Engine Model: RD-856. Manufacturer Name: RD-856. Other Designations: D-69M. Designer: Yuzhnoye. Developed in: 1962-67. Application: Tsyklon stage 2 attitude control engine. Propellants: N2O4/UDMH. Thrust(vac): 54.230 kN (12,191 lbf). Isp: 281 sec. Burn time: 163 sec. Mass Engine: 113 kg (248 lb). Diameter: 3.65 m (11.99 ft). Length: 1.12 m (3.68 ft). Chambers: 4. Chamber Pressure: 71.60 bar. Oxidizer to Fuel Ratio: 1.98. Thrust to Weight Ratio: 49.15. Country: Ukraine. Status: Out of Production. The autonomous four-chamber pump-fed single-run engine burned hypergolic propellants in a gas generator scheme (without afterburning of the generator gas). The engine flow scheme tapped off both propellants to the feed the oxidizer tank pressurization gas generator, as well generator gas for the fuel tank pressurization mixer.
Bibliography:- Shnyakin, V N, Shidkostnye Raketye Dvigateli - Opisanie i Osnovnye Tekhnicheskie Dannye, GKB Yuzhnoe "Yangel", Dnepropetrovsk 1996 via Dietrich Haeseler.
