Abstract: The liquid-propellant rocket engine comprises two combustion chambers, a gas generator, a turbopump assembly, pipelines as well as a frame having footpads and supports located in different planes that are perpendicular to the engine axis, said frame being made up of at least two welded rod sections. Said sections are fastened to each other by a plane rod joint. The engine pipelines are connected to the combustion chambers and comprise bellows balances or flexible hoses which have their movable ends connected directly to the combustion chambers or to pipes joined thereto. The frame is made demountable due to the use of threaded connections that joint together the frame sections and the plane rod joint. The frame is made as a compensation frame by placing the footpad plane over the support plane. A curved pipe joint comprises a curved pipe, a hinge and a frame.