RD-270

RD-270 (Russian: Ракетный Двигатель-270, romanized: Raketnyy Dvigatel-270, lit. 'Rocket Engine 270', GRAU index: 8D420) was a single-chamber liquid-fuel rocket engine designed by Energomash (USSR) in 1960–1970. It was to be used on the first stages of the proposed heavy-lift UR-700 and UR-900 rocket families, as well as on the N1. It has the highest thrust among single-chamber engines of the USSR, 640 metric tons at the surface of Earth. The propellants used are a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N2O4) oxidizer. The chamber pressure was among the highest considered, being about 26 MPa. This was achieved by applying the full-flow staged combustion cycle for all the incoming mass of fuel, which is turned into a gas and passes through multiple turbines before being burned in the combustion chamber. This allowed the engine to achieve a specific impulse of 301 s (2.95 km/s) at sea level. Engine testing was underway when the decision was made to cancel the program. Development was stopped with all other work on corresponding rocket projects on 11 December 1970.