Isayev LOx/Kerosene rocket engine. EKR (experimental winged missile). Study 1953. Derivative of S2.253 was proposed for use in EKR Stage 1 (project for an experimental winged missile).
Status: Study 1953. Thrust: 93.20 kN (20,952 lbf). Specific impulse: 250 s. Specific impulse sea level: 217 s. Burn time: 127 s.