RD-191
Encyclopedia
The RD-191 is a high performance single-combustion chamber
Combustion chamber
A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...

 rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

, developed in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. It is derived from the RD-170
RD-170 (rocket engine)
The RD-170 is the world's most powerful liquid-fuel rocket engine, designed and produced in the USSR by NPO Energomash for use with Energia launch vehicle...

 originally used in the Energia
Energia
Energia was a Soviet rocket that was designed by NPO Energia to serve as a heavy-lift expendable launch system as well as a booster for the Buran spacecraft. Control system main developer enterprise was the NPO "Electropribor"...

 launcher.

The RD-191 is fueled by a kerosene
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...

 / LOX
Lox
Lox is salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato, cucumber and capers...

 mixture and uses an extremely efficient, high-pressure staged combustion cycle
Staged combustion cycle (rocket)
The staged combustion cycle, also called topping cycle or pre-burner cycle, is a thermodynamic cycle of bipropellant rocket engines. Some of the propellant is burned in a pre-burner and the resulting hot gas is used to power the engine's turbines and pumps...

.

Design

Burn ignition is provided by a chemical method, by feeding into the combustion chamber special starting fuel which is self-igniting
Pyrophoricity
A pyrophoric substance is a substance that will ignite spontaneously in air. Examples are iron sulfide and many reactive metals including uranium, when powdered or sliced thin. Pyrophoric materials are often water-reactive as well and will ignite when they contact water or humid air...

 on contact with liquid oxygen. The engine is capable of throttling down to 30% of nominal thrust; the design also allows for a short-duration enhanced thrust (up to 5% of nominal level) in emergency situations. A Cardan suspension provides for yaw and pitch controls by gimballed thrust
Gimballed thrust
Gimbaled thrust is the system of thrust vectoring used in most modern rockets, including the Space Shuttle and the Saturn V lunar rockets.In a gimbaled thrust system, the exhaust nozzle of the rocket can be swiveled from side to side. As the nozzle is moved, the direction of the thrust is changed...

 deflection up to 8 degrees.

A modern design, the engine incorporates sensors monitoring burn conditions. The measurements are used for telemetry
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...

 and an emergency protection system.

The engine fulfills two additional functions: heating helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

 gas for pressurization of propellant tank
Propellant tank
A propellant tank is a container which is part of a vehicle, where propellant is stored prior to use. Propellant tanks vary in construction, and may be a fuel tank in the case of many aircraft....

s, and generating hydraulic power for hydraulic actuators to deflect the nozzle and aerodynamic rudders.

Development

On September 5, 2008, the creator of the engine, NPO Energomash
NPO Energomash
NPO Energomash “V. P. Glushko” is a Russian manufacturer originated from design bureau, which focuses primarily on the development and production of liquid propellant rocket engines. NPO Energomash is based in Moscow, with satellite facilities in Samara, Perm, and St. Petersburg, and employs close...

, reported that the engine has completed the full cycle of development and burn tests and is ready for manufacturing and delivery. The primary launch vehicle utilizing this engine is the Angara rocket, currently being developed.

A version of the RD-191 with thrust reduced to 170 tonnes, called RD-151, was fire-tested on July 30, 2009. The first flight test of this engine was conducted on August 25, 2009 as part of the first launch of South Korean Naro-1 rocket.

As of 2010, the engine has passed all development phases and its nine prototypes have accumulated over 23,000 seconds in 105 firing tests, with one of them reaching the maximum running time of 3,635 seconds in 12 tests. Currently, interdepartmental tests are under way and manufacturing of the engines for flight development tests has started. The flight tests will begin with a launch of the Angara-1.2 light-class rocket, and then of the Angara-5A heavy launcher. Despite problems with funding, work on the RD-191 engine is in line with the Angara rocket family's master schedule.

External links

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