The main helicopter rotor of a conventional helicopter contains $4$ blades and weighs $1000$ kg$.$ The helicopter climbs at $7\mathrm{.}2$ m$/$s and the induced air speed in hover is $9\mathrm{.}6$ m$/$s$.$ The main rotor speed is $252$ rpm and the main rotor radius is $4,2$ m$.$ Calculate the total inflow ratio. Provide the numerical value only in the answer box, including any signs. Do not include any units in the answer box. Provide your answer to three decimal places.