FIELD: liquid-propellant rocket engines started in dense atmospheric layers. SUBSTANCE: stimulation of gas flow separation in overextended part of nozzle is carried out by fillings separation zone by return swirl atmospheric air flow. Location of separation zone is adjusted by injecting water or water with antifreeze into gas flow through special belts. Water feeding is stopped when rocket rises to altitude at which atmospheric pressure is close to pressure at nozzle exit section. Such method of stimulation of gas flow separation in overextended part of nozzle reduces negative efforts built by atmospheric pressure on overextended part of nozzle and makes it possible to use nozzle with pressure at its exit section considerably lower than atmospheric pressure in engines started in dense atmospheric layers. EFFECT: considerable increase of engine specific impulse over entire flight trajectory of rocket. 2 cl, 2 dwg
