Experimental Rocket Motor ORM

the designation of a family of the first Soviet experimental liquid-propellant rocket motors designed by V. P. Glushko, with a thrust of 60–3,000 newtons (N), or 6–300 kilograms-force (kgf). The motors were designed for operation with various low-boiling and high-boiling liquid oxidants combined with liquid propellants.

In the period from 1930 to 1933 the Gas Dynamics Laboratory (GDL) developed a series of liquid-propellant rocket motors designated as ORM and ORM-1 through ORM-52. The ORM-50 (thrust, 1,500 N) and ORM-52 (thrust, 3,000 N) operated on nitric acid-kerosine fuel, with chemical ignition; they underwent official tests in 1933. The pressure in the combustion chambers was up to 2.5 meganewtons per sq m (MN/m²); the specific impulse was up to 210 sec. These engines were designed for repeated restarting. From 1934 to 1938 a special-projects group at the GDL that was working on the development of liquid-propellant rocket engines and constituted an independent group in the Research Institute for Reaction Engineering developed the liquid-propellant rocket engines ORM-53 through ORM-102. They were the prototypes for the development of structural components used for ignition and launching, for programmed operation with various liquid propellants, and for practical purposes in rocket-powered aircraft (the ORM-50, ORM-52, and ORM-65).

The ORM-65 was officially tested in 1936; it was the most advanced motor of its time. It used a nitric acid-kerosine propellant. The thrust was adjustable within the range of 0.5–1.75 kN, and the specific impulse was 210–215 sec. The engine could be started both manually and automatically; ignition (with signaling) was of the pyrotechnic type, using a glow plug. The ORM-65 could withstand more than 50 firings, with a total operating time of up to 30 minutes. The pressure in the combustion chamber was 2.5 MN/m² (25 kgf/cm²). The steel combustion chambers (with an inside diameter of 100 mm) and the conical (20°) nozzle, with a critical section 23 mm in diameter, were equipped with spiral fins to provide regenerative cooling by means of the oxidant. There were three centrifugal burners for each component. In 1937–38, 30 firing tests on the ground were carried out with RP-318–1 rocket airplanes, designed by S. P. Korolev. In 1940 the pilot V. P. Fedorov completed a flight in an RP-318–1 equipped with a motor that was a modification of the ORM-65. The model 212 winged missile, designed by Korolev and equipped with an ORM-65 motor, passed 13 ground firing tests (in 1937–38) and two flight tests (in 1939).