# 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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