( P \) from the input air density \( \rho \), main rotor radius \( R \), and gross weight \( W \). These equations assume a non-ideal rotor with figure of merit \( F \) and thrust \( T \) 2% larger than the helicopter weight (to counteract fuselage download from rotor wash). It's also assumed that the tail rotor consumes 10% of the power required by the main rotor. The assumptions and equations are only rough estimates of reality.

\[ A = \pi R^2 \] \[ T = 1.02 W \] \[ v_i = \sqrt{T / 2\rho A} \] \[ P_{MR} = T v_i / F \] \[ P = 1.1 P_{MR} \]

For more details including the derivation of these equations see our article on helicopter performance.

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