RD-270 (Russian: Ра́кетный дв́игатель 270, Rocket Engine 270, 8D420) - is a single chamber liquid bipropellant rocket engine designed by Energomash (USSR/Russia) in 1960-1970. It was to be used on the first stages of proposed heavy-lift UR-700 and UR-900 rocket families. It has the highest thrust among single chambered engines of USSR and Russia, 640 metric tons at the surface of Earth. The propellants used are unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N2O4). The chamber pressure is among the highest, being about 26 MPa. This was achieved by applying full flow staged combustion cycle for all the incoming mass of fuel, which is turned into a gas and passes through a couple of turbines before being burned in the combustion chamber. This allows it to achieve a specific impulse of 301s at the Earth's surface.
The engine testing was underway when the decision was made to cancel the program. The development of it was stopped with all other work on corresponding rocket projects on 11 December 1970.